iOS 实现gif 图片效果 以及 图片不变形处理

1. 在自定义的view上显示gif动画

//1.获取gif路径
    NSString *imagePath =[[NSBundle mainBundle] pathForResource:@"123" ofType:@"gif"];
    CGImageSourceRef  cImageSource = CGImageSourceCreateWithURL((__bridge CFURLRef)[NSURL fileURLWithPath:imagePath], NULL);

size_t imageCount = CGImageSourceGetCount(cImageSource);
    NSMutableArray *images = [[NSMutableArray alloc] initWithCapacity:imageCount];
    NSMutableArray *times = [[NSMutableArray alloc] initWithCapacity:imageCount];
    NSMutableArray *keyTimes = [[NSMutableArray alloc] initWithCapacity:imageCount];
CGFloat totalTime = 0;
    for (size_t i = 0; i < imageCount; i++) {
        CGImageRef cgimage= CGImageSourceCreateImageAtIndex(cImageSource, i, NULL);
        [images addObject:(__bridge id)cgimage];
        CGImageRelease(cgimage);

        NSDictionary *properties = (__bridge NSDictionary *)CGImageSourceCopyPropertiesAtIndex(cImageSource, i, NULL);
        NSDictionary *gifProperties = [properties valueForKey:(__bridge NSString *)kCGImagePropertyGIFDictionary];
        NSString *gifDelayTime = [gifProperties valueForKey:(__bridge NSString* )kCGImagePropertyGIFDelayTime];
        [times addObject:gifDelayTime];
        totalTime += [gifDelayTime floatValue];

    }

    float currentTime = 0;
    for (size_t i = 0; i < times.count; i++) {
        float keyTime = currentTime / totalTime;
        [keyTimes addObject:[NSNumber numberWithFloat:keyTime]];
        currentTime += [[times objectAtIndex:i] floatValue];
    }


    CAKeyframeAnimation *animation = [CAKeyframeAnimation animationWithKeyPath:@"contents"];
    [animation setTimingFunction:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear]];
    [animation setValues:images];
    [animation setKeyTimes:keyTimes];
    animation.duration = totalTime;
    animation.repeatCount = HUGE_VALF;

    view.image = nil;
    [view.layer addAnimation:animation forKey:@"gifAnimation"];

2.用纯色渲染图片 可在UIImage拓展类里拓展此方法

+ (UIImage *)NYimageWithColor:(UIColor *)color {
    CGRect rect = CGRectMake(0.0f, 0.0f, 1.0f, 1.0f);
    UIGraphicsBeginImageContext(rect.size);
    CGContextRef context = UIGraphicsGetCurrentContext();

    CGContextSetFillColorWithColor(context, [color CGColor]);
    CGContextFillRect(context, rect);

    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return image;
}

3.拉伸图片不变形

+ (UIImage *)NYresizableImageWithName:(NSString *)imageName
{
    // 加载原有图片
    UIImage *norImage = [UIImage imageNamed:imageName];
    // 获取原有图片的宽高的一半
    CGFloat w = norImage.size.width * 0.4;
    CGFloat h = norImage.size.width * 0.6;

    // 生成可以拉伸指定位置的图片
    UIImage *newImage = [norImage resizableImageWithCapInsets:UIEdgeInsetsMake(h, w, h, w) resizingMode:UIImageResizingModeStretch];

    return newImage;
}

4.各种图片显示状态

[btn.imageView setContentMode:UIViewContentModeScaleAspectFill]; 

typedef NS_ENUM(NSInteger, UIViewContentMode) {

    UIViewContentModeScaleToFill,

    UIViewContentModeScaleAspectFit,      // contents scaled to fit with fixed aspect. remainder is transparent

    UIViewContentModeScaleAspectFill,     // contents scaled to fill with fixed aspect. some portion of content may be clipped.

    UIViewContentModeRedraw,              // redraw on bounds change (calls -setNeedsDisplay)

    UIViewContentModeCenter,              // contents remain same size. positioned adjusted.

    UIViewContentModeTop,

    UIViewContentModeBottom,

    UIViewContentModeLeft,

    UIViewContentModeRight,

    UIViewContentModeTopLeft,

    UIViewContentModeTopRight,

    UIViewContentModeBottomLeft,

    UIViewContentModeBottomRight,

};