Canvas 图片平铺设置

/**
* 图片平铺
*/
function initDemo7(){
var canvas = document.getElementById("demo7");
if (!canvas) return;
var context = canvas.getContext("2d");
var type = [
"no-repeat", // 不平铺
"repeat-x", // 横向平铺
"repeat-y", // 纵向平铺
"repeat" // 全画布平铺
];
var index = 3;
var img = new Image();
img.src = "images/timg3.jpg";
img.onload = function () {
// 平铺方式
context.fillStyle = context.createPattern(img, type[index]);
context.fillRect(0, 0, canvas.width, canvas.height);
}
}