Change all the force decode method to be compatible with macOS. Update the documentation as well

SDWebImage/Core/SDImageCacheDefine.m

@@ -20,14 +20,12 @@ UIImage * _Nullable SDImageCacheDecodeImageData(NSData * _Nonnull imageData, NSS
     CGFloat scale = scaleValue.doubleValue >= 1 ? scaleValue.doubleValue : SDImageScaleFactorForKey(cacheKey);
     NSNumber *preserveAspectRatioValue = context[SDWebImageContextImagePreserveAspectRatio];
     NSValue *thumbnailSizeValue;
-#if SD_UIKIT || SD_WATCH
     BOOL shouldScaleDown = SD_OPTIONS_CONTAINS(options, SDWebImageScaleDownLargeImages);
     if (shouldScaleDown) {
         CGFloat thumbnailPixels = SDImageCoderHelper.defaultScaleDownLimitBytes / 4;
         CGFloat dimension = ceil(sqrt(thumbnailPixels));
         thumbnailSizeValue = @(CGSizeMake(dimension, dimension));
     }
-#endif
     if (context[SDWebImageContextImageThumbnailPixelSize]) {
         thumbnailSizeValue = context[SDWebImageContextImageThumbnailPixelSize];
     }
@@ -71,14 +69,9 @@ UIImage * _Nullable SDImageCacheDecodeImageData(NSData * _Nonnull imageData, NSS
             shouldDecode = NO;
         }
         if (shouldDecode) {
-            BOOL shouldScaleDown = SD_OPTIONS_CONTAINS(options, SDWebImageScaleDownLargeImages);
-            if (shouldScaleDown) {
-                image = [SDImageCoderHelper decodedAndScaledDownImageWithImage:image limitBytes:0];
-            } else {
             image = [SDImageCoderHelper decodedImageWithImage:image];
         }
     }
-    }
     
     return image;
 }

SDWebImage/Core/SDImageCoderHelper.h

@@ -89,13 +89,13 @@
  */
 + (UIImage * _Nullable)decodedAndScaledDownImageWithImage:(UIImage * _Nullable)image limitBytes:(NSUInteger)bytes;
 
-#if SD_UIKIT || SD_WATCH
 /**
  Control the default limit bytes to scale down larget images.
  This value must be larger than or equal to 1MB. Defaults to 60MB.
  */
 @property (class, readwrite) NSUInteger defaultScaleDownLimitBytes;
 
+#if SD_UIKIT || SD_WATCH
 /**
  Convert an EXIF image orientation to an iOS one.
 

SDWebImage/Core/SDImageCoderHelper.m

@@ -13,8 +13,8 @@
 #import "SDAnimatedImageRep.h"
 #import "UIImage+ForceDecode.h"
 #import "SDAssociatedObject.h"
+#import "UIImage+Metadata.h"
 
-#if SD_UIKIT || SD_WATCH
 static const size_t kBytesPerPixel = 4;
 static const size_t kBitsPerComponent = 8;
 
@@ -29,7 +29,6 @@ static const CGFloat kPixelsPerMB = kBytesPerMB / kBytesPerPixel;
 static CGFloat kDestImageLimitBytes = 60.f * kBytesPerMB;
 
 static const CGFloat kDestSeemOverlap = 2.0f;   // the numbers of pixels to overlap the seems where tiles meet.
-#endif
 
 @implementation SDImageCoderHelper
 
@@ -267,9 +266,6 @@ static const CGFloat kDestSeemOverlap = 2.0f;   // the numbers of pixels to over
 }
 
 + (UIImage *)decodedImageWithImage:(UIImage *)image {
-#if SD_MAC
-    return image;
-#else
     if (![self shouldDecodeImage:image]) {
         return image;
     }
@@ -278,18 +274,18 @@ static const CGFloat kDestSeemOverlap = 2.0f;   // the numbers of pixels to over
     if (!imageRef) {
         return image;
     }
+#if SD_MAC
+    UIImage *decodedImage = [[UIImage alloc] initWithCGImage:imageRef scale:image.scale orientation:kCGImagePropertyOrientationUp];
+#else
     UIImage *decodedImage = [[UIImage alloc] initWithCGImage:imageRef scale:image.scale orientation:image.imageOrientation];
+#endif
     CGImageRelease(imageRef);
     SDImageCopyAssociatedObject(image, decodedImage);
     decodedImage.sd_isDecoded = YES;
     return decodedImage;
-#endif
 }
 
 + (UIImage *)decodedAndScaledDownImageWithImage:(UIImage *)image limitBytes:(NSUInteger)bytes {
-#if SD_MAC
-    return image;
-#else
     if (![self shouldDecodeImage:image]) {
         return image;
     }
@@ -407,7 +403,11 @@ static const CGFloat kDestSeemOverlap = 2.0f;   // the numbers of pixels to over
         if (destImageRef == NULL) {
             return image;
         }
+#if SD_MAC
+        UIImage *destImage = [[UIImage alloc] initWithCGImage:destImageRef scale:image.scale orientation:kCGImagePropertyOrientationUp];
+#else
         UIImage *destImage = [[UIImage alloc] initWithCGImage:destImageRef scale:image.scale orientation:image.imageOrientation];
+#endif
         CGImageRelease(destImageRef);
         if (destImage == nil) {
             return image;
@@ -416,10 +416,8 @@ static const CGFloat kDestSeemOverlap = 2.0f;   // the numbers of pixels to over
         destImage.sd_isDecoded = YES;
         return destImage;
     }
-#endif
 }
 
-#if SD_UIKIT || SD_WATCH
 + (NSUInteger)defaultScaleDownLimitBytes {
     return kDestImageLimitBytes;
 }
@@ -431,6 +429,7 @@ static const CGFloat kDestSeemOverlap = 2.0f;   // the numbers of pixels to over
     kDestImageLimitBytes = defaultScaleDownLimitBytes;
 }
 
+#if SD_UIKIT || SD_WATCH
 // Convert an EXIF image orientation to an iOS one.
 + (UIImageOrientation)imageOrientationFromEXIFOrientation:(CGImagePropertyOrientation)exifOrientation {
     UIImageOrientation imageOrientation = UIImageOrientationUp;
@@ -501,7 +500,6 @@ static const CGFloat kDestSeemOverlap = 2.0f;   // the numbers of pixels to over
 #endif
 
 #pragma mark - Helper Fuction
-#if SD_UIKIT || SD_WATCH
 + (BOOL)shouldDecodeImage:(nullable UIImage *)image {
     // Avoid extra decode
     if (image.sd_isDecoded) {
@@ -512,7 +510,7 @@ static const CGFloat kDestSeemOverlap = 2.0f;   // the numbers of pixels to over
         return NO;
     }
     // do not decode animated images
-    if (image.images != nil) {
+    if (image.sd_isAnimated) {
         return NO;
     }
     
@@ -548,7 +546,6 @@ static const CGFloat kDestSeemOverlap = 2.0f;   // the numbers of pixels to over
     
     return shouldScaleDown;
 }
-#endif
 
 static inline CGAffineTransform SDCGContextTransformFromOrientation(CGImagePropertyOrientation orientation, CGSize size) {
     // Inspiration from @libfeihu

SDWebImage/Core/SDImageLoader.m

@@ -34,14 +34,12 @@ UIImage * _Nullable SDImageLoaderDecodeImageData(NSData * _Nonnull imageData, NS
     CGFloat scale = scaleValue.doubleValue >= 1 ? scaleValue.doubleValue : SDImageScaleFactorForKey(cacheKey);
     NSNumber *preserveAspectRatioValue = context[SDWebImageContextImagePreserveAspectRatio];
     NSValue *thumbnailSizeValue;
-#if SD_UIKIT || SD_WATCH
     BOOL shouldScaleDown = SD_OPTIONS_CONTAINS(options, SDWebImageScaleDownLargeImages);
     if (shouldScaleDown) {
         CGFloat thumbnailPixels = SDImageCoderHelper.defaultScaleDownLimitBytes / 4;
         CGFloat dimension = ceil(sqrt(thumbnailPixels));
         thumbnailSizeValue = @(CGSizeMake(dimension, dimension));
     }
-#endif
     if (context[SDWebImageContextImageThumbnailPixelSize]) {
         thumbnailSizeValue = context[SDWebImageContextImageThumbnailPixelSize];
     }
@@ -111,14 +109,12 @@ UIImage * _Nullable SDImageLoaderDecodeProgressiveImageData(NSData * _Nonnull im
     CGFloat scale = scaleValue.doubleValue >= 1 ? scaleValue.doubleValue : SDImageScaleFactorForKey(cacheKey);
     NSNumber *preserveAspectRatioValue = context[SDWebImageContextImagePreserveAspectRatio];
     NSValue *thumbnailSizeValue;
-#if SD_UIKIT || SD_WATCH
     BOOL shouldScaleDown = SD_OPTIONS_CONTAINS(options, SDWebImageScaleDownLargeImages);
     if (shouldScaleDown) {
         CGFloat thumbnailPixels = SDImageCoderHelper.defaultScaleDownLimitBytes / 4;
         CGFloat dimension = ceil(sqrt(thumbnailPixels));
         thumbnailSizeValue = @(CGSizeMake(dimension, dimension));
     }
-#endif
     if (context[SDWebImageContextImageThumbnailPixelSize]) {
         thumbnailSizeValue = context[SDWebImageContextImageThumbnailPixelSize];
     }

SDWebImage/Core/SDWebImageDefine.h

@@ -123,8 +123,8 @@ typedef NS_OPTIONS(NSUInteger, SDWebImageOptions) {
     
     /**
      * By default, images are decoded respecting their original size.
-     * On iOS/tvOS/watchOS, this flag will scale down the images to a size compatible with the constrained memory of devices. On macOS, this does nothing.
+     * This flag will scale down the images to a size compatible with the constrained memory of devices.
-     * To control the limit bytes, check `SDImageCoderHelper.defaultScaleDownLimitBytes` (Defaults to 60MB)
+     * To control the limit memory bytes, check `SDImageCoderHelper.defaultScaleDownLimitBytes` (Defaults to 60MB)
      * This will actually translate to use context option `.imageThumbnailPixelSize` from v5.5.0 (Defaults to (3966, 3966)). Previously does not.
      * This flags effect the progressive and animated images as well from v5.5.0. Previously does not.
      * @note If you need detail controls, it's better to use context option `imageThumbnailPixelSize` and `imagePreserveAspectRatio` instead.