GPUImage组过滤器 [英] GPUImage group filters

问题描述

我正在尝试在单个视图中实现亮度，对比度和曝光滤镜，就像在iPhoto应用程序中看到的一样.我试图做同样的组过滤器.但是它显示的是白色屏幕，而不是修改后的图片.这是我应用的代码.

I am trying to implement brightness,contrast and exposure filters in a single view same as you see in iPhoto app. I have tried to put up group filter for doing the same. But it shows up a white screen instead of modified picture. Here is the code I applied.

 GPUImageFilterGroup *groupFilter = [[GPUImageFilterGroup alloc]init];
    GPUImageBrightnessFilter *brightnessFilter = [[GPUImageBrightnessFilter alloc]init];
    [brightnessFilter setBrightness:brightnessValue];
    GPUImageContrastFilter *contrastFilter = [[GPUImageContrastFilter alloc]init];
    [contrastFilter setContrast:contrastValue];
    GPUImageExposureFilter *exposureFilter =[[GPUImageExposureFilter alloc]init];
    [exposureFilter setExposure:exposureValue];
    [groupFilter addFilter:brightnessFilter];
    [groupFilter addFilter:contrastFilter];
    [groupFilter addFilter:exposureFilter];
     GPUImagePicture *stillImage= [[GPUImagePicture alloc]initWithImage:self.imageToModify];
    [stillImage addTarget:groupFilter];


    [stillImage processImage];

    previewPicture.image = [groupFilter imageFromCurrentlyProcessedOutputWithOrientation:self.imageToModify.imageOrientation];

我什至试图将每个单独放置，但仍然显示白色图像.我使用的上述代码正确吗? 我也尝试使用GPUImageFilterPipeline而不是GPUImageFilterGroup，但是仍然存在相同的问题. 作为记录，该图像是静止图像而不是实时供稿.

I even tried to put each individually but still it shows up white image. Is the above code I am using correct? I have also tried using GPUImageFilterPipeline instead of GPUImageFilterGroup but still having the same issue. For the record, the image is a still image and not live feed.

推荐答案

您错过了执行以下操作的代码声明.

you have missed some code statement for doing it which is as below.

   [brightnessFilter addTarget: contrastFilter];
   [contrastFilter addTarget: exposureFilter];

  [(GPUImageFilterGroup *) groupFilter setInitialFilters:[NSArray arrayWithObject: brightnessFilter]];
  [(GPUImageFilterGroup *) groupFilter setTerminalFilter:exposureFilter];

谢谢

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