Added the support for max file size for lossy encoding

SDWebImage/Core/SDImageCoder.h

@@ -71,6 +71,13 @@ FOUNDATION_EXPORT SDImageCoderOption _Nonnull const SDImageCoderEncodeBackground
  */
 FOUNDATION_EXPORT SDImageCoderOption _Nonnull const SDImageCoderEncodeMaxPixelSize;
 
+/**
+ A NSUInteger value specify the max ouput data bytes size after encoding. Some lossy format like JPEG/HEIF supports the hint for codec to automatically reduce the quality and match the file size you want. Note this option will override the `SDImageCoderEncodeCompressionQuality`, because now the quality is decided by the encoder. (NSNumber)
+ @note Not all format supports this feature. And this options does not works for vector images.
+ @note works for `SDImageCoder`
+ */
+FOUNDATION_EXPORT SDImageCoderOption _Nonnull const SDImageCoderEncodeMaxFileSize;
+
 /**
  A SDWebImageContext object which hold the original context options from top-level API. (SDWebImageContext)
  This option is ignored for all built-in coders and take no effect.

SDWebImage/Core/SDImageCoder.m

@@ -17,5 +17,6 @@ SDImageCoderOption const SDImageCoderEncodeFirstFrameOnly = @"encodeFirstFrameOn
 SDImageCoderOption const SDImageCoderEncodeCompressionQuality = @"encodeCompressionQuality";
 SDImageCoderOption const SDImageCoderEncodeBackgroundColor = @"encodeBackgroundColor";
 SDImageCoderOption const SDImageCoderEncodeMaxPixelSize = @"encodeMaxPixelSize";
+SDImageCoderOption const SDImageCoderEncodeMaxFileSize = @"encodeMaxFileSize";
 
 SDImageCoderOption const SDImageCoderWebImageContext = @"webImageContext";

SDWebImage/Core/SDImageIOAnimatedCoder.m

@@ -16,6 +16,8 @@
 
 // Specify DPI for vector format in CGImageSource, like PDF
 static NSString * kSDCGImageSourceRasterizationDPI = @"kCGImageSourceRasterizationDPI";
+// Specify File Size for lossy format encoding, like JPEG
+static NSString * kSDCGImageDestinationRequestedFileSize = @"kCGImageDestinationRequestedFileSize";
 
 @interface SDImageIOCoderFrame : NSObject
 
@@ -462,6 +464,10 @@ static NSString * kSDCGImageSourceRasterizationDPI = @"kCGImageSourceRasterizati
             finalPixelSize = maxPixelSize.height;
         }
     }
+    NSUInteger maxFileSize = [options[SDImageCoderEncodeMaxFileSize] unsignedIntegerValue];
+    if (maxFileSize > 0) {
+        properties[kSDCGImageDestinationRequestedFileSize] = @(maxFileSize);
+    }
     
     BOOL encodeFirstFrame = [options[SDImageCoderEncodeFirstFrameOnly] boolValue];
     if (encodeFirstFrame || frames.count == 0) {

SDWebImage/Core/SDImageIOCoder.m

@@ -14,6 +14,9 @@
 #import "SDImageHEICCoderInternal.h"
 #import "SDImageIOAnimatedCoderInternal.h"
 
+// Specify File Size for lossy format encoding, like JPEG
+static NSString * kSDCGImageDestinationRequestedFileSize = @"kCGImageDestinationRequestedFileSize";
+
 @implementation SDImageIOCoder {
     size_t _width, _height;
     CGImagePropertyOrientation _orientation;
@@ -285,7 +288,10 @@
         }
         properties[(__bridge NSString *)kCGImageDestinationImageMaxPixelSize] = @(finalPixelSize);
     }
-    
+    NSUInteger maxFileSize = [options[SDImageCoderEncodeMaxFileSize] unsignedIntegerValue];
+    if (maxFileSize > 0) {
+        properties[kSDCGImageDestinationRequestedFileSize] = @(maxFileSize);
+    }
     
     // Add your image to the destination.
     CGImageDestinationAddImage(imageDestination, imageRef, (__bridge CFDictionaryRef)properties);