a category about UIImage class
//根据不同设备返回不同图片 (Ojbective-C)
- (UIImage *)imageMatchSizeWithName:(NSString *)imageName;
//拉伸图片 (Ojbective-C)
- (UIImage *)compressImage:(UIImage *)imgSrc toSize:(CGSize)size; //指定中间区域拉伸图片
- (UIImage *)strechImageWithName:(NSString *)imageName; //制定特定区域拉伸图片
- (UIImage *)strechImageWithName:(NSString *)imageName posX:(CGFloat)x posY:(CGFloat)y;
//截屏 (Ojbective-C)
- (UIImage *)screenshot;
//添加水印 (Ojbective-C)
- (UIImage *)addImage:(UIImage *)image addMsakImage:(UIImage *)maskImage maskFrame:(CGRect)pos;
//颜色 (Ojbective-C)
- (UIImage *)imageWithColor:(UIColor *)color;
//模糊 参数0.0~1.0 (Ojbective-C)
- (UIImage *)blurImage:(UIImage *)src amount:(CGFloat)amount;