iphone - 从 Photoshop 到 iOS 的颜色特定色相/饱和度

Question

我正在尝试使用 GPUImage 和 CIFilter 来映射此过滤器。请注意，我需要帮助将颜色(红色)特定(注意:不是大师，只是红色)photoshop 元素映射到 iOS。

有谁知道如何在 iOS 中操作 CIFilter 或 GPUImage 类来获得下面的 photoshop 效果？

Answer 1

您可以将 GPUImage 与查找过滤器一起使用:

GPUImageLookupFilter: Uses an RGB color lookup image to remap the colors in an image. First, use your favourite photo editing application to apply a filter to lookup.png from GPUImage/framework/Resources. For this to work properly each pixel color must not depend on other pixels (e.g. blur will not work). If you need a more complex filter you can create as many lookup tables as required. Once ready, use your new lookup.png file as a second input for GPUImageLookupFilter.

因此，在 Photoshop 的 GPUImage 中应用 lookup.png 文件中的所有颜色滤镜，保存它，然后应用滤镜:

- (UIImage *)applyMyFilter:(UIImage*)inputImage {
    //apply custom filter
    GPUImagePicture *stillImageSource = [[GPUImagePicture alloc] initWithImage:inputImage];

    GPUImagePicture *lookupImageSource = [[GPUImagePicture alloc] initWithImage:[UIImage imageNamed:@"my-lookup.png"]];
    GPUImageLookupFilter *lookupFilter = [[GPUImageLookupFilter alloc] init];
    [stillImageSource addTarget:lookupFilter];
    [lookupImageSource addTarget:lookupFilter];

    [stillImageSource processImage];
    [lookupImageSource processImage];
    UIImage *adjustedImage = [lookupFilter imageFromCurrentlyProcessedOutput];

    return adjustedImage;
}