qt quick canvas绘制圆角矩形baiguilin

import QtQuick 2.9

import QtQuick.Window 2.2

Window {
 

    visible: true

    width: 640

    height: 480

    title: qsTr("Hello World")

    Canvas{
 

        width: 400;

        height: 240;

        contextType: "2d";

        onPaint: {
 

            context.lineWidth = 10;

            context.strokeStyle = "red";

            roundRect(context,10,10,100,100,20)

            context.stroke();

        }

    }

    function roundRect(ctx, x, y, w, h, r) {
 

        // 开始绘制

        ctx.beginPath()

        // 左上角

        ctx.arc(x + r, y + r, r, Math.PI, Math.PI * 1.5)

        // 右上角

        ctx.arc