Add ICC profile embedding support for WebP encoding

- Extract ICC profile from input color space using CGColorSpaceCopyICCData
- Use WebPMux API to embed ICCP chunk in WebP container with copy_data=1
- Automatically convert Simple Format (VP8) to Extended Format (VP8X)
- Add iOS 10+ availability check for CGColorSpaceCopyICCData
- Skip ICC profile when maxFileSize is set (size limit takes priority)
- Add comprehensive test (testWebPEncodingEmbedICCProfile)

This fixes color reproduction issues with wide color gamut images
(Display P3, Adobe RGB, etc.) on platforms that assume sRGB when
ICC profile is missing.

Fixes #119

Author: KYHyeon

SDWebImageWebPCoder/Classes/SDImageWebPCoder.m

@@ -818,7 +818,7 @@ - (nullable NSData *)sd_encodedWebpDataWithImage:(nullable CGImageRef)imageRef
                                      maxFileSize:(NSUInteger)maxFileSize
                                          options:(nullable SDImageCoderOptions *)options
 {
-    NSData *webpData;
+    NSData *webpData = nil;
     if (!imageRef) {
         return nil;
     }
@@ -950,16 +950,55 @@ - (nullable NSData *)sd_encodedWebpDataWithImage:(nullable CGImageRef)imageRef
     result = WebPEncode(&config, &picture);
     WebPPictureFree(&picture);
     free(dest.data);
-    
+
     if (result) {
-        // success
-        webpData = [NSData dataWithBytes:writer.mem length:writer.size];
+        // Add ICC profile if present
+        // See: https://developers.google.com/speed/webp/docs/riff_container#color_profile
+        // Skip ICC profile when maxFileSize is set, as meeting the size limit takes priority
+        CFDataRef iccData = NULL;
+        if (colorSpace && maxFileSize == 0) {
+            if (@available(iOS 10, tvOS 10, macOS 10.12, watchOS 3, *)) {
+                iccData = CGColorSpaceCopyICCData(colorSpace);
+            }
+        }
+
+        if (iccData && CFDataGetLength(iccData) > 0) {
+            // Use WebPMux to add ICCP chunk
+            // This automatically converts Simple Format to Extended Format (VP8X)
+            WebPMux *mux = WebPMuxNew();
+            if (mux) {
+                WebPData webp_input = {
+                    .bytes = writer.mem,
+                    .size = writer.size
+                };
+
+                if (WebPMuxSetImage(mux, &webp_input, 1) == WEBP_MUX_OK) {
+                    WebPData icc_chunk = {
+                        .bytes = CFDataGetBytePtr(iccData),
+                        .size = CFDataGetLength(iccData)
+                    };
+
+                    if (WebPMuxSetChunk(mux, "ICCP", &icc_chunk, 1) == WEBP_MUX_OK) {
+                        WebPData output;
+                        if (WebPMuxAssemble(mux, &output) == WEBP_MUX_OK) {
+                            webpData = [NSData dataWithBytes:output.bytes length:output.size];
+                            WebPDataClear(&output);
+                        }
+                    }
+                }
+                WebPMuxDelete(mux);
+            }
+            CFRelease(iccData);
+        }
+
+        if (!webpData) {
+            webpData = [NSData dataWithBytes:writer.mem length:writer.size];
+        }
     } else {
-        // failed
         webpData = nil;
     }
     WebPMemoryWriterClear(&writer);
-    
+
     return webpData;
 }
 

Tests/SDWebImageWebPCoderTests.m

@@ -381,7 +381,7 @@ - (void)testWebPEncodingWithICCProfile {
     NSString *jpegPath = [[NSBundle bundleForClass:[self class]] pathForResource:@"TestColorspaceBefore" ofType:@"jpeg"];
     NSData *jpegData = [NSData dataWithContentsOfFile:jpegPath];
     UIImage *jpegImage = [[UIImage alloc] initWithData:jpegData];
-    
+
     NSData *webpData = [[SDImageWebPCoder sharedCoder] encodedDataWithImage:jpegImage format:SDImageFormatWebP options:nil];
     // Re-decode to pick color
     UIImage *webpImage = [[SDImageWebPCoder sharedCoder] decodedImageWithData:webpData options:nil];
@@ -404,6 +404,37 @@ - (void)testWebPEncodingWithICCProfile {
 #endif
 }
 
+- (void)testWebPEncodingEmbedICCProfile {
+    // Test that ICC profile is embedded in WebP
+    NSString *jpegPath = [[NSBundle bundleForClass:[self class]] pathForResource:@"TestColorspaceBefore" ofType:@"jpeg"];
+    NSData *jpegData = [NSData dataWithContentsOfFile:jpegPath];
+    UIImage *jpegImage = [[UIImage alloc] initWithData:jpegData];
+    expect(jpegImage).notTo.beNil();
+
+    NSData *webpData = [[SDImageWebPCoder sharedCoder] encodedDataWithImage:jpegImage format:SDImageFormatWebP options:nil];
+    expect(webpData).notTo.beNil();
+
+    // Check for ICCP chunk
+    WebPData webp_data;
+    WebPDataInit(&webp_data);
+    webp_data.bytes = webpData.bytes;
+    webp_data.size = webpData.length;
+
+    WebPDemuxer *demuxer = WebPDemux(&webp_data);
+    expect(demuxer).notTo.beNil();
+
+    uint32_t flags = WebPDemuxGetI(demuxer, WEBP_FF_FORMAT_FLAGS);
+    expect(flags & ICCP_FLAG).notTo.equal(0);
+
+    WebPChunkIterator chunk_iter;
+    int result = WebPDemuxGetChunk(demuxer, "ICCP", 1, &chunk_iter);
+    expect(result).notTo.equal(0);
+    expect(chunk_iter.chunk.size).to.beGreaterThan(0);
+
+    WebPDemuxReleaseChunkIterator(&chunk_iter);
+    WebPDemuxDelete(demuxer);
+}
+
 @end
 
 @implementation SDWebImageWebPCoderTests (Helpers)