核心图像过滤器应用于

Question

我如何申请CIToneCurve过滤我申请

filter= [CIFilter filterWithName:@"CIScreenBlendMode"]; 
    [filter setValue:beginImage1 forKey:kCIInputImageKey]; 
    [filter setValue:beginImage forKey:@"inputBackgroundImage"]; 

不同的过滤器以现在这种方式我想申请CIToneCurve我应该如何应用此与这些参数

inputImage 一个CIImage显示名称为Image的类。

inputPoint0 甲CIVector类，其属性类型是CIAttributeTypeOffset和显示名称是点1默认值：[0,0]身份：[0,0]

inputPoint1 甲CIVector类，其属性类型是CIAttributeTypeOffset和其显示名称是Point 2l。默认值：[0.25,0.25]身份：[0.25,0.25]

inputPoint2 CIVector类的属性类型为CIAttributeTypeOffset，其显示名称为Point 3l。默认值：[0.5，0.5]身份：[0.5，0.5]

inputPoint3 甲CIVector类，其属性类型是CIAttributeTypeOffset和显示名称是点4.默认值：[0.75，0.75]身份：[0.75， 0.75]

inputPoint4 甲CIVector类，其属性类型是CIAttributeTypeOffset和显示名称是点5.默认值：[1，1]身份：[1,1]

我写这些但我应用程序崩溃，出现任何错误

Answer 1

每个过滤器都接受不同类型的参数，但一旦使用它们就很容易。 你没有张贴你做了什么错误，但这个工作对我来说：

- (void)doCIToneCurveFilter 
{ 
    // Set an appropriate image. A bit dark so we see the results clearer 
    // This image is being taken from http://photo.tutsplus.com/tutorials/post-processing/adobe-camera-raw-for-beginners-tone-curve/ 
    imageView.image = [UIImage imageNamed:@"turtles"]; 
    imageView.frame = CGRectMake(0, 0, imageView.image.size.width*0.7, imageView.image.size.height*0.7); // shrank this a bit 2 images fit on screen 

    // Make the input image recipe 
    CIImage *inputImage = [CIImage imageWithCGImage:imageView.image.CGImage]; 

    // Make tone filter filter 
    // See mentioned link for visual reference 
    CIFilter *toneCurveFilter = [CIFilter filterWithName:@"CIToneCurve"]; 
    [toneCurveFilter setDefaults]; 
    [toneCurveFilter setValue:inputImage forKey:kCIInputImageKey]; 
    [toneCurveFilter setValue:[CIVector vectorWithX:0.0 Y:0.0] forKey:@"inputPoint0"]; // default 
    [toneCurveFilter setValue:[CIVector vectorWithX:0.27 Y:0.26] forKey:@"inputPoint1"]; 
    [toneCurveFilter setValue:[CIVector vectorWithX:0.5 Y:0.80] forKey:@"inputPoint2"]; 
    [toneCurveFilter setValue:[CIVector vectorWithX:0.7 Y:1.0] forKey:@"inputPoint3"]; 
    [toneCurveFilter setValue:[CIVector vectorWithX:1.0 Y:1.0] forKey:@"inputPoint4"]; // default 

    // Get the output image recipe 
    CIImage *outputImage = [toneCurveFilter outputImage]; 

    // Create the context and instruct CoreImage to draw the output image recipe into a CGImage 
    CIContext *context = [CIContext contextWithOptions:nil]; 
    CGImageRef cgimg = [context createCGImage:outputImage fromRect:[outputImage extent]]; 

    // Draw the image in screen 
    UIImageView *imageView2 = [[UIImageView alloc] initWithImage:[UIImage imageWithCGImage:cgimg]]; 
    CGRect f = imageView2.frame; 
    f.origin.y = CGRectGetMaxY(imageView.frame); 
    f.size.width = imageView.frame.size.width; 
    f.size.height = imageView.frame.size.height; 
    imageView2.frame = f; 

    [self.view addSubview:imageView2]; 
} 

这是结果：

我使用的图像是从here有你拍摄可以找到我在这个例子中近似曲线：

PS：如果你想知道为什么我的结果图像与the link的结果看起来不完全一样，那是因为我的图像是局部图像，颜色分布不同。一样但不完全一样。因此，应用完全相同的曲线不会给出完全相同的结果。我希望它有帮助