UIImage+Extension
/// 獲取后的數據 a.length > b.length. 同時，使用UIIMageJPEGRepresnetation壓縮圖片，如果compressionQuality設置為1.0，
得到的圖片大小比原圖大，測試之后，壓縮比在0.7--0.8之間大致為原圖的大小 NSData *a = UIImagePNGRepresentation(UIImage *image) NSData *b = UIIMageJPEGRepresnetation(UIImage * image, CGFloat compressionQuality)
1. 裁剪圖片上的某一部分
/// 獲取指定部分的圖片 - (UIImage *)FF_AcquireSpecialSizeImage:(CGRect)rect {CGImageRef imageRef = [self CGImage];CGImageRef needImageRef = CGImageCreateWithImageInRect(imageRef, rect);return [UIImage imageWithCGImage:needImageRef]; }
2.將圖片重畫在某一部分，會壓縮圖片的質量
/// 重畫圖片到指定的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; }
iOS應用開發？3.將圖片壓縮到指定大小，壓縮質量
/**將圖片壓縮到指定的質量@param kb 1MB == 1024KB@return 圖片壓縮后的質量使用二分法提高效率，一般通過6次，可以達到指定的大小，也有例外，之后通過縮小尺寸來實現目標*/ - (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; }
4 通過顏色獲取圖片
+ (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; }
5. 創建自定義的圖庫，并保存圖片到自定義相冊
/* 1. 導入框架 <Photo/Photo.h> 2. PHAsssetColoction 圖庫 3. PHAsset 圖片集合 4. PHPhotoLibrary 在Library中進行各種操作，創建圖庫，圖片等 5. PHAssetCollectionChangeRequest 創建PHAssetCollection 6. PHAssetChangeRequest 創建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; }/// 保存圖片到相機相冊 - (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;} }/// 保存到自定義相冊 - (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]; }
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