核心图像过滤器适用

Question

我如何应用我申请的CIToneCurve过滤器

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

使用这种方法的不同过滤器现在我想应用CIToneCurve我应该如何应用这些参数

inputImage 一个CIImage类,其显示名称为Image.

inputPoint0 一个CIVector类,其属性类型为CIAttributeTypeOffset,其显示名称为Point 1.默认值:[0,0]标识:[0,0]

inputPoint1 一个CIVector类,其属性类型为CIAttributeTypeOffset,其显示名称为Point 2l.默认值:[0.25,0.25]标识:[0.25,0.25]

inputPoint2 一个CIVector类,其属性类型为CIAttributeTypeOffset,其显示名称为Point 3l.默认值:[0.5,0.5]同一性:[0.5,0.5]

inputPoint3 一个CIVector类,其属性类型为CIAttributeTypeOffset,其显示名称为Point 4.默认值:[0.75,0.75]标识:[0.75,0.75]

inputPoint4 一个CIVector类,其属性类型为CIAttributeTypeOffset,其显示名称为Point 5.默认值:[1,1]标识:[1,1]

我写这些但我的应用程序崩溃没有给出任何错误

Answer 1

每个过滤器都接受不同类型的参数,但一旦你习惯它们就很容易了.你没有发布你得到的错误,但这对我有用:

- (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];
}

这就是结果:

我使用的图像是从这里和那里你可以找到我在这个例子中近似的曲线:

PS:如果你想知道为什么我的结果图像与链接中的结果看起来不完全相同,因为我的图像是部分图像,颜色分布不同.相似但不完全一样.因此,应用完全相同的曲线将不会给出完全相同的结果.

我希望它有所帮助