/// 获取后的数据 a.length > b.length. 同时，使用UIIMageJPEGRepresnetation压缩图片，如果compressionQuality设置为1.0，得到的图片大小比原图大，测试之后，压缩比在0.7--0.8之间大致为原图的大小
NSData *a = UIImagePNGRepresentation(UIImage *image)
NSData *b = UIIMageJPEGRepresnetation(UIImage * image, CGFloat compressionQuality)

/// 获取指定部分的图片
- (UIImage *)FF_AcquireSpecialSizeImage:(CGRect)rect {CGImageRef imageRef = [self CGImage];CGImageRef needImageRef = CGImageCreateWithImageInRect(imageRef, rect);return [UIImage imageWithCGImage:needImageRef];
}

/// 重画图片到指定的Size
- (UIImage *)FF_CompressSize:(CGSize)size {UIImage *result = self;UIGraphicsBeginImageContext(size);[result drawInRect:CGRectMake(0, 0, size.width, size.height)];result = UIGraphicsGetImageFromCurrentImageContext();UIGraphicsEndImageContext();return result;
}

/**将图片压缩到指定的质量@param kb 1MB == 1024KB@return 图片压缩后的质量使用二分法提高效率，一般通过6次，可以达到指定的大小，也有例外，之后通过缩小尺寸来实现目标*/
- (NSData *)FF_CompressQualityToSpecialKB:(CGFloat)kb {CGFloat specialBytes = kb * 1024;NSData *imageDate = UIImageJPEGRepresentation(self, 1.0);if (imageDate.length < specialBytes) {return imageDate;}CGFloat min = 0;CGFloat max = 1;CGFloat compress = 1;for (int i = 0; i < 6; i++) {compress = (max + min) / 2;imageDate = UIImageJPEGRepresentation(self, compress);if (imageDate.length < specialBytes * 0.9) {min = compress;}else if (imageDate.length > specialBytes) {max = compress;}else {break;}}if (imageDate.length <= specialBytes) {return imageDate;}UIImage *tempImage = [UIImage imageWithData:imageDate];NSUInteger lastDateLength = 0;while (imageDate.length > specialBytes && lastDateLength != imageDate.length) {lastDateLength = imageDate.length;CGFloat tempScale = specialBytes / imageDate.length;CGSize tempSize = CGSizeMake((NSUInteger)(tempImage.size.width * tempScale),(NSUInteger)(tempImage.size.height * tempScale));UIGraphicsBeginImageContext(tempSize);[tempImage drawInRect:CGRectMake(0, 0, tempSize.width, tempSize.height)];tempImage = UIGraphicsGetImageFromCurrentImageContext();UIGraphicsEndImageContext();imageDate = UIImageJPEGRepresentation(tempImage, compress);}return imageDate;
}

+ (UIImage *)FF_AcquireImageFromColor:(UIColor *)color {UIGraphicsBeginImageContext(CGSizeMake(1, 1));CGContextRef ref = UIGraphicsGetCurrentContext();CGContextSetFillColorWithColor(ref, color.CGColor);CGContextFillRect(ref, CGRectMake(0, 0, 1, 1));UIImage *img = UIGraphicsGetImageFromCurrentImageContext();UIGraphicsEndImageContext();return img;
}

/*
1. 导入框架 <Photo/Photo.h>
2. PHAsssetColoction 图库
3. PHAsset                图片集合
4. PHPhotoLibrary      在Library中进行各种操作，创建图库，图片等
5. PHAssetCollectionChangeRequest 创建PHAssetCollection
6. PHAssetChangeRequest   创建PHAsset
*/- (PHAssetCollection *)FF_CreatePhotoLibrary {NSString *title = [[NSBundle mainBundle].infoDictionary objectForKey:(NSString *)kCFBundleNameKey];PHFetchResult *result = [PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeAlbum subtype:PHAssetCollectionSubtypeAlbumRegular options:nil];PHAssetCollection *needCollection = nil;for (PHAssetCollection *collection in result) {if ([collection.localizedTitle isEqualToString:title]) {needCollection = collection;}}__block NSString *localIdentifierId = nil;if (!needCollection) {[[PHPhotoLibrary sharedPhotoLibrary] performChangesAndWait:^{localIdentifierId = [PHAssetCollectionChangeRequest creationRequestForAssetCollectionWithTitle:title].placeholderForCreatedAssetCollection.localIdentifier;} error:nil];}if (localIdentifierId) {needCollection = [PHAssetCollection fetchAssetCollectionsWithLocalIdentifiers:@[localIdentifierId] options:nil].firstObject;}return needCollection;
}/// 保存图片到相机相册
- (PHFetchResult<PHAsset *> *)FF_CreatedAssets {__block NSString *localIdentital = nil;[[PHPhotoLibrary sharedPhotoLibrary] performChangesAndWait:^{localIdentital = [PHAssetChangeRequest creationRequestForAssetFromImage:self].placeholderForCreatedAsset.localIdentifier;} error:nil];if (localIdentital) {return [PHAsset fetchAssetsWithLocalIdentifiers:@[localIdentital] options:nil];}else {return nil;}
}/// 保存到自定义相册
- (void)FF_SaveImageToAlbum {if (![self FF_PhotoLibraryAuthorization]) {return;}PHAssetCollection *collection = [self FF_CreatePhotoLibrary];PHFetchResult<PHAsset *> *result = [self FF_CreatedAssets];[[PHPhotoLibrary sharedPhotoLibrary] performChangesAndWait:^{PHAssetCollectionChangeRequest *request = [PHAssetCollectionChangeRequest changeRequestForAssetCollection:collection];[request insertAssets:result atIndexes:[NSIndexSet indexSetWithIndex:0]];} error:nil];
}