canvas坐标操作
这周不知道写什么好,写了一个基本的canvas坐标操作,蛮有用的,对于理解canvas有一定帮助,直接贴源码.
先看效果,人门总喜欢先看效果,后看代码,在线nothingDemo
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>test</title>
<style type="text/css">
*{margin:0;padding:0;}
canvas{display:block;margin:10px auto 0;}
</style>
</head>
<body>
<canvas id="g" width="550" height="400">
</canvas>
<script type="text/javascript">
new function () {
var canvas = document.getElementById("g"),
context = canvas.getContext("2d");
for (var x = 0.5; x < 550; x += 10) {
context.moveTo(x, 0);
context.lineTo(x, 400);
}
for (var y = 0.5; y < 400; y += 10) {
context.moveTo(0, y);
context.lineTo(550, y);
}
context.strokeStyle = "#cecece";
context.stroke();
context.beginPath();
context.moveTo(50, 150);
context.lineTo(300, 150);
context.moveTo(250, 100);
context.lineTo(300, 150);
context.moveTo(300, 50);
context.lineTo(250, 100);
context.moveTo(450, 200);
context.lineTo(300, 50);
/*symmetry*/
context.moveTo(50, 250);
context.lineTo(300, 250);
context.moveTo(250, 300);
context.lineTo(300, 250);
context.moveTo(300, 350);
context.lineTo(250, 300);
context.moveTo(450, 200);
context.lineTo(300, 350);
/*end*/
context.moveTo(50, 150);
context.lineTo(50, 250);
/*write coordinate*/
context.font = "bold 12px sans-serif";
context.fillText("( 0 , 0 )", 8, 5);
context.fillText("(50, 150)", 58, 155);
context.fillText("(300, 150)", 308, 155);
context.fillText("(250, 100)", 258, 105);
context.fillText("(300, 150)", 308, 155);
context.fillText("(300, 50)", 308, 55);
context.fillText("(50, 250)", 58, 255);
context.fillText("(300, 250)", 308, 255);
context.fillText("(250, 350)", 258, 355);
context.fillText("(450, 200)", 458, 205);
context.strokeStyle = "#f00";
context.stroke();
}
</script>
</body>
</html>
