How to maintain the aspect ratio when using GPUImage?
aspect-ratio, gpuimage
Solution
`-forceProcessingAtSize:` causes that filter to output an image of exactly the size you provide, ignoring aspect ratio. That squishes your image into a 300x300 square.
If you want to preserve the aspect ratio of your image, you'd want to use `-forceProcessingAtSizeRespectingAspectRatio:`.
However, that will letterbox your image. To replicate what Instagram does, you probably want to instead cut a square region out of the center of the image. For that, use a crop filter with a square aspect ratio.
Problem
I found the Instagram has a camera window like 300*300？ its a square, then Im trying to use the GPUImage to make the same camera size.so I wrote like this: ``` primaryView = [GPUImageView alloc] initWithFrame: CGRectMake(0,0,300,300)];//define a square view //define a still camera stillCamera = [[GPUImageStillCamera alloc] initWithSessionPreset:AVCaptureSessionPreset640x480 cameraPosition:AVCaptureDevicePositionFront]; //make it portrait stillCamera.outputImageOrientation = UIInterfaceOrientationPortrait; //define a filter filter = [[GPUImageFilter alloc] init]; //force the output to 300*300 [filter forceProcessingAtSize:((GPUImageView*)self.primaryView).sizeInPixels]; //set things up [stillCamera addTarget: filter]; [filter addTarget: primaryView]; [stillCamera startCameraCapture]; ``` Now I really get a square view..but the view looks so flat, its completely distortion, I think it might be something wrong with the aspect ratio.then I set the fill mode of the primary view like this: ``` [primaryView setFillMode:kGPUImageFillModePreserveAspectRatioAndFill]; ``` then this: ``` [primaryView setFillMode:kGPUImageFillModePreserveAspectRatio]; ``` then this: ``` [primaryView kGPUImageFillModeStretch]; ``` FINALLY! none of these work..so what I am missing, any one, help.