Ensure keepIccProfile retains CMYK input profiles #3906

docs/changelog.md

@@ -4,6 +4,11 @@
 
 Requires libvips v8.15.1
 
+### v0.33.3 - TBD
+
+* Ensure `keepIccProfile` retains CMYK input profiles.
+  [#3906](https://github.com/lovell/sharp/issues/3906)
+
 ### v0.33.2 - 12th January 2024
 
 * Upgrade to libvips v8.15.1 for upstream bug fixes.

src/pipeline.cc

@@ -776,7 +776,7 @@ class PipelineWorker : public Napi::AsyncWorker {
         // Convert colourspace, pass the current known interpretation so libvips doesn't have to guess
         image = image.colourspace(baton->colourspace, VImage::option()->set("source_space", image.interpretation()));
         // Transform colours from embedded profile to output profile
-        if ((baton->keepMetadata & VIPS_FOREIGN_KEEP_ICC) &&
+        if ((baton->keepMetadata & VIPS_FOREIGN_KEEP_ICC) && baton->colourspaceInput != VIPS_INTERPRETATION_CMYK &&
           baton->withIccProfile.empty() && sharp::HasProfile(image)) {
           image = image.icc_transform("srgb", VImage::option()
             ->set("embedded", TRUE)

test/unit/metadata.js

@@ -576,6 +576,19 @@ describe('Image metadata', function () {
     assert.strictEqual(description, 'Generic RGB Profile');
   });
 
+  it('keep existing CMYK ICC profile', async () => {
+    const data = await sharp(fixtures.inputJpgWithCmykProfile)
+      .pipelineColourspace('cmyk')
+      .toColourspace('cmyk')
+      .keepIccProfile()
+      .toBuffer();
+
+    const metadata = await sharp(data).metadata();
+    assert.strictEqual(metadata.channels, 4);
+    const { description } = icc.parse(metadata.icc);
+    assert.strictEqual(description, 'U.S. Web Coated (SWOP) v2');
+  });
+
   it('transform to ICC profile and attach', async () => {
     const data = await sharp({ create })
       .png()