ios - 联合 UIBezierPath 而不是追加路径

Question

我有一个应用程序，我在其中使用 UIBezierPath 并通过一系列 appendPath: 调用将其用作画笔。几次之后，使用非常复杂的画笔形状，内存就会耗尽，应用程序就会停止运行。我真正想做的是像 Paint Code 那样完全结合，但我找不到任何方法来做到这一点。

我将如何合并两个或多个 UIBezierPaths？

编辑:

这是我想要动态实现的视觉效果。

在 Paint Code 中，您采用两条路径并将它们重叠，如下所示:

但我想将它们合并/合并到一个新的单一路径中，例如:

请注意，在 Paint Code 的底部面板中，现在有一个单一形状的代码，这就是我希望能够以编程方式获得大约 1000 个原始路径的代码。

Answer 1

您可以通过遵循 Core Graphics 的两个概念轻松获得所需的结果:-

i)CGBlendMode ii)OverLap2Layer

混合模式告诉上下文如何将新内容应用于自身。它们决定了像素数据的数字混合方式。

 class UnionUIBezierPaths : UIView {

    var firstBeizerPath:UIImage!
    var secondBeizerPath:UIImage!

    override func draw(_ rect: CGRect) {
        super.draw(rect)

       firstBeizerPath = drawOverLapPath(firstBeizerpath: drawCircle(), secondBeizerPath: polygon())
       secondBeizerPath = drawOverLapPath(firstBeizerpath: polygon(), secondBeizerPath: drawCircle())

        let image = UIImage().overLap2Layer(firstLayer:firstBeizerPath , secondLayer:secondBeizerPath)
    }


    func drawCircle() -> UIBezierPath {
        let path = UIBezierPath(ovalIn: CGRect(x: 40, y: 120, width: 100, height: 100) )
        return path
    }

    func polygon() -> UIBezierPath {
        let beizerPath = UIBezierPath()
        beizerPath.move(to: CGPoint(x: 100, y: 10) )
        beizerPath.addLine(to: CGPoint(x: 200.0, y: 40.0) )
        beizerPath.addLine(to: CGPoint(x: 160, y: 140) )
        beizerPath.addLine(to: CGPoint(x: 40, y: 140) )
        beizerPath.addLine(to: CGPoint(x: 0, y: 40) )
        beizerPath.close()
        return beizerPath
    }

    func drawOverLapPath(firstBeizerpath:UIBezierPath ,secondBeizerPath:UIBezierPath )  -> UIImage {

        UIGraphicsBeginImageContext(self.frame.size)

        let firstpath = firstBeizerpath
        UIColor.white.setFill()
        UIColor.black.setStroke()
        firstpath.stroke()
        firstpath.fill()

        // sourceAtop = 20
        let mode = CGBlendMode(rawValue:20)
        UIGraphicsGetCurrentContext()!.setBlendMode(mode!)


        let secondPath = secondBeizerPath
        UIColor.white.setFill()
        UIColor.white.setStroke()
        secondPath.fill()
        secondPath.stroke()

        let image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()

        return image!
    }



    func drawImage(image1:UIImage , secondImage:UIImage ) ->UIImage
    {
        UIGraphicsBeginImageContext(self.frame.size)
        image1.draw(in: CGRect(x: 0, y: 0, width: frame.size.width, height: frame.size.height) )
        secondImage.draw(in: CGRect(x: 0, y: 0, width: frame.size.width, height: frame.size.height) )

        let newImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return newImage!
    }

      }

      //OverLap2Layer
      extension UIImage {
      func overLap2Layer(firstLayer:UIImage , secondLayer:UIImage ) -> UIImage {

                UIGraphicsBeginImageContext(firstLayer.size)
                firstLayer.draw(in: CGRect(x: 0, y: 0, width: firstLayer.size.width, height: firstLayer.size.height) )
                secondLayer.draw(in: CGRect(x: 0, y: 0, width: firstLayer.size.width, height: firstLayer.size.height) )

                let newImage = UIGraphicsGetImageFromCurrentImageContext()
                UIGraphicsEndImageContext()
                return newImage!
            }
        }

第一个路径:-

第二条路径:-

最终结果:-

引用:- Blend in Core Graphics , Creating Image

GitHub Demo