Xcode9学习笔记84-使用Quarz2d绘制自定义图形

import UIKit
class QuartzView: UIView {
    // Only override draw() if you perform custom drawing.
    // An empty implementation adversely affects performance during animation.
    override func draw(_ rect: CGRect) {
        // Drawing code
        let cOntext= UIGraphicsGetCurrentContext()
        
        context?.setFillColor(red: 1.0, green: 0.0, blue: 1.0, alpha: 1.0)
        context?.fill(rect)
        context?.setStrokeColor(red: 0, green: 0, blue: 0, alpha: 1.0)
        
        let rect2 = CGRect(x: 40, y: 80, width: 240, height: 40)
        context?.addRect(rect2)
        context?.setLineWidth(5.0)
        context?.strokePath()
        
        let fOnt= UIFont.boldSystemFont(ofSize: 32)
        let text:NSString = "Hello"
        let rect3 = CGRect(x: 50, y: 80, width: 80, height: 30)
        text.draw(in: rect3, withAttributes: [NSAttributedStringKey.font : font])
        
        context?.setLineWidth(5.0)
        context?.setLineCap(CGLineCap.round)
        context?.setStrokeColor(red: 1, green: 1, blue: 1, alpha: 1)
        
        let points = [CGPoint(x:40, y:200), CGPoint(x:40, y:300), CGPoint(x:280, y:300), CGPoint(x:40, y:200)]
        context?.addLines(between: points)
        context?.strokePath()
    }
}

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        
        let rect = self.view.bounds//获得当前根视图的显示区域
        let view = QuartzView()
        view.frame = rect
        
        self.view.addSubview(view)
    }