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Decode alpha using source dimensions and copy to destination later.

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(cherry picked from commit 703848ca45827b98b215c62d3c03d8663502e15d)
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tc-wleite 2023-03-14 21:01:29 -03:00 committed by Harald Kuhr
parent 214f0acf29
commit 7deaf47e65
1 changed files with 10 additions and 5 deletions
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15
imageio/imageio-webp/src/main/java/com/twelvemonkeys/imageio/plugins/webp/WebPImageReader.java
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@ -527,7 +527,8 @@ final class WebPImageReader extends ImageReaderBase {
System.out.println("compression: " + compression);
}
WritableRaster alphaRaster = destination.getAlphaRaster();
// Alpha raster must have same dimensions as the source, because of gradient filtering.
WritableRaster alphaRaster = Raster.createInterleavedRaster(DataBuffer.TYPE_BYTE, width, height, 1, null);
switch (compression) {
case 0:
readUncompressedAlpha(alphaRaster);
@ -536,8 +537,8 @@ final class WebPImageReader extends ImageReaderBase {
// Simulate header
imageInput.seek(imageInput.getStreamPosition() - 5);
WritableRaster tempRaster = Raster.createInterleavedRaster(DataBuffer.TYPE_BYTE, destination.getWidth(), destination.getHeight(), 4, null);
readVP8Lossless(tempRaster, param, width, height);
WritableRaster tempRaster = Raster.createInterleavedRaster(DataBuffer.TYPE_BYTE, width, height, 4, null);
readVP8Lossless(tempRaster, null, width, height);
// Copy from green (band 1) in temp to alpha in destination
alphaRaster.setRect(tempRaster.createChild(0, 0, tempRaster.getWidth(), tempRaster.getHeight(), 0, 0, new int[] {1}));
@ -549,13 +550,17 @@ final class WebPImageReader extends ImageReaderBase {
}
if (filtering != AlphaFiltering.NONE) {
for (int y = 0; y < destination.getHeight(); y++) {
for (int x = 0; x < destination.getWidth(); x++) {
for (int y = 0; y < height; y++) {
for (int x = 0; x < width; x++) {
int predictorAlpha = getPredictorAlpha(alphaRaster, filtering, y, x);
alphaRaster.setSample(x, y, 0, alphaRaster.getSample(x, y, 0) + predictorAlpha % 256);
}
}
}
// Copy into destination raster
WritableRaster dstRaster = destination.getAlphaRaster();
VP8LDecoder.copyIntoRasterWithParams(alphaRaster, dstRaster, param);
}
private int getPredictorAlpha(WritableRaster alphaRaster, int filtering, int y, int x) {