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Avoid fastShrinkOnLoad workaround

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This commit is contained in:
Kleis Auke Wolthuizen
2022-02-05 18:30:54 +01:00
committed by Lovell Fuller
parent 154eaff4ec
commit 7faacd91b0
13 changed files with 14 additions and 21 deletions
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35
src/pipeline.cc
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@@ -194,7 +194,7 @@ class PipelineWorker : public Napi::AsyncWorker {
jpegShrinkOnLoad = 2;
}
// Skip shrink-on-load for known libjpeg rounding errors
if (jpegShrinkOnLoad > 1 && shrink == jpegShrinkOnLoad) {
if (jpegShrinkOnLoad > 1 && static_cast<int>(shrink) == jpegShrinkOnLoad) {
jpegShrinkOnLoad /= 2;
}
} else if (inputImageType == sharp::ImageType::WEBP ||
@@ -274,35 +274,28 @@ class PipelineWorker : public Napi::AsyncWorker {
}
// Any pre-shrinking may already have been done
int thumbWidth = image.width();
int thumbHeight = image.height();
inputWidth = image.width();
inputHeight = image.height();
// After pre-shrink, but before the main shrink stage
// Reuse the initial pageHeight if we didn't pre-shrink
int preshrunkPageHeight = shouldPreShrink ? sharp::GetPageHeight(image) : pageHeight;
if (baton->fastShrinkOnLoad && jpegShrinkOnLoad > 1) {
// JPEG shrink-on-load rounds the output dimensions down, which
// may cause incorrect dimensions when fastShrinkOnLoad is enabled
// Just recalculate vshrink / hshrink on the main image instead of
// the pre-shrunk image when this is the case
hshrink = static_cast<double>(thumbWidth) / (static_cast<double>(inputWidth) / hshrink);
vshrink = static_cast<double>(preshrunkPageHeight) / (static_cast<double>(pageHeight) / vshrink);
} else {
// Shrink to preshrunkPageHeight, so we work for multi-page images
std::tie(hshrink, vshrink) = sharp::ResolveShrink(
thumbWidth, preshrunkPageHeight, targetResizeWidth, targetResizeHeight,
baton->canvas, swap, baton->withoutEnlargement);
if (shouldPreShrink) {
pageHeight = sharp::GetPageHeight(image);
}
int targetHeight = static_cast<int>(std::rint(static_cast<double>(preshrunkPageHeight) / vshrink));
// Shrink to pageHeight, so we work for multi-page images
std::tie(hshrink, vshrink) = sharp::ResolveShrink(
inputWidth, pageHeight, targetResizeWidth, targetResizeHeight,
baton->canvas, swap, baton->withoutEnlargement);
int targetHeight = static_cast<int>(std::rint(static_cast<double>(pageHeight) / vshrink));
int targetPageHeight = targetHeight;
// In toilet-roll mode, we must adjust vshrink so that we exactly hit
// preshrunkPageHeight or we'll have pixels straddling pixel boundaries
if (thumbHeight > preshrunkPageHeight) {
// pageHeight or we'll have pixels straddling pixel boundaries
if (inputHeight > pageHeight) {
targetHeight *= nPages;
vshrink = static_cast<double>(thumbHeight) / targetHeight;
vshrink = static_cast<double>(inputHeight) / targetHeight;
}
// Ensure we're using a device-independent colour space