imageView 展示gif

category

- (void)gifName:(NSString *)imgName bundle:(NSBundle * _Nullable)bundle {
    NSBundle *curBundle = bundle ? bundle : [NSBundle mainBundle];
    NSString * filePath = [curBundle pathForResource:imgName ofType:@"gif"];
    NSURL *imageUrl = [[NSURL alloc] initFileURLWithPath:filePath];
    __weak id __self = self;
    [self getGifImageWithUrl:imageUrl returnData:^(NSArray *imageArray, NSArray *timeArray, CGFloat totalTime, NSArray *widths, NSArray *heights) {
        //添加帧动画
        CAKeyframeAnimation *animation = [CAKeyframeAnimation animationWithKeyPath:@"contents"];
        NSMutableArray * times = [[NSMutableArray alloc]init];
        float currentTime = 0;
        //设置每一帧的时间占比
        for (int i = 0; i < imageArray.count; i++) {
            [times addObject:[NSNumber numberWithFloat:currentTime/totalTime]];
            currentTime += [timeArray[i] floatValue];
        }
        [animation setKeyTimes:times];
        [animation setValues:imageArray];
        [animation setTimingFunction:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear]];
        //设置循环
        animation.repeatCount = MAXFLOAT;
        //设置播放总时长
        animation.duration = totalTime;
        //Layer层添加
        [[(UIImageView *)__self layer] addAnimation:animation forKey:@"gifAnimation"];
    }];
}

- (void)getGifImageWithUrl:(NSURL *)url returnData:(void(^)(NSArray * imageArray, NSArray*timeArray, CGFloat totalTime, NSArray* widths, NSArray* heights))dataBlock {
    //通过文件的url来将gif文件读取为图片数据引用
    CGImageSourceRef source = CGImageSourceCreateWithURL((CFURLRef)url, NULL);
    //获取gif文件中图片的个数
    size_t count = CGImageSourceGetCount(source);
    //定义一个变量记录gif播放一轮的时间
    float allTime = 0;
    //存放所有图片
    NSMutableArray * imageArray = [[NSMutableArray alloc]init];
    //存放每一帧播放的时间
    NSMutableArray * timeArray = [[NSMutableArray alloc]init];
    //存放每张图片的宽度 （一般在一个gif文件中，所有图片尺寸都会一样）
    NSMutableArray * widthArray = [[NSMutableArray alloc]init];
    //存放每张图片的高度
    NSMutableArray * heightArray = [[NSMutableArray alloc]init];
    //遍历
    for(size_t i = 0; i < count; i++) {
        CGImageRef image = CGImageSourceCreateImageAtIndex(source, i, NULL);
        [imageArray addObject:(__bridge UIImage *)(image)];
        CGImageRelease(image);
        //获取图片信息
        NSDictionary * info = (__bridge NSDictionary*)CGImageSourceCopyPropertiesAtIndex(source, i, NULL);
        CGFloat width = [[info objectForKey:(__bridge NSString *)kCGImagePropertyPixelWidth] floatValue];
        CGFloat height = [[info objectForKey:(__bridge NSString *)kCGImagePropertyPixelHeight] floatValue];
        [widthArray addObject:[NSNumber numberWithFloat:width]];
        [heightArray addObject:[NSNumber numberWithFloat:height]];
        NSDictionary * timeDic = [info objectForKey:(__bridge NSString *)kCGImagePropertyGIFDictionary];
        CGFloat time = [[timeDic objectForKey:(__bridge NSString *)kCGImagePropertyGIFDelayTime]floatValue];
        allTime += time;
        [timeArray addObject:[NSNumber numberWithFloat:time]];
    }
    dataBlock(imageArray, timeArray, allTime, widthArray, heightArray);
}