How to crop an image with a given angle with swift - ios

Question

Does anyone know how to crop an image with a given angle with swift?
I put the demo image below.
I googled a little while and found almost all the solutions was about the image of no rotation or 90-degree rotation.
I want to rotate the image then crop it just like what the Photo App does in iPhone.
Thanks for any hint!

Answer 1

One option is to use the CGContext and CGAffineTransform to rotate according to your angle.
Make two rects one for rotated image and one for cropping image and use cropping(to rect: CGRect) -> CGImage?
finally according to your logic make only one image or two this is totally up to your approach.
here is a good reference for you:
https://www.raywenderlich.com/2305-core-image-tutorial-getting-started
hope it helps

Answer 2

Design storyboard and create outlets and properties in ViewController class.
let picker = UIImagePickerController()
var circlePath = UIBezierPath()
#IBOutlet weak var crop: CropView!
#IBOutlet weak var imageView: UIImageView!
#IBOutlet weak var scroll: UIScrollView!
The property crop has a custom UIView class. Add the below delegate function in it.
func point(inside point: CGPoint, with event: UIEvent?) -> Bool{
return false
}
Create extension for UIImage and UIImageView — refer. For zooming image, use delegate function viewForZooming ,then add UIScrollViewDelegate to class as the subtype and return imageView.
Pick image from gallery —
Create IBAction, To pick an image from Album and set the picker source type as photo library use the code below
picker.sourceType = .photoLibrary
present(picker, animated: true, completion: nil)
and add UIImagePickerControllerDelegate to class as sub type. In viewDidLoad,
picker.delegate = self
Use didFinishPickingMediaWithInfo —UIImagePickerControllerDelegate function to set image to the view after picking image from album.
let chosenImage = info[UIImagePickerControllerOriginalImage] as! UIImage
imageView.image = chosenImage.resizeImage()
dismiss(animated:true, completion: nil)
To dismiss the photo album when you did cancel, use imagePickerControllerDidCancel delegate.
Shoot picture from camera —
Create IBAction to shoot an image from the camera. First, check whether SourceTypeAvailable in the device. If it is set picker camera capture mode as a photo. Else handle the action.Then set source type as camera and camera capture mode as the photo.
if UIImagePickerController.isSourceTypeAvailable(.camera){
picker.sourceType = UIImagePickerControllerSourceType.camera
picker.cameraCaptureMode = UIImagePickerControllerCameraCaptureMode.photo
picker.modalPresentationStyle = .custom
present(picker,animated: true,completion: nil)
}else{
//action performed if there is no camera in device.
}
Cropping —
Add subLayer to the picked image — this layer provides an area to fix crop frame.
let path = UIBezierPath(roundedRect: CGRect(x: 0, y: 0, width: self.view.bounds.size.width, height: self.view.bounds.size.height), cornerRadius: 0)
Assign the path to the circle path property as of type UIBezierPath. Using BezierPath, you can change the crop frame into different shapes.
circlePath = UIBezierPath(roundedRect: CGRect(x: (self.view.frame.size.width / 2) - (size/2), y: (self.view.frame.size.height / 2) - (size / 2), width: size, height: size, cornerRadius: 0)
path.append(circlePath)
The CAShapeLayer that draws a cubic Bezier spline in its coordinate space.
let fillLayer = CAShapeLayer()
fillLayer.path = path.cgPath
Finally, add the layer to view,
view.layer.addSublayer(fillLayer)
Add crop area:
Create crop area. For that we need to set factor, dividing the imageView image width by view frame width set scale,
let factor = imageView.image!.size.width/view.frame.width
for zooming as scroll zoomScale.
let scale = 1/scroll.zoomScale
Then set crop area frame(x, y, width, height).
let x = (scroll.contentOffset.x + circlePath.bounds.origin.x - imageFrame.origin.x) * scale * factor
let y = (scroll.contentOffset.y + circlePath.bounds.origin.y - imageFrame.origin.y) * scale * factor
let width = circlePath.bounds.width * scale * factor
let height = circlePath.bounds.height * scale * factor
Finally , create a IBAction to crop the image.
let croppedCGImage = imageView.image?.cgImage?.cropping(to: croparea)
let croppedImage = UIImage(cgImage: croppedCGImage!)