jixin_new/shiku_im/3rd/SDWebImage/UIImage+GIF.m

/*
 * This file is part of the SDWebImage package.
 * (c) Olivier Poitrey <rs@dailymotion.com>
 * (c) Laurin Brandner
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

#import "UIImage+GIF.h"
#import <ImageIO/ImageIO.h>
#import "objc/runtime.h"
#import "NSImage+WebCache.h"

@implementation UIImage (GIF)

+ (UIImage *)sd_animatedGIFWithData:(NSData *)data {
    if (!data) {
        return nil;
    }
    
#if SD_MAC
    return [[UIImage alloc] initWithData:data];
#else

    CGImageSourceRef source = CGImageSourceCreateWithData((__bridge CFDataRef)data, NULL);

    size_t count = CGImageSourceGetCount(source);

    UIImage *staticImage;

    if (count <= 1) {
        staticImage = [[UIImage alloc] initWithData:data];
    } else {
        // we will only retrieve the 1st frame. the full GIF support is available via the FLAnimatedImageView category.
        // this here is only code to allow drawing animated images as static ones
//#if SD_WATCH
//        CGFloat scale = 1;
//        scale = [WKInterfaceDevice currentDevice].screenScale;
//#elif SD_UIKIT
//        CGFloat scale = 1;
//        scale = [UIScreen mainScreen].scale;
//#endif
//
//        CGImageRef CGImage = CGImageSourceCreateImageAtIndex(source, 0, NULL);
//#if SD_UIKIT || SD_WATCH
//        UIImage *frameImage = [UIImage imageWithCGImage:CGImage scale:scale orientation:UIImageOrientationUp];
//        staticImage = [UIImage animatedImageWithImages:@[frameImage] duration:0.0f];
//#endif
//        CGImageRelease(CGImage);
        staticImage = [self getGifImage:data withSource:source withCount:count];
    }

    CFRelease(source);

    return staticImage;
#endif
}

+ (UIImage *)getGifImage:(NSData *)data withSource:(CGImageSourceRef )source withCount:(size_t )count{
     UIImage * animationImage;
     if (count <= 1) {
         animationImage = [[UIImage alloc] initWithData:data];
     }
     else {
         NSMutableArray * imageArray = [NSMutableArray arrayWithCapacity:count];
         NSTimeInterval duration = 0.0f;
         //遍历获取每一张图片
         for (size_t i = 0; i < count; i++) {
             //解析图片拿到图片画笔拿到图片画笔
             CGImageRef imageRef = CGImageSourceCreateImageAtIndex(source, i, NULL);
             duration += [self imageDurationAtIndex:i source:source];
             //scale:图片缩放因子 默认1  orientation:图片绘制方向 默认网上
             [imageArray addObject:[UIImage imageWithCGImage:imageRef scale:[UIScreen mainScreen].scale orientation:UIImageOrientationUp]];
             CGImageRelease(imageRef);
         }
         
         //如果没有抓取到图片播放时间，则按照0.1秒一张的方式来了播放
         if (!duration) {
             duration = (1.0f / 10.0f) * count;
         }
         animationImage = [UIImage animatedImageWithImages:imageArray duration:duration];
     }
     
    return animationImage;
}

+(float)imageDurationAtIndex:(NSUInteger)index source:(CGImageSourceRef)source {
    float imageDuration = 0.1f;
    //获取指定图像的属性信息 如宽、高、持续时间等都在里面 详情参考 CGImageProperties
    CFDictionaryRef cfImageProperties = CGImageSourceCopyPropertiesAtIndex(source, index, nil);
    if (!cfImageProperties) {
        return imageDuration;
    }
    NSDictionary * imageProperties = (__bridge NSDictionary *) cfImageProperties;
    //拿到gif图的属性信息 获取每一帧的时间
    NSDictionary * gifProperties = [imageProperties valueForKey:(NSString *)kCGImagePropertyGIFDictionary];
    NSNumber * delayTime = [gifProperties valueForKey:(NSString *)kCGImagePropertyGIFUnclampedDelayTime];
    if (delayTime != nil) {
        return delayTime.floatValue;
    }
    
    return imageDuration;
}

- (BOOL)isGIF {
    return (self.images != nil);
}

@end