如何删除用户移动手指的 UIImage 区域？

Question

• IMAGECROPPER
• UIGESTURE
• 触摸

需要实现此目的，用户选择图像，然后使用触摸拖动将其剪切，例如 Photo Editing App.

Answer 1

         UIGraphicsBeginImageContext(drawImage.frame.size)
            var context = UIGraphicsGetCurrentContext()

            drawImage.image.draw(in: CGRect(x: 0, y: 0, width: view.frame.size.width, height: view.frame.size.height - 50))

            context?.move(to: fromPoint)
            context?.addLine(to: toPoint)
            context?.setLineCap(.butt)
            context?.setLineWidth(2)
            context?.setBlendMode(.clear)
            context?.setShouldAntialias(true)

            UIColor.clear.set()

            context?.strokePath()

            let newImage = UIGraphicsGetImageFromCurrentImageContext()!