Ensure ICC profiles are removed from PNG output #521

docs/changelog.md

@@ -18,6 +18,10 @@ Requires libvips v8.3.1
   [#511](https://github.com/lovell/sharp/pull/511)
   [@mhirsch](https://github.com/mhirsch)
 
+* Ensure ICC profiles are removed from PNG output unless withMetadata used.
+  [#521](https://github.com/lovell/sharp/issues/521)
+  [@ChrisPinewood](https://github.com/ChrisPinewood)
+
 #### v0.15.1 - 12<sup>th</sup> July 2016
 
 * Concat Stream-based input in single operation for ~+3% perf and less GC.

src/pipeline.cc

@@ -884,9 +884,12 @@ class PipelineWorker : public AsyncWorker {
           baton->formatOut = "jpeg";
           baton->channels = std::min(baton->channels, 3);
         } else if (baton->formatOut == "png" || (baton->formatOut == "input" && inputImageType == ImageType::PNG)) {
+          // Strip profile
+          if (!baton->withMetadata) {
+            vips_image_remove(image.get_image(), VIPS_META_ICC_NAME);
+          }
           // Write PNG to buffer
           VipsArea *area = VIPS_AREA(image.pngsave_buffer(VImage::option()
-            ->set("strip", !baton->withMetadata)
             ->set("compression", baton->compressionLevel)
             ->set("interlace", baton->progressive)
             ->set("filter", baton->withoutAdaptiveFiltering ?
@@ -961,9 +964,12 @@ class PipelineWorker : public AsyncWorker {
           baton->formatOut = "jpeg";
           baton->channels = std::min(baton->channels, 3);
         } else if (baton->formatOut == "png" || isPng || (matchInput && inputImageType == ImageType::PNG)) {
+          // Strip profile
+          if (!baton->withMetadata) {
+            vips_image_remove(image.get_image(), VIPS_META_ICC_NAME);
+          }
           // Write PNG to file
           image.pngsave(const_cast<char*>(baton->fileOut.data()), VImage::option()
-            ->set("strip", !baton->withMetadata)
             ->set("compression", baton->compressionLevel)
             ->set("interlace", baton->progressive)
             ->set("filter", baton->withoutAdaptiveFiltering ?

test/unit/metadata.js

@@ -328,6 +328,22 @@ describe('Image metadata', function() {
       });
   });
 
+  it('Remove metadata from PNG output', function(done) {
+    sharp(fixtures.inputJpgWithExif)
+      .png()
+      .toBuffer(function(err, buffer) {
+        if (err) throw err;
+        sharp(buffer).metadata(function(err, metadata) {
+          if (err) throw err;
+          assert.strictEqual(false, metadata.hasProfile);
+          assert.strictEqual('undefined', typeof metadata.orientation);
+          assert.strictEqual('undefined', typeof metadata.exif);
+          assert.strictEqual('undefined', typeof metadata.icc);
+          done();
+        });
+      });
+  });
+
   it('File input with corrupt header fails gracefully', function(done) {
     sharp(fixtures.inputJpgWithCorruptHeader)
       .metadata(function(err) {