HTML5 Canvas支持双缓冲吗？

对于画布的双缓冲，创建第二个画布元素并在其上绘制。之后使用drawImage()方法将图像绘制到第一个画布上。

// canvas element
var canvas1 = document.getElementById('canvas');
var context1 = canvas1.getContext('2d');

// buffer canvas
var canvas2 = document.createElement('canvas');
canvas2.width = 250;
canvas2.height =250;
var context2 = canvas2.getContext('2d');

// create on the canvas
context2.beginPath();
context2.moveTo(10,10);
context2.lineTo(10,30);
context2.stroke();

//render the buffered canvas
context1.drawImage(canvas2, 0, 0);