Bump commons-io:commons-io from 2.21.0 to 2.22.0

Bumps commons-io:commons-io from 2.21.0 to 2.22.0. --- updated-dependencies: - dependency-name: commons-io:commons-io dependency-version: 2.22.0 dependency-type: direct:production update-type: version-update:semver-minor ... Signed-off-by: dependabot[bot] <support@github.com>
Bump github/codeql-action from 4.35.1 to 4.35.2 in /.github/workflows
2026-05-01 00:00:02 -04:00 · 2026-04-27 16:22:11 +02:00 · 2026-04-22 13:18:18 +02:00 · 2026-04-17 11:00:08 +02:00 · 2026-04-06 14:25:27 +02:00 · 2026-04-06 12:53:18 +02:00
92 changed files with 3194 additions and 514 deletions
@@ -5,9 +5,13 @@ updates:
    directory: "/"
    schedule:
      interval: "daily"
+    cooldown:
+      default-days: 7
    open-pull-requests-limit: 10
  # GitHub actions updates
  - package-ecosystem: "github-actions"
    directory: "/.github/workflows"
    schedule:
      interval: "daily"
+    cooldown:
+      default-days: 7
@@ -17,13 +17,16 @@ jobs:
      fail-fast: false
      matrix:
        os: [ ubuntu-latest, windows-latest, macos-latest ]
-        java: [ 11, 17, 21, 25 ]
+        java: [ 8, 11, 17, 21, 25 ]
+        exclude:
+          - os: macos-latest
+            java: 8
    runs-on: ${{ matrix.os }}
    permissions:
      checks: write
    steps:
-      - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
-      - uses: actions/setup-java@dded0888837ed1f317902acf8a20df0ad188d165 # v5.0.0
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+      - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5.2.0
        with:
          distribution: 'temurin'
          java-version: ${{ matrix.java }}
@@ -32,33 +35,29 @@ jobs:
      - name: Run Tests
        run: mvn --batch-mode --no-transfer-progress test
      - name: Publish Test Report
-        uses: mikepenz/action-junit-report@3585e9575db828022551b4231f165eb59a0e74e3 # v5
+        uses: mikepenz/action-junit-report@bccf2e31636835cf0874589931c4116687171386 # v5
        if: ${{ !cancelled() }}
        with:
          report_paths: "**/target/surefire-reports/TEST*.xml"
          check_name: Unit Test Results for OpenJDK ${{ matrix.java }} on ${{ matrix.os }}

-  test-jdk8:
-    name: Test OpenJDK ${{ matrix.java }} on ${{ matrix.os }}
-    strategy:
-      fail-fast: false
-      matrix:
-        os: [ ubuntu-latest, windows-latest, macos-13 ]
-    runs-on: ${{ matrix.os }}
+  test-jdk8-macos:
+    name: Test OpenJDK 8 on macos-14
+    runs-on: macos-14
    permissions:
      checks: write
    steps:
-      - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
-      - uses: actions/setup-java@dded0888837ed1f317902acf8a20df0ad188d165 # v5.0.0
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+      - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5.2.0
        with:
-          distribution: 'temurin'
+          distribution: 'zulu'
          java-version: '8'
          java-package: jdk
          cache: 'maven'
      - name: Run Tests
        run: mvn --batch-mode --no-transfer-progress test
      - name: Publish Test Report
-        uses: mikepenz/action-junit-report@3585e9575db828022551b4231f165eb59a0e74e3 # v5
+        uses: mikepenz/action-junit-report@bccf2e31636835cf0874589931c4116687171386 # v5
        if: ${{ !cancelled() }}
        with:
          report_paths: "**/target/surefire-reports/TEST*.xml"
@@ -73,11 +72,11 @@ jobs:
      matrix:
        kcms: [ true, false ]
    steps:
-      - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
      - run: |
          download_url="https://javadl.oracle.com/webapps/download/AutoDL?BundleId=245038_d3c52aa6bfa54d3ca74e617f18309292"
          wget -O $RUNNER_TEMP/java_package.tar.gz $download_url
-      - uses: actions/setup-java@dded0888837ed1f317902acf8a20df0ad188d165 # v5.0.0
+      - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5.2.0
        with:
          distribution: 'jdkfile'
          jdkFile: ${{ runner.temp }}/java_package.tar.gz
@@ -92,26 +91,43 @@ jobs:
      - name: Run Tests
        run: mvn --batch-mode --no-transfer-progress test
      - name: Publish Test Report
-        uses: mikepenz/action-junit-report@3585e9575db828022551b4231f165eb59a0e74e3 # v5
+        uses: mikepenz/action-junit-report@bccf2e31636835cf0874589931c4116687171386 # v5
        if: ${{ !cancelled() }}
        with:
          report_paths: "**/target/surefire-reports/TEST*.xml"
          check_name: Unit Test Results for Oracle JDK 8 with KCMS=${{ matrix.kcms }}

+  javadoc:
+    name: Build JavaDoc on OpenJDK ${{ matrix.java }}
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        java: [8, 11, 25 ] # We only need a few versions here
+    steps:
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+      - uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5.2.0
+        with:
+          distribution: 'temurin'
+          java-version: ${{ matrix.java }}
+          java-package: jdk
+          cache: 'maven'
+      - name: Create JavaDoc
+        run: mvn --batch-mode --no-transfer-progress -DskipTests package javadoc:javadoc
+
  release:
    name: Deploy
-    needs: [ test, test-jdk8, test-oracle ]
+    needs: [ test, test-jdk8-macos, test-oracle, javadoc ]
    if: github.ref == 'refs/heads/master' # only perform on latest master
    runs-on: ubuntu-latest
    steps:
-      - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
      - name: Set up Maven Central
-        uses: actions/setup-java@dded0888837ed1f317902acf8a20df0ad188d165 # v5.0.0
+        uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5.2.0
        with: # running setup-java again overwrites the settings.xml
          distribution: 'temurin'
          java-version: '8'
          java-package: jdk
-          server-id: ossrh # Value of the distributionManagement/repository/id field of the pom.xml
+          server-id: central # Value of the distributionManagement/repository/id field of the pom.xml
          server-username: MAVEN_CENTRAL_USERNAME # env variable for username in deploy (1)
          server-password: MAVEN_CENTRAL_PASSWORD # env variable for token in deploy (2)
      - name: Get Project Version
@@ -121,7 +137,7 @@ jobs:
        if: ${{ endsWith(env.PROJECT_VERSION, '-SNAPSHOT') }}
        run: mvn --batch-mode --no-transfer-progress deploy -P release -DskipTests -Dgpg.signer=bc
        env:
-          MAVEN_CENTRAL_USERNAME: ${{ secrets.SONATYPE_USERNAME }} # must be the same env variable name as (1)
-          MAVEN_CENTRAL_PASSWORD: ${{ secrets.SONATYPE_PASSWORD }} # must be the same env variable name as (2)
+          MAVEN_CENTRAL_USERNAME: ${{ secrets.CENTRAL_USERNAME }} # must be the same env variable name as (1)
+          MAVEN_CENTRAL_PASSWORD: ${{ secrets.CENTRAL_PASSWORD }} # must be the same env variable name as (2)
          MAVEN_GPG_KEY: ${{ secrets.GPG_KEY }}                    # Value of the GPG private key to import
          MAVEN_GPG_PASSPHRASE: ${{ secrets.GPG_PASSPHRASE }}
@@ -33,11 +33,11 @@ jobs:

    steps:
    - name: Checkout repository
-      uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
+      uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2

    # Initializes the CodeQL tools for scanning.
    - name: Initialize CodeQL
-      uses: github/codeql-action/init@e296a935590eb16afc0c0108289f68c87e2a89a5 # v4.30.7
+      uses: github/codeql-action/init@95e58e9a2cdfd71adc6e0353d5c52f41a045d225 # v4.35.2
      with:
        languages: ${{ matrix.language }}
        # If you wish to specify custom queries, you can do so here or in a config file.
@@ -51,7 +51,7 @@ jobs:
    # Autobuild attempts to build any compiled languages (C/C++, C#, Go, Java, or Swift).
    # If this step fails, then you should remove it and run the build manually (see below)
    - name: Autobuild
-      uses: github/codeql-action/autobuild@e296a935590eb16afc0c0108289f68c87e2a89a5 # v4.30.7
+      uses: github/codeql-action/autobuild@95e58e9a2cdfd71adc6e0353d5c52f41a045d225 # v4.35.2

    # ℹ️ Command-line programs to run using the OS shell.
    # 📚 See https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actions#jobsjob_idstepsrun
@@ -64,6 +64,6 @@ jobs:
    #     ./location_of_script_within_repo/buildscript.sh

    - name: Perform CodeQL Analysis
-      uses: github/codeql-action/analyze@e296a935590eb16afc0c0108289f68c87e2a89a5 # v4.30.7
+      uses: github/codeql-action/analyze@95e58e9a2cdfd71adc6e0353d5c52f41a045d225 # v4.35.2
      with:
        category: "/language:${{matrix.language}}"
@@ -26,7 +26,7 @@ jobs:

    steps:
      - name: "Checkout code"
-        uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
        with:
          persist-credentials: false

@@ -49,7 +49,7 @@ jobs:
      # Upload the results as artifacts (optional). Commenting out will disable uploads of run results in SARIF
      # format to the repository Actions tab.
      - name: "Upload artifact"
-        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
+        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
        with:
          name: SARIF file
          path: results.sarif
@@ -57,6 +57,6 @@ jobs:

      # Upload the results to GitHub's code scanning dashboard.
      - name: "Upload to code-scanning"
-        uses: github/codeql-action/upload-sarif@e296a935590eb16afc0c0108289f68c87e2a89a5 # v4.30.7
+        uses: github/codeql-action/upload-sarif@95e58e9a2cdfd71adc6e0353d5c52f41a045d225 # v4.35.2
        with:
          sarif_file: results.sarif
@@ -4,7 +4,7 @@
 [![OpenSSF Best Practices](https://www.bestpractices.dev/projects/7900/badge)](https://www.bestpractices.dev/projects/7900)

 [![Maven Central](https://img.shields.io/maven-central/v/com.twelvemonkeys.imageio/imageio?color=slateblue)](https://search.maven.org/search?q=g:com.twelvemonkeys.imageio)
-[![Maven Snapshot](https://img.shields.io/nexus/s/com.twelvemonkeys.imageio/imageio?label=development&server=https%3A%2F%2Foss.sonatype.org&color=slateblue)](https://oss.sonatype.org/content/repositories/snapshots/com/twelvemonkeys/)
+[![Maven Snapshot](https://img.shields.io/maven-metadata/v?metadataUrl=https%3A%2F%2Fcentral.sonatype.com%2Frepository%2Fmaven-snapshots%2Fcom%2Ftwelvemonkeys%2Fimageio%2Fimageio%2Fmaven-metadata.xml&label=development&server=https%3A%2F%2Foss.sonatype.org&color=slateblue)](https://central.sonatype.com/repository/maven-snapshots/com/twelvemonkeys/imageio/imageio/maven-metadata.xml)
 [![StackOverflow](https://img.shields.io/badge/stack_overflow-twelvemonkeys-orange.svg)](https://stackoverflow.com/questions/tagged/twelvemonkeys)
 [![Donate](https://img.shields.io/badge/donate-PayPal-blue.svg)](https://paypal.me/haraldk76/100)

@@ -316,12 +316,12 @@ To depend on the JPEG and TIFF plugin using Maven, add the following to your POM
    <dependency>
        <groupId>com.twelvemonkeys.imageio</groupId>
        <artifactId>imageio-jpeg</artifactId>
-        <version>3.12.0</version>
+        <version>3.13.1</version>
    </dependency>
    <dependency>
        <groupId>com.twelvemonkeys.imageio</groupId>
        <artifactId>imageio-tiff</artifactId>
-        <version>3.12.0</version>
+        <version>3.13.1</version>
    </dependency>

    <!--
@@ -331,7 +331,7 @@ To depend on the JPEG and TIFF plugin using Maven, add the following to your POM
    <dependency>
        <groupId>com.twelvemonkeys.servlet</groupId>
        <artifactId>servlet</artifactId>
-        <version>3.12.0</version>
+        <version>3.13.1</version>
    </dependency>

    <!--
@@ -340,7 +340,7 @@ To depend on the JPEG and TIFF plugin using Maven, add the following to your POM
    <dependency>
        <groupId>com.twelvemonkeys.servlet</groupId>
        <artifactId>servlet</artifactId>
-        <version>3.12.0</version>
+        <version>3.13.1</version>
        <classifier>jakarta</classifier>
    </dependency>
 </dependencies>
@@ -350,13 +350,13 @@ To depend on the JPEG and TIFF plugin using Maven, add the following to your POM

 To depend on the JPEG and TIFF plugin in your IDE or program, add all of the following JARs to your class path:

-    twelvemonkeys-common-lang-3.12.0.jar
-    twelvemonkeys-common-io-3.12.0.jar
-    twelvemonkeys-common-image-3.12.0.jar
-    twelvemonkeys-imageio-core-3.12.0.jar
-    twelvemonkeys-imageio-metadata-3.12.0.jar
-    twelvemonkeys-imageio-jpeg-3.12.0.jar
-    twelvemonkeys-imageio-tiff-3.12.0.jar
+    twelvemonkeys-common-lang-3.13.1.jar
+    twelvemonkeys-common-io-3.13.1.jar
+    twelvemonkeys-common-image-3.13.1.jar
+    twelvemonkeys-imageio-core-3.13.1.jar
+    twelvemonkeys-imageio-metadata-3.13.1.jar
+    twelvemonkeys-imageio-jpeg-3.13.1.jar
+    twelvemonkeys-imageio-tiff-3.13.1.jar

 #### Deploying the plugins in a web app

@@ -432,46 +432,46 @@ Other "fat" JAR bundlers will probably have similar mechanisms to merge entries

 ### Links to prebuilt binaries

-##### Latest version (3.12.0)
+##### Latest version (3.13.1)

 The latest version that will run on Java 7 is 3.9.4. Later versions will require Java 8 or later.
 
 Common dependencies
-* [common-lang-3.12.0.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/common/common-lang/3.12.0/common-lang-3.12.0.jar)
-* [common-io-3.12.0.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/common/common-io/3.12.0/common-io-3.12.0.jar)
-* [common-image-3.12.0.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/common/common-image/3.12.0/common-image-3.12.0.jar)
+* [common-lang-3.13.1.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/common/common-lang/3.13.1/common-lang-3.13.1.jar)
+* [common-io-3.13.1.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/common/common-io/3.13.1/common-io-3.13.1.jar)
+* [common-image-3.13.1.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/common/common-image/3.13.1/common-image-3.13.1.jar)

 ImageIO dependencies
-* [imageio-core-3.12.0.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/imageio/imageio-core/3.12.0/imageio-core-3.12.0.jar)
-* [imageio-metadata-3.12.0.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/imageio/imageio-metadata/3.12.0/imageio-metadata-3.12.0.jar)
+* [imageio-core-3.13.1.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/imageio/imageio-core/3.13.1/imageio-core-3.13.1.jar)
+* [imageio-metadata-3.13.1.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/imageio/imageio-metadata/3.13.1/imageio-metadata-3.13.1.jar)

 ImageIO plugins
-* [imageio-bmp-3.12.0.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/imageio/imageio-bmp/3.12.0/imageio-bmp-3.12.0.jar)
-* [imageio-dds-3.12.0.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/imageio/imageio-dds/3.12.0/imageio-dds-3.12.0.jar)
-* [imageio-hdr-3.12.0.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/imageio/imageio-hdr/3.12.0/imageio-hdr-3.12.0.jar)
-* [imageio-icns-3.12.0.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/imageio/imageio-icns/3.12.0/imageio-icns-3.12.0.jar)
-* [imageio-iff-3.12.0.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/imageio/imageio-iff/3.12.0/imageio-iff-3.12.0.jar)
-* [imageio-jpeg-3.12.0.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/imageio/imageio-jpeg/3.12.0/imageio-jpeg-3.12.0.jar)
-* [imageio-pcx-3.12.0.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/imageio/imageio-pcx/3.12.0/imageio-pcx-3.12.0.jar)
-* [imageio-pict-3.12.0.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/imageio/imageio-pict/3.12.0/imageio-pict-3.12.0.jar)
-* [imageio-pnm-3.12.0.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/imageio/imageio-pnm/3.12.0/imageio-pnm-3.12.0.jar)
-* [imageio-psd-3.12.0.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/imageio/imageio-psd/3.12.0/imageio-psd-3.12.0.jar)
-* [imageio-sgi-3.12.0.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/imageio/imageio-sgi/3.12.0/imageio-sgi-3.12.0.jar)
-* [imageio-tga-3.12.0.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/imageio/imageio-tga/3.12.0/imageio-tga-3.12.0.jar)
-* [imageio-thumbsdb-3.12.0.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/imageio/imageio-thumbsdb/3.12.0/imageio-thumbsdb-3.12.0.jar)
-* [imageio-tiff-3.12.0.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/imageio/imageio-tiff/3.12.0/imageio-tiff-3.12.0.jar)
-* [imageio-webp-3.12.0.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/imageio/imageio-webp/3.12.0/imageio-webp-3.12.0.jar)
-* [imageio-xwd-3.12.0.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/imageio/imageio-xwd/3.12.0/imageio-xwd-3.12.0.jar)
+* [imageio-bmp-3.13.1.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/imageio/imageio-bmp/3.13.1/imageio-bmp-3.13.1.jar)
+* [imageio-dds-3.13.1.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/imageio/imageio-dds/3.13.1/imageio-dds-3.13.1.jar)
+* [imageio-hdr-3.13.1.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/imageio/imageio-hdr/3.13.1/imageio-hdr-3.13.1.jar)
+* [imageio-icns-3.13.1.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/imageio/imageio-icns/3.13.1/imageio-icns-3.13.1.jar)
+* [imageio-iff-3.13.1.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/imageio/imageio-iff/3.13.1/imageio-iff-3.13.1.jar)
+* [imageio-jpeg-3.13.1.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/imageio/imageio-jpeg/3.13.1/imageio-jpeg-3.13.1.jar)
+* [imageio-pcx-3.13.1.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/imageio/imageio-pcx/3.13.1/imageio-pcx-3.13.1.jar)
+* [imageio-pict-3.13.1.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/imageio/imageio-pict/3.13.1/imageio-pict-3.13.1.jar)
+* [imageio-pnm-3.13.1.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/imageio/imageio-pnm/3.13.1/imageio-pnm-3.13.1.jar)
+* [imageio-psd-3.13.1.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/imageio/imageio-psd/3.13.1/imageio-psd-3.13.1.jar)
+* [imageio-sgi-3.13.1.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/imageio/imageio-sgi/3.13.1/imageio-sgi-3.13.1.jar)
+* [imageio-tga-3.13.1.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/imageio/imageio-tga/3.13.1/imageio-tga-3.13.1.jar)
+* [imageio-thumbsdb-3.13.1.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/imageio/imageio-thumbsdb/3.13.1/imageio-thumbsdb-3.13.1.jar)
+* [imageio-tiff-3.13.1.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/imageio/imageio-tiff/3.13.1/imageio-tiff-3.13.1.jar)
+* [imageio-webp-3.13.1.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/imageio/imageio-webp/3.13.1/imageio-webp-3.13.1.jar)
+* [imageio-xwd-3.13.1.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/imageio/imageio-xwd/3.13.1/imageio-xwd-3.13.1.jar)

 ImageIO plugins requiring 3rd party libs
-* [imageio-batik-3.12.0.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/imageio/imageio-batik/3.12.0/imageio-batik-3.12.0.jar)
+* [imageio-batik-3.13.1.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/imageio/imageio-batik/3.13.1/imageio-batik-3.13.1.jar)

 Photoshop Path support for ImageIO
-* [imageio-clippath-3.12.0.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/imageio/imageio-clippath/3.12.0/imageio-clippath-3.12.0.jar)
+* [imageio-clippath-3.13.1.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/imageio/imageio-clippath/3.13.1/imageio-clippath-3.13.1.jar)

 Servlet support
-* [servlet-3.12.0.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/servlet/servlet/3.12.0/servlet-3.12.0.jar) for legacy Java EE (javax.servlet)
-* [servlet-3.12.0-jakarta.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/servlet/servlet/3.12.0/servlet-3.12.0-jakrta.jar) for Jakarta EE (jakarta.servlet)
+* [servlet-3.13.1.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/servlet/servlet/3.13.1/servlet-3.13.1.jar) for legacy Java EE (javax.servlet)
+* [servlet-3.13.1-jakarta.jar](https://search.maven.org/remotecontent?filepath=com/twelvemonkeys/servlet/servlet/3.13.1/servlet-3.13.1-jakrta.jar) for Jakarta EE (jakarta.servlet)

 ## License

@@ -5,7 +5,7 @@
    <parent>
        <groupId>com.twelvemonkeys</groupId>
        <artifactId>twelvemonkeys</artifactId>
-        <version>3.12.1-SNAPSHOT</version>
+        <version>3.13.2-SNAPSHOT</version>
    </parent>

    <groupId>com.twelvemonkeys.bom</groupId>
@@ -4,7 +4,7 @@
    <parent>
        <groupId>com.twelvemonkeys.common</groupId>
        <artifactId>common</artifactId>
-        <version>3.12.1-SNAPSHOT</version>
+        <version>3.13.2-SNAPSHOT</version>
    </parent>
    <artifactId>common-image</artifactId>
    <packaging>jar</packaging>
@@ -47,10 +47,10 @@ import java.util.Random;
 *  |3|5|1|
 *   - - -->
 * </p>
- * <table border="1" cellpadding="4" cellspacing="0">
+ * <table border="1">
 *     <caption>Floyd-Steinberg error-diffusion weights</caption>
- *     <tr><td bgcolor="#000000">&nbsp;</td><td class="TableHeadingColor"
- *          align="center">x</td><td>7/16</td></tr>
+ *     <tr><td style="background:#000000">&nbsp;</td><td class="TableHeadingColor"
+ *          style="text-align:center">x</td><td>7/16</td></tr>
 *     <tr><td>3/16</td><td>5/16</td><td>1/16</td></tr>
 * </table>
 * <p>
@@ -162,7 +162,7 @@ public final class ImageUtil {

    /**
     * The sharpen kernel. Uses the following 3 by 3 matrix:
-     * <table border="1" cellspacing="0">
+     * <table border="1">
     *     <caption>Sharpen Kernel Matrix</caption>
     *     <tr><td>0.0</td><td>-0.3</td><td>0.0</td></tr>
     *     <tr><td>-0.3</td><td>2.2</td><td>-0.3</td></tr>
@@ -1078,7 +1078,7 @@ public final class ImageUtil {
    /**
     * Sharpens an image using a convolution matrix.
     * The sharpen kernel used, is defined by the following 3 by 3 matrix:
-     * <table border="1" cellspacing="0">
+     * <table border="1">
     *     <caption>Sharpen Kernel Matrix</caption>
     *     <tr><td>0.0</td><td>-0.3</td><td>0.0</td></tr>
     *     <tr><td>-0.3</td><td>2.2</td><td>-0.3</td></tr>
@@ -1100,7 +1100,7 @@ public final class ImageUtil {
    /**
     * Sharpens an image using a convolution matrix.
     * The sharpen kernel used, is defined by the following 3 by 3 matrix:
-     * <table border="1" cellspacing="0">
+     * <table border="1">
     *     <caption>Sharpen Kernel Matrix</caption>
     *     <tr><td>0.0</td><td>-{@code pAmount}</td><td>0.0</td></tr>
     *     <tr><td>-{@code pAmount}</td>
@@ -4,7 +4,7 @@
    <parent>
        <groupId>com.twelvemonkeys.common</groupId>
        <artifactId>common</artifactId>
-        <version>3.12.1-SNAPSHOT</version>
+        <version>3.13.2-SNAPSHOT</version>
    </parent>
    <artifactId>common-io</artifactId>
    <packaging>jar</packaging>
@@ -4,7 +4,7 @@
    <parent>
        <groupId>com.twelvemonkeys.common</groupId>
        <artifactId>common</artifactId>
-        <version>3.12.1-SNAPSHOT</version>
+        <version>3.13.2-SNAPSHOT</version>
    </parent>
    <artifactId>common-lang</artifactId>
    <packaging>jar</packaging>
@@ -1765,12 +1765,11 @@ public final class StringUtil {
     * expression.
     * <p>
     * An invocation of this method of the form
-     * <tt>matches(<i>str</i>, <i>regex</i>)</tt> yields exactly the
+     * {@code matches(str, regex)} yields exactly the
     * same result as the expression
     * </p>
-     * <blockquote><tt> {@link Pattern}.
-     * {@link Pattern#matches(String, CharSequence) matches}
-     * (<i>regex</i>, <i>str</i>)</tt></blockquote>
+     * <blockquote>{@link Pattern}.
+     * {@link Pattern#matches(String, CharSequence) matches(regex, str)}</blockquote>
     *
     * @param pString the string
     * @param pRegex  the regular expression to which this string is to be matched
@@ -1789,16 +1788,14 @@ public final class StringUtil {
     * regular expression with the given pReplacement.
     * <p>
     * An invocation of this method of the form
-     * <tt>
-     *     replaceFirst(<i>str</i>, <i>regex</i>, <i>repl</i>)
-     * </tt>
+     * {@code replaceFirst(str, regex, repl)}
     * yields exactly the same result as the expression:
     * </p>
-     * <blockquote><tt>
-     * {@link Pattern}.{@link Pattern#compile(String) compile}(<i>regex</i>).
-     * {@link Pattern#matcher matcher}(<i>str</i>).
-     * {@link java.util.regex.Matcher#replaceFirst replaceFirst}(<i>repl</i>)
-     * </tt></blockquote>
+     * <blockquote>
+     * {@link Pattern#compile(String) Pattern.compile(regex)}
+     * {@link Pattern#matcher .matcher(str)}
+     * {@link java.util.regex.Matcher#replaceFirst .replaceFirst(repl)}
+     * </blockquote>
     *
     * @param pString      the string
     * @param pRegex       the regular expression to which this string is to be matched
@@ -1817,14 +1814,14 @@ public final class StringUtil {
     * regular expression with the given pReplacement.
     * <p>
     * An invocation of this method of the form
-     * <tt>replaceAll(<i>str</i>, <i>pRegex</i>, <i>repl</i>)</tt>
+     * {@code replaceAll(str, pRegex, repl)}
     * yields exactly the same result as the expression
     * </p>
-     * <blockquote><tt>
-     * {@link Pattern}.{@link Pattern#compile(String) compile}(<i>pRegex</i>).
-     * {@link Pattern#matcher matcher}(<i>str</i>{@code ).
-     * {@link java.util.regex.Matcher#replaceAll replaceAll}(}<i>repl</i>{@code )}
-     * </tt></blockquote>
+     * <blockquote>
+     * {@link Pattern#compile(String) Pattern.compile(pRegex)}
+     * {@link Pattern#matcher .matcher(str)}
+     * {@link java.util.regex.Matcher#replaceAll .replaceAll(repl)}
+     * </blockquote>
     *
     * @param pString      the string
     * @param pRegex       the regular expression to which this string is to be matched
@@ -1862,12 +1859,12 @@ public final class StringUtil {
     * </p>
     * <p>
     * An invocation of this method of the form
-     * <tt>split(<i>str</i>, <i>regex</i>, <i>n</i>)</tt>
+     * {@code split(str, regex, n)}
     * yields the same result as the expression:
     * </p>
     * <blockquote>{@link Pattern}.
-     * {@link Pattern#compile(String) compile}<tt>(<i>regex</i>).
-     * {@link Pattern#split(CharSequence,int) split}(<i>str</i>, <i>n</i>)</tt>
+     * {@link Pattern#compile(String) compile(regex)}.
+     * {@link Pattern#split(CharSequence,int) split(str, n)}
     * </blockquote>
     *
     * @param pString the string
@@ -4,7 +4,7 @@
    <parent>
        <groupId>com.twelvemonkeys</groupId>
        <artifactId>twelvemonkeys</artifactId>
-        <version>3.12.1-SNAPSHOT</version>
+        <version>3.13.2-SNAPSHOT</version>
    </parent>
    <groupId>com.twelvemonkeys.common</groupId>
    <artifactId>common</artifactId>
@@ -21,7 +21,7 @@
    </modules>

    <properties>
-        <junit.jupiter.version>5.14.0</junit.jupiter.version>
+        <junit.jupiter.version>5.14.3</junit.jupiter.version>
    </properties>

    <dependencyManagement>
@@ -4,7 +4,7 @@
    <parent>
        <groupId>com.twelvemonkeys</groupId>
        <artifactId>twelvemonkeys</artifactId>
-        <version>3.12.1-SNAPSHOT</version>
+        <version>3.13.2-SNAPSHOT</version>
    </parent>
    <groupId>com.twelvemonkeys.contrib</groupId>
    <artifactId>contrib</artifactId>
@@ -14,7 +14,7 @@
    </description>

    <properties>
-        <junit.jupiter.version>5.14.0</junit.jupiter.version>
+        <junit.jupiter.version>5.14.3</junit.jupiter.version>
    </properties>


@@ -4,7 +4,7 @@
    <parent>
        <groupId>com.twelvemonkeys.imageio</groupId>
        <artifactId>imageio</artifactId>
-        <version>3.12.1-SNAPSHOT</version>
+        <version>3.13.2-SNAPSHOT</version>
    </parent>
    <artifactId>imageio-batik</artifactId>
    <name>TwelveMonkeys :: ImageIO :: Batik Plugin</name>
@@ -63,7 +63,7 @@
        <dependency>
            <groupId>commons-io</groupId>
            <artifactId>commons-io</artifactId>
-            <version>2.20.0</version>
+            <version>2.22.0</version>
            <scope>provided</scope>
        </dependency>

@@ -36,9 +36,11 @@ import com.twelvemonkeys.lang.SystemUtil;
 import javax.imageio.ImageReader;
 import javax.imageio.spi.ServiceRegistry;
 import javax.imageio.stream.ImageInputStream;
+import java.io.ByteArrayOutputStream;
 import java.io.EOFException;
 import java.io.IOException;
 import java.util.Locale;
+import java.util.function.Predicate;

 import static com.twelvemonkeys.imageio.util.IIOUtil.deregisterProvider;

@@ -134,10 +136,42 @@ public final class SVGImageReaderSpi extends ImageReaderSpiBase {
                    if (buffer[0] == 's' && buffer[1] == 'v' && buffer[2] == 'g'
                            && (Character.isWhitespace((char) buffer[3]) || buffer[3] == ':')) {
                        // It's SVG, identified by root tag
-                        // TODO: Support svg with prefix + recognize namespace (http://www.w3.org/2000/svg)!
                        return true;
                    }

+                    // Read the full tag name (may contain a prefix of any length)
+                    final int MAX_TAG_NAME = 256;
+                    ByteArrayOutputStream nameBuf = new ByteArrayOutputStream(MAX_TAG_NAME);
+
+                    // We already have 4 bytes in 'buffer' (from input.readFully(buffer))
+                    int consumedFromBuffer = 0;
+                    for (; consumedFromBuffer < buffer.length; consumedFromBuffer++) {
+                        byte bb = buffer[consumedFromBuffer];
+                        if (bb == '>' || Character.isWhitespace((char) bb) || bb == '/') {
+                            break;
+                        }
+                        nameBuf.write(bb);
+                    }
+
+                    // If tag name not terminated yet, keep reading bytes (within limit)
+                    final boolean incompleteTagName = consumedFromBuffer == buffer.length;
+                    readBuffer(input, nameBuf, output -> incompleteTagName && output.size() < MAX_TAG_NAME,
+                        bb -> bb == '>' || Character.isWhitespace(bb) || bb == '/');
+
+                    final String name = nameBuf.toString("US-ASCII");
+                    if (name.toLowerCase(Locale.ENGLISH).endsWith(":svg")) {
+                        // Scan the rest of the tag attributes until '>' to find the SVG namespace URI
+                        ByteArrayOutputStream attrBuf = new ByteArrayOutputStream();
+                        final int MAX_ATTR_SCAN = 1024; // safe upper bound to keep it fast
+                        readBuffer(input, attrBuf, output -> output.size() < MAX_ATTR_SCAN, bb -> bb == '>');
+
+                        // If the tag contains the SVG namespace, it's SVG.
+                        if (attrBuf.toString("US-ASCII").matches(
+                            ".*xmlns:" + name.split(":")[0] + "\\s*=\\s*\"http://www.w3.org/2000/svg\".*")) {
+                            return true;
+                        }
+                    }
+
                    // If the tag is not "svg", this isn't SVG
                    return false;
                }
@@ -157,6 +191,17 @@ public final class SVGImageReaderSpi extends ImageReaderSpiBase {
        }
    }

+    private static void readBuffer(final ImageInputStream input, final ByteArrayOutputStream buffer,
+            final Predicate<ByteArrayOutputStream> loopCondition, Predicate<Byte> breakCondition) throws IOException {
+        while (loopCondition.test(buffer)) {
+            byte bb = input.readByte();
+            if (breakCondition.test(bb)) {
+                break;
+            }
+            buffer.write(bb);
+        }
+    }
+
    public ImageReader createReaderInstance(final Object extension) throws IOException {
        return new SVGImageReader(this);
    }
@@ -56,7 +56,7 @@ public class SVGImageReaderSpiTest {
            "/svg/Android_robot.svg", // Minimal, no xml dec, no namespace
            "/svg/batikLogo.svg",     // xml dec, comments, namespace
            "/svg/blue-square.svg",   // xml dec, namespace
-            "/svg/red-square.svg",
+            "/svg/red-square.svg",    // prefixed namespace
    };

    private static final String[] INVALID_INPUTS = {
@@ -70,6 +70,9 @@ public class SVGImageReaderSpiTest {
        "<!-- ", // #275 Infinite loop issue
        "<?123?>", // #275 Infinite loop issue
        "<svg",
+        "<ns0:svg>", // namespace prefix undefined
+        "<ns0:svg xmlns:ns0=\"foo\">", // not the official svg namespace
+        "<ns0:svg xmlns:ns1=\"http://www.w3.org/2000/svg\">", // mismatching prefix
    };

    static {
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
-<svg xmlns="http://www.w3.org/2000/svg" width="100" height="100" id="red-square" version="1.1">
-  <g id="layer1">
-    <rect id="rect2985" width="100" height="100" x="0" y="0"
+<ns0:svg xmlns:ns0="http://www.w3.org/2000/svg" width="100" height="100" id="red-square" version="1.1">
+  <ns0:g id="layer1">
+    <ns0:rect id="rect2985" width="100" height="100" x="0" y="0"
       style="color:#000000;fill:#ff0000;fill-opacity:1;fill-rule:nonzero;stroke:none;stroke-width:1;marker:none;visibility:visible;display:inline;overflow:visible;enable-background:accumulate" />
-  </g>
-</svg>
+  </ns0:g>
+</ns0:svg>
@@ -4,7 +4,7 @@
    <parent>
        <groupId>com.twelvemonkeys.imageio</groupId>
        <artifactId>imageio</artifactId>
-        <version>3.12.1-SNAPSHOT</version>
+        <version>3.13.2-SNAPSHOT</version>
    </parent>
    <artifactId>imageio-bmp</artifactId>
    <name>TwelveMonkeys :: ImageIO :: BMP plugin</name>
@@ -32,6 +32,7 @@ package com.twelvemonkeys.imageio.plugins.bmp;

 import com.twelvemonkeys.imageio.stream.SubImageOutputStream;
 import com.twelvemonkeys.imageio.util.ProgressListenerBase;
+import com.twelvemonkeys.imageio.util.SequenceSupport;

 import javax.imageio.IIOException;
 import javax.imageio.IIOImage;
@@ -64,7 +65,7 @@ public final class ICOImageWriter extends DIBImageWriter {
    private static final int ICO_MAX_DIMENSION = 256;
    private static final int INITIAL_ENTRY_COUNT = 8;

-    private int sequenceIndex = -1;
+    private final SequenceSupport sequence = new SequenceSupport();

    private ImageWriter pngDelegate;

@@ -74,7 +75,7 @@ public final class ICOImageWriter extends DIBImageWriter {

    @Override
    protected void resetMembers() {
-        sequenceIndex = -1;
+        sequence.reset();

        if (pngDelegate != null) {
            pngDelegate.dispose();
@@ -107,16 +108,12 @@ public final class ICOImageWriter extends DIBImageWriter {
    @Override
    public void prepareWriteSequence(final IIOMetadata streamMetadata) throws IOException {
        assertOutput();
-
-        if (sequenceIndex >= 0) {
-            throw new IllegalStateException("writeSequence already started");
-        }
+        sequence.start();

        writeICOHeader();

        // Count: Needs to be updated for each new image
        imageOutput.writeShort(0);
-        sequenceIndex = 0;

        // TODO: Allow passing the initial size of the directory in the stream metadata?
        // - as this is much more efficient than growing...
@@ -130,27 +127,19 @@ public final class ICOImageWriter extends DIBImageWriter {
    @Override
    public void endWriteSequence() {
        assertOutput();
-
-        if (sequenceIndex < 0) {
-            throw new IllegalStateException("prepareWriteSequence not called");
-        }
-
-        sequenceIndex = -1;
+        sequence.end();
    }

    @Override
    public void writeToSequence(final IIOImage image, final ImageWriteParam param) throws IOException {
        assertOutput();
-
-        if (sequenceIndex < 0) {
-            throw new IllegalStateException("prepareWriteSequence not called");
-        }
+        int imageIndex = sequence.advance();

        if (image.hasRaster()) {
            throw new UnsupportedOperationException("Raster not supported");
        }

-        if (sequenceIndex >= INITIAL_ENTRY_COUNT) {
+        if (imageIndex >= INITIAL_ENTRY_COUNT) {
            growIfNecessary();
        }

@@ -172,7 +161,7 @@ public final class ICOImageWriter extends DIBImageWriter {
        // Uncompressed, RLE4/RLE8 or PNG compressed
        boolean pngCompression = param != null && "BI_PNG".equals(param.getCompressionType());

-        processImageStarted(sequenceIndex);
+        processImageStarted(imageIndex);

        if (pngCompression) {
            // NOTE: Embedding a PNG in a ICO is slightly different than a BMP with BI_PNG compression,
@@ -198,17 +187,15 @@ public final class ICOImageWriter extends DIBImageWriter {

        // Update count
        imageOutput.seek(4);
-        imageOutput.writeShort(sequenceIndex + 1);
+        imageOutput.writeShort(imageIndex + 1);

        // Write entry
-        int entryPosition = 6 + sequenceIndex * ENTRY_SIZE;
+        int entryPosition = 6 + imageIndex * ENTRY_SIZE;
        imageOutput.seek(entryPosition);

        long size = nextPosition - imageOffset;
        writeEntry(width,  height, colorModel, (int) size, (int) imageOffset);

-        sequenceIndex++;
-
        imageOutput.seek(nextPosition);
    }

@@ -265,7 +252,7 @@ public final class ICOImageWriter extends DIBImageWriter {
            pngDelegate.addIIOWriteWarningListener(new IIOWriteWarningListener() {
                @Override
                public void warningOccurred(ImageWriter source, int imageIndex, String warning) {
-                    processWarningOccurred(sequenceIndex, warning);
+                    processWarningOccurred(sequence.current(), warning);
                }
            });
        }
@@ -4,7 +4,7 @@
    <parent>
        <groupId>com.twelvemonkeys.imageio</groupId>
        <artifactId>imageio</artifactId>
-        <version>3.12.1-SNAPSHOT</version>
+        <version>3.13.2-SNAPSHOT</version>
    </parent>
    <artifactId>imageio-clippath</artifactId>
    <name>TwelveMonkeys :: ImageIO :: Photoshop Path Support</name>
@@ -4,7 +4,7 @@
    <parent>
        <groupId>com.twelvemonkeys.imageio</groupId>
        <artifactId>imageio</artifactId>
-        <version>3.12.1-SNAPSHOT</version>
+        <version>3.13.2-SNAPSHOT</version>
    </parent>
    <artifactId>imageio-core</artifactId>
    <name>TwelveMonkeys :: ImageIO :: Core</name>
@@ -23,6 +23,7 @@ import static com.twelvemonkeys.lang.Validate.notNull;
 * {@link ImageTypeSpecifier}.
 * Other values or overrides may be specified using the builder.
 *
+ * @see <a href="https://docs.oracle.com/en/java/javase/11/docs/api/java.desktop/javax/imageio/metadata/doc-files/standard_metadata.html">Standard (Plug-in Neutral) Metadata Format Specification</a>
 * @author <a href="mailto:harald.kuhr@gmail.com">Harald Kuhr</a>
 */
 public class StandardImageMetadataSupport extends AbstractMetadata {
@@ -79,11 +80,11 @@ public class StandardImageMetadataSupport extends AbstractMetadata {
        textEntries = builder.textEntries;
    }

-    public static Builder builder(ImageTypeSpecifier type) {
+    protected static Builder builder(ImageTypeSpecifier type) {
        return new Builder(type);
    }

-    public static class Builder {
+    protected static class Builder {
        private final ImageTypeSpecifier type;
        private ColorSpaceType colorSpaceType;
        private boolean blackIsZero = true;
@@ -35,6 +35,8 @@ import com.twelvemonkeys.lang.Validate;

 import javax.imageio.IIOParam;
 import javax.imageio.ImageIO;
+import javax.imageio.ImageReadParam;
+import javax.imageio.ImageWriteParam;
 import javax.imageio.spi.IIOServiceProvider;
 import javax.imageio.spi.ServiceRegistry;
 import javax.imageio.stream.ImageInputStream;
@@ -45,7 +47,9 @@ import java.io.BufferedInputStream;
 import java.io.BufferedOutputStream;
 import java.io.InputStream;
 import java.io.OutputStream;
+import java.util.Arrays;
 import java.util.Iterator;
+import java.util.Objects;
 import java.util.SortedSet;
 import java.util.TreeSet;

@@ -68,7 +72,7 @@ public final class IIOUtil {
     */
    public static InputStream createStreamAdapter(final ImageInputStream pStream) {
        // TODO: Include stream start pos?
-        // TODO: Skip buffering for known in-memory implementations?
+        // TODO: Skip buffering for known in-memory implementations? pStream.isCachedMemory
        return new BufferedInputStream(new IIOInputStreamAdapter(pStream));
    }

@@ -82,7 +86,7 @@ public final class IIOUtil {
     */
    public static InputStream createStreamAdapter(final ImageInputStream pStream, final long pLength) {
        // TODO: Include stream start pos?
-        // TODO: Skip buffering for known in-memory implementations?
+        // TODO: Skip buffering for known in-memory implementations? pStream.isCachedMemory
        return new BufferedInputStream(new IIOInputStreamAdapter(pStream, pLength));
    }

@@ -359,4 +363,115 @@ public final class IIOUtil {
            System.arraycopy(srcRow, srcPos + x, destRow, destPos + x / samplePeriod, pixelStride);
        }
    }
+
+    /**
+     * Copies all the standard param values from source to destination.
+     * <p>
+     * Typical use (in some imaginary {@code FooImageWriter} class):
+     * </p>
+     *
+     * <pre>
+     * ImageWriteParam param = ...
+     * FooImageWriteparam fooParam = param instanceof FooImageWriteParam
+     *      ? (FooImageWriteParam) param
+     *      : copyStandardParams(param, getDefaultWriteParam());
+     * </pre>
+     *
+     * May also be useful for {@code ImageReader}s that delegate reading to other plugins
+     * (like a TIFF plugin delegating JPEG format decoding to a {@code JPEGImageReader}).
+     *
+     * @param source the source parameter, may be {@code null}
+     * @param destination the destination parameter
+     * @return destination
+     *
+     * @param <T> the plugin specific subclass of {@code IIOParam}
+     *
+     * @throws NullPointerException if destination is {@code null}
+     */
+    public static <T extends IIOParam> T copyStandardParams(IIOParam source, T destination) {
+        Objects.requireNonNull(destination);
+        Validate.isTrue(source != destination, "source must be different from destination");
+
+        if (source != null) {
+            copyIIOParams(source, destination);
+
+            // TODO: API & usage... Is it ever useful to copy from a read to a write param or vice versa?
+            //  If not, maybe throw an IllegalArgumentException instead
+
+            if (source instanceof ImageReadParam && destination instanceof ImageReadParam) {
+                copyImageReadParams((ImageReadParam) source, (ImageReadParam) destination);
+            }
+
+            if (source instanceof ImageWriteParam && destination instanceof ImageWriteParam) {
+                copyImageWriteParams((ImageWriteParam) source, (ImageWriteParam) destination);
+            }
+        }
+
+        return destination;
+    }
+
+    private static void copyImageWriteParams(ImageWriteParam source, ImageWriteParam destination) {
+        // TODO: Usage... It's very unlikely that compression settings of one plugin is compatible with another...
+        //  Is the the below useful?
+        //  Also, is it okay to just silently ignore settings from one format that isn't compatible with another?
+
+        // Quirky API, we can't query for compression mode, unless source.canWriteCompressed is true...
+        if (source.canWriteCompressed() && destination.canWriteCompressed()) {
+            int compressionMode = source.getCompressionMode();
+            destination.setCompressionMode(compressionMode);
+
+            if (compressionMode == ImageWriteParam.MODE_EXPLICIT
+                && source.getCompressionType() != null
+                && Arrays.asList(destination.getCompressionTypes()).contains(source.getCompressionType())) {
+                    destination.setCompressionType(source.getCompressionType());
+                    destination.setCompressionQuality(source.getCompressionQuality());
+            }
+        }
+
+        if (source.canWriteProgressive() && destination.canWriteProgressive()) {
+            destination.setProgressiveMode(source.getProgressiveMode());
+        }
+
+        if (source.canWriteTiles() && destination.canWriteTiles()) {
+            int tilingMode = source.getTilingMode();
+            destination.setTilingMode(tilingMode);
+
+            if (tilingMode == ImageWriteParam.MODE_EXPLICIT) {
+                // TODO: What if source can offset (and has offsets) and dest can't? Is it ok to just ignore the setting?
+                boolean canWriteOffsetTiles = source.canOffsetTiles() && destination.canOffsetTiles();
+
+                destination.setTiling(
+                    source.getTileWidth(), source.getTileHeight(),
+                    canWriteOffsetTiles ? source.getTileGridXOffset() : 0,
+                    canWriteOffsetTiles ? source.getTileGridYOffset() : 0
+                );
+            }
+        }
+    }
+
+    private static void copyImageReadParams(ImageReadParam source, ImageReadParam destination) {
+        destination.setDestination(source.getDestination());
+        destination.setDestinationBands(source.getDestinationBands());
+
+        if (destination.canSetSourceRenderSize()) {
+            destination.setSourceRenderSize(source.getSourceRenderSize());
+        }
+
+        destination.setSourceProgressivePasses(
+            source.getSourceMinProgressivePass(),
+            source.getSourceMaxProgressivePass()
+        );
+    }
+
+    private static void copyIIOParams(IIOParam source, IIOParam destination) {
+        destination.setController(source.getController());
+        destination.setSourceSubsampling(
+            source.getSourceXSubsampling(), source.getSourceYSubsampling(),
+            source.getSubsamplingXOffset(), source.getSubsamplingYOffset()
+        );
+        destination.setSourceRegion(source.getSourceRegion());
+        destination.setSourceBands(source.getSourceBands());
+        destination.setDestinationOffset(source.getDestinationOffset());
+        destination.setDestinationType(source.getDestinationType());
+    }
 }
@@ -0,0 +1,115 @@
+/*
+ * Copyright (c) 2026, Harald Kuhr
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * * Redistributions of source code must retain the above copyright notice, this
+ *   list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright notice,
+ *   this list of conditions and the following disclaimer in the documentation
+ *   and/or other materials provided with the distribution.
+ *
+ * * Neither the name of the copyright holder nor the names of its
+ *   contributors may be used to endorse or promote products derived from
+ *   this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package com.twelvemonkeys.imageio.util;
+
+import javax.imageio.IIOImage;
+import javax.imageio.ImageWriteParam;
+import javax.imageio.ImageWriter;
+import javax.imageio.metadata.IIOMetadata;
+
+/**
+ * A tiny utility class that keeps state for sequences.
+ * For use by {@code ImageWriter} implementations that supports sequence (multiple images in same stream).
+ *
+ * @see ImageWriter#canWriteSequence()
+ */
+public final class SequenceSupport {
+    // Initial state, no sequence running
+    private int index = -1;
+
+    /**
+     * Resets the sequence to initial state, regardless of the current sequence state.
+     */
+    public void reset() {
+        index = -1;
+    }
+
+    /**
+     * Starts a new sequence.
+     *
+     * @throws IllegalStateException if a sequence is already running.
+     * @see ImageWriter#prepareWriteSequence(IIOMetadata)
+     */
+    public void start() {
+        if (index >= 0) {
+            throw new IllegalStateException("prepareWriteSequence already invoked");
+        }
+
+        index = 0;
+    }
+
+    /**
+     * Advances the current sequence.
+     *
+     * @return the current sequence index.
+     * @throws IllegalStateException if a sequence is not running.
+     * @see ImageWriter#writeToSequence(IIOImage, ImageWriteParam)
+     */
+    public int advance() {
+        if (index < 0) {
+            throw new IllegalStateException("prepareWriteSequence not invoked");
+        }
+
+        return index++;
+    }
+
+    /**
+     * Gets the current sequence index.
+     *
+     * @return the current sequence index, or {@code -1} if a sequence is not running.
+     */
+    public int current() {
+        // This method does not throw IllegalStateException, to allow
+        // ImageWriters to use the index in cases that may or may not
+        // happen "inside" a sequence.
+        // I'm not entirely sure if this is a good idea...
+        return index;
+    }
+
+    /**
+     * Ends the current sequence.
+     * The sequence is reset to initial state, and a new sequence may be started.
+     *
+     * @return the current (last) sequence index
+     * @throws IllegalStateException if a sequence is not running.
+     * @see ImageWriter#endWriteSequence()
+     */
+    public int end() {
+        if (index < 0) {
+            throw new IllegalStateException("prepareWriteSequence not invoked");
+        }
+
+        int last = index;
+        index = -1;
+
+        return last;
+    }
+}
@@ -1,8 +1,19 @@
 package com.twelvemonkeys.imageio.util;

 import org.junit.jupiter.api.Test;
+
 import static org.junit.jupiter.api.Assertions.*;

+import java.awt.Point;
+import java.awt.Rectangle;
+import java.awt.image.BufferedImage;
+
+import javax.imageio.ImageReadParam;
+import javax.imageio.ImageTypeSpecifier;
+import javax.imageio.ImageWriteParam;
+import javax.imageio.plugins.bmp.BMPImageWriteParam;
+import javax.imageio.plugins.jpeg.JPEGImageReadParam;
+
 /**
 * IIOUtilTest
 */
@@ -204,4 +215,222 @@ public class IIOUtilTest {
    private int divCeil(int numerator, int denominator) {
        return (numerator + denominator - 1) / denominator;
    }
+
+    @Test
+    void copyStandardParamsDestinationNull() {
+        ImageReadParam param = new ImageReadParam();
+
+        assertThrows(NullPointerException.class, () -> IIOUtil.copyStandardParams(null, null));
+        assertThrows(NullPointerException.class, () -> IIOUtil.copyStandardParams(param, null));
+    }
+
+    @Test
+    void copyStandardParamsSame() {
+        ImageReadParam param = new ImageReadParam();
+        assertThrows(IllegalArgumentException.class, () -> IIOUtil.copyStandardParams(param, param));
+    }
+
+    @Test
+    void copyStandardParamsSourceNull() {
+        ImageReadParam param = new ImageReadParam() {
+            @Override
+            public void setSourceRegion(Rectangle sourceRegion) {
+                fail("Should not be invoked");
+            }
+        };
+
+        assertSame(param, IIOUtil.copyStandardParams(null, param));
+    }
+
+    @Test
+    void copyStandardParamsImageReadParam() {
+        int sourceXSubsampling = 3;
+        int sourceYSubsampling = 4;
+        int subsamplingXOffset = 1;
+        int subsamplingYOffset = 2;
+        Rectangle sourceRegion = new Rectangle(1, 2, 42, 43);
+        int[] sourceBands = { 0, 1, 2 };
+
+        Point destinationOffset = new Point(7, 9);
+        int[] destinationBands = { 2, 1, 0 };
+
+        ImageReadParam sourceParam = new ImageReadParam();
+        sourceParam.setSourceRegion(sourceRegion);
+        sourceParam.setSourceSubsampling(sourceXSubsampling, sourceYSubsampling, subsamplingXOffset, subsamplingYOffset);
+        sourceParam.setSourceBands(sourceBands);
+
+        sourceParam.setDestinationOffset(destinationOffset);
+        sourceParam.setDestinationBands(destinationBands);
+
+        JPEGImageReadParam jpegParam = IIOUtil.copyStandardParams(sourceParam, new JPEGImageReadParam());
+
+        assertEquals(sourceRegion, jpegParam.getSourceRegion());
+        assertEquals(sourceXSubsampling, jpegParam.getSourceXSubsampling());
+        assertEquals(sourceYSubsampling, jpegParam.getSourceYSubsampling());
+        assertEquals(subsamplingXOffset, jpegParam.getSubsamplingXOffset());
+        assertEquals(subsamplingYOffset, jpegParam.getSubsamplingYOffset());
+        assertArrayEquals(sourceBands, jpegParam.getSourceBands());
+
+        assertEquals(destinationOffset, jpegParam.getDestinationOffset());
+        assertArrayEquals(destinationBands, jpegParam.getDestinationBands());
+    }
+
+    @Test
+    void copyStandardParamsImageReadParamDestination() {
+        // Destination and destination type is mutually exclusive
+        BufferedImage destination = new BufferedImage(2, 2, BufferedImage.TYPE_INT_ARGB);
+
+        ImageReadParam sourceParam = new ImageReadParam();
+        sourceParam.setDestination(destination);
+
+        assertEquals(destination, IIOUtil.copyStandardParams(sourceParam, new JPEGImageReadParam()).getDestination());
+    }
+
+    @Test
+    void copyStandardParamsImageReadParamDestinationType() {
+        // Destination and destination type is mutually exclusive
+        ImageTypeSpecifier destinationType = ImageTypeSpecifier.createFromBufferedImageType(BufferedImage.TYPE_BYTE_GRAY);
+
+        ImageReadParam sourceParam = new ImageReadParam();
+        sourceParam.setDestinationType(destinationType);
+
+        assertEquals(destinationType, IIOUtil.copyStandardParams(sourceParam, new JPEGImageReadParam()).getDestinationType());
+    }
+
+    @Test
+    void copyStandardParamsReadToWrite() {
+        int sourceXSubsampling = 3;
+        int sourceYSubsampling = 4;
+        int subsamplingXOffset = 1;
+        int subsamplingYOffset = 2;
+        Rectangle sourceRegion = new Rectangle(1, 2, 42, 43);
+        int[] sourceBands = { 0, 1, 2 };
+
+        Point destinationOffset = new Point(7, 9);
+
+        ImageWriteParam sourceParam = new ImageWriteParam(null);
+        sourceParam.setSourceRegion(sourceRegion);
+        sourceParam.setSourceSubsampling(sourceXSubsampling, sourceYSubsampling, subsamplingXOffset, subsamplingYOffset);
+        sourceParam.setSourceBands(sourceBands);
+
+        sourceParam.setDestinationOffset(destinationOffset);
+
+        JPEGImageReadParam jpegParam = IIOUtil.copyStandardParams(sourceParam, new JPEGImageReadParam());
+
+        assertEquals(sourceRegion, jpegParam.getSourceRegion());
+        assertEquals(sourceXSubsampling, jpegParam.getSourceXSubsampling());
+        assertEquals(sourceYSubsampling, jpegParam.getSourceYSubsampling());
+        assertEquals(subsamplingXOffset, jpegParam.getSubsamplingXOffset());
+        assertEquals(subsamplingYOffset, jpegParam.getSubsamplingYOffset());
+        assertArrayEquals(sourceBands, jpegParam.getSourceBands());
+
+        assertEquals(destinationOffset, jpegParam.getDestinationOffset());
+        assertNull(jpegParam.getDestinationBands()); // Only in read param
+    }
+
+    @Test
+    void copyStandardParamsImageWriteParam() {
+        int sourceXSubsampling = 3;
+        int sourceYSubsampling = 4;
+        int subsamplingXOffset = 1;
+        int subsamplingYOffset = 2;
+        Rectangle sourceRegion = new Rectangle(1, 2, 42, 43);
+        int[] sourceBands = { 0, 1, 2 };
+
+        Point destinationOffset = new Point(7, 9);
+
+        ImageWriteParam sourceParam = new ImageWriteParam(null);
+        sourceParam.setSourceRegion(sourceRegion);
+        sourceParam.setSourceSubsampling(sourceXSubsampling, sourceYSubsampling, subsamplingXOffset, subsamplingYOffset);
+        sourceParam.setSourceBands(sourceBands);
+
+        sourceParam.setDestinationOffset(destinationOffset);
+
+        BMPImageWriteParam fooParam = IIOUtil.copyStandardParams(sourceParam, new BMPImageWriteParam());
+
+        assertEquals(sourceRegion, fooParam.getSourceRegion());
+        assertEquals(sourceXSubsampling, fooParam.getSourceXSubsampling());
+        assertEquals(sourceYSubsampling, fooParam.getSourceYSubsampling());
+        assertEquals(subsamplingXOffset, fooParam.getSubsamplingXOffset());
+        assertEquals(subsamplingYOffset, fooParam.getSubsamplingYOffset());
+        assertArrayEquals(sourceBands, fooParam.getSourceBands());
+
+        assertEquals(destinationOffset, fooParam.getDestinationOffset());
+    }
+
+    @Test
+    void copyStandardParamsImageWriteParamEverything() {
+        int sourceXSubsampling = 3;
+        int sourceYSubsampling = 4;
+        int subsamplingXOffset = 1;
+        int subsamplingYOffset = 2;
+        Rectangle sourceRegion = new Rectangle(1, 2, 42, 43);
+        int[] sourceBands = { 0, 1, 2 };
+
+        Point destinationOffset = new Point(7, 9);
+
+        String compressionType = "Foo";
+        float quality = 0.42f;
+
+        ImageWriteParam sourceParam = new ImageWriteParam() {
+            {
+                canWriteProgressive = true;
+
+                canWriteTiles = true;
+                canOffsetTiles = true;
+
+                canWriteCompressed = true;
+                compressionTypes = new String[] { "Foo", "Bar" };
+            }
+        };
+        sourceParam.setSourceRegion(sourceRegion);
+        sourceParam.setSourceSubsampling(sourceXSubsampling, sourceYSubsampling, subsamplingXOffset, subsamplingYOffset);
+        sourceParam.setSourceBands(sourceBands);
+
+        sourceParam.setDestinationOffset(destinationOffset);
+
+        sourceParam.setProgressiveMode(ImageWriteParam.MODE_DEFAULT); // Default is COPY_FROM_METADATA...
+        sourceParam.setTilingMode(ImageWriteParam.MODE_EXPLICIT);
+        sourceParam.setTiling(1, 2, 3, 4);
+        sourceParam.setCompressionMode(ImageWriteParam.MODE_EXPLICIT);
+        sourceParam.setCompressionType(compressionType);
+        sourceParam.setCompressionQuality(quality);
+
+        FooImageWriteParam fooParam = IIOUtil.copyStandardParams(sourceParam, new FooImageWriteParam());
+
+        assertEquals(sourceRegion, fooParam.getSourceRegion());
+        assertEquals(sourceXSubsampling, fooParam.getSourceXSubsampling());
+        assertEquals(sourceYSubsampling, fooParam.getSourceYSubsampling());
+        assertEquals(subsamplingXOffset, fooParam.getSubsamplingXOffset());
+        assertEquals(subsamplingYOffset, fooParam.getSubsamplingYOffset());
+        assertArrayEquals(sourceBands, fooParam.getSourceBands());
+
+        assertEquals(destinationOffset, fooParam.getDestinationOffset());
+
+        assertEquals(ImageWriteParam.MODE_DEFAULT, fooParam.getProgressiveMode());
+
+        assertEquals(ImageWriteParam.MODE_EXPLICIT, fooParam.getTilingMode());
+        assertEquals(1, fooParam.getTileWidth());
+        assertEquals(2, fooParam.getTileHeight());
+        assertEquals(3, fooParam.getTileGridXOffset());
+        assertEquals(4, fooParam.getTileGridYOffset());
+
+        assertEquals(ImageWriteParam.MODE_EXPLICIT, fooParam.getCompressionMode());
+        assertEquals(compressionType, fooParam.getCompressionType());
+        assertEquals(quality, fooParam.getCompressionQuality());
+    }
+
+    // A basic param that supports "everything"
+    static class FooImageWriteParam extends ImageWriteParam {
+        FooImageWriteParam() {
+            canWriteProgressive = true;
+
+            canWriteTiles = true;
+            canOffsetTiles = true;
+
+            canWriteCompressed = true;
+            compressionType = "Unset";
+            compressionTypes = new String[] { "Bar", "Foo" };
+        }
+    }
 }
@@ -34,6 +34,7 @@ import com.twelvemonkeys.imageio.stream.URLImageInputStreamSpi;

 import org.mockito.InOrder;

+import javax.imageio.IIOImage;
 import javax.imageio.ImageIO;
 import javax.imageio.ImageWriteParam;
 import javax.imageio.ImageWriter;
@@ -84,6 +85,7 @@ public abstract class ImageWriterAbstractTest<T extends ImageWriter> {

    protected static BufferedImage drawSomething(final BufferedImage image) {
        Graphics2D g = image.createGraphics();
+
        try {
            int width = image.getWidth();
            int height = image.getHeight();
@@ -131,18 +133,54 @@ public abstract class ImageWriterAbstractTest<T extends ImageWriter> {
    public void testWrite() throws IOException {
        ImageWriter writer = createWriter();

-        for (RenderedImage testData : getTestData()) {
-            ByteArrayOutputStream buffer = new ByteArrayOutputStream();
+        try {
+            for (RenderedImage testData : getTestData()) {
+                ByteArrayOutputStream buffer = new ByteArrayOutputStream();

-            try (ImageOutputStream stream = ImageIO.createImageOutputStream(buffer)) {
-                writer.setOutput(stream);
-                writer.write(drawSomething((BufferedImage) testData));
+                try (ImageOutputStream stream = ImageIO.createImageOutputStream(buffer)) {
+                    writer.setOutput(stream);
+                    writer.write(drawSomething((BufferedImage) testData));
+                }
+                catch (IOException e) {
+                    throw new AssertionError(e.getMessage(), e);
+                }
+
+                assertTrue(buffer.size() > 0, "No image data written");
            }
-            catch (IOException e) {
-                throw new AssertionError(e.getMessage(), e);
+        }
+        finally {
+            writer.dispose();
+        }
+    }
+
+    @Test
+    public void testWriteRaster() throws IOException {
+        ImageWriter writer = createWriter();
+
+        try {
+            if (!writer.canWriteRasters()) {
+                return;
            }

-            assertTrue(buffer.size() > 0, "No image data written");
+            ImageWriteParam param = writer.getDefaultWriteParam();
+
+            for (RenderedImage testData : getTestData()) {
+                ByteArrayOutputStream buffer = new ByteArrayOutputStream();
+
+                try (ImageOutputStream stream = ImageIO.createImageOutputStream(buffer)) {
+                    writer.setOutput(stream);
+
+                    writer.write(null, new IIOImage(testData.getTile(0, 0), null, null), param);
+                }
+                catch (IOException e) {
+                    throw new AssertionError(e.getMessage(), e);
+                }
+
+                assertTrue(buffer.size() > 0, "No image data written");
+            }
+        }
+        finally {
+            writer.dispose();
        }
    }

@@ -0,0 +1,89 @@
+package com.twelvemonkeys.imageio.util;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+
+class SequenceSupportTest {
+    @Test
+    void happyCase() {
+        SequenceSupport sequence = new SequenceSupport();
+
+        sequence.start();
+        assertEquals(0, sequence.current());
+
+        for (int i = 0; i < Byte.MAX_VALUE; i++) {
+            assertEquals(i, sequence.advance());
+            assertEquals(i + 1, sequence.current());
+        }
+
+        assertEquals(127, sequence.end());
+        assertEquals(-1, sequence.current());
+        assertThrows(IllegalStateException.class, sequence::advance);
+    }
+
+    @Test
+    void reset() {
+        SequenceSupport sequence = new SequenceSupport();
+        sequence.reset();
+
+        assertEquals(-1, sequence.current());
+        assertThrows(IllegalStateException.class, sequence::end);
+
+        sequence.start();
+        sequence.reset();
+
+        assertEquals(-1, sequence.current());
+        assertThrows(IllegalStateException.class, sequence::end);
+
+        sequence.start();
+        sequence.advance();
+        sequence.reset();
+
+        assertEquals(-1, sequence.current());
+        assertThrows(IllegalStateException.class, sequence::end);
+
+        sequence.start();
+        sequence.end();
+        sequence.reset();
+
+        assertEquals(-1, sequence.current());
+        assertThrows(IllegalStateException.class, sequence::end);
+    }
+
+    @Test
+    void startEnd() {
+        SequenceSupport sequence = new SequenceSupport();
+        sequence.start();
+        sequence.end();
+
+        assertEquals(-1, sequence.current());
+        assertThrows(IllegalStateException.class, sequence::end);
+    }
+
+    @Test
+    void startAlreadyStarted() {
+        SequenceSupport sequence = new SequenceSupport();
+        sequence.start();
+
+        assertThrows(IllegalStateException.class, sequence::start);
+    }
+
+    @Test
+    void advanceNotStarted() {
+        SequenceSupport sequence = new SequenceSupport();
+        assertThrows(IllegalStateException.class, sequence::advance);
+    }
+
+    @Test
+    void currentNotStarted() {
+        SequenceSupport sequence = new SequenceSupport();
+        assertEquals(-1, sequence.current());
+    }
+
+    @Test
+    void endNotStarted() {
+        SequenceSupport sequence = new SequenceSupport();
+        assertThrows(IllegalStateException.class, sequence::end);
+    }
+}
@@ -4,7 +4,7 @@
    <parent>
        <groupId>com.twelvemonkeys.imageio</groupId>
        <artifactId>imageio</artifactId>
-        <version>3.12.1-SNAPSHOT</version>
+        <version>3.13.2-SNAPSHOT</version>
    </parent>
    <artifactId>imageio-dds</artifactId>
    <name>TwelveMonkeys :: ImageIO :: DDS plugin</name>
@@ -43,6 +43,8 @@
                        <Provide-Capability>
                            osgi.serviceloader;
                            osgi.serviceloader=javax.imageio.spi.ImageReaderSpi
+                            osgi.serviceloader;
+                            osgi.serviceloader=javax.imageio.spi.ImageWriterSpi
                        </Provide-Capability>
                    </instructions>
                </configuration>
@@ -0,0 +1,11 @@
+package com.twelvemonkeys.imageio.plugins.dds;
+
+enum BlockCompression {
+    BC1,
+    BC2,
+    BC3,
+    BC4,
+    BC5,
+//    BC6H,
+//    BC7
+}
@@ -30,22 +30,35 @@

 package com.twelvemonkeys.imageio.plugins.dds;

+
@SuppressWarnings("unused")
 interface DDS {
-    byte[] MAGIC = new byte[]{'D', 'D', 'S', ' '};
+    int MAGIC = 'D' + ('D' << 8) + ('S' << 16) + (' ' << 24); // Little-Endian
+
    int HEADER_SIZE = 124;
+    int PIXELFORMAT_SIZE = 32;

    // Header Flags
-    int FLAG_CAPS = 0x1;              // Required in every .dds file.
-    int FLAG_HEIGHT = 0x2;            // Required in every .dds file.
-    int FLAG_WIDTH = 0x4;             // Required in every .dds file.
-    int FLAG_PITCH = 0x8;             // Required when pitch is provided for an uncompressed texture.
-    int FLAG_PIXELFORMAT = 0x1000;    // Required in every .dds file.
-    int FLAG_MIPMAPCOUNT = 0x20000;   // Required in a mipmapped texture.
-    int FLAG_LINEARSIZE = 0x80000;    // Required when pitch is provided for a compressed texture.
-    int FLAG_DEPTH = 0x800000;        // Required in a depth texture.
+    int FLAG_CAPS = 1;              // Required in every .dds file.
+    int FLAG_HEIGHT = 1 << 1;            // Required in every .dds file.
+    int FLAG_WIDTH = 1 << 2;             // Required in every .dds file.
+    int FLAG_PIXELFORMAT = 1 << 12;    // Required in every .dds file.
+    int FLAG_PITCH = 1 << 3;             // Required when pitch is provided for an uncompressed texture.
+    int FLAG_MIPMAPCOUNT = 1 << 17;   // Required in a mipmapped texture.
+    int FLAG_LINEARSIZE = 1 << 19;    // Required when pitch is provided for a compressed texture.
+    int FLAG_DEPTH = 1 << 23;        // Required in a depth texture.

    // Pixel Format Flags
+    int PIXEL_FORMAT_FLAG_ALPHAPIXELS = 0x1;
+    int PIXEL_FORMAT_FLAG_ALPHA = 0x2;
    int PIXEL_FORMAT_FLAG_FOURCC = 0x04;
    int PIXEL_FORMAT_FLAG_RGB = 0x40;
+
+    //DX10 Resource Dimensions
+    int D3D10_RESOURCE_DIMENSION_TEXTURE2D = 3;
+
+    //dwCaps
+    int DDSCAPS_COMPLEX = 0x8;
+    int DDSCAPS_MIPMAP = 0x400000;
+    int DDSCAPS_TEXTURE = 0x1000;
 }
@@ -30,16 +30,29 @@

 package com.twelvemonkeys.imageio.plugins.dds;

+import static com.twelvemonkeys.imageio.plugins.dds.DDSReader.A1R5G5B5_MASKS;
+import static com.twelvemonkeys.imageio.plugins.dds.DDSReader.A4R4G4B4_MASKS;
+import static com.twelvemonkeys.imageio.plugins.dds.DDSReader.A8B8G8R8_MASKS;
+import static com.twelvemonkeys.imageio.plugins.dds.DDSReader.A8R8G8B8_MASKS;
+import static com.twelvemonkeys.imageio.plugins.dds.DDSReader.R5G6B5_MASKS;
+import static com.twelvemonkeys.imageio.plugins.dds.DDSReader.R8G8B8_MASKS;
+import static com.twelvemonkeys.imageio.plugins.dds.DDSReader.X1R5G5B5_MASKS;
+import static com.twelvemonkeys.imageio.plugins.dds.DDSReader.X4R4G4B4_MASKS;
+import static com.twelvemonkeys.imageio.plugins.dds.DDSReader.X8B8G8R8_MASKS;
+import static com.twelvemonkeys.imageio.plugins.dds.DDSReader.X8R8G8B8_MASKS;
+
 import javax.imageio.IIOException;
 import javax.imageio.stream.ImageInputStream;
 import java.awt.Dimension;
 import java.io.IOException;
-import java.math.BigInteger;
 import java.util.Arrays;

+/**
+ * @see <a href="https://learn.microsoft.com/en-us/windows/win32/direct3ddds/dds-header">DDS_HEADER structure</a>
+ * @see <a href="https://learn.microsoft.com/en-us/windows/win32/direct3ddds/dx-graphics-dds-pguide">Programming Guide for DDS</a>
+ */
 final class DDSHeader {

-    // https://learn.microsoft.com/en-us/windows/win32/direct3ddds/dx-graphics-dds-pguide
    private int flags;

    private int mipMapCount;
@@ -53,19 +66,12 @@ final class DDSHeader {
    private int blueMask;
    private int alphaMask;

+    DXT10Header dxt10Header;
+
    @SuppressWarnings("unused")
    static DDSHeader read(final ImageInputStream imageInput) throws IOException {
        DDSHeader header = new DDSHeader();

-        // Read MAGIC bytes [0,3]
-        byte[] magic = new byte[DDS.MAGIC.length];
-        imageInput.readFully(magic);
-        if (!Arrays.equals(DDS.MAGIC, magic)) {
-            throw new IIOException(String.format("Not a DDS file. Expected DDS magic 0x%08x', read 0x%08x", new BigInteger(DDS.MAGIC), new BigInteger(magic)));
-        }
-
-        // DDS_HEADER structure
-        // https://learn.microsoft.com/en-us/windows/win32/direct3ddds/dds-header
        int dwSize = imageInput.readInt(); // [4,7]
        if (dwSize != DDS.HEADER_SIZE) {
            throw new IIOException(String.format("Invalid DDS header size (expected %d): %d", DDS.HEADER_SIZE, dwSize));
@@ -73,11 +79,9 @@ final class DDSHeader {

        // Verify flags
        header.flags = imageInput.readInt(); // [8,11]
-        if (!header.getFlag(DDS.FLAG_CAPS
-                | DDS.FLAG_HEIGHT
-                | DDS.FLAG_WIDTH
-                | DDS.FLAG_PIXELFORMAT)) {
-            throw new IIOException("Required DDS Flag missing in header: " + Integer.toBinaryString(header.flags));
+        if (!header.hasFlag(DDS.FLAG_CAPS | DDS.FLAG_HEIGHT | DDS.FLAG_WIDTH | DDS.FLAG_PIXELFORMAT)) {
+            // NOTE: The Microsoft DDS documentation mention that readers should not rely on these flags...
+            throw new IIOException("Required DDS flag missing in header: " + Integer.toBinaryString(header.flags));
        }

        // Read Height & Width
@@ -93,11 +97,13 @@ final class DDSHeader {
        // build dimensions list
        header.addDimensions(dwWidth, dwHeight);

-        byte[] dwReserved1 = new byte[11 * 4];  // [32,75]
-        imageInput.readFully(dwReserved1);
+        imageInput.skipBytes(44);

        // DDS_PIXELFORMAT structure
        int px_dwSize = imageInput.readInt(); // [76,79]
+        if (px_dwSize != DDS.PIXELFORMAT_SIZE) {
+            throw new IIOException(String.format("Invalid DDS pixel format structure size (expected %d): %d", DDS.PIXELFORMAT_SIZE, dwSize));
+        }

        header.pixelFormatFlags = imageInput.readInt(); // [80,83]
        header.fourCC = imageInput.readInt(); // [84,87]
@@ -114,6 +120,11 @@ final class DDSHeader {

        int dwReserved2 = imageInput.readInt(); // [124,127]

+        if (header.fourCC == DDSType.DXT10.fourCC()) {
+            // If DXT10, the DXT10 header will follow immediately
+            header.dxt10Header = DXT10Header.read(imageInput);
+        }
+
        return header;
    }

@@ -129,8 +140,8 @@ final class DDSHeader {
        }
    }

-    private boolean getFlag(int mask) {
-        return (flags & mask) != 0;
+    private boolean hasFlag(int mask) {
+        return (flags & mask) == mask;
    }

    int getWidth(int imageIndex) {
@@ -147,31 +158,101 @@ final class DDSHeader {
        return mipMapCount;
    }

-    int getBitCount() {
-        return bitCount;
+    DDSType getType() throws IIOException {
+        if (dxt10Header != null) {
+            return dxt10Header.getType();
+        }
+
+        return getRawType();
    }

-    int getFourCC() {
-        return fourCC;
+    DDSType getRawType() throws IIOException {
+        if ((pixelFormatFlags & DDS.PIXEL_FORMAT_FLAG_FOURCC) != 0) {
+            // DXT
+            return DDSType.fromFourCC(fourCC);
+        }
+        else if ((pixelFormatFlags & DDS.PIXEL_FORMAT_FLAG_RGB) != 0) {
+            // RGB
+            int alphaMask = ((pixelFormatFlags & 0x01) != 0) ? this.alphaMask : 0; // 0x01 alpha
+
+            if (bitCount == 16) {
+                if (redMask == A1R5G5B5_MASKS[0] && greenMask == A1R5G5B5_MASKS[1] && blueMask == A1R5G5B5_MASKS[2] && alphaMask == A1R5G5B5_MASKS[3]) {
+                    // A1R5G5B5
+                    return DDSType.A1R5G5B5;
+                }
+                else if (redMask == X1R5G5B5_MASKS[0] && greenMask == X1R5G5B5_MASKS[1] && blueMask == X1R5G5B5_MASKS[2] && alphaMask == X1R5G5B5_MASKS[3]) {
+                    // X1R5G5B5
+                    return DDSType.X1R5G5B5;
+                }
+                else if (redMask == A4R4G4B4_MASKS[0] && greenMask == A4R4G4B4_MASKS[1] && blueMask == A4R4G4B4_MASKS[2] && alphaMask == A4R4G4B4_MASKS[3]) {
+                    // A4R4G4B4
+                    return DDSType.A4R4G4B4;
+                }
+                else if (redMask == X4R4G4B4_MASKS[0] && greenMask == X4R4G4B4_MASKS[1] && blueMask == X4R4G4B4_MASKS[2] && alphaMask == X4R4G4B4_MASKS[3]) {
+                    // X4R4G4B4
+                    return DDSType.X4R4G4B4;
+                }
+                else if (redMask == R5G6B5_MASKS[0] && greenMask == R5G6B5_MASKS[1] && blueMask == R5G6B5_MASKS[2] && alphaMask == R5G6B5_MASKS[3]) {
+                    // R5G6B5
+                    return DDSType.R5G6B5;
+                }
+
+                throw new IIOException("Unsupported 16bit RGB image.");
+            }
+            else if (bitCount == 24) {
+                if (redMask == R8G8B8_MASKS[0] && greenMask == R8G8B8_MASKS[1] && blueMask == R8G8B8_MASKS[2] && alphaMask == R8G8B8_MASKS[3]) {
+                    // R8G8B8
+                    return DDSType.R8G8B8;
+                }
+
+                throw new IIOException("Unsupported 24bit RGB image.");
+            }
+            else if (bitCount == 32) {
+                if (redMask == A8B8G8R8_MASKS[0] && greenMask == A8B8G8R8_MASKS[1] && blueMask == A8B8G8R8_MASKS[2] && alphaMask == A8B8G8R8_MASKS[3]) {
+                    // A8B8G8R8
+                    return DDSType.A8B8G8R8;
+                }
+                else if (redMask == X8B8G8R8_MASKS[0] && greenMask == X8B8G8R8_MASKS[1] && blueMask == X8B8G8R8_MASKS[2] && alphaMask == X8B8G8R8_MASKS[3]) {
+                    // X8B8G8R8
+                    return DDSType.X8B8G8R8;
+                }
+                else if (redMask == A8R8G8B8_MASKS[0] && greenMask == A8R8G8B8_MASKS[1] && blueMask == A8R8G8B8_MASKS[2] && alphaMask == A8R8G8B8_MASKS[3]) {
+                    // A8R8G8B8
+                    return DDSType.A8R8G8B8;
+                }
+                else if (redMask == X8R8G8B8_MASKS[0] && greenMask == X8R8G8B8_MASKS[1] && blueMask == X8R8G8B8_MASKS[2] && alphaMask == X8R8G8B8_MASKS[3]) {
+                    // X8R8G8B8
+                    return DDSType.X8R8G8B8;
+                }
+
+                throw new IIOException("Unsupported 32bit RGB image.");
+            }
+
+            throw new IIOException("Unsupported bit count: " + bitCount);
+        }
+
+        throw new IIOException("Unsupported YUV or LUMINANCE image.");
    }

-    int getPixelFormatFlags() {
-        return pixelFormatFlags;
+    @Override
+    public String toString() {
+        return "DDSHeader{" +
+            "flags=" + Integer.toBinaryString(flags) +
+            ", mipMapCount=" + mipMapCount +
+            ", dimensions=" + Arrays.toString(Arrays.stream(dimensions)
+                                                    .map(DDSHeader::dimensionToString)
+                                                    .toArray(String[]::new)) +
+            ", pixelFormatFlags=" + Integer.toBinaryString(pixelFormatFlags) +
+            ", fourCC=" + fourCC +
+            ", bitCount=" + bitCount +
+            ", redMask=" + redMask +
+            ", greenMask=" + greenMask +
+            ", blueMask=" + blueMask +
+            ", alphaMask=" + alphaMask +
+            '}';
    }

-    int getRedMask() {
-        return redMask;
-    }
-
-    int getGreenMask() {
-        return greenMask;
-    }
-
-    int getBlueMask() {
-        return blueMask;
-    }
-
-    int getAlphaMask() {
-        return alphaMask;
+    private static String dimensionToString(Dimension dimension) {
+        return String.format("%dx%d", dimension.width, dimension.height);
    }
 }
@@ -0,0 +1,477 @@
+package com.twelvemonkeys.imageio.plugins.dds;
+
+import javax.imageio.stream.ImageOutputStream;
+import java.awt.Color;
+import java.awt.image.Raster;
+import java.io.IOException;
+
+import static com.twelvemonkeys.imageio.plugins.dds.DDSReader.ARGB_ORDER;
+import static com.twelvemonkeys.imageio.plugins.dds.DDSReader.BIT5;
+import static com.twelvemonkeys.imageio.plugins.dds.DDSReader.BIT6;
+import static com.twelvemonkeys.imageio.plugins.dds.DDSReader.RGB_16_ORDER;
+
+/**
+ * A designated class to encode image data to binary.
+ *
+ * @see <a href="https://www.ludicon.com/castano/blog/2009/03/gpu-dxt-decompression/">GPU DXT Decompression</a>.
+ * @see <a href="https://sv-journal.org/2014-1/06/en/index.php">TEXTURE COMPRESSION TECHNIQUES</a>.
+ * @see <a href="https://mrelusive.com/publications/papers/Real-Time-Dxt-Compression.pdf">Real-Time DXT Compression by J.M.P. van Waveren</a>
+ * @see <a href="https://registry.khronos.org/DataFormat/specs/1.4/dataformat.1.4.pdf">Khronos Data Format Specification v1.4 by Andrew Garrard</a>
+ */
+class DDSImageDataEncoder {
+    private DDSImageDataEncoder() {}
+    //A cap for alpha value for BC1 where if alpha value is smaller than this, the 4x4 block will enable alpha mode.
+    private static final int BC1_ALPHA_CAP = 124;
+    private static final int BC4_CHANNEL_RED = 0; //default for BC4.
+    private static final int BC4_CHANNEL_ALPHA = 3; //BC3 reuses algorithm from BC4 but uses alpha channelIndex for sampling.
+    private static final int BC4_CHANNEL_GREEN = 1; //same re-usage as BC3 but for green channel BC5 uses
+
+    static void writeImageData(ImageOutputStream imageOutput, Raster raster, BlockCompression compression) throws IOException {
+        // TODO: Support compression == null for uncompressed RGB(A/X) data?
+
+        switch (compression) {
+            case BC1:
+                new BlockCompressor1(false).encode(imageOutput, raster);
+                break;
+            case BC2:
+                new BlockCompressor2().encode(imageOutput, raster);
+                break;
+            case BC3:
+                new BlockCompressor3().encode(imageOutput, raster);
+                break;
+            case BC4:
+                new BlockCompressor4(BC4_CHANNEL_RED).encode(imageOutput, raster);
+                break;
+            case BC5:
+                new BlockCompressor5().encode(imageOutput, raster);
+                break;
+            default:
+                throw new IllegalArgumentException("DDS block compression is not supported yet: " + compression);
+        }
+    }
+
+    private static class BlockCompressor1 extends BlockCompressorBase {
+        private final boolean forceOpaque;
+        //color0,1 : space 565
+        //color2,3 : space 888
+        private final int[] palettes;
+        private final MutableColor[] color32s;
+
+        private BlockCompressor1(boolean forceOpaque) {
+            super();
+            this.forceOpaque = forceOpaque;
+            palettes = new int[4];
+            color32s = new MutableColor[16];
+            for (int i = 0; i < 16; i++) {
+                color32s[i] = new MutableColor();
+            }
+        }
+
+        //pack 32 bits of the colors to a single int value.
+        private static int color888ToInt(int r, int g, int b, int a) {
+            return (a << ARGB_ORDER.alphaShift) | (r << ARGB_ORDER.redShift) | (g << ARGB_ORDER.greenShift) | (b << ARGB_ORDER.blueShift);
+        }
+
+        void startEncodeBlock(ImageOutputStream imageOutput, int[] sampled) throws IOException {
+            boolean alphaMode = getBlockEndpoints(sampled, palettes);
+            imageOutput.writeShort((short) palettes[0]);
+            imageOutput.writeShort((short) palettes[1]);
+            //simulating color2,3
+            interpolate(alphaMode, palettes);
+            //indices encoding start.
+            int indices = encodeBlockIndices(alphaMode, sampled, palettes);
+            imageOutput.writeInt(indices);
+        }
+
+        //all palettes now in 8:8:8 space
+        int encodeBlockIndices(boolean alphaMode, int[] sampled, int[] palettes) {
+            int i = 0;
+            int colorPos = 0;
+            int indices = 0;
+
+            Color c0 = convertTo888(palettes[0]);
+            Color c1 = convertTo888(palettes[1]);
+            Color c2 = color888ToObject(palettes[2]);
+            Color c3 = color888ToObject(palettes[3]);
+
+            while (i < 64) {
+                Color c = setColorFor(colorPos, sampled[i++], sampled[i++], sampled[i++]);
+                byte index;
+                int a = sampled[i++];
+                if (alphaMode && isAlphaBelowCap(a)) {
+                    index = 0b11;
+                } else {
+                    double distance0 = calculateDistance(c, c0);
+                    double distance1 = calculateDistance(c, c1);
+                    double distance2 = calculateDistance(c, c2);
+                    double distance3 = calculateDistance(c, c3);
+                    index = getClosest(distance0, distance1, distance2, distance3);
+                }
+                indices |= (index << (colorPos * 2));
+                colorPos++;
+            }
+            return indices;
+        }
+
+        private Color setColorFor(int index, int r, int g, int b) {
+            color32s[index].setColor(r, g, b);
+            return color32s[index];
+        }
+
+        //color space 888
+        private static double calculateDistance(Color color1, Color color0) {
+            float r = Math.abs(color0.getRed() - color1.getRed());
+            float g = Math.abs(color0.getGreen() - color1.getGreen());
+            float b = Math.abs(color0.getBlue() - color1.getBlue());
+            return Math.sqrt(r * r + g * g + b * b);
+        }
+
+        private static byte getClosest(double d0, double d1, double d2, double d3) {
+            double min = Math.min(d0, Math.min(d1, Math.min(d2, d3)));
+            if (min == d0) return 0b00;
+            if (min == d1) return 0b01;
+            if (min == d2) return 0b10;
+            return 0b11;
+        }
+
+        //this method, we work in 888 space
+        @SuppressWarnings("DuplicatedCode")
+        //just in case intellij warns for 'duplication'
+        void interpolate(boolean alphaMode, int[] palettes) {
+            Color rgb0 = convertTo888(palettes[0]);
+            Color rgb1 = convertTo888(palettes[1]);
+            int rgb2;
+            int rgb3;
+            if (alphaMode) {
+                //alpha mode
+                int r2 = (rgb0.getRed() + rgb1.getRed()) / 2;
+                int g2 = (rgb0.getGreen() + rgb1.getGreen()) / 2;
+                int b2 = (rgb0.getBlue() + rgb1.getBlue()) / 2;
+                rgb2 = color888ToInt(r2, g2, b2, 0xff);
+                rgb3 = 0;
+            } else {
+                //opaque mode
+                int r2 = (2 * rgb0.getRed() + rgb1.getRed()) / 3;
+                int g2 = (2 * rgb0.getGreen() + rgb1.getGreen()) / 3;
+                int b2 = (2 * rgb0.getBlue() + rgb1.getBlue()) / 3;
+                rgb2 = color888ToInt(r2, g2, b2, 0xff);
+
+                int r3 = (rgb0.getRed() + 2 * rgb1.getRed()) / 3;
+                int g3 = (rgb0.getGreen() + 2 * rgb1.getGreen()) / 3;
+                int b3 = (rgb0.getBlue() + 2 * rgb1.getBlue()) / 3;
+                rgb3 = color888ToInt(r3, g3, b3, 0xff);
+            }
+
+            palettes[2] = rgb2;
+            palettes[3] = rgb3;
+        }
+
+        //this method, we work in 888 space, return color0&1 in 565 space
+        boolean getBlockEndpoints(int[] sampledColors, int[] paletteBuffer) {
+            if (sampledColors.length != 64)
+                throw new IllegalStateException("Unintended behaviour, expecting sampled colors of block to be 64, got " + sampledColors.length);
+            int minR = 0xff;
+            int minG = 0xff;
+            int minB = 0xff;
+
+            int maxR = 0;
+            int maxG = 0;
+            int maxB = 0;
+
+            boolean alphaMode = false;
+            int i = 0;
+            while (i < 64) {
+                int r = sampledColors[i++];
+                int g = sampledColors[i++];
+                int b = sampledColors[i++];
+                int a = sampledColors[i++];
+                if (!forceOpaque && isAlphaBelowCap(a)) {
+                    alphaMode = true;
+                    continue;
+                }
+
+                minR = Math.min(minR, r);
+                minG = Math.min(minG, g);
+                minB = Math.min(minB, b);
+
+                maxR = Math.max(maxR, r);
+                maxG = Math.max(maxG, g);
+                maxB = Math.max(maxB, b);
+            }
+
+            int color0 = convertTo565(maxR, maxG, maxB);
+            int color1 = convertTo565(minR, minG, minB);
+            if ((alphaMode && color0 > color1) || (!alphaMode && color0 < color1)) {
+                paletteBuffer[0] = color1;
+                paletteBuffer[1] = color0;
+            } else {
+                paletteBuffer[0] = color0;
+                paletteBuffer[1] = color1;
+            }
+
+            return alphaMode;
+        }
+
+        //Reference [3] Page 7
+        boolean getBlockEndpoints2(int[] sampled, int[] paletteBuffer) {
+            int maxDistance = -1;
+            boolean alphaMode = false;
+            for (int i = 0; i < 60; i += 4) {
+                for (int j = i + 4; j < 64; j += 4) {
+                    if (!forceOpaque && isAlphaBelowCap(Math.min(sampled[i + 3], sampled[j + 3]))) {
+                        alphaMode = true;
+                        continue;
+                    }
+                    int distance = getColorDistance(sampled[i], sampled[i + 1], sampled[i + 2], sampled[j], sampled[j + 1], sampled[j + 2]);
+                    if (distance > maxDistance) {
+                        maxDistance = distance;
+                        paletteBuffer[0] = convertTo565(sampled[i], sampled[i + 1], sampled[i + 2]);
+                        paletteBuffer[1] = convertTo565(sampled[j], sampled[j + 1], sampled[j + 2]);
+                    }
+                }
+            }
+
+            if ((alphaMode && paletteBuffer[0] > paletteBuffer[1]) || (!alphaMode && paletteBuffer[1] > paletteBuffer[0])) {
+                int a = paletteBuffer[0];
+                paletteBuffer[0] = paletteBuffer[1];
+                paletteBuffer[1] = a;
+            }
+            return alphaMode;
+        }
+
+        private static int getColorDistance(int r1, int g1, int b1, int r2, int g2, int b2) {
+            int r3 = r1 - r2;
+            int g3 = g1 - g2;
+            int b3 = b1 - b2;
+            return r3 * r3 + g3 * g3 + b3 * b3;
+        }
+
+
+        private static Color convertTo888(int c565) {
+            int r8 = BIT5[(c565 & 0xF800) >> 11];
+            int g8 = BIT6[(c565 & 0x07E0) >> 5];
+            int b8 = BIT5[(c565 & 0x001F)];
+            return new Color(r8, g8, b8, 0xff);
+        }
+
+        private static Color color888ToObject(int c888) {
+            return new Color(
+                    (c888 & 0xFF0000) >> ARGB_ORDER.redShift,
+                    (c888 & 0x00FF00) >> ARGB_ORDER.greenShift,
+                    (c888 & 0x0000FF) >> ARGB_ORDER.blueShift,
+                    (c888) >>> ARGB_ORDER.alphaShift
+            );
+        }
+    }
+
+    private static final class BlockCompressor2 extends BlockCompressor1 {
+
+        private BlockCompressor2() {
+            super(true);
+        }
+
+        @Override
+        void startEncodeBlock(ImageOutputStream imageOutput, int[] sampled) throws IOException {
+            //write 64 bit alpha first (4 bit alpha per pixel)
+            long alphaData = 0;
+            for (int i = 0; i < 16; i++) {
+                int alpha = sampled[i * 4 + 3] >> 4;
+                alphaData |= ((long) alpha) << (i * 4);
+            }
+            imageOutput.writeLong(alphaData);
+
+            super.startEncodeBlock(imageOutput, sampled);
+        }
+    }
+
+    private static final class BlockCompressor3 extends BlockCompressor1 {
+        private final BlockCompressor4 bc4;
+
+        private BlockCompressor3() {
+            super(true);
+            bc4 = new BlockCompressor4(BC4_CHANNEL_ALPHA);
+        }
+
+        @Override
+        void startEncodeBlock(ImageOutputStream imageOutput, int[] sampled) throws IOException {
+            bc4.startEncodeBlock(imageOutput, sampled);
+            super.startEncodeBlock(imageOutput, sampled);
+        }
+    }
+
+    private static final class BlockCompressor4 extends BlockCompressorBase {
+        private final int channelIndex;
+        private final int[] reds;
+
+        private BlockCompressor4(int channelIndex) {
+            super();
+            this.channelIndex = channelIndex;
+            this.reds = new int[8];
+        }
+
+        void startEncodeBlock(ImageOutputStream imageOutput, int[] samples) throws IOException {
+            getColorRange(samples, reds);
+            interpolate(reds);
+            long data = calculateIndices(samples, reds);
+            data |= (((long) (reds[1] & 0xff) << 8) | (reds[0] & 0xff));
+            imageOutput.writeLong(data);
+        }
+
+        // 6 bytes MSB will be for indices, the LSB is for the 2 red endpoints,
+        // as we write to file in LE the bytes will be swapped back to the desired order
+        private long calculateIndices(int[] samples, int[] reds) {
+            long data = 0;
+            for (int i = 0; i < 16; i++) {
+                int index;
+                int rSample = samples[i * 4 + channelIndex];
+                index = getNearest(rSample, reds);
+                data |= ((long) index << (16 + i * 3));
+            }
+            return data;
+        }
+
+        private int getNearest(int r, int[] reds) {
+            int nearest = 0;
+            int nearestValue = 255;
+            for (int i = 0; i < 8; i++) {
+                int v = Math.abs(r - reds[i]);
+                if (nearestValue > v) {
+                    nearest = i;
+                    nearestValue = v;
+                }
+            }
+            return nearest;
+        }
+
+        private void interpolate(int[] reds) {
+            int r0 = reds[0];
+            int r1 = reds[1];
+            for (int i = 0; i < 8; i++) {
+                reds[i] = DDSReader.getDXT5Alpha(r0, r1, i);
+            }
+        }
+
+        //r0 >  r1 : use 6 interpolated color values
+        //r0 <= r1 : use 4
+        private void getColorRange(int[] samples, int[] red01) {
+            int r0 = 0;
+            int r1 = 255;
+            for (int i = 0; i < 16; i++) {
+                int r = samples[i * 4 + channelIndex];
+                r0 = Math.max(r0, r);
+                r1 = Math.min(r1, r);
+            }
+            red01[0] = r0;
+            red01[1] = r1;
+        }
+    }
+
+    private static final class BlockCompressor5 extends BlockCompressorBase {
+        private final BlockCompressor4 bc4r;
+        private final BlockCompressor4 bc4g;
+
+        public BlockCompressor5() {
+            bc4r = new BlockCompressor4(BC4_CHANNEL_RED);
+            bc4g = new BlockCompressor4(BC4_CHANNEL_GREEN);
+        }
+
+        @Override
+        void startEncodeBlock(ImageOutputStream imageOutput, int[] samples) throws IOException {
+            bc4r.startEncodeBlock(imageOutput, samples);
+            bc4g.startEncodeBlock(imageOutput, samples);
+        }
+    }
+
+    //https://rgbcolorpicker.com/565
+    //pack 32 bits color into a single 5:6:5 16bits value
+    static int convertTo565(int r8, int g8, int b8) {
+        int r5 = (r8 >> 3);
+        int g6 = (g8 >> 2);
+        int b5 = (b8 >> 3);
+        return color565ToInt(r5, g6, b5);
+    }
+
+    //pack 16 bits of the colors to a single int value.
+    private static int color565ToInt(int r5, int g6, int b5) {
+        return (r5 << RGB_16_ORDER.redShift) | (g6 << RGB_16_ORDER.greenShift) | (b5 << RGB_16_ORDER.blueShift);
+    }
+
+    private abstract static class BlockCompressorBase {
+        final int[] samples;
+
+        BlockCompressorBase() {
+            this.samples = new int[64];
+        }
+
+        //workaround for 24 dpi (no alpha) -> 32dpi (with alpha default to 0xff)
+        //as this mess the color0 & color1 up spectacularly bc alpha is not present in 24dpi
+        private static void adjustSampledBands(Raster raster, int[] samples) {
+            if (raster.getNumBands() == 4) return;
+            for (int i = 15; i >= 0; i--) {
+                int r24Index = i * 3;
+                int r32Index = i * 4;
+                samples[r32Index + 3] = 0xFF;
+                samples[r32Index + 2] = samples[r24Index + 2];  //b24 -> b32
+                samples[r32Index + 1] = samples[r24Index + 1];  //g24 -> g32
+                samples[r32Index] = samples[r24Index];      //r24 -> r32
+            }
+        }
+
+        void encode(ImageOutputStream imageOutput, Raster raster) throws IOException {
+            int blocksXCount = (raster.getWidth() + 3) / 4;
+            int blocksYCount = (raster.getHeight() + 3) / 4;
+
+            for (int blockY = 0; blockY < blocksYCount; blockY++) {
+                for (int blockX = 0; blockX < blocksXCount; blockX++) {
+                    raster.getPixels(blockX * 4, blockY * 4, 4, 4, samples);
+                    adjustSampledBands(raster, samples);
+                    startEncodeBlock(imageOutput, samples);
+                }
+            }
+        }
+
+        boolean isAlphaBelowCap(int alpha) {
+            return alpha < BC1_ALPHA_CAP;
+        }
+
+        abstract void startEncodeBlock(ImageOutputStream imageOutput, int[] samples) throws IOException;
+    }
+
+    private static final class MutableColor extends Color {
+
+        int mutableValue;
+
+        public MutableColor() {
+            super(0, 0, 0);
+            this.mutableValue = 0;
+        }
+
+        void setColor(int red, int green, int blue) {
+            mutableValue = red << ARGB_ORDER.redShift;
+            mutableValue |= green << ARGB_ORDER.greenShift;
+            mutableValue |= blue << ARGB_ORDER.blueShift;
+        }
+
+        @Override
+        public int getRGB() {
+            return this.mutableValue;
+        }
+
+        //intellij generated
+        @Override
+        public boolean equals(Object object) {
+            if (!(object instanceof MutableColor)) return false;
+            if (!super.equals(object)) return false;
+
+            MutableColor that = (MutableColor) object;
+            return mutableValue == that.mutableValue;
+        }
+
+        @Override
+        public int hashCode() {
+            int result = super.hashCode();
+            result = 31 * result + mutableValue;
+            return result;
+        }
+    }
+}
@@ -30,29 +30,51 @@

 package com.twelvemonkeys.imageio.plugins.dds;

-import javax.imageio.ImageTypeSpecifier;
-
 import com.twelvemonkeys.imageio.StandardImageMetadataSupport;

-final class DDSMetadata extends StandardImageMetadataSupport {
-    DDSMetadata(ImageTypeSpecifier type, DDSHeader header) {
-        super(builder(type)
-                      .withCompressionTypeName(compressionName(header))
-                      .withFormatVersion("1.0")
+import javax.imageio.ImageTypeSpecifier;
+
+final class DDSImageMetadata extends StandardImageMetadataSupport {
+
+    DDSImageMetadata(ImageTypeSpecifier specifier, DDSType type) {
+        super(builder(specifier)
+            .withCompressionTypeName(compressionName(type))
+            .withCompressionLossless(!type.isBlockCompression())
+            .withBitsPerSample(bitsPerSample(type))
+            .withFormatVersion("1.0")
        );
    }

-    private static String compressionName(DDSHeader header) {
-        // If the fourCC is valid, compression is one of the DXTn versions, otherwise None
-        int flags = header.getPixelFormatFlags();
-
-        if ((flags & DDS.PIXEL_FORMAT_FLAG_FOURCC) != 0) {
-            // DXTn
-            DDSType type = DDSType.valueOf(header.getFourCC());
-
+    private static String compressionName(DDSType type) {
+        if (type != null && type.isFourCC()) {
            return type.name();
        }

        return "None";
    }
+
+    private static int[] bitsPerSample(DDSType type) {
+        if (type.isBlockCompression()) {
+            return null; // Use defaults
+        }
+
+        int[] bitsPerSample = new int[4];
+
+        for (int i = 0; i < bitsPerSample.length; i++) {
+            bitsPerSample[i] = countMaskBits(type.rgbaMasks[i]);
+        }
+
+        return bitsPerSample;
+    }
+
+    private static int countMaskBits(int mask) {
+        // See https://graphics.stanford.edu/~seander/bithacks.html#CountBitsSetKernighan
+        int count;
+
+        for (count = 0; mask != 0; count++) {
+            mask &= mask - 1; // clear the least significant bit set
+        }
+
+        return count;
+    }
 }
@@ -30,18 +30,16 @@

 package com.twelvemonkeys.imageio.plugins.dds;

-import static com.twelvemonkeys.imageio.util.IIOUtil.subsampleRow;
-
 import com.twelvemonkeys.imageio.ImageReaderBase;
 import com.twelvemonkeys.imageio.util.ImageTypeSpecifiers;

+import javax.imageio.IIOException;
 import javax.imageio.ImageIO;
 import javax.imageio.ImageReadParam;
 import javax.imageio.ImageTypeSpecifier;
 import javax.imageio.metadata.IIOMetadata;
 import javax.imageio.spi.ImageReaderSpi;
-
-import java.awt.*;
+import java.awt.Rectangle;
 import java.awt.image.BufferedImage;
 import java.io.File;
 import java.io.IOException;
@@ -49,6 +47,14 @@ import java.nio.ByteOrder;
 import java.util.Collections;
 import java.util.Iterator;

+import static com.twelvemonkeys.imageio.util.IIOUtil.subsampleRow;
+
+/**
+ * ImageReader implementation for Microsoft DirectDraw Surface (DDS) format.
+ *
+ * @author Paul Allen
+ * @author <a href="mailto:harald.kuhr@gmail.com">Harald Kuhr</a>
+ */
 public final class DDSImageReader extends ImageReaderBase {

    private DDSHeader header;
@@ -91,7 +97,16 @@ public final class DDSImageReader extends ImageReaderBase {
        checkBounds(imageIndex);
        readHeader();

-        // TODO: Implement for the specific formats...
+        DDSType type = header.getType();
+        if (!type.isBlockCompression() && type.rgbaMasks[3] == 0) {
+            return ImageTypeSpecifiers.createFromBufferedImageType(BufferedImage.TYPE_INT_RGB);
+        }
+
+        // TODO: DXT1 can have 1 bit alpha, usually don't...
+        //  DXT3/5 have alpha
+        //  DXT2/4 ...?
+
+
        return ImageTypeSpecifiers.createFromBufferedImageType(BufferedImage.TYPE_INT_ARGB);
    }

@@ -147,14 +162,19 @@ public final class DDSImageReader extends ImageReaderBase {
    public IIOMetadata getImageMetadata(int imageIndex) throws IOException {
        ImageTypeSpecifier imageType = getRawImageType(imageIndex);

-        return new DDSMetadata(imageType, header);
+        return new DDSImageMetadata(imageType, header.getType());
    }

    private void readHeader() throws IOException {
        if (header == null) {
            imageInput.setByteOrder(ByteOrder.LITTLE_ENDIAN);
-            header = DDSHeader.read(imageInput);

+            int magic = imageInput.readInt();
+            if (magic != DDS.MAGIC) {
+                throw new IIOException(String.format("Not a DDS file. Expected DDS magic 0x%8x', read 0x%8x", DDS.MAGIC, magic));
+            }
+
+            header = DDSHeader.read(imageInput);
            imageInput.flushBefore(imageInput.getStreamPosition());
        }

@@ -35,7 +35,7 @@ import com.twelvemonkeys.imageio.spi.ImageReaderSpiBase;
 import javax.imageio.ImageReader;
 import javax.imageio.stream.ImageInputStream;
 import java.io.IOException;
-import java.util.Arrays;
+import java.nio.ByteOrder;
 import java.util.Locale;

 public final class DDSImageReaderSpi extends ImageReaderSpiBase {
@@ -53,13 +53,15 @@ public final class DDSImageReaderSpi extends ImageReaderSpiBase {
        ImageInputStream stream = (ImageInputStream) source;

        stream.mark();
+        ByteOrder byteOrder = stream.getByteOrder();

        try {
-            byte[] magic = new byte[DDS.MAGIC.length];
-            stream.readFully(magic);
+            stream.setByteOrder(ByteOrder.LITTLE_ENDIAN);

-            return Arrays.equals(DDS.MAGIC, magic);
-        } finally {
+            return stream.readInt() == DDS.MAGIC;
+        }
+        finally {
+            stream.setByteOrder(byteOrder);
            stream.reset();
        }
    }
@@ -71,6 +73,6 @@ public final class DDSImageReaderSpi extends ImageReaderSpiBase {

    @Override
    public String getDescription(Locale locale) {
-        return "Direct DrawSurface (DDS) Image Reader";
+        return "DirectDraw Surface (DDS) Image Reader";
    }
 }
@@ -0,0 +1,62 @@
+package com.twelvemonkeys.imageio.plugins.dds;
+
+import javax.imageio.ImageWriteParam;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Collectors;
+
+public final class DDSImageWriteParam extends ImageWriteParam {
+
+    static final DDSType DEFAULT_TYPE = DDSType.DXT5;
+    private static final String[] COMPRESSION_TYPES = compressionTypes();
+
+    private static String[] compressionTypes() {
+        // TODO: Maybe hardcode subset of values that we actually support writing?
+        List<String> compressionTypes = Arrays.stream(DDSType.values())
+            .filter(DDSType::isBlockCompression)
+            .map(Enum::name)
+            .collect(Collectors.toList());
+        compressionTypes.add(0, "None");
+
+        return compressionTypes.toArray(new String[0]);
+    }
+
+    private boolean writeDXT10;
+
+    DDSImageWriteParam() {
+        canWriteCompressed = true;
+        compressionTypes = COMPRESSION_TYPES;
+        compressionType = DEFAULT_TYPE.name();
+    }
+
+    public void setWriteDX10() {
+        writeDXT10 = true;
+    }
+
+    public void clearWriteDX10() {
+        writeDXT10 = false;
+    }
+
+    public boolean isWriteDXT10() {
+        return writeDXT10;
+    }
+
+    DDSType type() {
+        if (compressionType == null || compressionType.equals("None")) {
+            return null;
+        }
+
+        return DDSType.valueOf(compressionType);
+    }
+
+    int getDxgiFormat() {
+        DDSType type = type();
+
+        if (type != null) {
+            return type.dxgiFormat();
+        }
+
+        return DXGI.DXGI_FORMAT_UNKNOWN;
+    }
+}
@@ -0,0 +1,330 @@
+package com.twelvemonkeys.imageio.plugins.dds;
+
+import com.twelvemonkeys.imageio.ImageWriterBase;
+import com.twelvemonkeys.imageio.util.IIOUtil;
+import com.twelvemonkeys.imageio.util.SequenceSupport;
+
+import javax.imageio.IIOException;
+import javax.imageio.IIOImage;
+import javax.imageio.ImageIO;
+import javax.imageio.ImageTypeSpecifier;
+import javax.imageio.ImageWriteParam;
+import javax.imageio.metadata.IIOMetadata;
+import javax.imageio.spi.ImageWriterSpi;
+import javax.imageio.stream.MemoryCacheImageOutputStream;
+
+import java.awt.Dimension;
+import java.awt.image.Raster;
+import java.awt.image.RenderedImage;
+import java.io.File;
+import java.io.IOException;
+import java.nio.ByteOrder;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+
+/**
+ * ImageWriter implementation for Microsoft DirectDraw Surface (DDS) format.
+ *
+ * @author KhanTypo
+ * @author <a href="mailto:harald.kuhr@gmail.com">Harald Kuhr</a>
+ */
+class DDSImageWriter extends ImageWriterBase {
+
+    private final SequenceSupport mipmapSequence = new SequenceSupport();
+
+    private long headerStartPos;
+    private DDSType mipmapType;
+    private Dimension mipmapDimension;
+
+    protected DDSImageWriter(ImageWriterSpi provider) {
+        super(provider);
+    }
+
+    @Override
+    public DDSImageWriteParam getDefaultWriteParam() {
+        return new DDSImageWriteParam();
+    }
+
+    @Override
+    protected void resetMembers() {
+        headerStartPos = 0;
+        mipmapSequence.reset();
+        mipmapType = null;
+        mipmapDimension = null;
+    }
+
+    @Override
+    public boolean canWriteRasters() {
+        return true;
+    }
+
+    @Override
+    public boolean canWriteSequence() {
+        return true;
+    }
+
+    @Override
+    public void prepareWriteSequence(IIOMetadata streamMetadata) throws IOException {
+        assertOutput();
+        mipmapSequence.start();
+
+        imageOutput.setByteOrder(ByteOrder.LITTLE_ENDIAN);
+        imageOutput.writeInt(DDS.MAGIC);
+        imageOutput.flush();
+
+        headerStartPos = imageOutput.getStreamPosition();
+    }
+
+    @Override
+    public void endWriteSequence() throws IOException {
+        int mipmapCount = mipmapSequence.end();
+
+        // Go back and update header
+        updateHeader(mipmapCount);
+
+        mipmapType = null;
+        mipmapDimension = null;
+
+        imageOutput.flush();
+    }
+
+    @Override
+    public void write(IIOMetadata streamMetadata, IIOImage image, ImageWriteParam param) throws IOException {
+        prepareWriteSequence(streamMetadata);
+        writeToSequence(image, param);
+        endWriteSequence();
+    }
+
+    @Override
+    public void writeToSequence(IIOImage image, ImageWriteParam param) throws IOException {
+        int mipmapIndex = mipmapSequence.advance();
+
+        Raster raster = getRaster(image);
+        ensureImageChannels(raster);
+        ensureTextureDimension(raster);
+        mipmapDimension = new Dimension(raster.getWidth(), raster.getHeight());
+
+        DDSImageWriteParam ddsParam = param instanceof DDSImageWriteParam
+            ? ((DDSImageWriteParam) param)
+            : IIOUtil.copyStandardParams(param, getDefaultWriteParam());
+
+        DDSType type = ddsParam.type();
+        if (mipmapType == null) {
+            mipmapType = type;
+        }
+        else if (type != mipmapType) {
+            processWarningOccurred(mipmapIndex, "All images in DDS mipmap must use same pixel format and compression");
+        }
+        if (mipmapType == null) {
+            throw new IIOException("Only compressed DDS using DXT1-5 or DXT10 with block compression is currently supported");
+        }
+
+        if (mipmapIndex == 0) {
+            writeHeader(raster.getWidth(), raster.getHeight(), mipmapType, ddsParam.isWriteDXT10());
+            if (ddsParam.isWriteDXT10()) {
+                writeDXT10Header(ddsParam.getDxgiFormat());
+            }
+        }
+
+        processImageStarted(mipmapIndex);
+        processImageProgress(0f);
+
+        DDSImageDataEncoder.writeImageData(imageOutput, raster, mipmapType.compression);
+
+        processImageProgress(100f);
+        processImageComplete();
+    }
+
+    private static Raster getRaster(IIOImage image) throws IIOException {
+        if (image.hasRaster()) {
+            return image.getRaster();
+        }
+        else {
+            RenderedImage renderedImage = image.getRenderedImage();
+
+            if (renderedImage.getNumXTiles() != 1 || renderedImage.getNumYTiles() != 1) {
+                throw new IIOException("Only single tile images supported");
+            }
+
+            return renderedImage.getTile(0, 0);
+        }
+    }
+
+    /**
+     * Checking if the image has 3 channels (RGB) or 4 channels (RGBA) and if image has 8 bits/channel.
+     *
+     * @see DDSImageWriterSpi#canEncodeImage(ImageTypeSpecifier)
+     */
+    private void ensureImageChannels(Raster data) throws IIOException {
+        int numBands = data.getNumBands();
+        if (numBands < 3 || numBands > 4) {
+            throw new IIOException(
+                "Only image with 3 channels (RGB) or 4 channels (RGBA) is supported, got " + numBands + " channels");
+        }
+
+        int sampleSize = data.getSampleModel().getSampleSize(0);
+        if (sampleSize != 8) {
+            throw new IIOException("Only image with 8 bits/channel is supported, got " + sampleSize);
+        }
+    }
+
+    /**
+     * Checking if an image can be evenly divided into blocks of 4x4, ideally a power of 2.
+     * e.g. 16x16, 32x32, 512x128, 512x512, 1024x512, 1024x1024, 2048x1024...
+     */
+    private void ensureTextureDimension(Raster raster) throws IIOException {
+        int width = raster.getWidth();
+        int height = raster.getHeight();
+
+        // Should also allow mipmaps 2x2 and 1x1?
+        if (width % 4 != 0 || height % 4 != 0) {
+            throw new IIOException(String.format("Image dimensions must be dividable by 4, ideally a power of 2; got %dx%d", width, height));
+        }
+
+        if (mipmapDimension != null && (mipmapDimension.width != width * 2|| mipmapDimension.height != height * 2)) {
+            throw new IIOException(
+                String.format("For mipmap, image dimensions must be exactly half of previous (%dx%d); got %dx%d",
+                mipmapDimension.width, mipmapDimension.height, width, height)
+            );
+        }
+    }
+
+    private void writeHeader(int width, int height, DDSType type, boolean writeDXT10) throws IOException {
+        imageOutput.writeInt(DDS.HEADER_SIZE);
+        int linearSizeOrPitch = type.isBlockCompression() ? DDS.FLAG_LINEARSIZE : DDS.FLAG_PITCH;
+        imageOutput.writeInt(DDS.FLAG_CAPS | DDS.FLAG_HEIGHT | DDS.FLAG_WIDTH | DDS.FLAG_PIXELFORMAT | linearSizeOrPitch);
+
+        imageOutput.writeInt(height);
+        imageOutput.writeInt(width);
+        writePitchOrLinearSize(height, width, type);
+        //dwDepth
+        imageOutput.writeInt(0);
+        //dwMipmapCount
+        imageOutput.writeInt(1); // Should probably write 0 here for non-mipmap?
+        //reserved
+        imageOutput.write(new byte[44]);
+        //pixFmt
+        writePixelFormat(type, writeDXT10);
+        //dwCaps, right now we keep it simple by only using DDSCAP_TEXTURE as it is required.
+        imageOutput.writeInt(DDS.DDSCAPS_TEXTURE);
+        //dwCaps2, unused for now as we are not working with cube maps
+        imageOutput.writeInt(0);
+        //dwCaps3, dwCaps4, dwReserved2 : 3 unused integers
+        imageOutput.write(new byte[12]);
+    }
+
+    private void updateHeader(int mipmapCount) throws IOException {
+        if (mipmapCount == 1) {
+            // Fast case, nothing to do
+            return;
+        }
+
+        long streamPosition = imageOutput.getStreamPosition();
+        imageOutput.seek(headerStartPos + 4); // Seek back to header start, skip 4 byte header size
+
+        int flags = imageOutput.readInt();
+        imageOutput.seek(imageOutput.getStreamPosition() - 4);
+        imageOutput.writeInt(flags | DDS.FLAG_MIPMAPCOUNT);
+
+        imageOutput.seek(imageOutput.getStreamPosition() + 16);
+        imageOutput.writeInt(mipmapCount);
+
+        imageOutput.seek(streamPosition); // Restore pos
+    }
+
+    //https://learn.microsoft.com/en-us/windows/win32/direct3ddds/dds-pixelformat
+    private void writePixelFormat(DDSType type, boolean writeDXT10) throws IOException {
+        imageOutput.writeInt(DDS.PIXELFORMAT_SIZE);
+        writePixelFormatFlags(type, writeDXT10);
+        writeFourCC(type, writeDXT10);
+        writeRGBAData(type, writeDXT10);
+    }
+
+    private void writeDXT10Header(int dxgiFormat) throws IOException {
+        //dxgiFormat
+        imageOutput.writeInt(dxgiFormat);
+        //resourceDimension
+        imageOutput.writeInt(DDS.D3D10_RESOURCE_DIMENSION_TEXTURE2D);
+        //miscFlag
+        imageOutput.writeInt(0);
+        //arraySize
+        imageOutput.writeInt(1);
+        //miscFlag2
+        imageOutput.writeInt(0);
+    }
+
+    private void writeRGBAData(DDSType type, boolean writeDXT10) throws IOException {
+        if (!writeDXT10 && !type.isFourCC()) {
+            //dwRGBBitCount
+            imageOutput.writeInt(type.blockSize() * 8); // TODO: Is bitcount always a multiple of 8?
+
+            //dwRBitMask
+            imageOutput.writeInt(type.rgbaMasks[0]);
+            //dwGBitMask
+            imageOutput.writeInt(type.rgbaMasks[1]);
+            //dwBBitMask
+            imageOutput.writeInt(type.rgbaMasks[2]);
+            //dwABitMask
+            imageOutput.writeInt(type.rgbaMasks[3]);
+        }
+        else {
+            //write 5 zero integers as fourCC is used
+            imageOutput.write(new byte[20]);
+        }
+    }
+
+    private void writeFourCC(DDSType type, boolean writeDXT10) throws IOException {
+        if (writeDXT10) {
+            imageOutput.writeInt(DDSType.DXT10.fourCC());
+        }
+        else if (type.isFourCC()) {
+            imageOutput.writeInt(type.fourCC());
+        }
+        else {
+            // No fourCC, custom format...
+            imageOutput.writeInt(0);
+        }
+    }
+
+    private void writePixelFormatFlags(DDSType type, boolean writeDXT10) throws IOException {
+        if (writeDXT10 || type.isFourCC()) {
+            imageOutput.writeInt(DDS.PIXEL_FORMAT_FLAG_FOURCC);
+        }
+        else {
+            imageOutput.writeInt(DDS.PIXEL_FORMAT_FLAG_RGB
+                | (type.rgbaMasks != null && type.rgbaMasks[3] != 0 ? DDS.PIXEL_FORMAT_FLAG_ALPHAPIXELS : 0));
+        }
+    }
+
+    private void writePitchOrLinearSize(int height, int width, DDSType type) throws IOException {
+        if (type.isBlockCompression()) {
+            imageOutput.writeInt(((width + 3) / 4) * ((height + 3) / 4) * type.blockSize());
+        }
+        else {
+            imageOutput.writeInt(width * type.blockSize());
+        }
+    }
+
+    @Override
+    public IIOMetadata getDefaultImageMetadata(ImageTypeSpecifier imageType, ImageWriteParam param) {
+        DDSType type = param instanceof DDSImageWriteParam
+            ? ((DDSImageWriteParam) param).type()
+            : DDSImageWriteParam.DEFAULT_TYPE;
+
+        return new DDSImageMetadata(imageType, type);
+    }
+
+    @Override
+    public IIOMetadata convertImageMetadata(IIOMetadata inData, ImageTypeSpecifier imageType, ImageWriteParam param) {
+        // Nothing useful to convert here...
+        return getDefaultImageMetadata(imageType, param);
+    }
+
+    public static void main(String[] args) throws IOException {
+        if (args.length != 1) {
+            throw new IllegalArgumentException("Use 1 input file at a time.");
+        }
+
+        ImageIO.write(ImageIO.read(new File(args[0])), "dds", new MemoryCacheImageOutputStream(Files.newOutputStream(Paths.get("output.dds"))));
+    }
+}
@@ -0,0 +1,34 @@
+package com.twelvemonkeys.imageio.plugins.dds;
+
+import com.twelvemonkeys.imageio.spi.ImageWriterSpiBase;
+
+import javax.imageio.ImageTypeSpecifier;
+import javax.imageio.ImageWriter;
+
+import java.util.Locale;
+
+public final class DDSImageWriterSpi extends ImageWriterSpiBase {
+    public DDSImageWriterSpi() {
+        super(new DDSProviderInfo());
+    }
+
+    @Override
+    public boolean canEncodeImage(ImageTypeSpecifier type) {
+        int numBands = type.getNumBands();
+        if (numBands < 3 || numBands > 4) {
+            return false;
+        }
+
+        return type.getSampleModel().getSampleSize(0) == 8;
+    }
+
+    @Override
+    public ImageWriter createWriterInstance(Object extension) {
+        return new DDSImageWriter(this);
+    }
+
+    @Override
+    public String getDescription(Locale locale) {
+        return "DirectDraw Surface (DDS) Image Writer";
+    }
+}
@@ -35,16 +35,16 @@ import com.twelvemonkeys.imageio.spi.ReaderWriterProviderInfo;
 final class DDSProviderInfo extends ReaderWriterProviderInfo {
    DDSProviderInfo() {
        super(
-                DDSProviderInfo.class,
-                new String[]{"DDS", "dds"},
-                new String[]{"dds"},
-                new String[]{"image/vnd-ms.dds"},
-                "com.twelvemonkeys.imageio.plugins.dds.DDSImageReader",
-                new String[]{"com.twelvemonkeys.imageio.plugins.dds.DDSImageReaderSpi"},
-                null,
-                null,
-                false, null, null, null, null,
-                true, null, null, null, null
+            DDSProviderInfo.class,
+            new String[] { "DDS", "dds" },
+            new String[] { "dds" },
+            new String[] { "image/vnd-ms.dds" },
+            "com.twelvemonkeys.imageio.plugins.dds.DDSImageReader",
+            new String[] { "com.twelvemonkeys.imageio.plugins.dds.DDSImageReaderSpi" },
+            "com.twelvemonkeys.imageio.plugins.dds.DDSImageWriter",
+            new String[] { "com.twelvemonkeys.imageio.plugins.dds.DDSImageWriterSpi" },
+            false, null, null, null, null,
+            true, null, null, null, null
        );
    }
 }
@@ -70,8 +70,8 @@ import java.io.IOException;
 * <a href="http://3dtech.jp/wiki/index.php?DDSReader">Japanese document</a>
 */
 final class DDSReader {
-
-    static final Order ARGB_ORDER = new Order(16, 8, 0, 24);
+    static final Order ARGB_ORDER = new Order(16, 8, 0, 24);   //  8 alpha | 8 red | 8 green | 8 blue
+    static final Order RGB_16_ORDER = new Order(11, 5, 0, -1); // no alpha | 5 red | 6 green | 5 blue

    private final DDSHeader header;

@@ -80,16 +80,21 @@ final class DDSReader {
    }

    int[] read(ImageInputStream imageInput, int imageIndex) throws IOException {
-
        // type
-        DDSType type = getType();
+        DDSType type = header.getType();

        // offset buffer to index mipmap image
        byte[] buffer = null;
        for (int i = 0; i <= imageIndex; i++) {
-            int len = getLength(type, i);
-            buffer = new byte[len];
-            imageInput.readFully(buffer);
+            int len = getBufferLength(type, i);
+
+            if (i == imageIndex) {
+                buffer = new byte[len];
+                imageInput.readFully(buffer);
+            }
+            else {
+                imageInput.seek(imageInput.getStreamPosition() + len);
+            }
        }

        int width = header.getWidth(imageIndex);
@@ -131,83 +136,17 @@ final class DDSReader {
        }
    }

-    private DDSType getType() throws IIOException {
-        int flags = header.getPixelFormatFlags();
-
-        if ((flags & DDS.PIXEL_FORMAT_FLAG_FOURCC) != 0) {
-            // DXT
-            int type = header.getFourCC();
-            return DDSType.valueOf(type);
-
-        } else if ((flags & DDS.PIXEL_FORMAT_FLAG_RGB) != 0) {
-            // RGB
-            int bitCount = header.getBitCount();
-            int redMask = header.getRedMask();
-            int greenMask = header.getGreenMask();
-            int blueMask = header.getBlueMask();
-            int alphaMask = ((flags & 0x01) != 0) ? header.getAlphaMask() : 0; // 0x01 alpha
-            if (bitCount == 16) {
-                if (redMask == A1R5G5B5_MASKS[0] && greenMask == A1R5G5B5_MASKS[1] && blueMask == A1R5G5B5_MASKS[2] && alphaMask == A1R5G5B5_MASKS[3]) {
-                    // A1R5G5B5
-                    return DDSType.A1R5G5B5;
-                } else if (redMask == X1R5G5B5_MASKS[0] && greenMask == X1R5G5B5_MASKS[1] && blueMask == X1R5G5B5_MASKS[2] && alphaMask == X1R5G5B5_MASKS[3]) {
-                    // X1R5G5B5
-                    return DDSType.X1R5G5B5;
-                } else if (redMask == A4R4G4B4_MASKS[0] && greenMask == A4R4G4B4_MASKS[1] && blueMask == A4R4G4B4_MASKS[2] && alphaMask == A4R4G4B4_MASKS[3]) {
-                    // A4R4G4B4
-                    return DDSType.A4R4G4B4;
-                } else if (redMask == X4R4G4B4_MASKS[0] && greenMask == X4R4G4B4_MASKS[1] && blueMask == X4R4G4B4_MASKS[2] && alphaMask == X4R4G4B4_MASKS[3]) {
-                    // X4R4G4B4
-                    return DDSType.X4R4G4B4;
-                } else if (redMask == R5G6B5_MASKS[0] && greenMask == R5G6B5_MASKS[1] && blueMask == R5G6B5_MASKS[2] && alphaMask == R5G6B5_MASKS[3]) {
-                    // R5G6B5
-                    return DDSType.R5G6B5;
-                } else {
-                    throw new IIOException("Unsupported 16bit RGB image.");
-                }
-            } else if (bitCount == 24) {
-                if (redMask == R8G8B8_MASKS[0] && greenMask == R8G8B8_MASKS[1] && blueMask == R8G8B8_MASKS[2] && alphaMask == R8G8B8_MASKS[3]) {
-                    // R8G8B8
-                    return DDSType.R8G8B8;
-                } else {
-                    throw new IIOException("Unsupported 24bit RGB image.");
-                }
-            } else if (bitCount == 32) {
-                if (redMask == A8B8G8R8_MASKS[0] && greenMask == A8B8G8R8_MASKS[1] && blueMask == A8B8G8R8_MASKS[2] && alphaMask == A8B8G8R8_MASKS[3]) {
-                    // A8B8G8R8
-                    return DDSType.A8B8G8R8;
-                } else if (redMask == X8B8G8R8_MASKS[0] && greenMask == X8B8G8R8_MASKS[1] && blueMask == X8B8G8R8_MASKS[2] && alphaMask == X8B8G8R8_MASKS[3]) {
-                    // X8B8G8R8
-                    return DDSType.X8B8G8R8;
-                } else if (redMask == A8R8G8B8_MASKS[0] && greenMask == A8R8G8B8_MASKS[1] && blueMask == A8R8G8B8_MASKS[2] && alphaMask == A8R8G8B8_MASKS[3]) {
-                    // A8R8G8B8
-                    return DDSType.A8R8G8B8;
-                } else if (redMask == X8R8G8B8_MASKS[0] && greenMask == X8R8G8B8_MASKS[1] && blueMask == X8R8G8B8_MASKS[2] && alphaMask == X8R8G8B8_MASKS[3]) {
-                    // X8R8G8B8
-                    return DDSType.X8R8G8B8;
-                } else {
-                    throw new IIOException("Unsupported 32bit RGB image.");
-                }
-            } else {
-                throw new IIOException("Unsupported bit count: " + bitCount);
-            }
-        } else {
-            throw new IIOException("Unsupported YUV or LUMINANCE image.");
-        }
-    }
-
-    private int getLength(DDSType type, int imageIndex) throws IIOException {
+    private int getBufferLength(DDSType type, int imageIndex) throws IIOException {
        int width = header.getWidth(imageIndex);
        int height = header.getHeight(imageIndex);

        switch (type) {
            case DXT1:
-                return 8 * ((width + 3) / 4) * ((height + 3) / 4);
            case DXT2:
            case DXT3:
            case DXT4:
            case DXT5:
-                return 16 * ((width + 3) / 4) * ((height + 3) / 4);
+                return type.blockSize() * ((width + 3) / 4) * ((height + 3) / 4);
            case A1R5G5B5:
            case X1R5G5B5:
            case A4R4G4B4:
@@ -218,12 +157,13 @@ final class DDSReader {
            case X8B8G8R8:
            case A8R8G8B8:
            case X8R8G8B8:
-                return (type.value() & 0xFF) * width * height;
+                return type.blockSize() * width * height;
            default:
-                throw new IIOException("Unknown type: " + Integer.toHexString(type.value()));
+                throw new IIOException("Unknown type: " + type);
        }
    }

+
    private static int[] decodeDXT1(int width, int height, byte[] buffer) {
        int[] pixels = new int[width * height];
        int index = 0;
@@ -241,7 +181,7 @@ final class DDSReader {
                    int t1 = (buffer[index] & 0x0C) >> 2;
                    int t2 = (buffer[index] & 0x30) >> 4;
                    int t3 = (buffer[index++] & 0xC0) >> 6;
-                    pixels[4 * width * i + 4 * j + width * k    ] = getDXTColor(c0, c1, 0xFF, t0);
+                    pixels[4 * width * i + 4 * j + width * k] = getDXTColor(c0, c1, 0xFF, t0);
                    if (4 * j + 1 >= width) continue;
                    pixels[4 * width * i + 4 * j + width * k + 1] = getDXTColor(c0, c1, 0xFF, t1);
                    if (4 * j + 2 >= width) continue;
@@ -286,7 +226,7 @@ final class DDSReader {
                    int t1 = (buffer[index] & 0x0C) >> 2;
                    int t2 = (buffer[index] & 0x30) >> 4;
                    int t3 = (buffer[index++] & 0xC0) >> 6;
-                    pixels[4 * width * i + 4 * j + width * k    ] = getDXTColor(c0, c1, alphaTable[4 * k    ], t0);
+                    pixels[4 * width * i + 4 * j + width * k] = getDXTColor(c0, c1, alphaTable[4 * k], t0);
                    if (4 * j + 1 >= width) continue;
                    pixels[4 * width * i + 4 * j + width * k + 1] = getDXTColor(c0, c1, alphaTable[4 * k + 1], t1);
                    if (4 * j + 2 >= width) continue;
@@ -344,7 +284,7 @@ final class DDSReader {
                    int t1 = (buffer[index] & 0x0C) >> 2;
                    int t2 = (buffer[index] & 0x30) >> 4;
                    int t3 = (buffer[index++] & 0xC0) >> 6;
-                    pixels[4 * width * i + 4 * j + width * k    ] = getDXTColor(c0, c1, getDXT5Alpha(a0, a1, alphaTable[4 * k    ]), t0);
+                    pixels[4 * width * i + 4 * j + width * k] = getDXTColor(c0, c1, getDXT5Alpha(a0, a1, alphaTable[4 * k]), t0);
                    if (4 * j + 1 >= width) continue;
                    pixels[4 * width * i + 4 * j + width * k + 1] = getDXTColor(c0, c1, getDXT5Alpha(a0, a1, alphaTable[4 * k + 1]), t1);
                    if (4 * j + 2 >= width) continue;
@@ -499,7 +439,7 @@ final class DDSReader {
        return pixels;
    }

-    private static int getDXTColor(int c0, int c1, int a, int t) {
+    static int getDXTColor(int c0, int c1, int a, int t) {
        switch (t) {
            case 0:
                return getDXTColor1(c0, a);
@@ -515,7 +455,7 @@ final class DDSReader {

    private static int getDXTColor2_1(int c0, int c1, int a) {
        // 2*c0/3 + c1/3
-        int r = (2 * BIT5[(c0 & 0xFC00) >> 11] + BIT5[(c1 & 0xFC00) >> 11]) / 3;
+        int r = (2 * BIT5[(c0 & 0xF800) >> 11] + BIT5[(c1 & 0xF800) >> 11]) / 3;
        int g = (2 * BIT6[(c0 & 0x07E0) >> 5] + BIT6[(c1 & 0x07E0) >> 5]) / 3;
        int b = (2 * BIT5[c0 & 0x001F] + BIT5[c1 & 0x001F]) / 3;
        return (a << ARGB_ORDER.alphaShift) | (r << ARGB_ORDER.redShift) | (g << ARGB_ORDER.greenShift) | (b << ARGB_ORDER.blueShift);
@@ -523,20 +463,20 @@ final class DDSReader {

    private static int getDXTColor1_1(int c0, int c1, int a) {
        // (c0+c1) / 2
-        int r = (BIT5[(c0 & 0xFC00) >> 11] + BIT5[(c1 & 0xFC00) >> 11]) / 2;
+        int r = (BIT5[(c0 & 0xF800) >> 11] + BIT5[(c1 & 0xF800) >> 11]) / 2;
        int g = (BIT6[(c0 & 0x07E0) >> 5] + BIT6[(c1 & 0x07E0) >> 5]) / 2;
        int b = (BIT5[c0 & 0x001F] + BIT5[c1 & 0x001F]) / 2;
        return (a << ARGB_ORDER.alphaShift) | (r << ARGB_ORDER.redShift) | (g << ARGB_ORDER.greenShift) | (b << ARGB_ORDER.blueShift);
    }

    private static int getDXTColor1(int c, int a) {
-        int r = BIT5[(c & 0xFC00) >> 11];
+        int r = BIT5[(c & 0xF800) >> 11];
        int g = BIT6[(c & 0x07E0) >> 5];
        int b = BIT5[(c & 0x001F)];
        return (a << ARGB_ORDER.alphaShift) | (r << ARGB_ORDER.redShift) | (g << ARGB_ORDER.greenShift) | (b << ARGB_ORDER.blueShift);
    }

-    private static int getDXT5Alpha(int a0, int a1, int t) {
+    static int getDXT5Alpha(int a0, int a1, int t) {
        if (a0 > a1) switch (t) {
            case 0:
                return a0;
@@ -577,22 +517,22 @@ final class DDSReader {
    }

    // RGBA Masks
-    private static final int[] A1R5G5B5_MASKS = {0x7C00, 0x03E0, 0x001F, 0x8000};
-    private static final int[] X1R5G5B5_MASKS = {0x7C00, 0x03E0, 0x001F, 0x0000};
-    private static final int[] A4R4G4B4_MASKS = {0x0F00, 0x00F0, 0x000F, 0xF000};
-    private static final int[] X4R4G4B4_MASKS = {0x0F00, 0x00F0, 0x000F, 0x0000};
-    private static final int[] R5G6B5_MASKS = {0xF800, 0x07E0, 0x001F, 0x0000};
-    private static final int[] R8G8B8_MASKS = {0xFF0000, 0x00FF00, 0x0000FF, 0x000000};
-    private static final int[] A8B8G8R8_MASKS = {0x000000FF, 0x0000FF00, 0x00FF0000, 0xFF000000};
-    private static final int[] X8B8G8R8_MASKS = {0x000000FF, 0x0000FF00, 0x00FF0000, 0x00000000};
-    private static final int[] A8R8G8B8_MASKS = {0x00FF0000, 0x0000FF00, 0x000000FF, 0xFF000000};
-    private static final int[] X8R8G8B8_MASKS = {0x00FF0000, 0x0000FF00, 0x000000FF, 0x00000000};
+    static final int[] A1R5G5B5_MASKS = {0x7C00, 0x03E0, 0x001F, 0x8000};
+    static final int[] X1R5G5B5_MASKS = {0x7C00, 0x03E0, 0x001F, 0x0000};
+    static final int[] A4R4G4B4_MASKS = {0x0F00, 0x00F0, 0x000F, 0xF000};
+    static final int[] X4R4G4B4_MASKS = {0x0F00, 0x00F0, 0x000F, 0x0000};
+    static final int[] R5G6B5_MASKS = {0xF800, 0x07E0, 0x001F, 0x0000};
+    static final int[] R8G8B8_MASKS = {0xFF0000, 0x00FF00, 0x0000FF, 0x000000};
+    static final int[] A8B8G8R8_MASKS = {0x000000FF, 0x0000FF00, 0x00FF0000, 0xFF000000};
+    static final int[] X8B8G8R8_MASKS = {0x000000FF, 0x0000FF00, 0x00FF0000, 0x00000000};
+    static final int[] A8R8G8B8_MASKS = {0x00FF0000, 0x0000FF00, 0x000000FF, 0xFF000000};
+    static final int[] X8R8G8B8_MASKS = {0x00FF0000, 0x0000FF00, 0x000000FF, 0x00000000};

    // BIT4 = 17 * index;
-    private static final int[] BIT5 = {0, 8, 16, 25, 33, 41, 49, 58, 66, 74, 82, 90, 99, 107, 115, 123, 132, 140, 148, 156, 165, 173, 181, 189, 197, 206, 214, 222, 230, 239, 247, 255};
-    private static final int[] BIT6 = {0, 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 45, 49, 53, 57, 61, 65, 69, 73, 77, 81, 85, 89, 93, 97, 101, 105, 109, 113, 117, 121, 125, 130, 134, 138, 142, 146, 150, 154, 158, 162, 166, 170, 174, 178, 182, 186, 190, 194, 198, 202, 206, 210, 215, 219, 223, 227, 231, 235, 239, 243, 247, 251, 255};
+    static final int[] BIT5 = {0, 8, 16, 25, 33, 41, 49, 58, 66, 74, 82, 90, 99, 107, 115, 123, 132, 140, 148, 156, 165, 173, 181, 189, 197, 206, 214, 222, 230, 239, 247, 255};
+    static final int[] BIT6 = {0, 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 45, 49, 53, 57, 61, 65, 69, 73, 77, 81, 85, 89, 93, 97, 101, 105, 109, 113, 117, 121, 125, 130, 134, 138, 142, 146, 150, 154, 158, 162, 166, 170, 174, 178, 182, 186, 190, 194, 198, 202, 206, 210, 215, 219, 223, 227, 231, 235, 239, 243, 247, 251, 255};

-    private static final class Order {
+    static final class Order {
        Order(int redShift, int greenShift, int blueShift, int alphaShift) {
            this.redShift = redShift;
            this.greenShift = greenShift;
@@ -30,41 +30,156 @@

 package com.twelvemonkeys.imageio.plugins.dds;

+import static com.twelvemonkeys.imageio.plugins.dds.BlockCompression.*;
+import static com.twelvemonkeys.imageio.plugins.dds.DDSReader.*;
+
+/**
+ * <a href="https://learn.microsoft.com/en-us/windows/win32/direct3d10/d3d10-graphics-programming-guide-resources-block-compression#compression-algorithms">Compression Algorithms</a>
+ * <a href="https://github.com/microsoft/DirectXTK12/wiki/DDSTextureLoader#remarks">An extended Non-DX10 FourCC list</a>
+ */
 enum DDSType {
+    // Compressed types
+    DXT1('D' + ('X' << 8) + ('T' << 16) + ('1' << 24),  8, DXGI.DXGI_FORMAT_BC1_UNORM, BC1),
+    DXT2('D' + ('X' << 8) + ('T' << 16) + ('2' << 24), 16, DXGI.DXGI_FORMAT_BC2_UNORM, BC2),
+    DXT3('D' + ('X' << 8) + ('T' << 16) + ('3' << 24), 16, DXGI.DXGI_FORMAT_BC2_UNORM, BC2),
+    DXT4('D' + ('X' << 8) + ('T' << 16) + ('4' << 24), 16, DXGI.DXGI_FORMAT_BC3_UNORM, BC3),
+    DXT5('D' + ('X' << 8) + ('T' << 16) + ('5' << 24), 16, DXGI.DXGI_FORMAT_BC3_UNORM, BC3),

-    DXT1(0x31545844),
-    DXT2(0x32545844),
-    DXT3(0x33545844),
-    DXT4(0x34545844),
-    DXT5(0x35545844),
-    A1R5G5B5((1 << 16) | 2),
-    X1R5G5B5((2 << 16) | 2),
-    A4R4G4B4((3 << 16) | 2),
-    X4R4G4B4((4 << 16) | 2),
-    R5G6B5((5 << 16) | 2),
-    R8G8B8((1 << 16) | 3),
-    A8B8G8R8((1 << 16) | 4),
-    X8B8G8R8((2 << 16) | 4),
-    A8R8G8B8((3 << 16) | 4),
-    X8R8G8B8((4 << 16) | 4);
+    ATI1('A' + ('T' << 8) + ('I' << 16) + ('1' << 24),  8, DXGI.DXGI_FORMAT_BC4_UNORM, BC4), // AKA BC4U
+    BC4U('B' + ('C' << 8) + ('4' << 16) + ('U' << 24),  8, DXGI.DXGI_FORMAT_BC4_UNORM, BC4),
+    BC4S('B' + ('C' << 8) + ('4' << 16) + ('S' << 24),  8, DXGI.DXGI_FORMAT_BC4_SNORM, BC4),
+    ATI2('A' + ('T' << 8) + ('I' << 16) + ('2' << 24), 16, DXGI.DXGI_FORMAT_BC5_UNORM, BC5), // AKA BC5U
+    BC5U('B' + ('C' << 8) + ('5' << 16) + ('U' << 24), 16, DXGI.DXGI_FORMAT_BC5_UNORM, BC5),
+    BC5S('B' + ('C' << 8) + ('5' << 16) + ('S' << 24), 16, DXGI.DXGI_FORMAT_BC5_SNORM, BC5),

-    private final int value;
+    // Special case, see DXT10Header.dxgiFormat for real format
+    DXT10('D' + ('X' << 8) + ('1' << 16) + ('0' << 24), -1, DXGI.DXGI_FORMAT_UNKNOWN, null),

-    DDSType(int value) {
-        this.value = value;
+    // Custom uncompressed pixel formats
+    // TODO: Consider swapping byte order to reflect the DXGI format?
+    A1R5G5B5(2, DXGI.DXGI_FORMAT_B5G5R5A1_UNORM,    A1R5G5B5_MASKS),
+    X1R5G5B5(2, DXGI.DXGI_FORMAT_UNKNOWN,           X1R5G5B5_MASKS),
+    A4R4G4B4(2, DXGI.DXGI_FORMAT_B4G4R4A4_UNORM,    A4R4G4B4_MASKS),
+    X4R4G4B4(2, DXGI.DXGI_FORMAT_UNKNOWN,           X4R4G4B4_MASKS),
+    R5G6B5(  2, DXGI.DXGI_FORMAT_B5G6R5_UNORM,      R5G6B5_MASKS),
+    R8G8B8(  3, DXGI.DXGI_FORMAT_UNKNOWN,           R8G8B8_MASKS),
+    A8B8G8R8(4, DXGI.DXGI_FORMAT_R8G8B8A8_UNORM,    A8B8G8R8_MASKS),
+    X8B8G8R8(4, DXGI.DXGI_FORMAT_UNKNOWN,           X8B8G8R8_MASKS),
+    A8R8G8B8(4, DXGI.DXGI_FORMAT_B8G8R8A8_UNORM,    A8R8G8B8_MASKS),
+    X8R8G8B8(4, DXGI.DXGI_FORMAT_B8G8R8X8_UNORM,    X8R8G8B8_MASKS);
+
+    private final int fourCC;
+    private final int blockSize;
+    private final int dxgiFormat;
+    final BlockCompression compression;
+    final int[] rgbaMasks;
+
+    DDSType(int fourCC, int blockSize, int dxgiFormat, BlockCompression compression) {
+        this(fourCC, blockSize, dxgiFormat, compression, null);
    }

-    public int value() {
-        return value;
+    DDSType(int blockSize, int dxgiFormat, int[] rgbaMasks) {
+        this(0, blockSize, dxgiFormat, null, rgbaMasks);
    }

-    public static DDSType valueOf(int value) {
-        for (DDSType type : DDSType.values()) {
-            if (value == type.value()) {
-                return type;
+    DDSType(int fourCC, int blockSize, int dxgiFormat, BlockCompression compression, int[] rgbaMasks) {
+        this.fourCC = fourCC;
+        this.blockSize = blockSize;
+        this.dxgiFormat = dxgiFormat;
+        this.compression = compression;
+        this.rgbaMasks = rgbaMasks;
+    }
+
+    public int fourCC() {
+        return fourCC;
+    }
+
+    public int blockSize() {
+        return blockSize;
+    }
+
+    public boolean isFourCC() {
+        return fourCC != 0;
+    }
+
+    public boolean isBlockCompression() {
+        return compression != null;
+    }
+
+    public int dxgiFormat() {
+        return dxgiFormat;
+    }
+
+    public static DDSType fromFourCC(int fourCC) {
+        if (fourCC != 0) {
+            for (DDSType type : values()) {
+                if (fourCC == type.fourCC()) {
+                    return type;
+                }
            }
        }

-        throw new IllegalArgumentException(String.format("Unknown type: 0x%08x", value));
+        throw new IllegalArgumentException(String.format("Unknown type: 0x%08x", fourCC));
+    }
+
+    public static DDSType fromDXGIFormat(int dxgiFormat) {
+        switch (dxgiFormat) {
+            case DXGI.DXGI_FORMAT_R8G8B8A8_TYPELESS:
+            case DXGI.DXGI_FORMAT_R8G8B8A8_UNORM:
+            case DXGI.DXGI_FORMAT_R8G8B8A8_UNORM_SRGB:
+            case DXGI.DXGI_FORMAT_R8G8B8A8_UINT:
+                return A8B8G8R8; // ABGR
+
+            case DXGI.DXGI_FORMAT_B8G8R8A8_TYPELESS:
+            case DXGI.DXGI_FORMAT_B8G8R8A8_UNORM:
+            case DXGI.DXGI_FORMAT_B8G8R8A8_UNORM_SRGB:
+                return A8R8G8B8; // ARGB
+
+            case DXGI.DXGI_FORMAT_B8G8R8X8_TYPELESS:
+            case DXGI.DXGI_FORMAT_B8G8R8X8_UNORM:
+            case DXGI.DXGI_FORMAT_B8G8R8X8_UNORM_SRGB:
+                return X8R8G8B8;
+
+            case DXGI.DXGI_FORMAT_B5G5R5A1_UNORM:
+                return A1R5G5B5;
+
+            case DXGI.DXGI_FORMAT_B4G4R4A4_UNORM:
+                return A4R4G4B4;
+
+            case DXGI.DXGI_FORMAT_B5G6R5_UNORM:
+                return R5G6B5;
+
+            case DXGI.DXGI_FORMAT_BC1_TYPELESS:
+            case DXGI.DXGI_FORMAT_BC1_UNORM:
+            case DXGI.DXGI_FORMAT_BC1_UNORM_SRGB:
+                return DXT1;
+
+            case DXGI.DXGI_FORMAT_BC2_TYPELESS:
+            case DXGI.DXGI_FORMAT_BC2_UNORM:
+            case DXGI.DXGI_FORMAT_BC2_UNORM_SRGB:
+                return DXT2;
+
+            case DXGI.DXGI_FORMAT_BC3_TYPELESS:
+            case DXGI.DXGI_FORMAT_BC3_UNORM:
+            case DXGI.DXGI_FORMAT_BC3_UNORM_SRGB:
+                return DXT4;
+
+            case DXGI.DXGI_FORMAT_BC4_TYPELESS:
+            case DXGI.DXGI_FORMAT_BC4_UNORM:
+                return BC4U;
+
+            case DXGI.DXGI_FORMAT_BC4_SNORM:
+                return BC4S;
+
+            case DXGI.DXGI_FORMAT_BC5_TYPELESS:
+            case DXGI.DXGI_FORMAT_BC5_UNORM:
+                return BC5U;
+
+            case DXGI.DXGI_FORMAT_BC5_SNORM:
+                return BC5S;
+
+            default:
+                throw new IllegalArgumentException("Unsupported DXGI_FORMAT: " + dxgiFormat);
+        }
    }
 }
@@ -0,0 +1,129 @@
+package com.twelvemonkeys.imageio.plugins.dds;
+
+/**
+ * <a href="https://learn.microsoft.com/en-us/windows/win32/api/dxgiformat/ne-dxgiformat-dxgi_format">DXGI Format List</a>
+ */
+interface DXGI {
+    int DXGI_FORMAT_UNKNOWN = 0;
+    int DXGI_FORMAT_R32G32B32A32_TYPELESS = 1;
+    int DXGI_FORMAT_R32G32B32A32_FLOAT = 2;
+    int DXGI_FORMAT_R32G32B32A32_UINT = 3;
+    int DXGI_FORMAT_R32G32B32A32_SINT = 4;
+    int DXGI_FORMAT_R32G32B32_TYPELESS = 5;
+    int DXGI_FORMAT_R32G32B32_FLOAT = 6;
+    int DXGI_FORMAT_R32G32B32_UINT = 7;
+    int DXGI_FORMAT_R32G32B32_SINT = 8;
+    int DXGI_FORMAT_R16G16B16A16_TYPELESS = 9;
+    int DXGI_FORMAT_R16G16B16A16_FLOAT = 10;
+    int DXGI_FORMAT_R16G16B16A16_UNORM = 11;
+    int DXGI_FORMAT_R16G16B16A16_UINT = 12;
+    int DXGI_FORMAT_R16G16B16A16_SNORM = 13;
+    int DXGI_FORMAT_R16G16B16A16_SINT = 14;
+    int DXGI_FORMAT_R32G32_TYPELESS = 15;
+    int DXGI_FORMAT_R32G32_FLOAT = 16;
+    int DXGI_FORMAT_R32G32_UINT = 17;
+    int DXGI_FORMAT_R32G32_SINT = 18;
+    int DXGI_FORMAT_R32G8X24_TYPELESS = 19;
+    int DXGI_FORMAT_D32_FLOAT_S8X24_UINT = 20;
+    int DXGI_FORMAT_R32_FLOAT_X8X24_TYPELESS = 21;
+    int DXGI_FORMAT_X32_TYPELESS_G8X24_UINT = 22;
+    int DXGI_FORMAT_R10G10B10A2_TYPELESS = 23;
+    int DXGI_FORMAT_R10G10B10A2_UNORM = 24;
+    int DXGI_FORMAT_R10G10B10A2_UINT = 25;
+    int DXGI_FORMAT_R11G11B10_FLOAT = 26;
+    int DXGI_FORMAT_R8G8B8A8_TYPELESS = 27;
+    int DXGI_FORMAT_R8G8B8A8_UNORM = 28;
+    int DXGI_FORMAT_R8G8B8A8_UNORM_SRGB = 29;
+    int DXGI_FORMAT_R8G8B8A8_UINT = 30;
+    int DXGI_FORMAT_R8G8B8A8_SNORM = 31;
+    int DXGI_FORMAT_R8G8B8A8_SINT = 32;
+    int DXGI_FORMAT_R16G16_TYPELESS = 33;
+    int DXGI_FORMAT_R16G16_FLOAT = 34;
+    int DXGI_FORMAT_R16G16_UNORM = 35;
+    int DXGI_FORMAT_R16G16_UINT = 36;
+    int DXGI_FORMAT_R16G16_SNORM = 37;
+    int DXGI_FORMAT_R16G16_SINT = 38;
+    int DXGI_FORMAT_R32_TYPELESS = 39;
+    int DXGI_FORMAT_D32_FLOAT = 40;
+    int DXGI_FORMAT_R32_FLOAT = 41;
+    int DXGI_FORMAT_R32_UINT = 42;
+    int DXGI_FORMAT_R32_SINT = 43;
+    int DXGI_FORMAT_R24G8_TYPELESS = 44;
+    int DXGI_FORMAT_D24_UNORM_S8_UINT = 45;
+    int DXGI_FORMAT_R24_UNORM_X8_TYPELESS = 46;
+    int DXGI_FORMAT_X24_TYPELESS_G8_UINT = 47;
+    int DXGI_FORMAT_R8G8_TYPELESS = 48;
+    int DXGI_FORMAT_R8G8_UNORM = 49;
+    int DXGI_FORMAT_R8G8_UINT = 50;
+    int DXGI_FORMAT_R8G8_SNORM = 51;
+    int DXGI_FORMAT_R8G8_SINT = 52;
+    int DXGI_FORMAT_R16_TYPELESS = 53;
+    int DXGI_FORMAT_R16_FLOAT = 54;
+    int DXGI_FORMAT_D16_UNORM = 55;
+    int DXGI_FORMAT_R16_UNORM = 56;
+    int DXGI_FORMAT_R16_UINT = 57;
+    int DXGI_FORMAT_R16_SNORM = 58;
+    int DXGI_FORMAT_R16_SINT = 59;
+    int DXGI_FORMAT_R8_TYPELESS = 60;
+    int DXGI_FORMAT_R8_UNORM = 61;
+    int DXGI_FORMAT_R8_UINT = 62;
+    int DXGI_FORMAT_R8_SNORM = 63;
+    int DXGI_FORMAT_R8_SINT = 64;
+    int DXGI_FORMAT_A8_UNORM = 65;
+    int DXGI_FORMAT_R1_UNORM = 66;
+    int DXGI_FORMAT_R9G9B9E5_SHAREDEXP = 67;
+    int DXGI_FORMAT_R8G8_B8G8_UNORM = 68;
+    int DXGI_FORMAT_G8R8_G8B8_UNORM = 69;
+    int DXGI_FORMAT_BC1_TYPELESS = 70;
+    int DXGI_FORMAT_BC1_UNORM = 71;
+    int DXGI_FORMAT_BC1_UNORM_SRGB = 72;
+    int DXGI_FORMAT_BC2_TYPELESS = 73;
+    int DXGI_FORMAT_BC2_UNORM = 74;
+    int DXGI_FORMAT_BC2_UNORM_SRGB = 75;
+    int DXGI_FORMAT_BC3_TYPELESS = 76;
+    int DXGI_FORMAT_BC3_UNORM = 77;
+    int DXGI_FORMAT_BC3_UNORM_SRGB = 78;
+    int DXGI_FORMAT_BC4_TYPELESS = 79;
+    int DXGI_FORMAT_BC4_UNORM = 80;
+    int DXGI_FORMAT_BC4_SNORM = 81;
+    int DXGI_FORMAT_BC5_TYPELESS = 82;
+    int DXGI_FORMAT_BC5_UNORM = 83;
+    int DXGI_FORMAT_BC5_SNORM = 84;
+    int DXGI_FORMAT_B5G6R5_UNORM = 85;
+    int DXGI_FORMAT_B5G5R5A1_UNORM = 86;
+    int DXGI_FORMAT_B8G8R8A8_UNORM = 87;
+    int DXGI_FORMAT_B8G8R8X8_UNORM = 88;
+    int DXGI_FORMAT_R10G10B10_XR_BIAS_A2_UNORM = 89;
+    int DXGI_FORMAT_B8G8R8A8_TYPELESS = 90;
+    int DXGI_FORMAT_B8G8R8A8_UNORM_SRGB = 91;
+    int DXGI_FORMAT_B8G8R8X8_TYPELESS = 92;
+    int DXGI_FORMAT_B8G8R8X8_UNORM_SRGB = 93;
+    int DXGI_FORMAT_BC6H_TYPELESS = 94;
+    int DXGI_FORMAT_BC6H_UF16 = 95;
+    int DXGI_FORMAT_BC6H_SF16 = 96;
+    int DXGI_FORMAT_BC7_TYPELESS = 97;
+    int DXGI_FORMAT_BC7_UNORM = 98;
+    int DXGI_FORMAT_BC7_UNORM_SRGB = 99;
+    int DXGI_FORMAT_AYUV = 100;
+    int DXGI_FORMAT_Y410 = 101;
+    int DXGI_FORMAT_Y416 = 102;
+    int DXGI_FORMAT_NV12 = 103;
+    int DXGI_FORMAT_P010 = 104;
+    int DXGI_FORMAT_P016 = 105;
+    int DXGI_FORMAT_420_OPAQUE = 106;
+    int DXGI_FORMAT_YUY2 = 107;
+    int DXGI_FORMAT_Y210 = 108;
+    int DXGI_FORMAT_Y216 = 109;
+    int DXGI_FORMAT_NV11 = 110;
+    int DXGI_FORMAT_AI44 = 111;
+    int DXGI_FORMAT_IA44 = 112;
+    int DXGI_FORMAT_P8 = 113;
+    int DXGI_FORMAT_A8P8 = 114;
+    int DXGI_FORMAT_B4G4R4A4_UNORM = 115;
+    int DXGI_FORMAT_P208 = 130;
+    int DXGI_FORMAT_V208 = 131;
+    int DXGI_FORMAT_V408 = 132;
+    int DXGI_FORMAT_SAMPLER_FEEDBACK_MIN_MIP_OPAQUE = 189;
+    int DXGI_FORMAT_SAMPLER_FEEDBACK_MIP_REGION_USED_OPAQUE = 190;
+    int DXGI_FORMAT_FORCE_UINT = 0xffffffff;
+}
@@ -0,0 +1,45 @@
+package com.twelvemonkeys.imageio.plugins.dds;
+
+import javax.imageio.stream.ImageInputStream;
+import java.io.IOException;
+
+/**
+ * @see <a href="https://learn.microsoft.com/en-us/windows/win32/direct3ddds/dds-header-dxt10">DDS_HEADER_DXT10 structure</a>
+ */
+final class DXT10Header {
+    final int dxgiFormat;
+    final int resourceDimension;
+    final int miscFlag;
+    final int arraySize;
+    final int miscFlags2;
+
+    private final DDSType type;
+
+    private DXT10Header(int dxgiFormat, int resourceDimension, int miscFlag, int arraySize, int miscFlags2) {
+        type = DDSType.fromDXGIFormat(dxgiFormat); // Validates dxgiFormat
+        if (resourceDimension != DDS.D3D10_RESOURCE_DIMENSION_TEXTURE2D) {
+            throw new IllegalArgumentException(String.format("Resource dimension %d is not supported, expected: %d",
+                resourceDimension, DDS.D3D10_RESOURCE_DIMENSION_TEXTURE2D));
+        }
+
+        this.dxgiFormat = dxgiFormat;
+        this.resourceDimension = resourceDimension;
+        this.miscFlag = miscFlag;
+        this.arraySize = arraySize;
+        this.miscFlags2 = miscFlags2;
+    }
+
+    static DXT10Header read(ImageInputStream inputStream) throws IOException {
+        int dxgiFormat = inputStream.readInt();
+        int resourceDimension = inputStream.readInt();
+        int miscFlag = inputStream.readInt();
+        int arraySize = inputStream.readInt();
+        int miscFlags2 = inputStream.readInt();
+
+        return new DXT10Header(dxgiFormat, resourceDimension, miscFlag, arraySize, miscFlags2);
+    }
+
+    DDSType getType() {
+        return type;
+    }
+}
@@ -0,0 +1 @@
+com.twelvemonkeys.imageio.plugins.dds.DDSImageWriterSpi
@@ -0,0 +1,101 @@
+package com.twelvemonkeys.imageio.plugins.dds;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.awt.image.BufferedImage;
+
+import javax.imageio.ImageTypeSpecifier;
+import javax.imageio.metadata.IIOMetadataFormatImpl;
+import javax.imageio.metadata.IIOMetadataNode;
+
+import org.junit.jupiter.api.Test;
+import org.w3c.dom.NodeList;
+
+class DDSImageMetadataTest {
+    @Test
+    void standardMetadataDXT1() {
+        DDSImageMetadata metadata = createDDSImageMetadata(BufferedImage.TYPE_INT_ARGB, DDSType.DXT1);
+        IIOMetadataNode tree = (IIOMetadataNode) metadata.getAsTree(IIOMetadataFormatImpl.standardMetadataFormatName);
+
+        NodeList compressionTypeNames = tree.getElementsByTagName("CompressionTypeName");
+        assertEquals(1, compressionTypeNames.getLength());
+        IIOMetadataNode compressionTypeName = (IIOMetadataNode) compressionTypeNames.item(0);
+        assertEquals("DXT1", compressionTypeName.getAttribute("value"));
+
+        NodeList losslesses = tree.getElementsByTagName("Lossless");
+        assertEquals(1, losslesses.getLength());
+        IIOMetadataNode lossless = (IIOMetadataNode) losslesses.item(0);
+        assertEquals("FALSE", lossless.getAttribute("value"));
+
+        NodeList bitsPerSamples = tree.getElementsByTagName("BitsPerSample");
+        assertEquals(1, bitsPerSamples.getLength());
+        IIOMetadataNode bitsPerSample = (IIOMetadataNode) bitsPerSamples.item(0);
+        assertEquals("8 8 8 8", bitsPerSample.getAttribute("value"));
+
+        NodeList alphas = tree.getElementsByTagName("Alpha");
+        assertEquals(1, alphas.getLength());
+        IIOMetadataNode alpha = (IIOMetadataNode) alphas.item(0);
+        assertEquals("nonpremultiplied", alpha.getAttribute("value"));
+    }
+
+    @Test
+    void standardMetadataA8R8G8B8() {
+        DDSImageMetadata metadata = createDDSImageMetadata(BufferedImage.TYPE_INT_ARGB, DDSType.A8R8G8B8);
+        IIOMetadataNode tree = (IIOMetadataNode) metadata.getAsTree(IIOMetadataFormatImpl.standardMetadataFormatName);
+
+        NodeList compressions = tree.getElementsByTagName("Compression");
+        assertEquals(0, compressions.getLength());
+
+        NodeList bitsPerSamples = tree.getElementsByTagName("BitsPerSample");
+        assertEquals(1, bitsPerSamples.getLength());
+        IIOMetadataNode bitsPerSample = (IIOMetadataNode) bitsPerSamples.item(0);
+        assertEquals("8 8 8 8", bitsPerSample.getAttribute("value"));
+
+        NodeList alphas = tree.getElementsByTagName("Alpha");
+        assertEquals(1, alphas.getLength());
+        IIOMetadataNode alpha = (IIOMetadataNode) alphas.item(0);
+        assertEquals("nonpremultiplied", alpha.getAttribute("value"));
+    }
+
+    @Test
+    void standardMetadataX8R8G8B8() {
+        DDSImageMetadata metadata = createDDSImageMetadata(BufferedImage.TYPE_INT_RGB, DDSType.X8R8G8B8);
+        IIOMetadataNode tree = (IIOMetadataNode) metadata.getAsTree(IIOMetadataFormatImpl.standardMetadataFormatName);
+
+        NodeList compressions = tree.getElementsByTagName("Compression");
+        assertEquals(0, compressions.getLength());
+
+        NodeList bitsPerSamples = tree.getElementsByTagName("BitsPerSample");
+        assertEquals(1, bitsPerSamples.getLength());
+        IIOMetadataNode bitsPerSample = (IIOMetadataNode) bitsPerSamples.item(0);
+        assertEquals("8 8 8 0", bitsPerSample.getAttribute("value")); // Or just 8 8 8?
+
+        NodeList alphas = tree.getElementsByTagName("Alpha");
+        assertEquals(1, alphas.getLength());
+        IIOMetadataNode alpha = (IIOMetadataNode) alphas.item(0);
+        assertEquals("none", alpha.getAttribute("value"));
+    }
+
+    @Test
+    void standardMetadataX1R5G5B5() {
+        DDSImageMetadata metadata = createDDSImageMetadata(BufferedImage.TYPE_INT_RGB, DDSType.X1R5G5B5);
+        IIOMetadataNode tree = (IIOMetadataNode) metadata.getAsTree(IIOMetadataFormatImpl.standardMetadataFormatName);
+
+        NodeList compressions = tree.getElementsByTagName("Compression");
+        assertEquals(0, compressions.getLength());
+
+        NodeList bitsPerSamples = tree.getElementsByTagName("BitsPerSample");
+        assertEquals(1, bitsPerSamples.getLength());
+        IIOMetadataNode bitsPerSample = (IIOMetadataNode) bitsPerSamples.item(0);
+        assertEquals("5 5 5 0", bitsPerSample.getAttribute("value"));  // Or just 5 5 5?
+
+        NodeList alphas = tree.getElementsByTagName("Alpha");
+        assertEquals(1, alphas.getLength());
+        IIOMetadataNode alpha = (IIOMetadataNode) alphas.item(0);
+        assertEquals("none", alpha.getAttribute("value"));
+    }
+
+    private static DDSImageMetadata createDDSImageMetadata(int bufferedImageType, DDSType ddsType) {
+        return new DDSImageMetadata(ImageTypeSpecifier.createFromBufferedImageType(bufferedImageType), ddsType);
+    }
+}
@@ -30,14 +30,27 @@

 package com.twelvemonkeys.imageio.plugins.dds;

+import static org.junit.jupiter.api.Assertions.assertEquals;
+
 import com.twelvemonkeys.imageio.util.ImageReaderAbstractTest;

+import javax.imageio.ImageIO;
+import javax.imageio.ImageReader;
+import javax.imageio.metadata.IIOMetadata;
+import javax.imageio.metadata.IIOMetadataFormatImpl;
+import javax.imageio.metadata.IIOMetadataNode;
 import javax.imageio.spi.ImageReaderSpi;
+import javax.imageio.stream.ImageInputStream;
+
 import java.awt.Dimension;
+import java.io.IOException;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;

+import org.junit.jupiter.api.Test;
+import org.w3c.dom.NodeList;
+
 public class DDSImageReaderTest extends ImageReaderAbstractTest<DDSImageReader> {
    @Override
    protected ImageReaderSpi createProvider() {
@@ -86,7 +99,13 @@ public class DDSImageReaderTest extends ImageReaderAbstractTest<DDSImageReader>
                new TestData(getClassLoaderResource("/dds/dds_X8B8G8R8.dds"), dim256),
                new TestData(getClassLoaderResource("/dds/dds_X8B8G8R8_mipmap.dds"), dim256, dim128, dim64),
                new TestData(getClassLoaderResource("/dds/dds_X8R8G8B8.dds"), dim256),
-                new TestData(getClassLoaderResource("/dds/dds_X8R8G8B8_mipmap.dds"), dim256, dim128, dim64)
+                new TestData(getClassLoaderResource("/dds/dds_X8R8G8B8_mipmap.dds"), dim256, dim128, dim64),
+                new TestData(getClassLoaderResource("/dds/dxt10_BC1_sRGB.dds"), dim256),
+                new TestData(getClassLoaderResource("/dds/dxt10_BC2_sRGB.dds"), dim256),
+                new TestData(getClassLoaderResource("/dds/dxt10_BC3_sRGB.dds"), dim256),
+                new TestData(getClassLoaderResource("/dds/dxt10_B8G8R8A8.dds"), dim256),
+                new TestData(getClassLoaderResource("/dds/dxt10_B8G8R8X8.dds"), dim256),
+                new TestData(getClassLoaderResource("/dds/dxt10_R8G8B8A8.dds"), dim256)
        );
    }

@@ -104,4 +123,67 @@ public class DDSImageReaderTest extends ImageReaderAbstractTest<DDSImageReader>
    protected List<String> getMIMETypes() {
        return Collections.singletonList("image/vnd-ms.dds");
    }
+
+    @Test
+    void metadataDXT5() throws IOException {
+        ImageReader reader = createReader();
+
+        try (ImageInputStream inputStream = ImageIO.createImageInputStream(getClassLoaderResource("/dds/dds_DXT5.dds"))) {
+            reader.setInput(inputStream);
+
+            IIOMetadata metadata = reader.getImageMetadata(0);
+            IIOMetadataNode tree = (IIOMetadataNode) metadata.getAsTree(IIOMetadataFormatImpl.standardMetadataFormatName);
+
+            NodeList compressionTypeNames = tree.getElementsByTagName("CompressionTypeName");
+            assertEquals(1, compressionTypeNames.getLength());
+            IIOMetadataNode compressionTypeName = (IIOMetadataNode) compressionTypeNames.item(0);
+            assertEquals("DXT5", compressionTypeName.getAttribute("value"));
+
+            NodeList losslesses = tree.getElementsByTagName("Lossless");
+            assertEquals(1, losslesses.getLength());
+            IIOMetadataNode lossless = (IIOMetadataNode) losslesses.item(0);
+            assertEquals("FALSE", lossless.getAttribute("value"));
+
+            NodeList bitsPerSamples = tree.getElementsByTagName("BitsPerSample");
+            assertEquals(1, bitsPerSamples.getLength());
+            IIOMetadataNode bitsPerSample = (IIOMetadataNode) bitsPerSamples.item(0);
+            assertEquals("8 8 8 8", bitsPerSample.getAttribute("value"));
+
+            NodeList alphas = tree.getElementsByTagName("Alpha");
+            assertEquals(1, alphas.getLength());
+            IIOMetadataNode alpha = (IIOMetadataNode) alphas.item(0);
+            assertEquals("nonpremultiplied", alpha.getAttribute("value"));
+        }
+        finally {
+            reader.dispose();
+        }
+    }
+
+    @Test
+    void metadataRGB565() throws IOException {
+        ImageReader reader = createReader();
+
+        try (ImageInputStream inputStream = ImageIO.createImageInputStream(getClassLoaderResource("/dds/dds_R5G6B5.dds"))) {
+            reader.setInput(inputStream);
+
+            IIOMetadata metadata = reader.getImageMetadata(0);
+            IIOMetadataNode tree = (IIOMetadataNode) metadata.getAsTree(IIOMetadataFormatImpl.standardMetadataFormatName);
+
+            NodeList compressions = tree.getElementsByTagName("Compression");
+            assertEquals(0, compressions.getLength());
+
+            NodeList bitsPerSamples = tree.getElementsByTagName("BitsPerSample");
+            assertEquals(1, bitsPerSamples.getLength());
+            IIOMetadataNode bitsPerSample = (IIOMetadataNode) bitsPerSamples.item(0);
+            assertEquals("5 6 5 0", bitsPerSample.getAttribute("value")); // or "5 6 5"
+
+            NodeList alphas = tree.getElementsByTagName("Alpha");
+            assertEquals(1, alphas.getLength());
+            IIOMetadataNode alpha = (IIOMetadataNode) alphas.item(0);
+            assertEquals("none", alpha.getAttribute("value"));
+        }
+        finally {
+            reader.dispose();
+        }
+    }
 }
@@ -0,0 +1,55 @@
+package com.twelvemonkeys.imageio.plugins.dds;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import java.util.Arrays;
+
+import javax.imageio.ImageWriteParam;
+
+import org.junit.jupiter.api.Test;
+
+class DDSImageWriteParamTest {
+    @Test
+    void defaultParam() {
+        DDSImageWriteParam param = new DDSImageWriteParam();
+        assertEquals(DDSImageWriteParam.DEFAULT_TYPE, param.type());
+    }
+
+    @Test
+    void compressionTypes() {
+        DDSImageWriteParam param = new DDSImageWriteParam();
+
+        String[] compressionTypes = param.getCompressionTypes();
+        DDSType[] values = Arrays.stream(DDSType.values())
+            .filter(DDSType::isBlockCompression)
+            .toArray(DDSType[]::new);
+
+        assertEquals(values.length + 1, compressionTypes.length);
+
+        for (int i = 0; i < values.length; i++) {
+            DDSType type = values[i];
+            assertEquals(type.name(), compressionTypes[i + 1]);
+        }
+
+        assertEquals("None", compressionTypes[0]);
+    }
+
+    @Test
+    void setCompression() {
+        DDSImageWriteParam param = new DDSImageWriteParam();
+
+        param.setCompressionMode(ImageWriteParam.MODE_EXPLICIT);
+
+        String[] compressionTypes = param.getCompressionTypes();
+        for (String compressionType : compressionTypes) {
+            param.setCompressionType(compressionType);
+            assertEquals(compressionType, param.getCompressionType());
+
+            if (!"None".equals(compressionType)) {
+                DDSType type = DDSType.valueOf(compressionType);
+
+                assertEquals(type, param.type());
+            }
+        }
+    }
+}
@@ -0,0 +1,186 @@
+package com.twelvemonkeys.imageio.plugins.dds;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoMoreInteractions;
+
+import com.twelvemonkeys.imageio.util.ImageWriterAbstractTest;
+
+import javax.imageio.IIOException;
+import javax.imageio.IIOImage;
+import javax.imageio.ImageIO;
+import javax.imageio.ImageReader;
+import javax.imageio.ImageWriteParam;
+import javax.imageio.ImageWriter;
+import javax.imageio.event.IIOWriteWarningListener;
+import javax.imageio.spi.ImageWriterSpi;
+import javax.imageio.stream.ImageInputStream;
+import javax.imageio.stream.ImageOutputStream;
+
+import java.awt.image.BufferedImage;
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.List;
+
+import org.junit.jupiter.api.Test;
+
+class DDSImageWriterTest extends ImageWriterAbstractTest<DDSImageWriter> {
+    @Override
+    protected ImageWriterSpi createProvider() {
+        return new DDSImageWriterSpi();
+    }
+
+    @Override
+    protected List<BufferedImage> getTestData() {
+        return Arrays.asList(
+            new BufferedImage(256, 256, BufferedImage.TYPE_INT_ARGB),
+            new BufferedImage(128, 128, BufferedImage.TYPE_INT_ARGB),
+            new BufferedImage(64, 64, BufferedImage.TYPE_INT_RGB),
+            new BufferedImage(32, 32, BufferedImage.TYPE_4BYTE_ABGR),
+            new BufferedImage(16, 16, BufferedImage.TYPE_3BYTE_BGR)
+        );
+    }
+
+    @Test
+    void writeRasters() throws IOException {
+        ImageWriter writer = createWriter();
+
+        assertTrue(writer.canWriteRasters());
+
+        // Full tests in super class
+    }
+
+    @Test
+    void writeMipmap() throws IOException {
+        ImageWriter writer = createWriter();
+
+        try {
+            assertTrue(writer.canWriteSequence());
+
+            List<BufferedImage> testData = getTestData();
+            ByteArrayOutputStream buffer = new ByteArrayOutputStream();
+            int previousSize = 0;
+
+            try (ImageOutputStream stream = ImageIO.createImageOutputStream(buffer)) {
+                writer.setOutput(stream);
+                writer.prepareWriteSequence(null);
+                ImageWriteParam param = writer.getDefaultWriteParam();
+
+                assertTrue(buffer.size() > previousSize);
+                previousSize = buffer.size();
+
+                for (BufferedImage image : testData) {
+                    writer.writeToSequence(new IIOImage(drawSomething(image), null, null), param);
+                }
+
+                writer.endWriteSequence();
+                assertTrue(buffer.size() > previousSize, "No image data written");
+            }
+            catch (IOException e) {
+                throw new AssertionError(e.getMessage(), e);
+            }
+
+            // Verify that we can read the file back...
+            ImageReader reader = ImageIO.getImageReader(writer);
+
+            try (ImageInputStream stream = ImageIO.createImageInputStream(new ByteArrayInputStream(buffer.toByteArray()))) {
+                stream.seek(0);
+                reader.setInput(stream);
+
+                assertEquals(testData.size(), reader.getNumImages(false));
+
+                for (int i = 0; i < testData.size(); i++) {
+                    BufferedImage image = reader.read(i, null);
+
+                    assertNotNull(image);
+                    assertEquals(testData.get(i).getWidth(), image.getWidth());
+                    assertEquals(testData.get(i).getHeight(), image.getHeight());
+                }
+            }
+            finally {
+                reader.dispose();
+            }
+
+        }
+        finally {
+            writer.dispose();
+        }
+    }
+
+    @Test
+    void writeMipmapDifferentCompression() throws IOException {
+        ImageWriter writer = createWriter();
+
+        try {
+            ByteArrayOutputStream buffer = new ByteArrayOutputStream();
+
+            try (ImageOutputStream stream = ImageIO.createImageOutputStream(buffer)) {
+                IIOWriteWarningListener listener = mock();
+                writer.addIIOWriteWarningListener(listener);
+                writer.setOutput(stream);
+
+                writer.prepareWriteSequence(null);
+                ImageWriteParam param = writer.getDefaultWriteParam();
+                param.setCompressionMode(ImageWriteParam.MODE_EXPLICIT);
+                param.setCompressionType("DXT2");
+
+                // Write first with DXT2
+                List<BufferedImage> testData = getTestData();
+                writer.writeToSequence(new IIOImage(drawSomething(testData.get(0)), null, null), param);
+
+                // Repeat with different type
+                IIOImage image = new IIOImage(drawSomething(testData.get(1)), null, null);
+                param.setCompressionType("DXT1");
+
+                writer.writeToSequence(image, param);
+
+                // Verify warning is issued
+                verify(listener).warningOccurred(eq(writer), eq(1), anyString());
+                verifyNoMoreInteractions(listener);
+            }
+            catch (IOException e) {
+                throw new AssertionError(e.getMessage(), e);
+            }
+        }
+        finally {
+            writer.dispose();
+        }
+    }
+
+    @Test
+    void writeMipmapUnexpectedSize() throws IOException {
+        ImageWriter writer = createWriter();
+
+        try {
+            ByteArrayOutputStream buffer = new ByteArrayOutputStream();
+
+            try (ImageOutputStream stream = ImageIO.createImageOutputStream(buffer)) {
+                writer.setOutput(stream);
+
+                writer.prepareWriteSequence(null);
+                ImageWriteParam param = writer.getDefaultWriteParam();
+                BufferedImage testData = getTestData().get(0);
+
+                IIOImage image = new IIOImage(drawSomething(testData), null, null);
+                writer.writeToSequence(image, param);
+
+                // Repeat with same size... boom.
+                assertThrows(IIOException.class, () -> writer.writeToSequence(image, param));
+            }
+            catch (IOException e) {
+                throw new AssertionError(e.getMessage(), e);
+            }
+        }
+        finally {
+            writer.dispose();
+        }
+    }
+}
@@ -4,7 +4,7 @@
    <parent>
        <groupId>com.twelvemonkeys.imageio</groupId>
        <artifactId>imageio</artifactId>
-        <version>3.12.1-SNAPSHOT</version>
+        <version>3.13.2-SNAPSHOT</version>
    </parent>
    <artifactId>imageio-hdr</artifactId>
    <name>TwelveMonkeys :: ImageIO :: HDR plugin</name>
@@ -4,7 +4,7 @@
    <parent>
        <groupId>com.twelvemonkeys.imageio</groupId>
        <artifactId>imageio</artifactId>
-        <version>3.12.1-SNAPSHOT</version>
+        <version>3.13.2-SNAPSHOT</version>
    </parent>
    <artifactId>imageio-icns</artifactId>
    <name>TwelveMonkeys :: ImageIO :: ICNS plugin</name>
@@ -33,6 +33,7 @@ package com.twelvemonkeys.imageio.plugins.icns;
 import com.twelvemonkeys.imageio.ImageWriterBase;
 import com.twelvemonkeys.imageio.stream.SubImageOutputStream;
 import com.twelvemonkeys.imageio.util.ProgressListenerBase;
+import com.twelvemonkeys.imageio.util.SequenceSupport;

 import javax.imageio.IIOException;
 import javax.imageio.IIOImage;
@@ -55,7 +56,7 @@ import java.util.Iterator;
 */
 public final class ICNSImageWriter extends ImageWriterBase {

-    private int sequenceIndex = -1;
+    private final SequenceSupport sequence = new SequenceSupport();
    private ImageWriter pngDelegate;

    ICNSImageWriter(ImageWriterSpi provider) {
@@ -64,7 +65,7 @@ public final class ICNSImageWriter extends ImageWriterBase {

    @Override
    protected void resetMembers() {
-        sequenceIndex = -1;
+        sequence.reset();

        if (pngDelegate != null) {
            pngDelegate.dispose();
@@ -97,41 +98,29 @@ public final class ICNSImageWriter extends ImageWriterBase {
    @Override
    public void prepareWriteSequence(final IIOMetadata streamMetadata) throws IOException {
        assertOutput();
+        sequence.start();

        // TODO: Allow TOC resource to be passed as stream metadata?
        // - We only need number of icons to be written later
        // - The contents of the TOC could be updated while adding to the sequence

-        if (sequenceIndex >= 0) {
-            throw new IllegalStateException("writeSequence already started");
-        }
-
        writeICNSHeader();
-        sequenceIndex = 0;
    }

    @SuppressWarnings("RedundantThrows")
    @Override
    public void endWriteSequence() throws IOException {
        assertOutput();
-
-        if (sequenceIndex < 0) {
-            throw new IllegalStateException("prepareWriteSequence not called");
-        }
+        sequence.end();

        // TODO: Now that we know the number of icon resources, we could move all data backwards
        // and write a TOC... But I don't think the benefit will outweigh the cost.
-
-        sequenceIndex = -1;
    }

    @Override
    public void writeToSequence(final IIOImage image, final ImageWriteParam param) throws IOException {
        assertOutput();
-
-        if (sequenceIndex < 0) {
-            throw new IllegalStateException("prepareWriteSequence not called");
-        }
+        int imageIndex = sequence.advance();

        if (image.hasRaster()) {
            throw new UnsupportedOperationException("image has a Raster");
@@ -148,7 +137,7 @@ public final class ICNSImageWriter extends ImageWriterBase {
        imageOutput.writeInt(IconResource.typeFromImage(image.getRenderedImage(), "PNG"));
        imageOutput.writeInt(0); // Size, update later

-        processImageStarted(sequenceIndex);
+        processImageStarted(imageIndex);

        // Write icon in PNG format
        ImageWriter writer = getPNGDelegate();
@@ -208,7 +197,7 @@ public final class ICNSImageWriter extends ImageWriterBase {
            pngDelegate.addIIOWriteWarningListener(new IIOWriteWarningListener() {
                @Override
                public void warningOccurred(ImageWriter source, int imageIndex, String warning) {
-                    processWarningOccurred(sequenceIndex, warning);
+                    processWarningOccurred(sequence.current(), warning);
                }
            });
        }
@@ -4,7 +4,7 @@
    <parent>
        <groupId>com.twelvemonkeys.imageio</groupId>
        <artifactId>imageio</artifactId>
-        <version>3.12.1-SNAPSHOT</version>
+        <version>3.13.2-SNAPSHOT</version>
    </parent>
    <artifactId>imageio-iff</artifactId>
    <name>TwelveMonkeys :: ImageIO :: IFF plugin</name>
@@ -4,7 +4,7 @@
    <parent>
        <groupId>com.twelvemonkeys.imageio</groupId>
        <artifactId>imageio</artifactId>
-        <version>3.12.1-SNAPSHOT</version>
+        <version>3.13.2-SNAPSHOT</version>
    </parent>
    <artifactId>imageio-jpeg-jai-interop</artifactId>
    <name>TwelveMonkeys :: ImageIO :: JPEG/JAI TIFF Interop</name>
@@ -4,7 +4,7 @@
    <parent>
        <groupId>com.twelvemonkeys.imageio</groupId>
        <artifactId>imageio</artifactId>
-        <version>3.12.1-SNAPSHOT</version>
+        <version>3.13.2-SNAPSHOT</version>
    </parent>
    <artifactId>imageio-jpeg-jep262-interop</artifactId>
    <name>TwelveMonkeys :: ImageIO :: JPEG/JEP-262 Interop</name>
@@ -4,7 +4,7 @@
    <parent>
        <groupId>com.twelvemonkeys.imageio</groupId>
        <artifactId>imageio</artifactId>
-        <version>3.12.1-SNAPSHOT</version>
+        <version>3.13.2-SNAPSHOT</version>
    </parent>
    <artifactId>imageio-jpeg</artifactId>
    <name>TwelveMonkeys :: ImageIO :: JPEG plugin</name>
@@ -3,7 +3,7 @@
    <parent>
 	<groupId>com.twelvemonkeys.imageio</groupId>
 	<artifactId>imageio</artifactId>        
-        <version>3.12.1-SNAPSHOT</version>
+        <version>3.13.2-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>
    <artifactId>imageio-metadata</artifactId>
@@ -41,7 +41,11 @@ import javax.imageio.stream.ImageOutputStream;
 import java.io.IOException;
 import java.nio.ByteOrder;
 import java.nio.charset.StandardCharsets;
-import java.util.*;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;

 import static com.twelvemonkeys.imageio.metadata.tiff.TIFFEntry.getType;
 import static com.twelvemonkeys.imageio.metadata.tiff.TIFFEntry.getValueLength;
@@ -176,7 +180,7 @@ public final class TIFFWriter extends MetadataWriter {
                stream.seek(dataOffset);
                Directory subIFD = (Directory) value;
                writeIFD(subIFD, stream, true);
-                dataOffset += computeDataSize(subIFD);
+                dataOffset += computeDataSize(subIFD) + directoryCountLength + subIFD.size() * entryLength;
                stream.seek(streamPosition);
            }
            else {
@@ -30,14 +30,23 @@

 package com.twelvemonkeys.imageio.metadata.tiff;

-import com.twelvemonkeys.imageio.metadata.*;
+import com.twelvemonkeys.imageio.metadata.AbstractDirectory;
+import com.twelvemonkeys.imageio.metadata.AbstractEntry;
+import com.twelvemonkeys.imageio.metadata.CompoundDirectory;
+import com.twelvemonkeys.imageio.metadata.Directory;
+import com.twelvemonkeys.imageio.metadata.Entry;
+import com.twelvemonkeys.imageio.metadata.MetadataWriterAbstractTest;
+import com.twelvemonkeys.imageio.metadata.exif.EXIF;
 import com.twelvemonkeys.imageio.stream.ByteArrayImageInputStream;
 import com.twelvemonkeys.io.FastByteArrayOutputStream;

+import org.junit.jupiter.api.Test;

 import javax.imageio.ImageIO;
+import javax.imageio.stream.ImageInputStream;
 import javax.imageio.stream.ImageOutputStream;
 import javax.imageio.stream.ImageOutputStreamImpl;
+import javax.imageio.stream.MemoryCacheImageOutputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
@@ -46,8 +55,10 @@ import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;

-import org.junit.jupiter.api.Test;
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertInstanceOf;
+import static org.junit.jupiter.api.Assertions.assertNotNull;

 /**
 * TIFFWriterTest
@@ -272,7 +283,7 @@ public class TIFFWriterTest extends MetadataWriterAbstractTest {
        Directory read = new TIFFReader().read(new ByteArrayImageInputStream(data));

        assertNotNull(read.getEntryById(TIFF.TAG_SOFTWARE));
-        assertTrue(read.getEntryById(TIFF.TAG_SOFTWARE).getValue() instanceof String[], "value not an string array");
+        assertInstanceOf(String[].class, read.getEntryById(TIFF.TAG_SOFTWARE).getValue(), "value not an string array");
        assertArrayEquals(strings, (String[]) read.getEntryById(TIFF.TAG_SOFTWARE).getValue());
    }

@@ -285,7 +296,7 @@ public class TIFFWriterTest extends MetadataWriterAbstractTest {
        TIFFEntry subSubIFD = new TIFFEntry(TIFF.TAG_SUB_IFD, TIFF.TYPE_LONG, new IFD(Collections.singletonList(subSubSubIFD)));
        TIFFEntry subIFD = new TIFFEntry(TIFF.TAG_SUB_IFD, TIFF.TYPE_LONG, new IFD(Collections.singletonList(subSubIFD)));

-        List<Entry> entries = Collections.<Entry>singletonList(subIFD);
+        List<Entry> entries = Collections.singletonList(subIFD);

        TIFFWriter writer = createWriter();

@@ -296,24 +307,67 @@ public class TIFFWriterTest extends MetadataWriterAbstractTest {
        assertEquals(96, stream.getStreamPosition()); // 96 = 4 + 5 * (2 + 12) + 22
    }

-    private static class NullImageOutputStream extends ImageOutputStreamImpl {
+    @Test
+    void testWriteNestedExifIFD() throws IOException {
+        String expectedUserComment = "This ia the expected user comment";
+        String expectedDateTime = "2026:01:01 00:00:01";
+
+        List<Entry> entries = new ArrayList<>();
+        List<Entry> subDirectoryEntries = new ArrayList<>();
+        subDirectoryEntries.add(new TIFFEntry(EXIF.TAG_USER_COMMENT, TIFF.TYPE_ASCII, expectedUserComment));
+        entries.add(new TIFFEntry(TIFF.TAG_DATE_TIME, expectedDateTime));
+        entries.add(new TIFFEntry(TIFF.TAG_EXIF_IFD, TIFF.TYPE_IFD, new IFD(subDirectoryEntries)));
+        // NOTE! For the test, it is important that this tag is > Exif IFD and inside IDF0 (even if this is an Exif tag)
+        entries.add(new TIFFEntry(EXIF.TAG_DATE_TIME_ORIGINAL, TIFF.TYPE_ASCII, expectedDateTime));
+
+        IFD expectedSub = new IFD(subDirectoryEntries);
+        IFD expected = new IFD(entries);
+
+        try (ByteArrayOutputStream bytes = new ByteArrayOutputStream()) {
+            // Write the TIFF w/Exif sub IFD
+            try (ImageOutputStream stream = new MemoryCacheImageOutputStream(bytes)) {
+                new TIFFWriter().write(expected, stream);
+            }
+
+            try (ImageInputStream stream = new ByteArrayImageInputStream(bytes.toByteArray())) {
+                // Read the TIFF back, and compare content
+                Directory directory = new TIFFReader().read(stream);
+
+                Entry dateTimeEntry = directory.getEntryById(EXIF.TAG_DATE_TIME_ORIGINAL);
+                assertNotNull(dateTimeEntry);
+                assertEquals(expectedDateTime, dateTimeEntry.getValue());
+
+                Entry exifEntry = directory.getEntryById(TIFF.TAG_EXIF_IFD);
+                IFD exifIFD = (IFD) exifEntry.getValue();
+
+                Entry userCommentEntry = exifIFD.getEntryById(EXIF.TAG_USER_COMMENT);
+                assertNotNull(userCommentEntry);
+
+                assertEquals(expectedUserComment, userCommentEntry.getValue());
+                assertEquals(expectedSub, exifIFD);
+                assertEquals(expected, ((CompoundDirectory) directory).getDirectory(0));
+            }
+        }
+    }
+
+    private static final class NullImageOutputStream extends ImageOutputStreamImpl {
        @Override
-        public void write(int b) throws IOException {
+        public void write(int b) {
            streamPos++;
        }

        @Override
-        public void write(byte[] b, int off, int len) throws IOException {
+        public void write(byte[] b, int off, int len) {
            streamPos += len;
        }

        @Override
-        public int read() throws IOException {
+        public int read() {
            throw new UnsupportedOperationException("Method read not implemented");
        }

        @Override
-        public int read(byte[] b, int off, int len) throws IOException {
+        public int read(byte[] b, int off, int len) {
            throw new UnsupportedOperationException("Method read not implemented");
        }
    }
@@ -4,7 +4,7 @@
    <parent>
        <groupId>com.twelvemonkeys.imageio</groupId>
        <artifactId>imageio</artifactId>
-        <version>3.12.1-SNAPSHOT</version>
+        <version>3.13.2-SNAPSHOT</version>
    </parent>
    <artifactId>imageio-pcx</artifactId>
    <name>TwelveMonkeys :: ImageIO :: PCX plugin</name>
@@ -4,7 +4,7 @@
    <parent>
        <groupId>com.twelvemonkeys.imageio</groupId>
        <artifactId>imageio</artifactId>
-        <version>3.12.1-SNAPSHOT</version>
+        <version>3.13.2-SNAPSHOT</version>
    </parent>
    <artifactId>imageio-pdf</artifactId>
    <name>TwelveMonkeys :: ImageIO :: PDF plugin</name>
@@ -4,7 +4,7 @@
    <parent>
        <groupId>com.twelvemonkeys.imageio</groupId>
        <artifactId>imageio</artifactId>
-        <version>3.12.1-SNAPSHOT</version>
+        <version>3.13.2-SNAPSHOT</version>
    </parent>
    <artifactId>imageio-pict</artifactId>
    <name>TwelveMonkeys :: ImageIO :: PICT plugin</name>
@@ -4,7 +4,7 @@
    <parent>
        <groupId>com.twelvemonkeys.imageio</groupId>
        <artifactId>imageio</artifactId>
-        <version>3.12.1-SNAPSHOT</version>
+        <version>3.13.2-SNAPSHOT</version>
    </parent>
    <artifactId>imageio-pnm</artifactId>
    <name>TwelveMonkeys :: ImageIO :: PNM plugin</name>
@@ -111,6 +111,7 @@ enum TupleType {

    static TupleType forPAM(Raster raster) {
        SampleModel sampleModel = raster.getSampleModel();
+
        switch (sampleModel.getTransferType()) {
            case DataBuffer.TYPE_BYTE:
            case DataBuffer.TYPE_USHORT:
@@ -145,8 +146,12 @@ enum TupleType {
                    return TupleType.RGB;
                }
                else if (bands == 4) {
+                    // Ambiguous, could also be CMYK...
                    return TupleType.RGB_ALPHA;
                }
+                else if (bands == 5) {
+                    return TupleType.CMYK_ALPHA;
+                }
                // ...else fall through...
        }

@@ -154,7 +159,7 @@ enum TupleType {
    }
    
    static TupleType forPAM(ImageTypeSpecifier type) {
-        // Support only 1 bit b/w, 8-16 bit gray and 8-16 bit/sample RGB
+        // Support only 1 bit b/w, 8-16 bit gray, 8-16 bit/sample RGB and 8-16 bit/sample CMYK
        switch (type.getBufferedImageType()) {
            // 1 bit b/w  or b/w + a
            case BufferedImage.TYPE_BYTE_BINARY:
@@ -4,7 +4,7 @@
    <parent>
        <groupId>com.twelvemonkeys.imageio</groupId>
        <artifactId>imageio</artifactId>
-        <version>3.12.1-SNAPSHOT</version>
+        <version>3.13.2-SNAPSHOT</version>
    </parent>
    <artifactId>imageio-psd</artifactId>
    <name>TwelveMonkeys :: ImageIO :: PSD plugin</name>
@@ -410,9 +410,9 @@ public final class PSDMetadata extends AbstractMetadata {
            if ((psdLayerInfo.blendMode.flags & 0x01) != 0) {
                node.setAttribute("transparencyProtected", "true");
            }
-            if ((psdLayerInfo.blendMode.flags & 0x02) != 0) {
-                node.setAttribute("visible", "true");
-            }
+            // Include always, to avoid ambiguity, as the flag is really "hidden", not "visible"...   
+            boolean hidden = (psdLayerInfo.blendMode.flags & 0x02) != 0;
+            node.setAttribute("visible", hidden ? "false" : "true");
            if ((psdLayerInfo.blendMode.flags & 0x04) != 0) {
                node.setAttribute("obsolete", "true");
            }
@@ -0,0 +1,119 @@
+package com.twelvemonkeys.imageio.plugins.psd;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import java.io.IOException;
+import java.net.URL;
+
+import javax.imageio.ImageIO;
+import javax.imageio.metadata.IIOMetadata;
+import javax.imageio.metadata.IIOMetadataNode;
+import javax.imageio.spi.IIORegistry;
+import javax.imageio.spi.ImageReaderSpi;
+import javax.imageio.stream.ImageInputStream;
+
+import org.junit.jupiter.api.Test;
+import org.w3c.dom.NodeList;
+
+import com.twelvemonkeys.imageio.stream.URLImageInputStreamSpi;
+
+class PSDMetadataTest {
+    static {
+        IIORegistry.getDefaultInstance().registerServiceProvider(new URLImageInputStreamSpi());
+        ImageIO.setUseCache(false);
+    }
+
+    protected final PSDImageReaderSpi provider = createProvider();
+
+    private PSDImageReaderSpi createProvider() {
+        return new PSDImageReaderSpi();
+    }
+
+    private PSDImageReader createReader() throws IOException {
+        return (PSDImageReader) provider.createReaderInstance(null);
+    }
+
+    protected URL getClassLoaderResource(final String resource) {
+        return getClass().getResource(resource);
+    }
+
+    @Test
+    void testLayerInfo() throws IOException {
+        PSDImageReader imageReader = createReader();
+
+        try (ImageInputStream stream = ImageIO.createImageInputStream(getClassLoaderResource("/psd/photoshopping.psd"))) {
+            imageReader.setInput(stream);
+
+            IIOMetadata metadata = imageReader.getImageMetadata(0);
+            IIOMetadataNode root = (IIOMetadataNode) metadata.getAsTree(PSDMetadata.NATIVE_METADATA_FORMAT_NAME);
+            NodeList layerInfos = root.getElementsByTagName("LayerInfo");
+
+            assertEquals(5, layerInfos.getLength()); // Sanity
+
+            IIOMetadataNode layer1Info = (IIOMetadataNode) layerInfos.item(0);
+            assertEquals("Layer 1", layer1Info.getAttribute("name"));
+            assertEquals("2", layer1Info.getAttribute("layerId"));
+            assertEquals("0", layer1Info.getAttribute("top"));
+            assertEquals("0", layer1Info.getAttribute("left"));
+            assertEquals("225", layer1Info.getAttribute("bottom"));
+            assertEquals("300", layer1Info.getAttribute("right"));
+            assertEquals("norm", layer1Info.getAttribute("blendMode"));
+            assertEquals("255", layer1Info.getAttribute("opacity"));
+            assertEquals("base", layer1Info.getAttribute("clipping"));
+            assertEquals("true", layer1Info.getAttribute("visible"));
+            assertEquals("8", layer1Info.getAttribute("flags"));
+
+            IIOMetadataNode layer2Info = (IIOMetadataNode) layerInfos.item(1);
+            assertEquals("Layer 0 copy", layer2Info.getAttribute("name"));
+            assertEquals("11", layer2Info.getAttribute("layerId"));
+            assertEquals("0", layer2Info.getAttribute("top"));
+            assertEquals("0", layer2Info.getAttribute("left"));
+            assertEquals("225", layer2Info.getAttribute("bottom"));
+            assertEquals("300", layer2Info.getAttribute("right"));
+            assertEquals("norm", layer2Info.getAttribute("blendMode"));
+            assertEquals("255", layer2Info.getAttribute("opacity"));
+            assertEquals("base", layer2Info.getAttribute("clipping"));
+            assertEquals("true", layer2Info.getAttribute("visible"));
+            assertEquals("8", layer2Info.getAttribute("flags"));
+
+            IIOMetadataNode layer3Info = (IIOMetadataNode) layerInfos.item(2);
+            assertEquals("Layer 0 copy 2", layer3Info.getAttribute("name"));
+            assertEquals("12", layer3Info.getAttribute("layerId"));
+            assertEquals("0", layer3Info.getAttribute("top"));
+            assertEquals("0", layer3Info.getAttribute("left"));
+            assertEquals("225", layer3Info.getAttribute("bottom"));
+            assertEquals("159", layer3Info.getAttribute("right"));
+            assertEquals("norm", layer3Info.getAttribute("blendMode"));
+            assertEquals("255", layer3Info.getAttribute("opacity"));
+            assertEquals("base", layer3Info.getAttribute("clipping"));
+            assertEquals("true", layer3Info.getAttribute("visible"));
+            assertEquals("8", layer3Info.getAttribute("flags"));
+
+            IIOMetadataNode layer4Info = (IIOMetadataNode) layerInfos.item(3);
+            assertEquals("Layer 0 copy 3", layer4Info.getAttribute("name"));
+            assertEquals("13", layer4Info.getAttribute("layerId"));
+            assertEquals("0", layer4Info.getAttribute("top"));
+            assertEquals("0", layer4Info.getAttribute("left"));
+            assertEquals("225", layer4Info.getAttribute("bottom"));
+            assertEquals("300", layer4Info.getAttribute("right"));
+            assertEquals("norm", layer4Info.getAttribute("blendMode"));
+            assertEquals("255", layer4Info.getAttribute("opacity"));
+            assertEquals("base", layer4Info.getAttribute("clipping"));
+            assertEquals("false", layer4Info.getAttribute("visible"));
+            assertEquals("10", layer4Info.getAttribute("flags"));
+
+            IIOMetadataNode layer5Info = (IIOMetadataNode) layerInfos.item(4);
+            assertEquals("Layer 0", layer5Info.getAttribute("name"));
+            assertEquals("3", layer5Info.getAttribute("layerId"));
+            assertEquals("0", layer5Info.getAttribute("top"));
+            assertEquals("0", layer5Info.getAttribute("left"));
+            assertEquals("225", layer5Info.getAttribute("bottom"));
+            assertEquals("300", layer5Info.getAttribute("right"));
+            assertEquals("norm", layer5Info.getAttribute("blendMode"));
+            assertEquals("255", layer5Info.getAttribute("opacity"));
+            assertEquals("base", layer5Info.getAttribute("clipping"));
+            assertEquals("false", layer5Info.getAttribute("visible"));
+            assertEquals("10", layer5Info.getAttribute("flags"));
+        }
+    }
+}
@@ -4,7 +4,7 @@
    <parent>
        <groupId>com.twelvemonkeys.imageio</groupId>
        <artifactId>imageio</artifactId>
-        <version>3.12.1-SNAPSHOT</version>
+        <version>3.13.2-SNAPSHOT</version>
    </parent>
    <artifactId>imageio-reference</artifactId>
    <name>TwelveMonkeys :: ImageIO :: JDK Reference Tests</name>
@@ -4,7 +4,7 @@
    <parent>
        <groupId>com.twelvemonkeys.imageio</groupId>
        <artifactId>imageio</artifactId>
-        <version>3.12.1-SNAPSHOT</version>
+        <version>3.13.2-SNAPSHOT</version>
    </parent>
    <artifactId>imageio-sgi</artifactId>
    <name>TwelveMonkeys :: ImageIO :: SGI plugin</name>
@@ -4,7 +4,7 @@
    <parent>
        <groupId>com.twelvemonkeys.imageio</groupId>
        <artifactId>imageio</artifactId>
-        <version>3.12.1-SNAPSHOT</version>
+        <version>3.13.2-SNAPSHOT</version>
    </parent>
    <artifactId>imageio-tga</artifactId>
    <name>TwelveMonkeys :: ImageIO :: TGA plugin</name>
@@ -4,7 +4,7 @@
    <parent>
        <groupId>com.twelvemonkeys.imageio</groupId>
        <artifactId>imageio</artifactId>
-        <version>3.12.1-SNAPSHOT</version>
+        <version>3.13.2-SNAPSHOT</version>
    </parent>
    <artifactId>imageio-thumbsdb</artifactId>
    <name>TwelveMonkeys :: ImageIO :: Thumbs.db plugin</name>
@@ -4,7 +4,7 @@
    <parent>
        <groupId>com.twelvemonkeys.imageio</groupId>
        <artifactId>imageio</artifactId>
-        <version>3.12.1-SNAPSHOT</version>
+        <version>3.13.2-SNAPSHOT</version>
    </parent>
    <artifactId>imageio-tiff-jai-interop</artifactId>
    <name>TwelveMonkeys :: ImageIO :: TIFF/JAI Metadata Interop</name>
@@ -4,7 +4,7 @@
    <parent>
        <groupId>com.twelvemonkeys.imageio</groupId>
        <artifactId>imageio</artifactId>
-        <version>3.12.1-SNAPSHOT</version>
+        <version>3.13.2-SNAPSHOT</version>
    </parent>
    <artifactId>imageio-tiff-jdk-interop</artifactId>
    <name>TwelveMonkeys :: ImageIO :: TIFF/JDK JPEG Interop</name>
@@ -4,7 +4,7 @@
    <parent>
        <groupId>com.twelvemonkeys.imageio</groupId>
        <artifactId>imageio</artifactId>
-        <version>3.12.1-SNAPSHOT</version>
+        <version>3.13.2-SNAPSHOT</version>
    </parent>
    <artifactId>imageio-tiff</artifactId>
    <name>TwelveMonkeys :: ImageIO :: TIFF plugin</name>
@@ -42,6 +42,7 @@ import com.twelvemonkeys.imageio.stream.SubImageOutputStream;
 import com.twelvemonkeys.imageio.util.IIOUtil;
 import com.twelvemonkeys.imageio.util.ImageTypeSpecifiers;
 import com.twelvemonkeys.imageio.util.ProgressListenerBase;
+import com.twelvemonkeys.imageio.util.SequenceSupport;
 import com.twelvemonkeys.io.enc.EncoderStream;
 import com.twelvemonkeys.io.enc.PackBitsEncoder;
 import com.twelvemonkeys.lang.Validate;
@@ -110,12 +111,7 @@ public final class TIFFImageWriter extends ImageWriterBase {
    // Support storing multiple images in one stream (multi-page TIFF)
    // Support more of the ImageIO metadata (ie. compression from metadata, etc)

-    /**
-     * Flag for active sequence writing
-     */
-    private boolean writingSequence = false;
-
-    private int sequenceIndex = 0;
+    private final SequenceSupport sequence = new SequenceSupport();

    /**
     * Metadata writer for sequence writing
@@ -751,7 +747,7 @@ public final class TIFFImageWriter extends ImageWriterBase {
            ifd = ((TIFFImageMetadata) inData).getIFD();
        }
        else {
-            TIFFImageMetadata outData = new TIFFImageMetadata(Collections.<Entry>emptySet());
+            TIFFImageMetadata outData = new TIFFImageMetadata(Collections.emptySet());

            try {
                if (Arrays.asList(inData.getMetadataFormatNames()).contains(SUN_NATIVE_IMAGE_METADATA_FORMAT_NAME)) {
@@ -766,7 +762,7 @@ public final class TIFFImageWriter extends ImageWriterBase {
                }
            }
            catch (IIOInvalidTreeException e) {
-                processWarningOccurred(sequenceIndex, "Could not convert image meta data: " + e.getMessage());
+                processWarningOccurred(sequence.current(), "Could not convert image meta data: " + e.getMessage());
            }

            ifd = outData.getIFD();
@@ -966,14 +962,11 @@ public final class TIFFImageWriter extends ImageWriterBase {

    @Override
    public void prepareWriteSequence(final IIOMetadata streamMetadata) throws IOException {
-        if (writingSequence) {
-            throw new IllegalStateException("sequence writing has already been started!");
-        }
+        sequence.start();

        assertOutput();
        configureStreamByteOrder(streamMetadata, imageOutput);

-        writingSequence = true;
        sequenceTIFFWriter = new TIFFWriter(isBigTIFF() ? 8 : 4);
        sequenceTIFFWriter.writeTIFFHeader(imageOutput);
        sequenceLastIFDPos = imageOutput.getStreamPosition();
@@ -985,26 +978,20 @@ public final class TIFFImageWriter extends ImageWriterBase {

    @Override
    public void writeToSequence(final IIOImage image, final ImageWriteParam param) throws IOException {
-        if (!writingSequence) {
-            throw new IllegalStateException("prepareWriteSequence() must be called before writeToSequence()!");
-        }
+        int sequenceIndex = sequence.advance();

        if (sequenceIndex > 0) {
            imageOutput.flushBefore(sequenceLastIFDPos);
            imageOutput.seek(imageOutput.length());
        }

-        sequenceLastIFDPos = writePage(sequenceIndex++, image, param, sequenceTIFFWriter, sequenceLastIFDPos);
+        sequenceLastIFDPos = writePage(sequenceIndex, image, param, sequenceTIFFWriter, sequenceLastIFDPos);
    }

    @Override
    public void endWriteSequence() throws IOException {
-        if (!writingSequence) {
-            throw new IllegalStateException("prepareWriteSequence() must be called before endWriteSequence()!");
-        }
+        sequence.end();

-        writingSequence = false;
-        sequenceIndex = 0;
        sequenceTIFFWriter = null;
        sequenceLastIFDPos = -1;
        imageOutput.flush();
@@ -1014,8 +1001,7 @@ public final class TIFFImageWriter extends ImageWriterBase {
    protected void resetMembers() {
        super.resetMembers();

-        writingSequence = false;
-        sequenceIndex = 0;
+        sequence.reset();
        sequenceTIFFWriter = null;
        sequenceLastIFDPos = -1;
    }
@@ -4,7 +4,7 @@
    <parent>
        <groupId>com.twelvemonkeys.imageio</groupId>
        <artifactId>imageio</artifactId>
-        <version>3.12.1-SNAPSHOT</version>
+        <version>3.13.2-SNAPSHOT</version>
    </parent>
    <artifactId>imageio-webp</artifactId>
    <name>TwelveMonkeys :: ImageIO :: WebP plugin</name>
@@ -565,7 +565,7 @@ final class WebPImageReader extends ImageReaderBase {
                readVP8Lossless(tempRaster, null, width, height);

                // Copy from green (band 1) in temp to alpha in destination
-                WritableRaster alphaChannel = tempRaster.createWritableChild(0, 0, tempRaster.getWidth(), tempRaster.getHeight(), 0, 0, new int[]{1});
+                WritableRaster alphaChannel = tempRaster.createWritableChild(0, 0, width, height, 0, 0, new int[]{1});
                alphaFilter(alphaChannel, filtering);
                copyIntoRasterWithParams(alphaChannel, alphaRaster, param);
                break;
@@ -166,73 +166,81 @@ final class HuffmanTable {
        if (numPosCodeLens == 1) {
            // Length is 0 so mask to clear length bits
            Arrays.fill(level1, lengthsAndSymbols[0] & 0xffff);
+            return;
        }

        // Due to the layout of the elements this effectively first sorts by length and then symbol.
        Arrays.sort(lengthsAndSymbols);

+        int[] count = new int[16];
+        for (int lengthAndSymbol : lengthsAndSymbols) {
+            count[lengthAndSymbol >>> 16]++;
+        }
+
        // The next code, in the bit order it would appear on the input stream, i.e. it is reversed.
        // Only the lowest bits (corresponding to the bit length of the code) are considered.
        // Example: code 0..010 (length 2) would appear as 0..001.
        int code = 0;
+        int step = 2;
+        index = 0;

-        // Used for level2 lookup
+        for (int length = 1; length <= LEVEL1_BITS; length++, step <<= 1) {
+            for (; count[length] > 0; count[length]--) {
+                int lengthAndSymbol = lengthsAndSymbols[index++];
+
+                for (int j = code; j < level1.length; j += step) {
+                    level1[j] = lengthAndSymbol;
+                }
+
+                code = nextCode(code, length);
+            }
+        }
+
+        int rootMask = (1 << LEVEL1_BITS) - 1;
        int rootEntry = -1;
        int[] currentTable = null;

-        for (int i = 0; i < lengthsAndSymbols.length; i++) {
-            int lengthAndSymbol = lengthsAndSymbols[i];
+        step = 2;
+        for (int length = LEVEL1_BITS + 1; length <= 15; length++, step <<= 1) {
+            for (; count[length] > 0; count[length]--) {
+                int lengthAndSymbol = lengthsAndSymbols[index++];

-            int length = lengthAndSymbol >>> 16;
+                if ((code & rootMask) != rootEntry) {
+                    int level2Bits = nextTableBitSize(count, length, LEVEL1_BITS);
+                    int level2Size = 1 << level2Bits;

-            if (length <= LEVEL1_BITS) {
-                for (int j = code; j < level1.length; j += 1 << length) {
-                    level1[j] = lengthAndSymbol;
-                }
-            }
-            else {
-                // Existing level2 table not fitting
-                if ((code & ((1 << LEVEL1_BITS) - 1)) != rootEntry) {
-                    // Figure out needed table size.
-                    // Start at current symbol and length.
-                    // Every symbol uses 1 slot at the current bit length.
-                    // Going up 1 bit in length multiplies the slots by 2.
-                    // No more open slots indicate the table size to be big enough.
-                    int maxLength = length;
-
-                    for (int j = i, openSlots = 1 << (length - LEVEL1_BITS);
-                         j < lengthsAndSymbols.length && openSlots > 0;
-                         j++, openSlots--) {
-
-                        int innerLength = lengthsAndSymbols[j] >>> 16;
-
-                        while (innerLength != maxLength) {
-                            maxLength++;
-                            openSlots <<= 1;
-                        }
-                    }
-
-                    int level2Size = maxLength - LEVEL1_BITS;
-
-                    currentTable = new int[1 << level2Size];
-                    rootEntry = code & ((1 << LEVEL1_BITS) - 1);
+                    currentTable = new int[level2Size];
+                    rootEntry = code & rootMask;
                    level2.add(currentTable);

                    // Set root table indirection
-                    level1[rootEntry] = (LEVEL1_BITS + level2Size) << 16 | (level2.size() - 1);
+                    level1[rootEntry] = (LEVEL1_BITS + level2Bits) << 16 | (level2.size() - 1);
                }

-                // Add to existing (or newly generated) 2nd level table
-                for (int j = (code >>> LEVEL1_BITS); j < currentTable.length; j += 1 << (length - LEVEL1_BITS)) {
-                    currentTable[j] = (length - LEVEL1_BITS) << 16 | (lengthAndSymbol & 0xffff);
+                int value = (length - LEVEL1_BITS) << 16 | (lengthAndSymbol & 0xffff);
+                for (int j = (code >>> LEVEL1_BITS); j < currentTable.length; j += step) {
+                    currentTable[j] = value;
                }
+
+                code = nextCode(code, length);
            }
-
-            code = nextCode(code, length);
-
        }
    }

+    private static int nextTableBitSize(int[] count, int length, int rootBits) {
+        int left = 1 << (length - rootBits);
+        while (length < 15) {
+            left -= count[length];
+            if (left <= 0) {
+                break;
+            }
+            length++;
+            left <<= 1;
+        }
+
+        return length - rootBits;
+    }
+
    /**
     * Computes the next code
     *
@@ -148,8 +148,7 @@ public final class VP8LDecoder {
            if (param.getSourceRegion() != null && !param.getSourceRegion().contains(bounds) ||
                    param.getSourceXSubsampling() != 1 || param.getSourceYSubsampling() != 1) {
                // Can't reuse existing
-                return Raster.createInterleavedRaster(DataBuffer.TYPE_BYTE, bounds.width, bounds.height,
-                        4 * bounds.width, 4, new int[] {0, 1, 2, 3}, null);
+                return createCompatibleRaster(raster, bounds.width, bounds.height);
            }
            else {
                bounds.setLocation(param.getDestinationOffset());
@@ -159,8 +158,7 @@ public final class VP8LDecoder {

        if (!raster.getBounds().contains(bounds)) {
            // Can't reuse existing
-            return Raster.createInterleavedRaster(DataBuffer.TYPE_BYTE, bounds.width, bounds.height, 4 * bounds.width,
-                    4, new int[] {0, 1, 2, 3}, null);
+            return createCompatibleRaster(raster, bounds.width, bounds.height);
        }

        return originSet ?
@@ -169,6 +167,11 @@ public final class VP8LDecoder {
                raster;
    }

+    private static WritableRaster createCompatibleRaster(WritableRaster src, int width, int height) {
+        SampleModel sampleModel = src.getSampleModel().createCompatibleSampleModel(width, height);
+        return Raster.createWritableRaster(sampleModel, sampleModel.createDataBuffer(), null);
+    }
+
    /**
     * Copy a source raster into a destination raster with optional settings applied.
     */
@@ -182,7 +185,8 @@ public final class VP8LDecoder {

        if (sourceXSubsampling == 1 && sourceYSubsampling == 1) {
            // Only apply offset (and limit to requested region)
-            dstRaster.setRect(destinationOffset.x, destinationOffset.y, srcRaster);
+            dstRaster.setRect(destinationOffset.x, destinationOffset.y, srcRaster.createChild(
+                    sourceRegion.x, sourceRegion.y, sourceRegion.width, sourceRegion.height, 0, 0, null));
        }
        else {
            // Subsampled case
@@ -272,6 +276,12 @@ public final class VP8LDecoder {
    private int decodeBwRef(WritableRaster raster, ColorCache colorCache, int width, HuffmanCodeGroup curCodeGroup, byte[] rgba, short code, int x, int y) throws IOException {
        int length = lz77decode(code - 256);

+        int remaining = width * raster.getHeight() - (y * width + x);
+        if (length > remaining) {
+            throw new IIOException("Corrupt WebP stream, backward reference exceeds image bounds: length=" + length +
+                                   ", remaining=" + remaining + ", x=" + x + ", y=" + y);
+        }
+
        short distancePrefix = curCodeGroup.distanceCode.readSymbol(lsbBitReader);
        int distanceCode = lz77decode(distancePrefix);

@@ -298,6 +308,11 @@ public final class VP8LDecoder {
            ySrc++;
        }

+        if (ySrc < 0 || ySrc >= raster.getHeight()) {
+            throw new IIOException("Corrupt WebP stream, backward reference outside image: distance=" + distanceCode +
+                                   ", x=" + x + ", y=" + y + ", xSrc=" + xSrc + ", ySrc=" + ySrc);
+        }
+
        for (int l = length; l > 0; x++, l--) {
            // Check length and xSrc, ySrc not falling outside raster? (Should not occur if image is correct)
            if (x == width) {
@@ -1,3 +1,4 @@
+
 package com.twelvemonkeys.imageio.plugins.webp;

 import com.twelvemonkeys.imageio.util.ImageReaderAbstractTest;
@@ -11,6 +12,8 @@ import javax.imageio.stream.MemoryCacheImageInputStream;
 import java.awt.*;
 import java.awt.image.*;
 import java.io.IOException;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
 import java.util.List;

 import static java.util.Arrays.asList;
@@ -43,6 +46,7 @@ public class WebPImageReaderTest extends ImageReaderAbstractTest<WebPImageReader
                new TestData(getClassLoaderResource("/webp/1_webp_ll.webp"), new Dimension(400, 301)),
                new TestData(getClassLoaderResource("/webp/2_webp_ll.webp"), new Dimension(386, 395)),
                new TestData(getClassLoaderResource("/webp/2_webp_ll_alt.webp"), new Dimension(386, 395)),
+                new TestData(getClassLoaderResource("/webp/2_webp_ll_noalpha.webp"), new Dimension(386, 395)),
                new TestData(getClassLoaderResource("/webp/3_webp_ll.webp"), new Dimension(800, 600)),
                new TestData(getClassLoaderResource("/webp/4_webp_ll.webp"), new Dimension(421, 163)),
                new TestData(getClassLoaderResource("/webp/5_webp_ll.webp"), new Dimension(300, 300)),
@@ -188,4 +192,153 @@ public class WebPImageReaderTest extends ImageReaderAbstractTest<WebPImageReader
            reader.dispose();
        }
    }
+
+    @Test
+    public void testLosslessSourceRegionSubsampling() throws IOException {
+        WebPImageReader reader = createReader();
+
+        try (ImageInputStream stream = ImageIO.createImageInputStream(getClassLoaderResource("/webp/2_webp_ll_noalpha.webp"))) {
+            reader.setInput(stream);
+
+            // We'll read a small portion of the image using a subsampling factor of 2
+            ImageReadParam param = reader.getDefaultReadParam();
+            param.setSourceRegion(new Rectangle(100, 20, 200, 200));
+            param.setSourceSubsampling(2, 2, 0, 0);
+
+            BufferedImage image = reader.read(0, param);
+
+            for (int x = 0; x < 23; x++) {
+                assertRGBEquals("Expected white at (" + x + ", 0)", 0xFFFFFFFF, image.getRGB(x, 0), 0);
+            }
+
+            for (int x = 24; x < 29; x++) {
+                assertRGBEquals("Expected black at (" + x + ", 0)", 0xFF000000, image.getRGB(x, 0), 0);
+            }
+
+            for (int x = 30; x < 64; x++) {
+                assertRGBEquals("Expected grey at (" + x + ", 0)", 0xFFF1F1F1, image.getRGB(x, 0), 0);
+            }
+
+            for (int x = 66; x < 69; x++) {
+                assertRGBEquals("Expected black at (" + x + ", 0)", 0xFF000000, image.getRGB(x, 0), 0);
+            }
+
+            for (int x = 70; x < 100; x++) {
+                assertRGBEquals("Expected white at (" + x + ", 0)", 0xFFFFFFFF, image.getRGB(x, 0), 0);
+            }
+        }
+        finally {
+            reader.dispose();
+        }
+    }
+
+    @Test
+    public void testLosslessSourceRegionNoSubsampling() throws IOException {
+        WebPImageReader reader = createReader();
+
+        try (ImageInputStream stream = ImageIO.createImageInputStream(getClassLoaderResource("/webp/2_webp_ll_noalpha.webp"))) {
+            reader.setInput(stream);
+
+            // We'll read a small portion of the image without using subsampling
+            ImageReadParam param = reader.getDefaultReadParam();
+            param.setSourceRegion(new Rectangle(100, 20, 200, 200));
+
+            BufferedImage image = reader.read(0, param);
+
+            for (int x = 0; x < 45; x++) {
+                assertRGBEquals("Expected white at (" + x + ", 0)", 0xFFFFFFFF, image.getRGB(x, 0), 0);
+            }
+
+            for (int x = 48; x < 58; x++) {
+                assertRGBEquals("Expected black at (" + x + ", 0)", 0xFF000000, image.getRGB(x, 0), 0);
+            }
+
+            for (int x = 60; x < 128; x++) {
+                assertRGBEquals("Expected grey at (" + x + ", 0)", 0xFFF1F1F1, image.getRGB(x, 0), 0);
+            }
+
+            for (int x = 131; x < 138; x++) {
+                assertRGBEquals("Expected black at (" + x + ", 0)", 0xFF000000, image.getRGB(x, 0), 0);
+            }
+
+            for (int x = 140; x < 200; x++) {
+                assertRGBEquals("Expected white at (" + x + ", 0)", 0xFFFFFFFF, image.getRGB(x, 0), 0);
+            }
+        }
+        finally {
+            reader.dispose();
+        }
+    }
+
+    /**
+     * This test compares alpha channel information that is decoded by the WebPImageReader with the known "good" alpha 
+     * channel information. To generate the known "good" alpha channel information, we use the command line and libwebp,
+     * e.g.
+     * 
+     * <pre>{@code
+     * dwebp imageio/imageio-webp/src/test/resources/webp/lossless.transparent.webp -o /tmp/lossless.transparent.png
+     * magick /tmp/lossless.transparent.png -alpha extract -depth 8 gray:/tmp/lossless.transparent-alpha.raw
+     * shasum -a 256 /tmp/lossless.transparent-alpha.raw
+     * }</pre>
+     * 
+     * @throws IOException
+     */
+    @Test
+    public void testReadWriteTransparentWebP() throws IOException {
+        WebPImageReader reader = createReader();
+  
+        try (ImageInputStream stream = ImageIO.createImageInputStream(getClassLoaderResource("/webp/lossless.transparent.webp"))) {
+            reader.setInput(stream);
+
+            // Read dimensions
+            int width = reader.getWidth(0);
+            int height = reader.getHeight(0);
+            assertEquals(1920, width, "Expected width of 1920");
+            assertEquals(1477, height, "Expected height of 1477");
+
+            // Read the full image and validate alpha output (exercises long LZ77 back-references).
+            BufferedImage image = reader.read(0);
+            assertNotNull(image, "Image should not be null");
+            assertEquals(width, image.getWidth(), "Image width should match");
+            assertEquals(height, image.getHeight(), "Image height should match");
+            assertTrue(image.getColorModel().hasAlpha(), "Image should have alpha channel");
+            assertEquals("79ffff20392a9cef308b317cbac9d3e57f78e26a4f49fb38b3f3b4dbc4e63c50",
+                    sha256Alpha(image), "Alpha plane hash mismatch");
+        }
+        finally {
+            reader.dispose();
+        }
+    }
+
+    private static String sha256Alpha(BufferedImage image) {
+        WritableRaster alphaRaster = image.getAlphaRaster();
+        assertNotNull(alphaRaster, "Image should have alpha raster");
+
+        int width = alphaRaster.getWidth();
+        int height = alphaRaster.getHeight();
+        int[] samples = alphaRaster.getSamples(0, 0, width, height, 0, (int[]) null);
+
+        MessageDigest digest;
+        try {
+            digest = MessageDigest.getInstance("SHA-256");
+        }
+        catch (NoSuchAlgorithmException e) {
+            throw new AssertionError("SHA-256 not available", e);
+        }
+
+        for (int sample : samples) {
+            digest.update((byte) sample);
+        }
+
+        return toHex(digest.digest());
+    }
+
+    private static String toHex(byte[] bytes) {
+        StringBuilder builder = new StringBuilder(bytes.length * 2);
+        for (byte b : bytes) {
+            builder.append(Character.forDigit((b >>> 4) & 0x0f, 16));
+            builder.append(Character.forDigit(b & 0x0f, 16));
+        }
+        return builder.toString();
+    }
 }
@@ -4,7 +4,7 @@
    <parent>
        <groupId>com.twelvemonkeys.imageio</groupId>
        <artifactId>imageio</artifactId>
-        <version>3.12.1-SNAPSHOT</version>
+        <version>3.13.2-SNAPSHOT</version>
    </parent>
    <artifactId>imageio-xwd</artifactId>
    <name>TwelveMonkeys :: ImageIO :: XWD plugin</name>
@@ -3,7 +3,7 @@
    <parent>
        <groupId>com.twelvemonkeys</groupId>
        <artifactId>twelvemonkeys</artifactId>
-        <version>3.12.1-SNAPSHOT</version>
+        <version>3.13.2-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.twelvemonkeys.imageio</groupId>
@@ -61,7 +61,7 @@
    </modules>

    <properties>
-        <junit.jupiter.version>5.14.0</junit.jupiter.version>
+        <junit.jupiter.version>5.14.3</junit.jupiter.version>
    </properties>

    <dependencies>
@@ -4,7 +4,7 @@

    <groupId>com.twelvemonkeys</groupId>
    <artifactId>twelvemonkeys</artifactId>
-    <version>3.12.1-SNAPSHOT</version>
+    <version>3.13.2-SNAPSHOT</version>
    <packaging>pom</packaging>
    <name>TwelveMonkeys</name>
    <description>TwelveMonkeys parent POM</description>
@@ -85,8 +85,8 @@

    <distributionManagement>
        <snapshotRepository>
-            <id>ossrh</id>
-            <url>https://oss.sonatype.org/content/repositories/snapshots</url>
+            <id>central</id>
+            <url>https://central.sonatype.com/repository/maven-snapshots/</url>
        </snapshotRepository>
    </distributionManagement>

@@ -160,7 +160,7 @@
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-source-plugin</artifactId>
-                <version>3.3.1</version>
+                <version>3.4.0</version>
                <executions>
                    <execution>
                        <phase>package</phase>
@@ -174,14 +174,14 @@
            </plugin>

            <plugin>
-                <groupId>org.sonatype.plugins</groupId>
-                <artifactId>nexus-staging-maven-plugin</artifactId>
-                <version>1.7.0</version>
+                <groupId>org.sonatype.central</groupId>
+                <artifactId>central-publishing-maven-plugin</artifactId>
+                <version>0.10.0</version>
                <extensions>true</extensions>
                <configuration>
-                    <serverId>ossrh</serverId>
-                    <nexusUrl>https://oss.sonatype.org/</nexusUrl>
-                    <autoReleaseAfterClose>true</autoReleaseAfterClose>
+                    <publishingServerId>central</publishingServerId>
+                    <autoPublish>true</autoPublish>
+                    <waitUntil>published</waitUntil>
                </configuration>
            </plugin>
        </plugins>
@@ -191,7 +191,7 @@
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-resources-plugin</artifactId>
-                    <version>3.3.1</version>
+                    <version>3.5.0</version>
                    <configuration>
                        <encoding>UTF-8</encoding>
                    </configuration>
@@ -199,7 +199,7 @@
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-jar-plugin</artifactId>
-                    <version>3.4.2</version>
+                    <version>3.5.0</version>
                    <inherited>true</inherited>
                    <executions>
                        <execution>
@@ -250,7 +250,7 @@
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-compiler-plugin</artifactId>
-                    <version>3.14.1</version>
+                    <version>3.15.0</version>
                    <inherited>true</inherited>
                    <configuration>
                        <source>8</source>
@@ -265,7 +265,7 @@
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-surefire-plugin</artifactId>
-                    <version>3.5.4</version>
+                    <version>3.5.5</version>
                    <configuration>
                        <systemProperties>
                            <property>
@@ -278,7 +278,7 @@
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-release-plugin</artifactId>
-                    <version>3.1.1</version>
+                    <version>3.3.1</version>
                    <configuration>
                        <autoVersionSubmodules>true</autoVersionSubmodules>
                        <releaseProfiles>release</releaseProfiles>
@@ -300,7 +300,7 @@
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-surefire-report-plugin</artifactId>
-                    <version>3.5.4</version>
+                    <version>3.5.5</version>
                </plugin>
                <plugin>
                    <groupId>org.codehaus.mojo</groupId>
@@ -310,7 +310,7 @@
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-pmd-plugin</artifactId>
-                    <version>3.27.0</version>
+                    <version>3.28.0</version>
                </plugin>
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
@@ -3,7 +3,7 @@
    <parent>
        <groupId>com.twelvemonkeys</groupId>
        <artifactId>twelvemonkeys</artifactId>
-        <version>3.12.1-SNAPSHOT</version>
+        <version>3.13.2-SNAPSHOT</version>
    </parent>

    <modelVersion>4.0.0</modelVersion>
@@ -15,7 +15,7 @@
    </description>

    <properties>
-        <junit.jupiter.version>5.14.0</junit.jupiter.version>
+        <junit.jupiter.version>5.14.3</junit.jupiter.version>
    </properties>

    <dependencies>
@@ -61,7 +61,7 @@
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-jar-plugin</artifactId>
-                <version>3.4.2</version>
+                <version>3.5.0</version>
                <configuration>
                    <archive>
                        <manifestEntries>
@@ -82,7 +82,7 @@
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-shade-plugin</artifactId>
-                <version>3.6.1</version>
+                <version>3.6.2</version>
                <executions>
                    <execution>
                        <id>jakarta</id>
				`@@ -0,0 +1 @@`
				`com.twelvemonkeys.imageio.plugins.dds.DDSImageWriterSpi`