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Gamma correction and premultiply do not mix

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Skip premultiply for fast blur/sharpen

Automate gamma correction tests
This commit is contained in:
Lovell Fuller
2015-08-11 21:51:22 +01:00
parent 9c83d98bbb
commit 36ac8828f2
7 changed files with 58 additions and 39 deletions
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50
src/pipeline.cc
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@@ -445,7 +445,7 @@ class PipelineWorker : public NanAsyncWorker {
}
// Gamma encoding (darken)
if (baton->gamma >= 1 && baton->gamma <= 3) {
if (baton->gamma >= 1 && baton->gamma <= 3 && !HasAlpha(image)) {
VipsImage *gammaEncoded;
if (vips_gamma(image, &gammaEncoded, "exponent", 1.0 / baton->gamma, NULL)) {
return Error();
@@ -493,11 +493,9 @@ class PipelineWorker : public NanAsyncWorker {
}
bool shouldAffineTransform = xresidual != 0.0 || yresidual != 0.0;
bool shouldBlur = baton->blurSigma != 0.0;
bool shouldSharpen = baton->sharpenRadius != 0;
bool shouldTransform = shouldAffineTransform || shouldBlur || shouldSharpen;
bool willConvolve = baton->blurSigma > 0.0 || baton->sharpenRadius > 0;
bool hasOverlay = !baton->overlayPath.empty();
bool shouldPremultiplyAlpha = HasAlpha(image) && image->Bands == 4 && (shouldTransform || hasOverlay);
bool shouldPremultiplyAlpha = HasAlpha(image) && (shouldAffineTransform || willConvolve || hasOverlay);
// Premultiply image alpha channel before all transformations to avoid
// dark fringing around bright pixels
@@ -681,7 +679,7 @@ class PipelineWorker : public NanAsyncWorker {
}
// Blur
if (shouldBlur) {
if (baton->blurSigma != 0.0) {
VipsImage *blurred;
if (Blur(hook, image, &blurred, baton->blurSigma)) {
return Error();
@@ -690,7 +688,7 @@ class PipelineWorker : public NanAsyncWorker {
}
// Sharpen
if (shouldSharpen) {
if (baton->sharpenRadius != 0) {
VipsImage *sharpened;
if (Sharpen(hook, image, &sharpened, baton->sharpenRadius, baton->sharpenFlat, baton->sharpenJagged)) {
return Error();
@@ -698,25 +696,6 @@ class PipelineWorker : public NanAsyncWorker {
image = sharpened;
}
// Gamma decoding (brighten)
if (baton->gamma >= 1 && baton->gamma <= 3) {
VipsImage *gammaDecoded;
if (vips_gamma(image, &gammaDecoded, "exponent", baton->gamma, NULL)) {
return Error();
}
vips_object_local(hook, gammaDecoded);
image = gammaDecoded;
}
// Apply normalization - stretch luminance to cover full dynamic range
if (baton->normalize) {
VipsImage *normalized;
if (Normalize(hook, image, &normalized)) {
return Error();
}
image = normalized;
}
// Composite with overlay, if present
if (hasOverlay) {
VipsImage *overlayImage = NULL;
@@ -789,6 +768,25 @@ class PipelineWorker : public NanAsyncWorker {
image = imageUnpremultiplied;
}
// Gamma decoding (brighten)
if (baton->gamma >= 1 && baton->gamma <= 3 && !HasAlpha(image)) {
VipsImage *gammaDecoded;
if (vips_gamma(image, &gammaDecoded, "exponent", baton->gamma, NULL)) {
return Error();
}
vips_object_local(hook, gammaDecoded);
image = gammaDecoded;
}
// Apply normalization - stretch luminance to cover full dynamic range
if (baton->normalize) {
VipsImage *normalized;
if (Normalize(hook, image, &normalized)) {
return Error();
}
image = normalized;
}
// Convert image to sRGB, if not already
if (image->Type != VIPS_INTERPRETATION_sRGB) {
// Switch interpretation to sRGB