iOS GIF图片转UIImage

多平台保持统一风格的UI设计，少不了一些动态图片的使用

1、本地GIF图片使用

 1.1 将本地GIF转为NSdata类型

 NSData *tempdata = [NSData dataWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"networkLoading" ofType:@"gif"]];
 UIImageView *imgView = [[UIImageView alloc] initWithImage:[self decodeGifImageByData:tempdata]];

 1.2 通过自定义方法处理GIF的data数据

//解压gif的data为图片数组
-(UIImage *)decodeGifImageByData:(NSData *)data {
    //获取data资源器，这个可以直接操作图片data
    CGImageSourceRef source = CGImageSourceCreateWithData((__bridge CFDataRef)data, nil);
    //获取图片数量 size_t 类似于无符号int
    size_t count = CGImageSourceGetCount(source);
    UIImage * animationImage;
    
    //如果只有一张则直接解压
    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];
    }
    
    
    CFRelease(source);
    return animationImage;
}

//获取每一张图片的持续时间
-(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;
}