Added encodeWithFrames API for animation encoding in custom coder, better for usage

The exist API need wrap the frames into a new image and extract, consume RAM and CPU

SDWebImage/Core/SDImageCoder.h

@@ -9,6 +9,7 @@
 #import <Foundation/Foundation.h>
 #import "SDWebImageCompat.h"
 #import "NSData+ImageContentType.h"
+#import "SDImageFrame.h"
 
 typedef NSString * SDImageCoderOption NS_STRING_ENUM;
 typedef NSDictionary<SDImageCoderOption, id> SDImageCoderOptions;
@@ -171,7 +172,8 @@ FOUNDATION_EXPORT SDImageCoderOption _Nonnull const SDImageCoderWebImageContext
 
 /**
  Encode the image to image data.
- @note This protocol may supports encode animated image frames. You can use `+[SDImageCoderHelper framesFromAnimatedImage:]` to assemble an animated image with frames.
+ @note This protocol may supports encode animated image frames. You can use `+[SDImageCoderHelper framesFromAnimatedImage:]` to assemble an animated image with frames. But this consume time is not always reversible. In 5.15.0, we introduce `encodedDataWithFrames` API for better animated image encoding. Use that instead.
+ @note Which means, this just forward to `encodedDataWithFrames([SDImageFrame(image: image, duration: 0], image.sd_imageLoopCount))`
 
  @param image The image to be encoded
  @param format The image format to encode, you should note `SDImageFormatUndefined` format is also  possible
@@ -182,6 +184,21 @@ FOUNDATION_EXPORT SDImageCoderOption _Nonnull const SDImageCoderWebImageContext
                                    format:(SDImageFormat)format
                                   options:(nullable SDImageCoderOptions *)options;
 
+#pragma mark - Animated Encoding
+@optional
+/**
+ Encode the animated image frames to image data.
+
+ @param frames The animated image frames to be encoded, should be at least 1 element, or it will fallback to static image encode.
+ @param loopCount The final animated image loop count. 0 means infinity loop. This config ignore each frame's `sd_imageLoopCount`
+ @param format The image format to encode, you should note `SDImageFormatUndefined` format is also  possible
+ @param options A dictionary containing any encoding options. Pass @{SDImageCoderEncodeCompressionQuality: @(1)} to specify compression quality.
+ @return The encoded image data
+ */
+- (nullable NSData *)encodedDataWithFrames:(nonnull NSArray<SDImageFrame *>*)frames
+                                 loopCount:(NSUInteger)loopCount
+                                    format:(SDImageFormat)format
+                                   options:(nullable SDImageCoderOptions *)options;
 @end
 
 #pragma mark - Progressive Coder

SDWebImage/Core/SDImageCodersManager.m

@@ -127,4 +127,19 @@
     return nil;
 }
 
+- (NSData *)encodedDataWithFrames:(NSArray<SDImageFrame *> *)frames loopCount:(NSUInteger)loopCount format:(SDImageFormat)format options:(SDImageCoderOptions *)options {
+    if (!frames || frames.count < 1) {
+        return nil;
+    }
+    NSArray<id<SDImageCoder>> *coders = self.coders;
+    for (id<SDImageCoder> coder in coders.reverseObjectEnumerator) {
+        if ([coder canEncodeToFormat:format]) {
+            if ([coder respondsToSelector:@selector(encodedDataWithFrames:loopCount:format:options:)]) {
+                return [coder encodedDataWithFrames:frames loopCount:loopCount format:format options:options];
+            }
+        }
+    }
+    return nil;
+}
+
 @end

SDWebImage/Core/SDImageFrame.h

@@ -24,6 +24,11 @@
  */
 @property (nonatomic, readonly, assign) NSTimeInterval duration;
 
+/// Create a frame instance with specify image and duration
+/// @param image current frame's image
+/// @param duration current frame's duration
+- (nonnull instancetype)initWithImage:(nonnull UIImage *)image duration:(NSTimeInterval)duration;
+
 /**
  Create a frame instance with specify image and duration
 
@@ -31,6 +36,9 @@
  @param duration current frame's duration
  @return frame instance
  */
-+ (instancetype _Nonnull)frameWithImage:(UIImage * _Nonnull)image duration:(NSTimeInterval)duration;
++ (nonnull instancetype)frameWithImage:(nonnull UIImage *)image duration:(NSTimeInterval)duration;
+
+- (nonnull instancetype)init NS_UNAVAILABLE;
++ (nonnull instancetype)new  NS_UNAVAILABLE;
 
 @end

SDWebImage/Core/SDImageFrame.m

@@ -17,11 +17,17 @@
 
 @implementation SDImageFrame
 
+- (instancetype)initWithImage:(UIImage *)image duration:(NSTimeInterval)duration {
+    self = [super init];
+    if (self) {
+        _image = image;
+        _duration = duration;
+    }
+    return self;
+}
+
 + (instancetype)frameWithImage:(UIImage *)image duration:(NSTimeInterval)duration {
-    SDImageFrame *frame = [[SDImageFrame alloc] init];
-    frame.image = image;
-    frame.duration = duration;
-    
+    SDImageFrame *frame = [[SDImageFrame alloc] initWithImage:image duration:duration];
     return frame;
 }
 

SDWebImage/Core/SDImageIOAnimatedCoder.m

@@ -552,6 +552,23 @@ static CGImageRef __nullable SDCGImageCreateCopy(CGImageRef cg_nullable image) {
 }
 
 - (NSData *)encodedDataWithImage:(UIImage *)image format:(SDImageFormat)format options:(nullable SDImageCoderOptions *)options {
+    if (!image) {
+        return nil;
+    }
+    if (format != self.class.imageFormat) {
+        return nil;
+    }
+    
+    NSArray<SDImageFrame *> *frames = [SDImageCoderHelper framesFromAnimatedImage:image];
+    if (!frames || frames.count == 0) {
+        SDImageFrame *frame = [SDImageFrame frameWithImage:image duration:0];
+        frames = @[frame];
+    }
+    return [self encodedDataWithFrames:frames loopCount:image.sd_imageLoopCount format:format options:options];
+}
+
+- (NSData *)encodedDataWithFrames:(NSArray<SDImageFrame *> *)frames loopCount:(NSUInteger)loopCount format:(SDImageFormat)format options:(SDImageCoderOptions *)options {
+    UIImage *image = frames.firstObject.image; // Primary image
     if (!image) {
         return nil;
     }
@@ -561,13 +578,8 @@ static CGImageRef __nullable SDCGImageCreateCopy(CGImageRef cg_nullable image) {
         return nil;
     }
     
-    if (format != self.class.imageFormat) {
-        return nil;
-    }
-    
     NSMutableData *imageData = [NSMutableData data];
     CFStringRef imageUTType = [NSData sd_UTTypeFromImageFormat:format];
-    NSArray<SDImageFrame *> *frames = [SDImageCoderHelper framesFromAnimatedImage:image];
     
     // Create an image destination. Animated Image does not support EXIF image orientation TODO
     // The `CGImageDestinationCreateWithData` will log a warning when count is 0, use 1 instead.
@@ -630,12 +642,11 @@ static CGImageRef __nullable SDCGImageCreateCopy(CGImageRef cg_nullable image) {
     properties[(__bridge NSString *)kCGImageDestinationEmbedThumbnail] = @(embedThumbnail);
     
     BOOL encodeFirstFrame = [options[SDImageCoderEncodeFirstFrameOnly] boolValue];
-    if (encodeFirstFrame || frames.count == 0) {
+    if (encodeFirstFrame || frames.count <= 1) {
         // for static single images
         CGImageDestinationAddImage(imageDestination, imageRef, (__bridge CFDictionaryRef)properties);
     } else {
         // for animated images
-        NSUInteger loopCount = image.sd_imageLoopCount;
         NSDictionary *containerProperties = @{
             self.class.dictionaryProperty: @{self.class.loopCountProperty : @(loopCount)}
         };