iOS中滤镜的使用（一） 马赛克滤镜_ios cipixellate demo

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"]];
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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];
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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]];
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最后，导出图片，注意内存的释放

 UIImage *showImage = [UIImage imageWithCGImage:cgImage];

CGImageRelease(cgImage);
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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];
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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];
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