72 lines
2.5 KiB
Objective-C
72 lines
2.5 KiB
Objective-C
/*
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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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if (image.images) {
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// Do not decode animated images
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return image;
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}
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CGImageRef imageRef = image.CGImage;
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CGSize imageSize = CGSizeMake(CGImageGetWidth(imageRef), CGImageGetHeight(imageRef));
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CGRect imageRect = (CGRect){.origin = CGPointZero, .size = imageSize};
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CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
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CGBitmapInfo bitmapInfo = CGImageGetBitmapInfo(imageRef);
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int infoMask = (bitmapInfo & kCGBitmapAlphaInfoMask);
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BOOL anyNonAlpha = (infoMask == kCGImageAlphaNone ||
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infoMask == kCGImageAlphaNoneSkipFirst ||
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infoMask == kCGImageAlphaNoneSkipLast);
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// CGBitmapContextCreate doesn't support kCGImageAlphaNone with RGB.
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// https://developer.apple.com/library/mac/#qa/qa1037/_index.html
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if (infoMask == kCGImageAlphaNone && CGColorSpaceGetNumberOfComponents(colorSpace) > 1) {
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// Unset the old alpha info.
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bitmapInfo &= ~kCGBitmapAlphaInfoMask;
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// Set noneSkipFirst.
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bitmapInfo |= kCGImageAlphaNoneSkipFirst;
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}
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// Some PNGs tell us they have alpha but only 3 components. Odd.
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else if (!anyNonAlpha && CGColorSpaceGetNumberOfComponents(colorSpace) == 3) {
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// Unset the old alpha info.
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bitmapInfo &= ~kCGBitmapAlphaInfoMask;
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bitmapInfo |= kCGImageAlphaPremultipliedFirst;
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}
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// It calculates the bytes-per-row based on the bitsPerComponent and width arguments.
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CGContextRef context = CGBitmapContextCreate(NULL,
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imageSize.width,
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imageSize.height,
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CGImageGetBitsPerComponent(imageRef),
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0,
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colorSpace,
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bitmapInfo);
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CGColorSpaceRelease(colorSpace);
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// If failed, return undecompressed image
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if (!context) return image;
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CGContextDrawImage(context, imageRect, imageRef);
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CGImageRef decompressedImageRef = CGBitmapContextCreateImage(context);
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CGContextRelease(context);
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UIImage *decompressedImage = [UIImage imageWithCGImage:decompressedImageRef scale:image.scale orientation:image.imageOrientation];
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CGImageRelease(decompressedImageRef);
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return decompressedImage;
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}
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@end
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