使用XML語法來描述圖形
SVG 定義了七種元素
<rect>
<circle>
<ellipse>
<line>
<polyline>
<polygon>
<path>
<canvas id='Canvas' width='300' height='300'></canvas>
var canvas = document.getElementById("myCanvas");
var ctx = canvas.getContext("2d"); // 取得 Canvas 渲染環境
var W = canvas.width;
var H = canvas.Height;
.....