Avoid force-decode by apply the byte alignment for static WebP images, using runtime detection for bitmap info

Cartfile

@@ -1,2 +1,2 @@
-github "SDWebImage/SDWebImage" ~> 5.16
+github "SDWebImage/SDWebImage" ~> 5.17
 github "SDWebImage/libwebp-Xcode" ~> 1.0

Package.swift

@@ -17,7 +17,7 @@ let package = Package(
     dependencies: [
         // Dependencies declare other packages that this package depends on.
         // .package(url: /* package url */, from: "1.0.0"),
-        .package(url: "https://github.com/SDWebImage/SDWebImage.git", from: "5.16.0"),
+        .package(url: "https://github.com/SDWebImage/SDWebImage.git", from: "5.17.0"),
         .package(url: "https://github.com/SDWebImage/libwebp-Xcode.git", from: "1.1.0")
     ],
     targets: [

SDWebImageWebPCoder.podspec

@@ -28,7 +28,7 @@ This is a SDWebImage coder plugin to support WebP image.
     'USER_HEADER_SEARCH_PATHS' => '$(inherited) $(SRCROOT)/libwebp/src'
   }
   s.framework = 'CoreGraphics'
-  s.dependency 'SDWebImage/Core', '~> 5.16'
+  s.dependency 'SDWebImage/Core', '~> 5.17'
   s.dependency 'libwebp', '~> 1.0'
 
 end

SDWebImageWebPCoder/Classes/SDImageWebPCoder.m

@@ -71,8 +71,8 @@
 /// Used for animated WebP, which need a canvas for decoding (rendering), possible apply a scale transform for thumbnail decoding (avoiding post-rescale using vImage)
 /// See more in #73
 static inline CGContextRef _Nullable CreateWebPCanvas(BOOL hasAlpha, CGSize canvasSize, CGSize thumbnailSize, BOOL preserveAspectRatio) {
-    CGBitmapInfo bitmapInfo = kCGBitmapByteOrder32Host;
-    bitmapInfo |= hasAlpha ? kCGImageAlphaPremultipliedFirst : kCGImageAlphaNoneSkipFirst;
+    // From SDWebImage v5.17.0, use runtime detection of bitmap info instead of hardcode.
+    CGBitmapInfo bitmapInfo = [SDImageCoderHelper preferredPixelFormat:hasAlpha].bitmapInfo;
     // Check whether we need to use thumbnail
     CGSize scaledSize = [SDImageCoderHelper scaledSizeWithImageSize:CGSizeMake(canvasSize.width, canvasSize.height) scaleSize:thumbnailSize preserveAspectRatio:preserveAspectRatio shouldScaleUp:NO];
     CGContextRef canvas = CGBitmapContextCreate(NULL, scaledSize.width, scaledSize.height, 8, 0, [SDImageCoderHelper colorSpaceGetDeviceRGB], bitmapInfo);
@@ -88,18 +88,87 @@ static inline CGContextRef _Nullable CreateWebPCanvas(BOOL hasAlpha, CGSize canv
     return canvas;
 }
 
-// TODO, share this logic for multiple coders, or do refactory in v6.0 (The coder plugin should provide image information back to Core, like `CGImageSourceCopyPropertiesAtIndex`)
-static inline CGSize SDCalculateScaleDownPixelSize(NSUInteger limitBytes, CGSize originalSize, NSUInteger frameCount, NSUInteger bytesPerPixel) {
-    if (CGSizeEqualToSize(originalSize, CGSizeZero)) return CGSizeMake(1, 1);
-    NSUInteger totalFramePixelSize = limitBytes / bytesPerPixel / (frameCount ?: 1);
-    CGFloat ratio = originalSize.height / originalSize.width;
-    CGFloat width = sqrt(totalFramePixelSize / ratio);
-    CGFloat height = width * ratio;
-    width = MAX(1, floor(width));
-    height = MAX(1, floor(height));
-    CGSize size = CGSizeMake(width, height);
-
-    return size;
+WEBP_CSP_MODE ConvertCSPMode(CGBitmapInfo bitmapInfo) {
+    // Get alpha info, byteOrder info
+    CGImageAlphaInfo alphaInfo = bitmapInfo & kCGBitmapAlphaInfoMask;
+    CGBitmapInfo byteOrderInfo = bitmapInfo & kCGBitmapByteOrderMask;
+    BOOL byteOrderNormal = NO;
+    switch (byteOrderInfo) {
+        case kCGBitmapByteOrderDefault: {
+            byteOrderNormal = YES;
+        } break;
+        case kCGBitmapByteOrder32Little: {
+        } break;
+        case kCGBitmapByteOrder32Big: {
+            byteOrderNormal = YES;
+        } break;
+        default: break;
+    }
+    switch (alphaInfo) {
+        case kCGImageAlphaPremultipliedFirst: {
+            if (byteOrderNormal) {
+                // ARGB8888, premultiplied
+                return MODE_Argb;
+            } else {
+                // BGRA8888, premultiplied
+                return MODE_bgrA;
+            }
+        }
+            break;
+        case kCGImageAlphaPremultipliedLast: {
+            if (byteOrderNormal) {
+                // RGBA8888, premultiplied
+                return MODE_rgbA;
+            } else {
+                // ABGR8888, premultiplied
+                // Unsupported!
+                return MODE_LAST;
+            }
+        }
+            break;
+        case kCGImageAlphaNone: {
+            if (byteOrderNormal) {
+                // RGB
+                return MODE_RGB;
+            } else {
+                // BGR
+                return MODE_BGR;
+            }
+        }
+            break;
+        case kCGImageAlphaLast:
+        case kCGImageAlphaNoneSkipLast: {
+            if (byteOrderNormal) {
+                // RGBA or RGBX
+                return MODE_RGBA;
+            } else {
+                // ABGR or XBGR
+                // Unsupported!
+                return MODE_LAST;
+            }
+        }
+            break;
+        case kCGImageAlphaFirst:
+        case kCGImageAlphaNoneSkipFirst: {
+            if (byteOrderNormal) {
+                // ARGB or XRGB
+                return MODE_ARGB;
+            } else {
+                // BGRA or BGRX
+                return MODE_BGRA;
+            }
+        }
+            break;
+        case kCGImageAlphaOnly: {
+            // A
+            // Unsupported
+            return MODE_LAST;
+        }
+            break;
+        default:
+            break;
+    }
+    return MODE_LAST;
 }
 
 @interface SDWebPCoderFrame : NSObject
@@ -245,7 +314,7 @@ - (UIImage *)decodedImageWithData:(NSData *)data options:(nullable SDImageCoderO
     if (limitBytes > 0) {
         // Hack 32 BitsPerPixel
         CGSize imageSize = CGSizeMake(canvasWidth, canvasHeight);
-        CGSize framePixelSize = SDCalculateScaleDownPixelSize(limitBytes, imageSize, frameCount, 4);
+        CGSize framePixelSize = [SDImageCoderHelper scaledSizeWithImageSize:imageSize limitBytes:limitBytes bytesPerPixel:4 frameCount:frameCount];
         // Override thumbnail size
         thumbnailSize = framePixelSize;
         preserveAspectRatio = YES;
@@ -317,8 +386,8 @@ - (UIImage *)decodedImageWithData:(NSData *)data options:(nullable SDImageCoderO
 - (instancetype)initIncrementalWithOptions:(nullable SDImageCoderOptions *)options {
     self = [super init];
     if (self) {
-        // Progressive images need transparent, so always use premultiplied BGRA
-        _idec = WebPINewRGB(MODE_bgrA, NULL, 0, 0);
+        // Progressive images need transparent, so always use premultiplied RGBA
+        _idec = WebPINewRGB(MODE_rgbA, NULL, 0, 0);
         CGFloat scale = 1;
         NSNumber *scaleFactor = options[SDImageCoderDecodeScaleFactor];
         if (scaleFactor != nil) {
@@ -394,7 +463,7 @@ - (void)updateIncrementalData:(NSData *)data finished:(BOOL)finished {
     if (_limitBytes > 0) {
         // Hack 32 BitsPerPixel
         CGSize imageSize = CGSizeMake(_canvasWidth, _canvasHeight);
-        CGSize framePixelSize = SDCalculateScaleDownPixelSize(_limitBytes, imageSize, _frameCount, 4);
+        CGSize framePixelSize = [SDImageCoderHelper scaledSizeWithImageSize:imageSize limitBytes:_limitBytes bytesPerPixel:4 frameCount:_frameCount];
         // Override thumbnail size
         _thumbnailSize = framePixelSize;
         _preserveAspectRatio = YES;
@@ -428,17 +497,18 @@ - (UIImage *)incrementalDecodedImageWithOptions:(SDImageCoderOptions *)options {
         CGDataProviderRef provider =
         CGDataProviderCreateWithData(NULL, rgba, rgbaSize, NULL);
         CGColorSpaceRef colorSpaceRef = [SDImageCoderHelper colorSpaceGetDeviceRGB];
-
-        CGBitmapInfo bitmapInfo = kCGBitmapByteOrder32Host | kCGImageAlphaPremultipliedFirst;
+        // Because _idec use MODE_rgbA
+        CGBitmapInfo bitmapInfo = kCGBitmapByteOrderDefault | kCGImageAlphaPremultipliedLast;
         size_t components = 4;
+        BOOL shouldInterpolate = YES;
         CGColorRenderingIntent renderingIntent = kCGRenderingIntentDefault;
         // Why to use last_y for image height is because of libwebp's bug (https://bugs.chromium.org/p/webp/issues/detail?id=362)
         // It will not keep memory barrier safe on x86 architechure (macOS & iPhone simulator) but on ARM architecture (iPhone & iPad & tv & watch) it works great
         // If different threads use WebPIDecGetRGB to grab rgba bitmap, it will contain the previous decoded bitmap data
         // So this will cause our drawed image looks strange(above is the current part but below is the previous part)
         // We only grab the last_y height and draw the last_y height instead of total height image
         // Besides fix, this can enhance performance since we do not need to create extra bitmap
-        CGImageRef imageRef = CGImageCreate(width, last_y, 8, components * 8, components * width, colorSpaceRef, bitmapInfo, provider, NULL, NO, renderingIntent);
+        CGImageRef imageRef = CGImageCreate(width, last_y, 8, components * 8, components * width, colorSpaceRef, bitmapInfo, provider, NULL, shouldInterpolate, renderingIntent);
 
         CGDataProviderRelease(provider);
 
@@ -546,20 +616,46 @@ - (nullable CGImageRef)sd_createWebpImageWithData:(WebPData)webpData colorSpace:
     }
 
     BOOL hasAlpha = config.input.has_alpha;
-    // iOS prefer BGRA8888 (premultiplied) or BGRX8888 bitmapInfo for screen rendering, which is same as `UIGraphicsBeginImageContext()` or `- [CALayer drawInContext:]`
-    // use this bitmapInfo, combined with right colorspace, even without decode, can still avoid extra CA::Render::copy_image(which marked `Color Copied Images` from Instruments)
-    CGBitmapInfo bitmapInfo = kCGBitmapByteOrder32Host;
-    bitmapInfo |= hasAlpha ? kCGImageAlphaPremultipliedFirst : kCGImageAlphaNoneSkipFirst;
+    // From SDWebImage v5.17.0, use runtime detection of bitmap info instead of hardcode.
+    SDImagePixelFormat pixelFormat = [SDImageCoderHelper preferredPixelFormat:hasAlpha];
+    CGBitmapInfo bitmapInfo = pixelFormat.bitmapInfo;
+    WEBP_CSP_MODE mode = ConvertCSPMode(bitmapInfo);
+    if (mode == MODE_LAST) {
+        NSAssert(NO, @"Unsupported libwebp preferred CGBitmapInfo: %d", bitmapInfo);
+        return nil;
+    }
+    config.output.colorspace = mode;
     config.options.use_threads = 1;
-    config.output.colorspace = MODE_bgrA;
+
 
     // Use scaling for thumbnail
+    size_t width = config.input.width;
+    size_t height = config.input.height;
     if (scaledSize.width != 0 && scaledSize.height != 0) {
         config.options.use_scaling = 1;
         config.options.scaled_width = scaledSize.width;
         config.options.scaled_height = scaledSize.height;
+        width = scaledSize.width;
+        height = scaledSize.height;
     }
 
+    // We alloc the buffer and do byte alignment by ourself. libwebp defaults does not byte alignment to `bitsPerPixel`, which cause the CoreAnimation unhappy and always trigger the `CA::Render::copy_image`
+    size_t bitsPerComponent = 8;
+    size_t components = (mode == MODE_RGB || mode == MODE_BGR) ? 3 : 4; // Actually always 4
+    size_t bitsPerPixel = bitsPerComponent * components;
+    // Read: https://github.com/path/FastImageCache#byte-alignment
+    // A properly aligned bytes-per-row value must be a multiple of 8 pixels × bytes per pixel
+    // For a typical ARGB image, the aligned bytes-per-row value is a multiple of 64.
+    size_t alignment = pixelFormat.alignment;
+    size_t bytesPerRow = SDByteAlign(width * (bitsPerPixel / 8), alignment);
+    //size_t bytesPerRow = 6688;
+
+    void *rgba = WebPMalloc(bytesPerRow * height);
+    config.output.is_external_memory = 1;
+    config.output.u.RGBA.rgba = rgba;
+    config.output.u.RGBA.stride = (int)bytesPerRow;
+    config.output.u.RGBA.size = height * bytesPerRow;
+
     // Decode the WebP image data into a RGBA value array
     if (WebPDecode(webpData.bytes, webpData.size, &config) != VP8_STATUS_OK) {
         return nil;
@@ -568,13 +664,9 @@ - (nullable CGImageRef)sd_createWebpImageWithData:(WebPData)webpData colorSpace:
     // Construct a UIImage from the decoded RGBA value array
     CGDataProviderRef provider =
     CGDataProviderCreateWithData(NULL, config.output.u.RGBA.rgba, config.output.u.RGBA.size, FreeImageData);
-    size_t bitsPerComponent = 8;
-    size_t bitsPerPixel = 32;
-    size_t bytesPerRow = config.output.u.RGBA.stride;
-    size_t width = config.output.width;
-    size_t height = config.output.height;
+    BOOL shouldInterpolate = YES;
     CGColorRenderingIntent renderingIntent = kCGRenderingIntentDefault;
-    CGImageRef imageRef = CGImageCreate(width, height, bitsPerComponent, bitsPerPixel, bytesPerRow, colorSpaceRef, bitmapInfo, provider, NULL, NO, renderingIntent);
+    CGImageRef imageRef = CGImageCreate(width, height, bitsPerComponent, bitsPerPixel, bytesPerRow, colorSpaceRef, bitmapInfo, provider, NULL, shouldInterpolate, renderingIntent);
 
     CGDataProviderRelease(provider);
 
@@ -756,9 +848,6 @@ - (nullable NSData *)sd_encodedWebpDataWithImage:(nullable CGImageRef)imageRef
     }
 
     size_t bytesPerRow = CGImageGetBytesPerRow(imageRef);
-    size_t bitsPerComponent = CGImageGetBitsPerComponent(imageRef);
-    size_t bitsPerPixel = CGImageGetBitsPerPixel(imageRef);
-    size_t components = bitsPerPixel / bitsPerComponent;
     CGBitmapInfo bitmapInfo = CGImageGetBitmapInfo(imageRef);
     CGImageAlphaInfo alphaInfo = bitmapInfo & kCGBitmapAlphaInfoMask;
     CGBitmapInfo byteOrderInfo = bitmapInfo & kCGBitmapByteOrderMask;
@@ -891,7 +980,7 @@ - (void) updateWebPOptionsToConfig:(WebPConfig * _Nonnull)config
 }
 
 static void FreeImageData(void *info, const void *data, size_t size) {
-    free((void *)data);
+    WebPFree((void *)data);
 }
 
 static int GetIntValueForKey(NSDictionary * _Nonnull dictionary, NSString * _Nonnull key, int defaultValue) {
@@ -968,7 +1057,7 @@ - (instancetype)initWithAnimatedImageData:(NSData *)data options:(nullable SDIma
         if (_limitBytes > 0) {
             // Hack 32 BitsPerPixel
             CGSize imageSize = CGSizeMake(_canvasWidth, _canvasHeight);
-            CGSize framePixelSize = SDCalculateScaleDownPixelSize(_limitBytes, imageSize, _frameCount, 4);
+            CGSize framePixelSize = [SDImageCoderHelper scaledSizeWithImageSize:imageSize limitBytes:_limitBytes bytesPerPixel:4 frameCount:_frameCount];
             // Override thumbnail size
             _thumbnailSize = framePixelSize;
             _preserveAspectRatio = YES;
@@ -1236,6 +1325,7 @@ - (UIImage *)safeAnimatedImageFrameAtIndex:(NSUInteger)index {
 #else
     image = [[UIImage alloc] initWithCGImage:imageRef scale:_scale orientation:kCGImagePropertyOrientationUp];
 #endif
+    image.sd_imageFormat = SDImageFormatWebP;
     CGImageRelease(imageRef);
 
     WebPDemuxReleaseIterator(&iter);

Tests/SDWebImageWebPCoderTests.m

@@ -218,6 +218,18 @@ - (void)test45WebPEncodingMaxFileSize {
     XCTAssertLessThanOrEqual(dataWithLimit.length, maxFileSize);
 }
 
+- (void)testWebPDecodeDoesNotTriggerCACopyImage {
+    NSURL *staticWebPURL = [[NSBundle bundleForClass:[self class]] URLForResource:@"TestColorspaceStatic" withExtension:@"webp"];
+    NSData *data = [NSData dataWithContentsOfURL:staticWebPURL];
+    UIImage *image = [SDImageWebPCoder.sharedCoder decodedImageWithData:data options:@{SDImageCoderDecodeThumbnailPixelSize: @(CGSizeMake(1023, 680))}]; // 1023 * 4 need aligned to 4096
+    CGImageRef cgImage = [image CGImage];
+    size_t bytesPerRow = CGImageGetBytesPerRow(cgImage);
+    XCTAssertEqual(bytesPerRow, 4096);
+    CGColorSpaceRef colorspace = CGImageGetColorSpace(cgImage);
+    NSString *colorspaceName = (__bridge_transfer NSString *)CGColorSpaceCopyName(colorspace);
+    XCTAssertEqual(colorspaceName, (__bridge NSString *)kCGColorSpaceSRGB, @"Color space is not sRGB");
+}
+
 - (void)testEncodingSettings {
     WebPConfig config;
     WebPConfigPreset(&config, WEBP_PRESET_DEFAULT, 0.2);

Tests/SDWebImageWebPCoderTests.xcodeproj/project.pbxproj

@@ -10,6 +10,7 @@
 		0EF5B6264833B7BC20894578 /* Pods_SDWebImageWebPCoderTests.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 46F21AD7D1692EBAC4D0FF33 /* Pods_SDWebImageWebPCoderTests.framework */; };
 		3219F3B2228B0453003822A6 /* TestImageBlendAnimated.webp in Resources */ = {isa = PBXBuildFile; fileRef = 3219F3B1228B0453003822A6 /* TestImageBlendAnimated.webp */; };
 		325E268E25C82BE1000B807B /* TestImageGrayscale.jpg in Resources */ = {isa = PBXBuildFile; fileRef = 325E268D25C82BE1000B807B /* TestImageGrayscale.jpg */; };
+		326420312A5D53E300EE3E46 /* TestColorspaceStatic.webp in Resources */ = {isa = PBXBuildFile; fileRef = 326420302A5D53E300EE3E46 /* TestColorspaceStatic.webp */; };
 		808C918E213FD131004B0F7C /* SDWebImageWebPCoderTests.m in Sources */ = {isa = PBXBuildFile; fileRef = 808C918D213FD131004B0F7C /* SDWebImageWebPCoderTests.m */; };
 		808C919C213FD2B2004B0F7C /* TestImageStatic.webp in Resources */ = {isa = PBXBuildFile; fileRef = 808C919A213FD2B2004B0F7C /* TestImageStatic.webp */; };
 		808C919D213FD2B2004B0F7C /* TestImageAnimated.webp in Resources */ = {isa = PBXBuildFile; fileRef = 808C919B213FD2B2004B0F7C /* TestImageAnimated.webp */; };
@@ -19,6 +20,7 @@
 		28D8AA3D3015E075692FD3E3 /* Pods-SDWebImageWebPCoderTests.debug.xcconfig */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = text.xcconfig; name = "Pods-SDWebImageWebPCoderTests.debug.xcconfig"; path = "../Pods/Target Support Files/Pods-SDWebImageWebPCoderTests/Pods-SDWebImageWebPCoderTests.debug.xcconfig"; sourceTree = "<group>"; };
 		3219F3B1228B0453003822A6 /* TestImageBlendAnimated.webp */ = {isa = PBXFileReference; lastKnownFileType = file; path = TestImageBlendAnimated.webp; sourceTree = "<group>"; };
 		325E268D25C82BE1000B807B /* TestImageGrayscale.jpg */ = {isa = PBXFileReference; lastKnownFileType = image.jpeg; path = TestImageGrayscale.jpg; sourceTree = "<group>"; };
+		326420302A5D53E300EE3E46 /* TestColorspaceStatic.webp */ = {isa = PBXFileReference; lastKnownFileType = file; path = TestColorspaceStatic.webp; sourceTree = "<group>"; };
 		46F21AD7D1692EBAC4D0FF33 /* Pods_SDWebImageWebPCoderTests.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; includeInIndex = 0; path = Pods_SDWebImageWebPCoderTests.framework; sourceTree = BUILT_PRODUCTS_DIR; };
 		808C918B213FD130004B0F7C /* SDWebImageWebPCoderTests.xctest */ = {isa = PBXFileReference; explicitFileType = wrapper.cfbundle; includeInIndex = 0; path = SDWebImageWebPCoderTests.xctest; sourceTree = BUILT_PRODUCTS_DIR; };
 		808C918D213FD131004B0F7C /* SDWebImageWebPCoderTests.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = SDWebImageWebPCoderTests.m; sourceTree = "<group>"; };
@@ -80,6 +82,7 @@
 		808C9199213FD2B2004B0F7C /* Images */ = {
 			isa = PBXGroup;
 			children = (
+				326420302A5D53E300EE3E46 /* TestColorspaceStatic.webp */,
 				325E268D25C82BE1000B807B /* TestImageGrayscale.jpg */,
 				808C919A213FD2B2004B0F7C /* TestImageStatic.webp */,
 				808C919B213FD2B2004B0F7C /* TestImageAnimated.webp */,
@@ -157,6 +160,7 @@
 				3219F3B2228B0453003822A6 /* TestImageBlendAnimated.webp in Resources */,
 				808C919D213FD2B2004B0F7C /* TestImageAnimated.webp in Resources */,
 				808C919C213FD2B2004B0F7C /* TestImageStatic.webp in Resources */,
+				326420312A5D53E300EE3E46 /* TestColorspaceStatic.webp in Resources */,
 				325E268E25C82BE1000B807B /* TestImageGrayscale.jpg in Resources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
@@ -377,6 +381,7 @@
 					"$(inherited)",
 				);
 				INFOPLIST_FILE = Info.plist;
+				IPHONEOS_DEPLOYMENT_TARGET = 9.0;
 				PRODUCT_BUNDLE_IDENTIFIER = org.SDWebImage.SDWebImageWebPCoderTests;
 				PRODUCT_NAME = "$(TARGET_NAME)";
 			};
@@ -387,6 +392,7 @@
 			baseConfigurationReference = D92E6791BF088D1A101E670E /* Pods-SDWebImageWebPCoderTests.release.xcconfig */;
 			buildSettings = {
 				INFOPLIST_FILE = Info.plist;
+				IPHONEOS_DEPLOYMENT_TARGET = 9.0;
 				PRODUCT_BUNDLE_IDENTIFIER = org.SDWebImage.SDWebImageWebPCoderTests;
 				PRODUCT_NAME = "$(TARGET_NAME)";
 			};