执行基本的HTML5 Canvas动画
HTML5canvas提供了绘制图像并将其完全擦除的必要方法。我们可以利用JavaScript帮助在HTML5画布上模拟良好的动画。
示例
您可以尝试运行以下代码以执行基本的HTML5Canvas动画-
<!DOCTYPE HTML>
<html>
<head>
<script>
var pattern= new Image();
function animate(){
pattern.src = '/html5/images/pattern.jpg';
setInterval(drawShape, 100);
}
function drawShape(){
// get the canvas element using the DOM
var canvas = document.getElementById('mycanvas');
// Make sure we don't execute when canvas isn't supported
if (canvas.getContext){
// use getContext to use the canvas for drawing
var ctx = canvas.getContext('2d');
ctx.fillStyle = 'rgba(0,0,0,0.4)';
ctx.strokeStyle = 'rgba(0,153,255,0.4)';
ctx.save();
ctx.translate(150,150);
var time = new Date();
ctx.rotate( ((2*Math.PI)/6)*time.getSeconds() + ( (2*Math.PI)/6000)*time.getMilliseconds() );
ctx.translate(0,28.5);
ctx.drawImage(pattern,-3.5,-3.5);
ctx.restore();
} else {
alert('You need Safari or Firefox 1.5+ to see this demo.');
}
}
</script>
</head>
<body onload="animate();">
<canvas id="mycanvas" width="400" height="400"></canvas>
</body>
</html>