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Ensure trim op works with CMYK input #3636

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Lovell Fuller
2023-04-20 10:49:39 +01:00
parent a39f959dcc
commit 8408e99aa3
3 changed files with 38 additions and 19 deletions
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28
src/operations.cc
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@@ -269,30 +269,20 @@ namespace sharp {
if (image.width() < 3 && image.height() < 3) {
throw VError("Image to trim must be at least 3x3 pixels");
}
// Scale up 8-bit values to match 16-bit input image
double multiplier = sharp::Is16Bit(image.interpretation()) ? 256.0 : 1.0;
threshold *= multiplier;
std::vector<double> backgroundAlpha(1);
if (background.size() == 0) {
// Top-left pixel provides the default background colour if none is given
background = image.extract_area(0, 0, 1, 1)(0, 0);
multiplier = 1.0;
} else if (sharp::Is16Bit(image.interpretation())) {
for (size_t i = 0; i < background.size(); i++) {
background[i] *= 256.0;
}
threshold *= 256.0;
}
if (HasAlpha(image) && background.size() == 4) {
// Just discard the alpha because flattening the background colour with
// itself (effectively what find_trim() does) gives the same result
backgroundAlpha[0] = background[3] * multiplier;
}
if (image.bands() > 2) {
background = {
background[0] * multiplier,
background[1] * multiplier,
background[2] * multiplier
};
std::vector<double> backgroundAlpha({ background.back() });
if (HasAlpha(image)) {
background.pop_back();
} else {
background[0] = background[0] * multiplier;
background.resize(image.bands());
}
int left, top, width, height;
left = image.find_trim(&top, &width, &height, VImage::option()