顯示gif圖通常使用的方式如下：
1.使用UIImageView;
2,使用sdwebImage险毁；
3,使用YYImage;
4,使用webview效床；

但是顯示方式無非兩種：
1：先一次性把gif圖解析成多個(gè)圖片，然后輪流播放這些圖片,比如使用UIImageView和sdwebImage邓尤；這種方式因?yàn)橐４娼馕龊蟮膱D片拍鲤，所以占用內(nèi)存比較高；
2汞扎，播放到哪一張圖片時(shí)季稳，去gif圖中解析對(duì)應(yīng)的這張照片，用完就釋放澈魄，不占用內(nèi)存景鼠，比如YYImage和webview，但是因?yàn)橐l繁地解析圖片痹扇，當(dāng)照片分辨率很高時(shí)铛漓，會(huì)造成cpu占用率高溯香，導(dǎo)致手機(jī)發(fā)熱；

如果使用的gif圖分辨率較低票渠，影響還不是很大逐哈，個(gè)人測(cè)試當(dāng)使用的gif圖分辨率為1280*720附帽，gif圖大于8M缓苛，數(shù)量超過6個(gè)時(shí)，使用sdwebImage會(huì)由于內(nèi)存暴漲導(dǎo)致崩潰承璃；而使用YYImage雖然不會(huì)導(dǎo)致內(nèi)存暴漲杜窄，但是cpu占用率過高導(dǎo)致手機(jī)溫度上升肠骆；

綜合考慮：不能使用內(nèi)存暴增導(dǎo)致程序崩潰的方式，只能使用YYImage或者webview去顯示塞耕；既然是因?yàn)閳D片分辨率高導(dǎo)致手機(jī)溫度升高蚀腿，如果把圖片分辨率降低，就可以解決問題了扫外。具體操作如下：
1莉钙，從相冊(cè)選擇圖片后，使用ALAssetsLibrary取到圖片的原始數(shù)據(jù)：

//獲取選擇的圖片
-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<NSString *,id> *)info {
    [picker dismissViewControllerAnimated:YES completion:nil];
    [MeetHUD showLoadingTo:self.view animated:YES];
    __weak typeof(self)weakSelf = self;
    dispatch_async(dispatch_get_global_queue(0, 0), ^{
        NSURL *imageURL = [info valueForKey:UIImagePickerControllerReferenceURL];
        NSString *assetString = [imageURL absoluteString];
        __strong typeof(weakSelf)strongSelf = weakSelf;
        ALAssetsLibrary *assetLibrary = [[ALAssetsLibrary alloc]init];
        [assetLibrary assetForURL:imageURL resultBlock:^(ALAsset *asset) {
            ALAssetRepresentation *re = nil;
            if([assetString hasSuffix:@"GIF"] || [assetString hasSuffix:@"gif"]){
                re = [asset representationForUTI:(__bridge NSString *)kUTTypeGIF];
            } else {
                re = [asset defaultRepresentation];
            }
            NSUInteger size = [re size];
             uint8_t *buffer = malloc(size);
             NSError *error;
             NSUInteger bytes = [re getBytes:buffer fromOffset:0 length:size error:&error];
             NSData *data = [NSData dataWithBytes:buffer length:bytes];//這個(gè)就是選取的圖片的原二進(jìn)制數(shù)據(jù)
             free(buffer);
           NSData*scaleData = [self DataToScaleGifData: data];
         } failureBlock:^(NSError *error) {

         }];
    });
}

2筛谚，解析出gif圖中的每張圖片磁玉；

-(NSData*)DataToScaleGifData:(NSData*)data{
    CGImageSourceRef gifSource = CGImageSourceCreateWithData((__bridge CFDataRef)data, NULL);
    size_t gifCount = CGImageSourceGetCount(gifSource);
    NSMutableArray *scaleImgArray = [NSMutableArray array];
    NSTimeInterval totalDuration = 0;//播放的總時(shí)長(zhǎng)
    float scale = 1;
    float imgSize = data.length/1024/1024;
//小于2M不進(jìn)行縮放，2M帶4M縮放60%驾讲，4M到8M縮放40%蚊伞，超過8M縮放20%
    if(imgSize <= 2){
        scale = 1;
    } else if (imgSize > 2 && imgSize < 4){
        scale = 0.6;
    } else if(imgSize >= 4 && imgSize < 8){
        scale = 0.4;
    } else {
        scale = 0.2;
    }
  float imgWidth = 0;
  float imgHeight = 0;
    for (size_t i = 0; i< gifCount; i++) {
        CGImageRef imageRef = CGImageSourceCreateImageAtIndex(gifSource, i, NULL);
        imgWidth = CGImageGetWidth(imageRef);
        imgHeight = CGImageGetHeight(imageRef);
        UIImage *uiImage = [UIImage imageWithCGImage:imageRef];
        if(scale == 1){
            [scaleImgArray addObject:uiImage];
        } else {
            UIImage *scaleImg = [[self class] imageCompresswithsimple:uiImage scaledtosize:CGSizeMake(imgWidth*scale, imgHeight*scale)];
            [scaleImgArray addObject:scaleImg];
        }
        NSTimeInterval duration = [MeetVirtualHeaderTool gifImageDeleyTime:gifSource index:i];
        totalDuration += duration;
        CGImageRelease(imageRef);
    }
    CFRelease(gifSource);
  //重新生成一個(gè)縮放后的gif圖data
    NSData *resultData = [[self class] creategifWithImgArray:scaleImgArray duration:totalDuration];
    return resultData;
}

圖片縮放方法如下：

+ (UIImage*)imageCompresswithsimple:(UIImage*)image scaledtosize:(CGSize)size{
  UIGraphicsBeginImageContext(size);
  [image drawInRect:CGRectMake(0,0,size.width,size.height)];
    UIImage* newimage = UIGraphicsGetImageFromCurrentImageContext();
  UIGraphicsEndImageContext();
  return newimage;
}

重新生成縮放后的gif圖data方法：

+ (NSData *)creategifWithImgArray:(NSArray *)imgArray duration:(float)duration{
    // 1.獲取圖片數(shù)據(jù)
    NSMutableArray *imageArray = [NSMutableArray arrayWithArray:imgArray];
    //每幀時(shí)長(zhǎng)
    float perDuration = duration*1.0/imgArray.count;
    // 2.創(chuàng)建gif文件
    NSArray *document = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *docString = [document objectAtIndex:0];
    NSFileManager *fileManager = [NSFileManager defaultManager];
    NSString *pathString = [docString stringByAppendingString:@"/gif"];
    [fileManager createDirectoryAtPath:pathString withIntermediateDirectories:YES attributes:nil error:nil];
    NSString *path = [pathString stringByAppendingString:@"test1.gif"];
    
    // 3.配置gif屬性
    CGImageDestinationRef destion;
    // 將 path 映射成 CFURLRef 的路徑
    CFURLRef url = CFURLCreateWithFileSystemPath(kCFAllocatorDefault, (CFStringRef)path, kCFURLPOSIXPathStyle, false);
    destion = CGImageDestinationCreateWithURL(url, kUTTypeGIF, imageArray.count, NULL);
    
//    [mutDict setObject:[NSNumber numberWithFloat:perDuration] forKey:kCGImagePropertyGIFUnclampedDelayTime];
    NSDictionary *dict = [NSDictionary dictionaryWithObject:[NSMutableDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithFloat:perDuration],(NSString *)kCGImagePropertyGIFDelayTime, nil] forKey:(NSString *)kCGImagePropertyGIFDelayTime];
    
    NSMutableDictionary *mutDict = [NSMutableDictionary dictionaryWithCapacity:2];
    [mutDict setObject:[NSNumber numberWithBool:YES] forKey:(NSString *)kCGImagePropertyGIFHasGlobalColorMap];
    [mutDict setObject:(NSString *)kCGImagePropertyColorModelRGB forKey:(NSString *)kCGImagePropertyColorModel];
    [mutDict setObject:[NSNumber numberWithInt:8] forKey:(NSString *)kCGImagePropertyDepth];
    [mutDict setObject:[NSNumber numberWithInt:0] forKey:(NSString *)kCGImagePropertyGIFLoopCount];
    NSDictionary *gifPropertyDict = [NSDictionary dictionaryWithObject:mutDict forKey:(NSString *)kCGImagePropertyGIFDictionary];
    
    CGImageDestinationSetProperties(destion, (__bridge CFDictionaryRef)gifPropertyDict);
    // 單幀添加到gif
    for (UIImage *image in imageArray) {
        CGImageDestinationAddImage(destion, image.CGImage, (__bridge CFDictionaryRef)dict);
    }
    CGImageDestinationFinalize(destion);
    CFRelease(destion);
    NSData *gifData = [NSData dataWithContentsOfFile:path];
    NSError *err;
    [fileManager removeItemAtPath:path error:&err];
    if(err == nil){
        
    }
    return gifData;
}

3,使用縮放后的data，不管是使用yyImage還是webView吮铭，cpu的使用率都降低了时迫，手機(jī)也不再發(fā)熱了，能夠解決問題谓晌。
4掠拳，如果需要把原始數(shù)據(jù)傳給服務(wù)器，可以再發(fā)送數(shù)據(jù)時(shí)纸肉，對(duì)縮小后的data進(jìn)行放大處理溺欧，然后再發(fā)送給服務(wù)器，但是這種方式會(huì)造成gif圖顯示模糊毁靶，可以保留原始數(shù)據(jù)進(jìn)行發(fā)送胧奔，也可以發(fā)送壓縮后的數(shù)據(jù)逊移。