QQ:609162385

方法解釋，畫任意角度原理是旋轉了painter.rotate(210);座標軸，繪圖結束後將座標軸還原即可painter.restore();

    QPainter painter(this);
    painter.save(); //儲存原來座標系統
    painter.translate(200, 300);
    painter.rotate(210); //座標旋轉degrees 度
    painter.drawRect (60,30,50,40);
    painter.drawEllipse (0,0,50,80);
    painter.drawEllipse (0,0,5,6);
    painter.restore(); //回覆原來的座標系統