如何使用多个核心图像过滤器实现图像(不重置结果)

Question

我有一个带有几个核心图像过滤器的项目,每个过滤器都连接到不同的滑块.一切正常但我还没有找到将结果从一个过滤器传递到下一个过滤器的最佳方法.每次我更改任何其他滑块时,它们都会重置.原因是因为从导入的图像创建的原始图像被每个滤镜作为输入图像绘制.但不知道如何解决这个问题.

我试图想出将多个滤镜的结果传递到一个输出图像的最佳方法.

这是项目:owolf.net/uploads/StackOverflow/CoreImageFilter.zip

以及下面粘贴的一些viewControler代码:

- (void)viewDidLoad
{
    //Create CIImage
    UIImage *aUIImage = [imageView image];
    CGImageRef aCGImage = aUIImage.CGImage;
    aCIImage = [CIImage imageWithCGImage:aCGImage];

    //Create context
    context = [CIContext contextWithOptions:nil];

    saturationFilter = [CIFilter filterWithName:@"CIColorControls" keysAndValues: @"inputImage", aCIImage, nil];
    brightnessFilter = [CIFilter filterWithName:@"CIColorControls" keysAndValues: @"inputImage", aCIImage, nil];
    contrastFilter = [CIFilter filterWithName:@"CIColorControls" keysAndValues: @"inputImage", aCIImage, nil];
        [super viewDidLoad];
}


- (IBAction)saturationSliderValueChanged:(id)sender {
    outputImage = [saturationFilter outputImage];
    CGImageRef cgimg = [context createCGImage:outputImage fromRect:[outputImage extent]];
    newUIImage = [UIImage imageWithCGImage:cgimg];
    CGImageRelease(cgimg);
    [imageView setImage:newUIImage];   
}

- (IBAction)brightnessSliderValueChanged:(id)sender {
    [brightnessFilter setValue:[NSNumber numberWithFloat:brigtnessSlider.value] forKey: @"inputBrightness"];
    outputImage = [brightnessFilter outputImage];
    CGImageRef cgimg = [context createCGImage:outputImage fromRect:[outputImage extent]];
    newUIImage = [UIImage imageWithCGImage:cgimg];
    CGImageRelease(cgimg);
    [imageView setImage:newUIImage];
}

- (IBAction)contrastSliderValueChanged:(id)sender { 
    [contrastFilter setValue:[NSNumber numberWithFloat:contrastSlider.value] forKey: @"inputContrast"];
    outputImage = [contrastFilter outputImage];
    CGImageRef cgimg = [context createCGImage:outputImage fromRect:[outputImage extent]];
    newUIImage = [UIImage imageWithCGImage:cgimg];
    CGImageRelease(cgimg);
    [imageView setImage:newUIImage];
}

Answer 1

您需要选择应用过滤器的顺序,然后使用第一个过滤器的输出作为第二个过滤器的输入图像,依此类推.以下是我的一个项目的示例:

CIImage *adjustedImage = self.originalImage;

[self.vibranceFilter setValue:adjustedImage forKey:@"inputImage"];
adjustedImage = [self.vibranceFilter outputImage];

[self.hueFilter setValue:adjustedImage forKey:@"inputImage"];
adjustedImage = [self.hueFilter outputImage];

[self.vignetteFilter setValue:adjustedImage forKey:@"inputImage"];
adjustedImage = [self.vignetteFilter outputImage];

CGImageRef cgImage = [self.imageContext createCGImage:adjustedImage fromRect:[adjustedImage extent]];

self.imageView.image = [UIImage imageWithCGImage:cgImage];

CGImageRelease(cgImage);

该值adjustedImage有效地累积了核心图像滤镜的效果.这一切都在它自己的方法中,只要你的任何滑块值发生变化就会调用它.