/**

 * 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);

    }

}