GPUImage 库的 GPUImagePicture 中不支持 alpha

使用了 GPUImage

代码如下

- (void)setupDisplayFiltering; { UIImage *inputImage = [UIImage imageNamed:@"grossini.png"]; // The WID.jpg example is greater than 2048 pixels tall, so it fails on older devices sourcePicture = [[GPUImagePicture alloc] initWithImage:inputImage smoothlyScaleOutput:YES]; GPUImageView *imageView = (GPUImageView *)self.view; [sourcePicture addTarget:imageView]; [sourcePicture processImage]; }