这是我到目前为止,它确实通过改变旋转点来旋转图像(不是变换,我的坏...)
它不做它不会创建一个流畅的动画,它很粗糙..我怎么能完成那个?
另一件事我需要的是一个背景必须是透明的
这里是到目前为止我的代码:
<script>
var degree=10;
function docanvas() {
var canvas = document.getElementById('canvas');
var cContext = canvas.getContext('2d');
var img = new Image();
// Create new Image object
img.src = 'http://www.gravatar.com/avatar/e555bd971bc2f4910893cd5b785c30ff?s=128&d=identicon&r=PG'; // Set source path // set img src
var cw = img.width, ch = img.height, cx = 0, cy = 0;
canvas.setAttribute('width', 300);
canvas.setAttribute('height', 300);
cContext.fillStyle = "rgba(0, 0, 255, .5)";
cContext.fillRect(0, 0, 300, 300);
cContext.translate(150, 150);
cContext.rotate(degree * Math.PI/180);
cContext.drawImage(img, -64, -128,128,128);
degree+=5;
}
</script>
</head>
<body onload="setInterval('docanvas()',50);">
<canvas id="canvas"></canvas>
<script>
docanvas(30);
</script>
</body>
</html>
见http://stackoverflow.com/questions/4697041/rotating-and-moving -an-image-in-a-canvas-element/4697139#4697139和http://stackoverflow.com/questions/4649836/using-html5-canvas-rotate-image-about-arbitrary-point/4650102#4650102 – Phrogz 2011-02-15 19:54:41