Skip shrink-on-load where one dimension <4px #2653

docs/changelog.md

@@ -4,6 +4,11 @@
 
 Requires libvips v8.10.6
 
+### v0.28.2 - TBD
+
+* Skip shrink-on-load where one dimension <4px.
+  [#2653](https://github.com/lovell/sharp/issues/2653)
+
 ### v0.28.1 - 5th April 2021
 
 * Ensure all installation errors are logged with a more obvious prefix.

src/pipeline.cc

@@ -226,7 +226,8 @@ class PipelineWorker : public Napi::AsyncWorker {
       if (
         xshrink == yshrink && xshrink >= 2 * shrink_on_load_factor &&
         (inputImageType == sharp::ImageType::JPEG || inputImageType == sharp::ImageType::WEBP) &&
-        baton->gamma == 0 && baton->topOffsetPre == -1 && baton->trimThreshold == 0.0
+        baton->gamma == 0 && baton->topOffsetPre == -1 && baton->trimThreshold == 0.0 &&
+        image.width() > 3 && image.height() > 3
       ) {
         if (xshrink >= 8 * shrink_on_load_factor) {
           xfactor = xfactor / 8;

test/unit/resize.js

@@ -605,6 +605,26 @@ describe('Resize dimensions', function () {
       });
   });
 
+  it('Skip shrink-on-load where one dimension <4px', async () => {
+    const jpeg = await sharp({
+      create: {
+        width: 100,
+        height: 3,
+        channels: 3,
+        background: 'red'
+      }
+    })
+      .jpeg()
+      .toBuffer();
+
+    const { info } = await sharp(jpeg)
+      .resize(8)
+      .toBuffer({ resolveWithObject: true });
+
+    assert.strictEqual(info.width, 8);
+    assert.strictEqual(info.height, 1);
+  });
+
   it('unknown kernel throws', function () {
     assert.throws(function () {
       sharp().resize(null, null, { kernel: 'unknown' });