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#253: Fix for non-subsampled YCbCr encoded JPEG-in-TIFF being decoded as RGB.

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Harald Kuhr
2016-06-28 12:54:25 +02:00
parent 788b11e4fa
commit 458ef92af5
4 changed files with 240 additions and 51 deletions
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25
imageio/imageio-core/src/main/java/com/twelvemonkeys/imageio/color/YCbCrConverter.java
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@@ -47,17 +47,30 @@ public final class YCbCrConverter {
buildYCCtoRGBtable();
}
public static void convertYCbCr2RGB(final byte[] yCbCr, final byte[] rgb, final double[] coefficients, final int offset) {
double y = (yCbCr[offset] & 0xff);
double cb = (yCbCr[offset + 1] & 0xff) - 128;
double cr = (yCbCr[offset + 2] & 0xff) - 128;
public static void convertYCbCr2RGB(final byte[] yCbCr, final byte[] rgb, final double[] coefficients, double[] referenceBW, final int offset) {
double y;
double cb;
double cr;
if (referenceBW == null) {
// Default case
y = (yCbCr[offset] & 0xff);
cb = (yCbCr[offset + 1] & 0xff) - 128;
cr = (yCbCr[offset + 2] & 0xff) - 128;
}
else {
// Custom values
y = ((yCbCr[offset] & 0xff) - referenceBW[0]) * 255.0 / (referenceBW[1] - referenceBW[0]);
cb = ((yCbCr[offset + 1] & 0xff) - referenceBW[2]) * 127.0 / (referenceBW[3] - referenceBW[2]);
cr = ((yCbCr[offset + 2] & 0xff) - referenceBW[4]) * 127.0 / (referenceBW[5] - referenceBW[4]);
}
double lumaRed = coefficients[0];
double lumaGreen = coefficients[1];
double lumaBlue = coefficients[2];
int red = (int) Math.round(cr * (2 - 2 * lumaRed) + y);
int blue = (int) Math.round(cb * (2 - 2 * lumaBlue) + y);
int red = (int) Math.round(cr * (2.0 - 2.0 * lumaRed) + y);
int blue = (int) Math.round(cb * (2.0 - 2.0 * lumaBlue) + y);
int green = (int) Math.round((y - lumaRed * red - lumaBlue * blue) / lumaGreen);
rgb[offset] = clamp(red);