How to convert CAShapeLayer coordinates to CIRectangleFeature for manual crop

问题

I am dealing with manual image crop functionality. For this am drawing CAShapeLayer with four coordinates called topLeft, topRight, bottomRight and bottomLeft. User can pan the points and select the crop area. I am stuck at converting these points to Core image coordinates and further cropping with CIPerspectiveTransform.

回答1:

Set image to imageView And masking imageView with shape layer.

self.imageView = img
imageView.layer.mask = shapeLayer // set here your shape layer

Now your imageView have crop image.

Get image from current context as follow

UIGraphicsBeginImageContextWithOptions(imageView.bounds.size, false, 0);
imageView.layer.render(in: UIGraphicsGetCurrentContext()!)
let image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

// check cropping image
let resultImageView = UIImageView(frame: self.view.frame)
resultImageView.image = image
self.view.addSubview(resultImageView)

来源：https://stackoverflow.com/questions/42664076/how-to-convert-cashapelayer-coordinates-to-cirectanglefeature-for-manual-crop