iOS11中iOS处理GIF图片的方式

GIF 五部走如下 ：

1 从相册中取出GIF图的Data
2 通过腾讯的IM发送Gif图
3 展示GIF图
4 GIF图URL缓存机制
5 将展示的GIF图存到相册中

一 从相册中取出GIF图中的Data

1.TZImagePickerController中利用方法来获取到gif图片的image和asses

- (void)imagePickerController:(TZImagePickerController *)picker didFinishPickingGifImage:(UIImage *)animatedImage sourceAssets:(id)asset

2.通过如下方法判断是否是gif格式：

if ([[asset valueForKey:@"filename"] tz_containsString:@"GIF"])

3.如果是gif图片格式，通过 PHImageManager 的方法利用字段assets来获取gif动图的data数据

二 通过腾讯的IM发送Gif图

1.将gif的数据存到临时文件夹

NSString *tempDir = NSTemporaryDirectory();
NSString *snapshotPath = [NSStringstringWithFormat:@"%@%3.f%@.gif", tempDir, [NSDatetimeIntervalSinceReferenceDate],[[NSProcessInfoprocessInfo] globallyUniqueString]];
NSError *err;
NSFileManager *fileMgr = [NSFileManagerdefaultManager];
if (![fileMgr createFileAtPath:snapshotPath contents:imageData attributes:nil])
{
DebugLog(@"Upload Image Failed: fail to create uploadfile: %@", err);
}

2.封装成消息体发送

TIMMessage * msg = [[TIMMessagealloc] init];
TIMImageElem * image_elem = [[TIMImageElemalloc] init];

image_elem.path = snapshotPath;
image_elem.format = TIM_IMAGE_FORMAT_GIF;
image_elem.level = TIM_IMAGE_COMPRESS_ORIGIN;
[msg addElem:image_elem];

@weakify(self);
[self.conversationsendMessage:msg succ:^() {
@strongify(self);
//IDSPostNFWithObj(kIMPartyRoomSendMessage,msg);
[selfforceUpdataTableView];
NSLog(@"ddsuccess");

} fail:^(int code, NSString *err) {
NSLog(@"ddfailed");
}];

三 展示GIF图

1.在 MJPhoto 中本地路径展示方式：

MJPhoto *photo = [[MJPhotoalloc] init];
NSData *data = [NSDatadataWithContentsOfFile:picModel.picPath];
photo.photodata = data;
photo.image = [UIImagesd_tz_animatedGIFWithData:data];

2.在 MJPhoto 远程url路径展示方式：

photo.image = [UIImagesd_tz_animatedGIFWithData:[NSDatadataWithContentsOfURL:[NSURLURLWithString:imageURL]]];

3.在 cell 中使用 FLAnimatedImageView 展示方式：

[self.animatedImageViewsd_setImageWithURL:imageURL];

Ps：前提是需要更新SDWebImage版本，需要有 FLAnimatedImageView+WebCache 文件

四 GIF图URL缓存机制

1.通过 gifURL 加入缓存机制：

NSURL *newUrl = [NSURLURLWithString:imageURL];
[[SDWebImageDownloadersharedDownloader] downloadImageWithURL:newUrl
options:0
progress:nil
completed:^(UIImage *image, NSData *data, NSError *error, BOOL finished) {
[[[SDWebImageManagersharedManager] imageCache] storeImage:image imageData:data forKey:newUrl.absoluteStringtoDisk:YEScompletion:^{
photo.image = [UIImagesd_tz_animatedGIFWithData:data];
photo.photodata = data;
}];
}];
}

- (NSData *)imageDataFromDiskCacheWithKey:(NSString *)key
{
NSString *path = [[[SDWebImageManagersharedManager] imageCache] defaultCachePathForKey:key];
return [NSDatadataWithContentsOfFile:path];
}

五 将展示的GIF图存到相册中

if ([UIDevicecurrentDevice].systemVersion.floatValue >= 9.0f) {
[[PHPhotoLibrarysharedPhotoLibrary] performChanges:^{
PHAssetResourceCreationOptions *options = [[PHAssetResourceCreationOptionsalloc] init];
[[PHAssetCreationRequestcreationRequestForAsset] addResourceWithType:PHAssetResourceTypePhotodata:photo.photodataoptions:options];
} completionHandler:^(BOOL success, NSError * _Nullable error)

if (success) {
。。。
}
else {
。。。
}
}];
}
else {
UIImageWriteToSavedPhotosAlbum(photo.image, self, @selector(image:didFinishSavingWithError:contextInfo:), nil);
}

思考与行动：

1.写出 Gif格式的 URL 转换成 GIF格式的data数据类型的转换函数

2.写出 Gif格式的 UIImage 转换成 GIF格式的data数据类型的转换函数

3.写出Gif格式的data数据类型的转换成 GIF格式的UIImage的转换函数

4.写出 Gif格式的 Assets 转换成 GIF格式的data数据类型的转换函数

======

附录：

+ (UIImage *)sd_tz_animatedGIFWithData:(NSData *)data {
if (!data) {
returnnil;
}

CGImageSourceRef source = CGImageSourceCreateWithData((__bridgeCFDataRef)data, NULL);

size_t count = CGImageSourceGetCount(source);

UIImage *animatedImage;

if (count <= 1) {
animatedImage = [[UIImagealloc] initWithData:data];
}
else {
NSMutableArray *images = [NSMutableArrayarray];

NSTimeInterval duration = 0.0f;

for (size_t i = 0; i < count; i++) {
CGImageRef image = CGImageSourceCreateImageAtIndex(source, i, NULL);
if (!image) {
continue;
}

duration += [selfsd_frameDurationAtIndex:i source:source];

[images addObject:[UIImageimageWithCGImage:image scale:[UIScreenmainScreen].scaleorientation:UIImageOrientationUp]];

CGImageRelease(image);
}

if (!duration) {
duration = (1.0f / 10.0f) * count;
}

animatedImage = [UIImageanimatedImageWithImages:images duration:duration];
}

CFRelease(source);

return animatedImage;
}

...