Prevent over-compute in affine rotate #3722

docs/changelog.md

@@ -16,6 +16,9 @@ Requires libvips v8.14.2
   [#3674](https://github.com/lovell/sharp/pull/3674)
   [@bianjunjie1981](https://github.com/bianjunjie1981)
 
+* Prevent over-compute in affine-based rotate before resize.
+  [#3722](https://github.com/lovell/sharp/issues/3722)
+
 ### v0.32.1 - 27th April 2023
 
 * Add experimental `unflatten` operation.

src/pipeline.cc

@@ -116,7 +116,7 @@ class PipelineWorker : public Napi::AsyncWorker {
           MultiPageUnsupported(nPages, "Rotate");
           std::vector<double> background;
           std::tie(image, background) = sharp::ApplyAlpha(image, baton->rotationBackground, FALSE);
-          image = image.rotate(baton->rotationAngle, VImage::option()->set("background", background));
+          image = image.rotate(baton->rotationAngle, VImage::option()->set("background", background)).cache();
         }
       }
 

test/unit/rotate.js

@@ -473,4 +473,20 @@ describe('Rotation', function () {
     assert.strictEqual(g, 64);
     assert.strictEqual(b, 30);
   });
+
+  it('Resize after affine-based rotation does not overcompute', async () =>
+    sharp({
+      create: {
+        width: 4640,
+        height: 2610,
+        channels: 3,
+        background: 'black'
+      }
+    })
+      .rotate(28)
+      .resize({ width: 640, height: 360 })
+      .raw()
+      .timeout({ seconds: 5 })
+      .toBuffer()
+  );
 });