Thomas Elsner created IMAGING-204:
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Summary: reading monochrome TIFF leads to unhandled exception
Key: IMAGING-204
URL: https://issues.apache.org/jira/browse/IMAGING-204
Project: Commons Imaging
Issue Type: Bug
Components: Format: TIFF
Affects Versions: 1.0
Reporter: Thomas Elsner
reading monochrome TIFF doesn't work.
wrong function getSamplesAsBytes(bis, samples);
Here with having 1 Bit per Pixel it returns value samples[0] = 255 instead of 1.
Then photometricInterpreter.interpretPixel(imageBuilder, samples, x, y); has a
problem
public void interpretPixel(final ImageBuilder imageBuilder, final int[]
samples, final int x,
final int y) throws ImageReadException, IOException {
imageBuilder.setRGB(x, y, indexColorMap[samples[0]]);
}
as the indexColorMaps only has two entries (black and white), but not 256
entries
The same problem will occur as the colour does not have 8 Bit.
The fix seems simple:
In routine
void getSamplesAsBytes(final BitInputStream bis, final int[] result) throws
IOException {
for (int i = 0; i < bitsPerSample.length; i++) {
final int bits = bitsPerSample[i];
int sample = bis.readBits(bits);
if (bits < 8) {
final int sign = sample & 1;
sample = sample << (8 - bits); // scale to byte.
if (sign > 0) {
sample = sample | ((1 << (8 - bits)) - 1); // extend to byte
}
}...
if 'sign>0' don't fill up to 8 bits, but to 'bits' amount of '1'.
I am not sure about other side effects, so I post this suggestion.
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