#287 Support for TIFF with color map + discrete alpha channel.

imageio/imageio-tiff/src/main/java/com/twelvemonkeys/imageio/plugins/tiff/TIFFImageReader.java

@@ -52,7 +52,6 @@ import com.twelvemonkeys.io.FastByteArrayOutputStream;
 import com.twelvemonkeys.io.LittleEndianDataInputStream;
 import com.twelvemonkeys.io.enc.DecoderStream;
 import com.twelvemonkeys.io.enc.PackBitsDecoder;
-import com.twelvemonkeys.xml.XMLSerializer;
 import org.w3c.dom.NodeList;
 
 import javax.imageio.*;
@@ -459,7 +458,7 @@ public class TIFFImageReader extends ImageReaderBase {
                 }
             case TIFFBaseline.PHOTOMETRIC_PALETTE:
                 // Palette
-                if (samplesPerPixel != 1) {
+                if (samplesPerPixel != 1 && !(samplesPerPixel == 2 && extraSamples != null && extraSamples.length == 1)) {
                     throw new IIOException("Bad SamplesPerPixel value for Palette TIFF (expected 1): " + samplesPerPixel);
                 }
                 else if (bitsPerSample <= 0 || bitsPerSample > 16) {
@@ -474,6 +473,12 @@ public class TIFFImageReader extends ImageReaderBase {
 
                 IndexColorModel icm = createIndexColorModel(bitsPerSample, dataType, (int[]) colorMap.getValue());
 
+                if (extraSamples != null && extraSamples.length > 0
+                        && (extraSamples[0] == TIFFBaseline.EXTRASAMPLE_ASSOCIATED_ALPHA
+                        || extraSamples[0] == TIFFBaseline.EXTRASAMPLE_UNASSOCIATED_ALPHA)) {
+                    return ImageTypeSpecifiers.createDiscreteAlphaIndexedFromIndexColorModel(icm);
+                }
+
                 return ImageTypeSpecifiers.createFromIndexColorModel(icm);
 
             case TIFFExtension.PHOTOMETRIC_SEPARATED:
@@ -808,8 +813,11 @@ public class TIFFImageReader extends ImageReaderBase {
 
         int tilesAcross = (width + stripTileWidth - 1) / stripTileWidth;
         int tilesDown = (height + stripTileHeight - 1) / stripTileHeight;
+
+        // TODO: Get number of extra samples not part of the rawType spec...
         // TODO: If extrasamples, we might need to create a raster with more samples...
         WritableRaster rowRaster = rawType.createBufferedImage(stripTileWidth, 1).getRaster();
+//        WritableRaster rowRaster = Raster.createInterleavedRaster(DataBuffer.TYPE_BYTE, stripTileWidth, 1, 2, null).createWritableChild(0, 0, stripTileWidth, 1, 0, 0, new int[]{0});
         Rectangle clip = new Rectangle(srcRegion);
         int row = 0;
         Boolean needsCSConversion = null;

imageio/imageio-tiff/src/test/java/com/twelvemonkeys/imageio/plugins/tiff/TIFFImageReaderTest.java

@@ -93,6 +93,7 @@ public class TIFFImageReaderTest extends ImageReaderAbstractTest<TIFFImageReader
                 new TestData(getClassLoaderResource("/tiff/lzw-colormap-iiobe.tif"), new Dimension(2550, 3300)), // RGBA, LZW compression, will throw IOOBE if small buffer
                 new TestData(getClassLoaderResource("/tiff/scan-mono-iccgray.tif"), new Dimension(2408, 3436)), // B/W, PackBits w/gray ICC profile
                 new TestData(getClassLoaderResource("/tiff/planar-striped-lzw.tif"), new Dimension(229, 229)), // RGB 8 bit/sample, planar, LZW compression
+                new TestData(getClassLoaderResource("/tiff/colormap-with-extrasamples.tif"), new Dimension(10, 10)), // Palette, 8 bit/sample, 2 samples/pixel, extra samples, LZW
                 // CCITT
                 new TestData(getClassLoaderResource("/tiff/ccitt/group3_1d.tif"), new Dimension(6, 4)), // B/W, CCITT T4 1D
                 new TestData(getClassLoaderResource("/tiff/ccitt/group3_1d_fill.tif"), new Dimension(6, 4)), // B/W, CCITT T4 1D