为UIImage添加滤镜效果

#import <UIKit/UIKit.h>

@interface UIImage (UIImageCategory)

- (UIImage *)addFilter:(NSString *)filter;

@end

#import "UIImage+UIImageCategory.h"
#import <CoreGraphics/CoreGraphics.h>

@implementation UIImage (UIImageCategory)

- (UIImage *)addFilter:(NSString *)filterName
{
//将UIImage转换成CIImage
CIImage *ciImage = [[CIImage alloc] initWithImage:self];

//创建滤镜
CIFilter *filter = [CIFilter filterWithName:filterName keysAndValues:kCIInputImageKey, ciImage, nil];

//已有的值不变，其他的设为默认值
[filter setDefaults];

//获取绘制上下文
CIContext *context = [CIContext contextWithOptions:nil];

//渲染并输出CIImage
CIImage *outputImage = [filter outputImage];

//创建CGImage句柄
CGImageRef cgImage = [context createCGImage:outputImage fromRect:[outputImage extent]];

//获取图片
UIImage *image = [UIImage imageWithCGImage:cgImage];

//释放CGImage句柄
CGImageRelease(cgImage);

return image;
}

@end

[NSArray arrayWithObjects:@"original", @"ColorInvert", @"ColorMonochrome", @"ColorPosterize", @"FalseColor",

@"RGBToneCurve", @"MaximumComponent", @"MinimumComponent", @"PhotoEffectChrome", @"PhotoEffectMono", @"PhotoEffectNoir",

@"PhotoEffectProcess", @"PhotoEffectTonal", @"PhotoEffectTransfer", @"SepiaTone", nil];