Ensure animated GIF to WebP conversion retains loop #3394

This commit is contained in:
Lovell Fuller 2025-04-23 15:43:58 +01:00
parent 38b6f44611
commit 701143afb3
5 changed files with 26 additions and 13 deletions

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@ -8,6 +8,9 @@ Requires libvips v8.16.1
### v0.34.2 - TBD
* Ensure animated GIF to WebP conversion retains loop (regression in 0.34.0).
[#3394](https://github.com/lovell/sharp/issues/3394)
* Ensure `pdfBackground` constructor property is used.
[#4207](https://github.com/lovell/sharp/pull/4207)

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@ -298,7 +298,7 @@ const Sharp = function (input, options) {
withExif: {},
withExifMerge: true,
resolveWithObject: false,
loop: 1,
loop: -1,
delay: [],
// output format
jpegQuality: 80,

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@ -651,22 +651,21 @@ namespace sharp {
*/
VImage SetAnimationProperties(VImage image, int nPages, int pageHeight, std::vector<int> delay, int loop) {
bool hasDelay = !delay.empty();
// Avoid a copy if none of the animation properties are needed.
if (nPages == 1 && !hasDelay && loop == -1) return image;
if (delay.size() == 1) {
// We have just one delay, repeat that value for all frames.
delay.insert(delay.end(), nPages - 1, delay[0]);
}
// Attaching metadata, need to copy the image.
VImage copy = image.copy();
// Only set page-height if we have more than one page, or this could
// accidentally turn into an animated image later.
if (nPages > 1) copy.set(VIPS_META_PAGE_HEIGHT, pageHeight);
if (hasDelay) copy.set("delay", delay);
if (hasDelay) {
if (delay.size() == 1) {
// We have just one delay, repeat that value for all frames.
delay.insert(delay.end(), nPages - 1, delay[0]);
}
copy.set("delay", delay);
}
if (nPages == 1 && !hasDelay && loop == -1) {
loop = 1;
}
if (loop != -1) copy.set("loop", loop);
return copy;

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@ -384,7 +384,7 @@ struct PipelineBaton {
ensureAlpha(-1.0),
colourspacePipeline(VIPS_INTERPRETATION_LAST),
colourspace(VIPS_INTERPRETATION_LAST),
loop(1),
loop(-1),
tileSize(256),
tileOverlap(0),
tileContainer(VIPS_FOREIGN_DZ_CONTAINER_FS),

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@ -238,4 +238,15 @@ describe('GIF input', () => {
assert.strictEqual(1, loop);
}
});
it('Animated GIF to animated WebP merges identical frames', async () => {
const webp = await sharp(fixtures.inputGifAnimated, { animated: true })
.webp()
.toBuffer();
const { delay, loop, pages } = await sharp(webp).metadata();
assert.deepStrictEqual([120, 120, 90, 120, 120, 90, 120, 90, 30], delay);
assert.strictEqual(0, loop);
assert.strictEqual(9, pages);
});
});