/*
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* This file is part of the SDWebImage package.
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* (c) Olivier Poitrey <rs@dailymotion.com>
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*
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* Created by james <https://github.com/mystcolor> on 9/28/11.
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*
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* For the full copyright and license information, please view the LICENSE
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* file that was distributed with this source code.
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*/
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#import "SDWebImageDecoder.h"
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@implementation UIImage (ForceDecode)
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+ (UIImage *)decodedImageWithImage:(UIImage *)image {
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// while downloading huge amount of images
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// autorelease the bitmap context
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// and all vars to help system to free memory
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// when there are memory warning.
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// on iOS7, do not forget to call
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// [[SDImageCache sharedImageCache] clearMemory];
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if (image == nil) { // Prevent "CGBitmapContextCreateImage: invalid context 0x0" error
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return nil;
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}
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@autoreleasepool{
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// do not decode animated images
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if (image.images != nil) {
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return image;
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}
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CGImageRef imageRef = image.CGImage;
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CGImageAlphaInfo alpha = CGImageGetAlphaInfo(imageRef);
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BOOL anyAlpha = (alpha == kCGImageAlphaFirst ||
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alpha == kCGImageAlphaLast ||
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alpha == kCGImageAlphaPremultipliedFirst ||
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alpha == kCGImageAlphaPremultipliedLast);
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if (anyAlpha) {
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return image;
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}
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// current
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CGColorSpaceModel imageColorSpaceModel = CGColorSpaceGetModel(CGImageGetColorSpace(imageRef));
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CGColorSpaceRef colorspaceRef = CGImageGetColorSpace(imageRef);
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BOOL unsupportedColorSpace = (imageColorSpaceModel == kCGColorSpaceModelUnknown ||
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imageColorSpaceModel == kCGColorSpaceModelMonochrome ||
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imageColorSpaceModel == kCGColorSpaceModelCMYK ||
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imageColorSpaceModel == kCGColorSpaceModelIndexed);
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if (unsupportedColorSpace) {
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colorspaceRef = CGColorSpaceCreateDeviceRGB();
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}
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size_t width = CGImageGetWidth(imageRef);
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size_t height = CGImageGetHeight(imageRef);
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NSUInteger bytesPerPixel = 4;
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NSUInteger bytesPerRow = bytesPerPixel * width;
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NSUInteger bitsPerComponent = 8;
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// kCGImageAlphaNone is not supported in CGBitmapContextCreate.
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// Since the original image here has no alpha info, use kCGImageAlphaNoneSkipLast
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// to create bitmap graphics contexts without alpha info.
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CGContextRef context = CGBitmapContextCreate(NULL,
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width,
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height,
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bitsPerComponent,
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bytesPerRow,
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colorspaceRef,
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kCGBitmapByteOrderDefault|kCGImageAlphaNoneSkipLast);
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// Draw the image into the context and retrieve the new bitmap image without alpha
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CGContextDrawImage(context, CGRectMake(0, 0, width, height), imageRef);
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CGImageRef imageRefWithoutAlpha = CGBitmapContextCreateImage(context);
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UIImage *imageWithoutAlpha = [UIImage imageWithCGImage:imageRefWithoutAlpha
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scale:image.scale
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orientation:image.imageOrientation];
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if (unsupportedColorSpace) {
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CGColorSpaceRelease(colorspaceRef);
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}
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CGContextRelease(context);
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CGImageRelease(imageRefWithoutAlpha);
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return imageWithoutAlpha;
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}
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}
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@end
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