#577 Fix TGA subsampling + bonus metadata fix and palette conversion.

imageio/imageio-tga/src/main/java/com/twelvemonkeys/imageio/plugins/tga/TGAHeader.java

@@ -200,12 +200,12 @@ final class TGAHeader {
             int components = colorMap.hasAlpha() ? 4 : 3;
             byte[] cmap = new byte[rgb.length * components];
             for (int i = 0; i < rgb.length; i++) {
-                cmap[i * components    ] = (byte) ((rgb[i] >> 16) & 0xff);
+                cmap[i * components    ] = (byte) ((rgb[i]      ) & 0xff); // B
-                cmap[i * components + 1] = (byte) ((rgb[i] >>  8) & 0xff);
+                cmap[i * components + 1] = (byte) ((rgb[i] >>  8) & 0xff); // G
-                cmap[i * components + 2] = (byte) ((rgb[i]      ) & 0xff);
+                cmap[i * components + 2] = (byte) ((rgb[i] >> 16) & 0xff); // R
 
                 if (components == 4) {
-                    cmap[i * components + 3] = (byte) ((rgb[i] >>> 24) & 0xff);
+                    cmap[i * components + 3] = (byte) ((rgb[i] >>> 24) & 0xff); // A
                 }
             }
 
@@ -298,9 +298,23 @@ final class TGAHeader {
                 hasAlpha = false;
                 break;
             case 24:
+                // BGR -> RGB
+                for (int i = 0; i < cmap.length; i += 3) {
+                    byte b = cmap[i];
+                    cmap[i    ] = cmap[i + 2];
+                    cmap[i + 2] = b;
+                }
+
                 hasAlpha = false;
                 break;
             case 32:
+                // BGRA -> RGBA
+                for (int i = 0; i < cmap.length; i += 4) {
+                    byte b = cmap[i];
+                    cmap[i    ] = cmap[i + 2];
+                    cmap[i + 2] = b;
+                }
+
                 hasAlpha = true;
                 break;
             default:

imageio/imageio-tga/src/main/java/com/twelvemonkeys/imageio/plugins/tga/TGAImageReader.java

@@ -224,7 +224,7 @@ final class TGAImageReader extends ImageReaderBase {
                              byte[] rowDataByte, WritableRaster destChannel, Raster srcChannel, int y) throws IOException {
         // If subsampled or outside source region, skip entire row
         if (y % ySub != 0 || height - 1 - y < srcRegion.y || height - 1 - y >= srcRegion.y + srcRegion.height) {
-            imageInput.skipBytes(rowDataByte.length);
+            input.skipBytes(rowDataByte.length);
 
             return;
         }
@@ -251,7 +251,8 @@ final class TGAImageReader extends ImageReaderBase {
                 destChannel.setDataElements(0, dstY, srcChannel);
                 break;
             case TGA.ORIGIN_UPPER_LEFT:
-                destChannel.setDataElements(0, y, srcChannel);
+                dstY = y / ySub;
+                destChannel.setDataElements(0, dstY, srcChannel);
                 break;
             default:
                 throw new IIOException("Unsupported origin: " + origin);
@@ -289,7 +290,8 @@ final class TGAImageReader extends ImageReaderBase {
                 destChannel.setDataElements(0, dstY, srcChannel);
                 break;
             case TGA.ORIGIN_UPPER_LEFT:
-                destChannel.setDataElements(0, y, srcChannel);
+                dstY = y / ySub;
+                destChannel.setDataElements(0, dstY, srcChannel);
                 break;
             default:
                 throw new IIOException("Unsupported origin: " + origin);

imageio/imageio-tga/src/main/java/com/twelvemonkeys/imageio/plugins/tga/TGAMetadata.java

@@ -189,6 +189,7 @@ final class TGAMetadata extends AbstractMetadata {
         switch (header.getPixelDepth()) {
             case 8:
                 bitsPerSample.setAttribute("value", createListValue(1, Integer.toString(header.getPixelDepth())));
+                break;
             case 16:
                 if (header.getAttributeBits() > 0 && extensions != null && extensions.hasAlpha()) {
                     bitsPerSample.setAttribute("value", "5, 5, 5, 1");

imageio/imageio-tga/src/test/java/com/twelvemonkeys/imageio/plugins/tga/TGAImageReaderTest.java

@@ -32,11 +32,19 @@ package com.twelvemonkeys.imageio.plugins.tga;
 
 import com.twelvemonkeys.imageio.util.ImageReaderAbstractTest;
 
+import org.junit.Test;
+
+import javax.imageio.ImageReadParam;
+import javax.imageio.ImageReader;
 import javax.imageio.spi.ImageReaderSpi;
+import javax.imageio.stream.ImageInputStream;
 import java.awt.*;
+import java.io.IOException;
 import java.util.Arrays;
 import java.util.List;
 
+import static org.junit.Assert.assertNotNull;
+
 /**
  * TGAImageReaderTest
  *
@@ -104,4 +112,23 @@ public class TGAImageReaderTest extends ImageReaderAbstractTest<TGAImageReader>
                 "image/targa", "image/x-targa"
         );
     }
+
+    @Test
+    public void testSubsampling() throws IOException {
+        ImageReader reader = createReader();
+        ImageReadParam param = reader.getDefaultReadParam();
+        param.setSourceSubsampling(3, 5, 0, 0);
+
+        for (TestData testData : getTestData()) {
+            try (ImageInputStream input = testData.getInputStream()) {
+                reader.setInput(input);
+                assertNotNull(reader.read(0, param));
+            }
+            finally {
+                reader.reset();
+            }
+        }
+
+        reader.dispose();
+    }
 }