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Allow use of extend with greyscale input (#623)

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This commit is contained in:
Patrick Paskaris
2016-11-14 17:09:43 -05:00
committed by Lovell Fuller
parent dd9d66ef20
commit 6ccccf8c39
3 changed files with 30 additions and 5 deletions
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20
src/pipeline.cc
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@@ -521,11 +521,21 @@ class PipelineWorker : public Nan::AsyncWorker {
// Scale up 8-bit values to match 16-bit input image
double const multiplier = sharp::Is16Bit(image.interpretation()) ? 256.0 : 1.0;
// Create background colour
std::vector<double> background {
baton->background[0] * multiplier,
baton->background[1] * multiplier,
baton->background[2] * multiplier
};
std::vector<double> background;
if (image.bands() > 2) {
background = {
multiplier * baton->background[0],
multiplier * baton->background[1],
multiplier * baton->background[2]
};
} else {
// Convert sRGB to greyscale
background = { multiplier * (
0.2126 * baton->background[0] +
0.7152 * baton->background[1] +
0.0722 * baton->background[2]
)};
}
// Add alpha channel to background colour
if (baton->background[3] < 255.0 || HasAlpha(image)) {
background.push_back(baton->background[3] * multiplier);