从相机上剪下预定义的一张照片

For an application I am developing, I let the user specify dimensions of an object they want to capture on camera (for example 30" x 40"). The next thing I want to do, is show the camera feed with a cameraOverlayView on top of it, showing nothing but a stroked transparent square which has the right ratio to capture that object.For an application I am developing, I let the u