[提问]关于Canvas的绘图旋转问题？ [复制链接]

找的qml书上的例子，实现旋转后，原来的矩形为何没有保存，请问下是否代码少了东西？！

import QtQuick 2.1

Canvas {
    id: root
    width: 240; height: 120
    onPaint: {
        var ctx = getContext("2d")
        ctx.strokeStyle = "blue"
        ctx.lineWidth = 4

        ctx.beginPath()
        ctx.rect(-20, -20, 40, 40)
        ctx.translate(120,60)
        ctx.stroke()

        // draw path now rotated
        ctx.strokeStyle = "green"
        ctx.rotate(Math.PI/4)
        ctx.stroke()
    }
}