Prevent rounding err with shrink-on-load and 90/270 rot #1241

This commit is contained in:
Lovell Fuller 2018-06-19 21:19:34 +01:00
parent 09263455b5
commit da0b0348a2
4 changed files with 33 additions and 26 deletions

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@ -4,6 +4,12 @@
Requires libvips v8.6.1.
#### v0.20.3 - TBD
* Prevent possible rounding error when using shrink-on-load and 90/270 degree rotation.
[#1241](https://github.com/lovell/sharp/issues/1241)
[@anahit42](https://github.com/anahit42)
#### v0.20.3 - 29<sup>th</sup> May 2018
* Fix tint operation by ensuring LAB interpretation and allowing negative values.

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@ -281,16 +281,18 @@ class PipelineWorker : public Nan::AsyncWorker {
}
}
// Recalculate integral shrink and double residual
int shrunkOnLoadWidth = image.width();
int shrunkOnLoadHeight = image.height();
int const shrunkOnLoadWidth = image.width();
int const shrunkOnLoadHeight = image.height();
if (!baton->rotateBeforePreExtract &&
(rotation == VIPS_ANGLE_D90 || rotation == VIPS_ANGLE_D270)) {
// Swap input output width and height when rotating by 90 or 270 degrees
std::swap(shrunkOnLoadWidth, shrunkOnLoadHeight);
}
// Swap when rotating by 90 or 270 degrees
xfactor = static_cast<double>(shrunkOnLoadWidth) / static_cast<double>(targetResizeHeight);
yfactor = static_cast<double>(shrunkOnLoadHeight) / static_cast<double>(targetResizeWidth);
} else {
xfactor = static_cast<double>(shrunkOnLoadWidth) / static_cast<double>(targetResizeWidth);
yfactor = static_cast<double>(shrunkOnLoadHeight) / static_cast<double>(targetResizeHeight);
}
}
// Ensure we're using a device-independent colour space
if (sharp::HasProfile(image)) {
@ -381,7 +383,6 @@ class PipelineWorker : public Nan::AsyncWorker {
) {
throw vips::VError("Unknown kernel");
}
image = image.resize(1.0 / xfactor, VImage::option()
->set("vscale", 1.0 / yfactor)
->set("kernel", kernel));

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@ -177,25 +177,6 @@ describe('Crop', function () {
});
});
it('Clamp before crop when one post-resize dimension is below target', function () {
return sharp(fixtures.inputJpg)
.resize(1024, 1034)
.toBuffer()
.then(function (input) {
return sharp(input)
.rotate(270)
.resize(256)
.crop(sharp.strategy.entropy)
.toBuffer({ resolveWithObject: true })
.then(function (result) {
assert.strictEqual(256, result.info.width);
assert.strictEqual(253, result.info.height);
assert.strictEqual(0, result.info.cropOffsetLeft);
assert.strictEqual(0, result.info.cropOffsetTop);
});
});
});
describe('Entropy-based strategy', function () {
it('JPEG', function (done) {
sharp(fixtures.inputJpg)

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@ -130,6 +130,25 @@ describe('Resize dimensions', function () {
});
});
it('JPEG shrink-on-load with 90 degree rotation, ensure recalculation is correct', function (done) {
sharp(fixtures.inputJpg)
.resize(1920, 1280)
.toBuffer(function (err, data, info) {
if (err) throw err;
assert.strictEqual(1920, info.width);
assert.strictEqual(1280, info.height);
sharp(data)
.rotate(90)
.resize(533, 800)
.toBuffer(function (err, data, info) {
if (err) throw err;
assert.strictEqual(533, info.width);
assert.strictEqual(800, info.height);
done();
});
});
});
it('TIFF embed known to cause rounding errors', function (done) {
sharp(fixtures.inputTiff)
.resize(240, 320)