iOS：Gif动画功能（显示gif动画、获取gif动画时长、获取gif动画执行次数）

一、简单介绍

gif动画是iOS开发中很常用的一个功能，有的是为了显示加载视频的过程，更多的是为了显示一个结果状态（动画更直观）。

那么如何执行gif动画，方法有很多。（这里只写一下方法三，前两种之前都用过）

方法一使用UIWebView来显示；

方法二使用UIImageView的帧动画显示；

方法三使用SDWebImage这个三方框架来显示。

二、简单使用

1、显示gif动画（三方框架SDWebImage的UIImage+GIF分类） 

#import "UIImage+GIF.h"
#import "SDWebImageGIFCoder.h"
#import "NSImage+WebCache.h"

@implementation UIImage (GIF)

+ (UIImage *)sd_animatedGIFWithData:(NSData *)data {
    if (!data) {
        return nil;
    }
    return [[SDWebImageGIFCoder sharedCoder] decodedImageWithData:data];
}

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

@end

//使用
NSData *gifData = [NSData dataWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"live_sign" ofType:@"gif"]];
UIImage  *signSuccessGifImg = [UIImage sd_animatedGIFWithData:gifData];
self.imageView.image = signSuccessGifImg;

2、获取gif动画时长

//获取gif图片的总时长
- (NSTimeInterval)durationForGifData:(NSData *)data{
    
    //将GIF图片转换成对应的图片源
    CGImageSourceRef gifSource = CGImageSourceCreateWithData((__bridge CFDataRef)data, NULL);
    
    //获取其中图片源个数，即由多少帧图片组成
    size_t frameCout = CGImageSourceGetCount(gifSource);

    //定义数组存储拆分出来的图片
    NSMutableArray* frames = [[NSMutableArray alloc] init];
    NSTimeInterval totalDuration = 0;
    for (size_t i=0; i<frameCout; i++) {

        //从GIF图片中取出源图片
        CGImageRef imageRef = CGImageSourceCreateImageAtIndex(gifSource, i, NULL);

        //将图片源转换成UIimageView能使用的图片源
        UIImage* imageName = [UIImage imageWithCGImage:imageRef];

        //将图片加入数组中
        [frames addObject:imageName];
        NSTimeInterval duration = [self gifImageDeleyTime:gifSource index:i];
        totalDuration += duration;
        CGImageRelease(imageRef);
    }
    
    //获取循环次数
    NSInteger loopCount;//循环次数
    CFDictionaryRef properties = CGImageSourceCopyProperties(gifSource, NULL);
    if (properties) {
        CFDictionaryRef gif = CFDictionaryGetValue(properties, kCGImagePropertyGIFDictionary);
        if (gif) {
            CFTypeRef loop = CFDictionaryGetValue(gif, kCGImagePropertyGIFLoopCount);
            if (loop) {
                //如果loop == NULL，表示不循环播放，当loopCount  == 0时，表示无限循环；
                CFNumberGetValue(loop, kCFNumberNSIntegerType, &loopCount);
            };
        }
    }
    CFRelease(gifSource);
    return totalDuration;
}

//获取GIF图片每帧的时长
- (NSTimeInterval)gifImageDeleyTime:(CGImageSourceRef)imageSource index:(NSInteger)index {
    NSTimeInterval duration = 0;
    CFDictionaryRef imageProperties = CGImageSourceCopyPropertiesAtIndex(imageSource, index, NULL);
    if (imageProperties) {
        CFDictionaryRef gifProperties;
        BOOL result = CFDictionaryGetValueIfPresent(imageProperties, kCGImagePropertyGIFDictionary, (const void **)&gifProperties);
        if (result) {
            const void *durationValue;
            if (CFDictionaryGetValueIfPresent(gifProperties, kCGImagePropertyGIFUnclampedDelayTime, &durationValue)) {
                duration = [(__bridge NSNumber *)durationValue doubleValue];
                if (duration < 0) {
                    if (CFDictionaryGetValueIfPresent(gifProperties, kCGImagePropertyGIFDelayTime, &durationValue)) {
                        duration = [(__bridge NSNumber *)durationValue doubleValue];
                    }
                }
            }
        }
    }
    
    return duration;
}

3、获取gif动画执行次数

//获取gif图片的循环次数
-(NSInteger)repeatCountForGifData:(NSData *)data{
    
    //将GIF图片转换成对应的图片源
    CGImageSourceRef gifSource = CGImageSourceCreateWithData((__bridge CFDataRef)data, NULL);
    
    //获取循环次数
    NSInteger loopCount = 0;//循环次数
    CFDictionaryRef properties = CGImageSourceCopyProperties(gifSource, NULL);
    if (properties) {
        CFDictionaryRef gif = CFDictionaryGetValue(properties, kCGImagePropertyGIFDictionary);
        if (gif) {
            CFTypeRef loop = CFDictionaryGetValue(gif, kCGImagePropertyGIFLoopCount);
            if (loop) {
                //如果loop == NULL，表示不循环播放，当loopCount  == 0时，表示无限循环；
                CFNumberGetValue(loop, kCFNumberNSIntegerType, &loopCount);
            };
        }
    }
    CFRelease(gifSource);
    
    return loopCount;
}

三、创建分类

#import "UIImageView+GIFProperty.h"

//
//  UIImageView+GIFProperty.h
//  YuwenParent
//
//  Created by 夏远全 on 2019/4/11.
//  Copyright © 2019年 xiaoshuang. All rights reserved.
//

#import <UIKit/UIKit.h>

NS_ASSUME_NONNULL_BEGIN

@interface UIImageView (GIFProperty)
-(NSTimeInterval)durationForGifData:(NSData *)data;//获取gif动画总时长
-(NSInteger)repeatCountForGifData:(NSData *)data;  //获取gif动画循环总次数 0:表示无限循环
@end

NS_ASSUME_NONNULL_END

//
//  UIImageView+GIFProperty.m
//  YuwenParent
//
//  Created by 夏远全 on 2019/4/11.
//  Copyright © 2019年 xiaoshuang. All rights reserved.
//

#import "UIImageView+GIFProperty.h"

@implementation UIImageView (GIFProperty)

//获取gif图片的总时长
- (NSTimeInterval)durationForGifData:(NSData *)data{
    
    //将GIF图片转换成对应的图片源
    CGImageSourceRef gifSource = CGImageSourceCreateWithData((__bridge CFDataRef)data, NULL);
    
    //获取其中图片源个数，即由多少帧图片组成
    size_t frameCout = CGImageSourceGetCount(gifSource);

    //定义数组存储拆分出来的图片
    NSMutableArray* frames = [[NSMutableArray alloc] init];
    NSTimeInterval totalDuration = 0;
    for (size_t i=0; i<frameCout; i++) {

        //从GIF图片中取出源图片
        CGImageRef imageRef = CGImageSourceCreateImageAtIndex(gifSource, i, NULL);

        //将图片源转换成UIimageView能使用的图片源
        UIImage* imageName = [UIImage imageWithCGImage:imageRef];

        //将图片加入数组中
        [frames addObject:imageName];
        NSTimeInterval duration = [self gifImageDeleyTime:gifSource index:i];
        totalDuration += duration;
        CGImageRelease(imageRef);
    }
    
    //获取循环次数
    NSInteger loopCount;//循环次数
    CFDictionaryRef properties = CGImageSourceCopyProperties(gifSource, NULL);
    if (properties) {
        CFDictionaryRef gif = CFDictionaryGetValue(properties, kCGImagePropertyGIFDictionary);
        if (gif) {
            CFTypeRef loop = CFDictionaryGetValue(gif, kCGImagePropertyGIFLoopCount);
            if (loop) {
                //如果loop == NULL，表示不循环播放，当loopCount  == 0时，表示无限循环；
                CFNumberGetValue(loop, kCFNumberNSIntegerType, &loopCount);
            };
        }
    }
    CFRelease(gifSource);
    return totalDuration;
}

//获取gif图片的循环次数
-(NSInteger)repeatCountForGifData:(NSData *)data{
    
    //将GIF图片转换成对应的图片源
    CGImageSourceRef gifSource = CGImageSourceCreateWithData((__bridge CFDataRef)data, NULL);
    
    //获取循环次数
    NSInteger loopCount = 0;//循环次数
    CFDictionaryRef properties = CGImageSourceCopyProperties(gifSource, NULL);
    if (properties) {
        CFDictionaryRef gif = CFDictionaryGetValue(properties, kCGImagePropertyGIFDictionary);
        if (gif) {
            CFTypeRef loop = CFDictionaryGetValue(gif, kCGImagePropertyGIFLoopCount);
            if (loop) {
                //如果loop == NULL，表示不循环播放，当loopCount  == 0时，表示无限循环；
                CFNumberGetValue(loop, kCFNumberNSIntegerType, &loopCount);
            };
        }
    }
    CFRelease(gifSource);
    
    return loopCount;
}

//获取GIF图片每帧的时长
- (NSTimeInterval)gifImageDeleyTime:(CGImageSourceRef)imageSource index:(NSInteger)index {
    NSTimeInterval duration = 0;
    CFDictionaryRef imageProperties = CGImageSourceCopyPropertiesAtIndex(imageSource, index, NULL);
    if (imageProperties) {
        CFDictionaryRef gifProperties;
        BOOL result = CFDictionaryGetValueIfPresent(imageProperties, kCGImagePropertyGIFDictionary, (const void **)&gifProperties);
        if (result) {
            const void *durationValue;
            if (CFDictionaryGetValueIfPresent(gifProperties, kCGImagePropertyGIFUnclampedDelayTime, &durationValue)) {
                duration = [(__bridge NSNumber *)durationValue doubleValue];
                if (duration < 0) {
                    if (CFDictionaryGetValueIfPresent(gifProperties, kCGImagePropertyGIFDelayTime, &durationValue)) {
                        duration = [(__bridge NSNumber *)durationValue doubleValue];
                    }
                }
            }
        }
    }
    
    return duration;
}

@end