GPUImage在另一個視圖中顯示直方圖

Question

我目前正在嘗試使用GPUImage顯示直方圖。我目前有以下代碼：

GPUImageOutput<GPUImageInput> *filter = [[GPUImageHistogramFilter alloc] initWithHistogramType:kGPUImageHistogramLuminance]; 
[self.stillCamera removeTarget:filter]; 
GPUImageGammaFilter *gammaFilter = [[GPUImageGammaFilter alloc] init]; 
[self.stillCamera addTarget:gammaFilter]; 
[gammaFilter addTarget:filter]; 

GPUImageHistogramGenerator *histogramGraph = [[GPUImageHistogramGenerator alloc] init]; 

[histogramGraph forceProcessingAtSize:CGSizeMake(500.0, 500)]; 
[filter addTarget:histogramGraph]; 

GPUImageAlphaBlendFilter *blendFilter = [[GPUImageAlphaBlendFilter alloc] init]; 
blendFilter.mix = 0.75; 
[blendFilter forceProcessingAtSize:CGSizeMake(500, 500)]; 

[self.stillCamera addTarget:blendFilter]; 
[histogramGraph addTarget:blendFilter]; 

[blendFilter addTarget:previewView]; 

上面顯示的直方圖overplayed在我的previewView。 （然而，另一個問題，另一天閃爍，另一個問題）

我想在視圖上的特定位置的小視圖上顯示此直方圖。我怎樣才能做到這一點？

Answer 1

要在分開的視圖中顯示直方圖，您需要爲主視圖和點直方圖過濾器添加另一個GPUImageView。這裏是基於SimpleImageFilter示例的源代碼。

- (void)loadView 
{  
    CGRect mainScreenFrame = [[UIScreen mainScreen] applicationFrame]; 

    GPUImageView *primaryView = [[GPUImageView alloc] initWithFrame:mainScreenFrame]; 
    self.view = primaryView; 

    UIImage *inputImage = [UIImage imageNamed:@"WID-small.jpg"]; 
    GPUImagePicture *sourcePicture = [[GPUImagePicture alloc] initWithImage:inputImage smoothlyScaleOutput:YES]; 

    // Creating another view to show histogram 
    GPUImageView *histView = [[GPUImageView alloc] initWithFrame:CGRectMake(mainScreenFrame.size.width - 100, mainScreenFrame.size.height - 100, 100, 100)]; 
    [primaryView addSubview:histView]; 

    // Create histogram filter and generator and point it to histogram view 
    GPUImageOutput<GPUImageInput> *histFilter = [[GPUImageHistogramFilter alloc] initWithHistogramType:kGPUImageHistogramLuminance]; 
    GPUImageOutput<GPUImageInput> *histGenerator = [[GPUImageHistogramGenerator alloc] init]; 
    [histGenerator forceProcessingAtSize:histView.sizeInPixels]; 
    [sourcePicture addTarget:histFilter]; 
    [histFilter addTarget:histGenerator]; 
    // Note target - hist view 
    [histGenerator addTarget:histView]; 

    // Setup sepia filter just to show main picture 
    GPUImageOutput<GPUImageInput> *sepiaFilter = [[GPUImageSepiaFilter alloc] init]; 
    [sepiaFilter forceProcessingAtSize:primaryView.sizeInPixels]; 
    [sourcePicture addTarget:sepiaFilter]; 
    // Note target - main view 
    [sepiaFilter addTarget:primaryView]; 

    [sourcePicture processImage]; 
} 

而且最終的結果：