Use kCGImageSourceCreateUnpremultipliedPNG on iOS family to correctly…

… read PNG files without premultiplication.

https://bugs.webkit.org/show_bug.cgi?id=240137
<rdar://93198134>

Patch by John Cunningham <johncunningham@apple.com> on 2022-05-23
Reviewed by Simon Fraser.

* Source/WTF/wtf/PlatformHave.h:
* Source/WebCore/platform/graphics/cg/ImageDecoderCG.cpp:
(WebCore::createImageSourceOptions):

Canonical link: https://commits.webkit.org/250880@main
git-svn-id: https://svn.webkit.org/repository/webkit/trunk@294660 268f45cc-cd09-0410-ab3c-d52691b4dbfc

Source/WTF/wtf/PlatformHave.h

@@ -1169,6 +1169,12 @@
 #define HAVE_SKADNETWORK_v4 1
 #endif
 
+#if (PLATFORM(IOS) && __IPHONE_OS_VERSION_MAX_ALLOWED >= 160000) \
+    || (PLATFORM(WATCHOS) && __WATCH_OS_VERSION_MAX_ALLOWED >= 90000) \
+    || (PLATFORM(APPLETV) && __TV_OS_VERSION_MAX_ALLOWED >= 160000)
+#define HAVE_IMAGEIO_CREATE_UNPREMULTIPLIED_PNG 1
+#endif
+
 #if !defined(HAVE_UI_CONTEXT_MENU_PREVIEW_ITEM_IDENTIFIER) \
     && (((PLATFORM(IOS) || PLATFORM(MACCATALYST)) && __IPHONE_OS_VERSION_MIN_REQUIRED >= 160000) \
     || (PLATFORM(WATCHOS) && __WATCH_OS_VERSION_MIN_REQUIRED >= 90000) \

Source/WebCore/platform/graphics/cg/ImageDecoderCG.cpp

@@ -61,6 +61,10 @@ const CFStringRef kCGImageSourceUseHardwareAcceleration = CFSTR("kCGImageSourceU
 
 const CFStringRef kCGImageSourceEnableRestrictedDecoding = CFSTR("kCGImageSourceEnableRestrictedDecoding");
 
+#if HAVE(IMAGEIO_CREATE_UNPREMULTIPLIED_PNG)
+const CFStringRef kCGImageSourceCreateUnpremultipliedPNG = CFSTR("kCGImageSourceCreateUnpremultipliedPNG");
+#endif
+
 static RetainPtr<CFMutableDictionaryRef> createImageSourceOptions()
 {
     RetainPtr<CFMutableDictionaryRef> options = adoptCF(CFDictionaryCreateMutable(nullptr, 0, &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks));
@@ -75,6 +79,10 @@ static RetainPtr<CFMutableDictionaryRef> createImageSourceOptions()
     if (ImageDecoderCG::restrictedDecodingEnabled())
         CFDictionarySetValue(options.get(), kCGImageSourceEnableRestrictedDecoding, kCFBooleanTrue);
 #endif
+
+#if HAVE(IMAGEIO_CREATE_UNPREMULTIPLIED_PNG)
+    CFDictionarySetValue(options.get(), kCGImageSourceCreateUnpremultipliedPNG, kCFBooleanTrue);
+#endif
     return options;
 }