Canvas rotate from bottom center image angle?
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by Tom
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Published on 2008-12-13T16:21:00Z
Indexed on
2010/06/01
12:33 UTC
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How do you rotate an image with the canvas html5 element from the bottom center angle? See http://uptowar.com/test.php for my current code and image:
<html>
<head>
<title>test</title>
<script type="text/javascript">
function startup() {
var canvas = document.getElementById('canvas');
var ctx = canvas.getContext('2d');
var img = new Image();
img.src = 'player.gif';
img.onload = function() {
ctx.translate(185, 185);
ctx.rotate(90 * Math.PI / 180);
ctx.drawImage(img, 0, 0, 64, 120);
}
}
</script>
</head>
<body onload='startup();'>
<canvas id="canvas" style="position: absolute; left: 300px; top: 300px;" width="800" height="800"></canvas>
</body>
</html>
Unfortunately this seems to rotate it from the top left angle of the image. Any idea?
Edit: in the end the object (space ship) has to rotate like a clock pointer, as if it is turning right/left.
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