Ensure correct dimensions when contain 1px image #2951

docs/changelog.md

@@ -4,6 +4,11 @@
 
 Requires libvips v8.11.3
 
+### v0.29.3 - TBD
+
+* Ensure correct dimensions when containing image resized to 1px.
+  [#2951](https://github.com/lovell/sharp/issues/2951)
+
 ### v0.29.2 - 21st October 2021
 
 * Add `timeout` function to limit processing time.

src/pipeline.cc

@@ -382,12 +382,16 @@ class PipelineWorker : public Napi::AsyncWorker {
         // Ensure shortest edge is at least 1 pixel
         if (image.width() / xfactor < 0.5) {
           xfactor = 2 * image.width();
+          if (baton->canvas != Canvas::EMBED) {
             baton->width = 1;
           }
+        }
         if (image.height() / yfactor < 0.5) {
           yfactor = 2 * image.height();
+          if (baton->canvas != Canvas::EMBED) {
             baton->height = 1;
           }
+        }
         image = image.resize(1.0 / xfactor, VImage::option()
           ->set("vscale", 1.0 / yfactor)
           ->set("kernel", kernel));

test/unit/resize.js

@@ -605,6 +605,40 @@ describe('Resize dimensions', function () {
       });
   });
 
+  it('Ensure embedded shortest edge (height) is at least 1 pixel', function () {
+    return sharp({
+      create: {
+        width: 200,
+        height: 1,
+        channels: 3,
+        background: 'red'
+      }
+    })
+      .resize({ width: 50, height: 50, fit: sharp.fit.contain })
+      .toBuffer({ resolveWithObject: true })
+      .then(function (output) {
+        assert.strictEqual(50, output.info.width);
+        assert.strictEqual(50, output.info.height);
+      });
+  });
+
+  it('Ensure embedded shortest edge (width) is at least 1 pixel', function () {
+    return sharp({
+      create: {
+        width: 1,
+        height: 200,
+        channels: 3,
+        background: 'red'
+      }
+    })
+      .resize({ width: 50, height: 50, fit: sharp.fit.contain })
+      .toBuffer({ resolveWithObject: true })
+      .then(function (output) {
+        assert.strictEqual(50, output.info.width);
+        assert.strictEqual(50, output.info.height);
+      });
+  });
+
   it('Skip shrink-on-load where one dimension <4px', async () => {
     const jpeg = await sharp({
       create: {