iOS中滤镜的使用（一） 马赛克滤镜

iOS中滤镜的使用（一）

马赛克滤镜

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首先 要加载图片并转化为CIImage

CIImage *ciImage = [[CIImage alloc] initWithImage:[UIImage imageNamed:@"IMG_0160"]];

其次，创建filter滤镜

CIFilter *filter = [CIFilter filterWithName:@"CIPixellate"];NSLog(@"%@",filter.attributes);[filter setValue:ciImage  forKey:kCIInputImageKey];[filter setDefaults];CIImage *outImage = [filter           valueForKey:kCIOutputImageKey];

然后，用CIContext将滤镜中的图片渲染出来，原因，导出图片过过程中用到CGImageRef。

CIContext *context = [CIContext contextWithOptions:nil];CGImageRef cgImage = [context createCGImage:outImage fromRect:[outImage extent]];

最后，导出图片，注意内存的释放

 UIImage *showImage = [UIImage imageWithCGImage:cgImage];CGImageRelease(cgImage);

剩下的工作就是加载马赛克图片了

 UIImageView *imageView = [[UIImageView alloc] initWithFrame: CGRectMake(0, 0, 600, 400)];imageView.image = showImage;imageView.center = self.view.center;[self.view addSubview:imageView];

而Filter的属性有如下：

总的代码如下：

 //0:导入图片    CIImage *ciImage = [[CIImage alloc] initWithImage:[UIImage imageNamed:@"IMG_0160"]];    //1:创建filter滤镜    CIFilter *filter = [CIFilter filterWithName:@"CIPixellate"];    NSLog(@"%@",filter.attributes);    [filter setValue:ciImage  forKey:kCIInputImageKey];    [filter setDefaults];    CIImage *outImage = [filter valueForKey:kCIOutputImageKey];    //2:用CIContext将滤镜中的图片渲染出来    CIContext *context = [CIContext contextWithOptions:nil];    CGImageRef cgImage = [context createCGImage:outImage fromRect:[outImage extent]];    //3:导出图片    UIImage *showImage = [UIImage imageWithCGImage:cgImage];    CGImageRelease(cgImage);    //4:加载出来    UIImageView *imageView = [[UIImageView alloc] initWithFrame: CGRectMake(0, 0, 600, 400)];    imageView.image = showImage;    imageView.center = self.view.center;    [self.view addSubview:imageView];