77 lines
2.0 KiB
HTML
77 lines
2.0 KiB
HTML
<!DOCTYPE html>
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<html lang="en">
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<head>
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<meta charset=utf-8 />
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<title>Canvas Gradient</title>
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<style>
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body {
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background: #000;
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}
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canvas {
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position: absolute;
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top: 0;
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left: 0;
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height: 100%;
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width: 100%;
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}
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</style>
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</head>
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<body>
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<canvas height="600" width="600"></canvas>
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<script>
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var canvas = document.getElementsByTagName('canvas')[0],
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ctx = null,
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grad = null,
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body = document.getElementsByTagName('body')[0],
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color = 255;
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if (canvas.getContext('2d')) {
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ctx = canvas.getContext('2d');
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ctx.clearRect(0, 0, 600, 600);
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ctx.save();
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// Create radial gradient
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grad = ctx.createRadialGradient(0,0,0,0,0,600);
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grad.addColorStop(0, '#000');
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grad.addColorStop(1, 'rgb(' + color + ', ' + color + ', ' + color + ')');
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// assign gradients to fill
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ctx.fillStyle = grad;
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// draw 600x600 fill
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ctx.fillRect(0,0,600,600);
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ctx.save();
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body.onmousemove = function (event) {
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var width = window.innerWidth,
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height = window.innerHeight,
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x = event.clientX,
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y = event.clientY,
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rx = 600 * x / width,
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ry = 600 * y / height;
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var xc = ~~(256 * x / width);
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var yc = ~~(256 * y / height);
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grad = ctx.createRadialGradient(rx, ry, 0, rx, ry, 600);
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grad.addColorStop(0, '#000');
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grad.addColorStop(1, ['rgb(', xc, ', ', (255 - xc), ', ', yc, ')'].join(''));
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// ctx.restore();
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ctx.fillStyle = grad;
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ctx.fillRect(0,0,600,600);
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// ctx.save();
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};
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}
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</script>
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<a href="http://github.com/remy/html5demos"><img style="position: absolute; top: 0; left: 0; border: 0;" src="http://s3.amazonaws.com/github/ribbons/forkme_left_darkblue_121621.png" alt="Fork me on GitHub" /></a>
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<script>
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var gaJsHost = (("https:" == document.location.protocol) ? "https://ssl." : "http://www.");
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document.write(unescape("%3Cscript src='" + gaJsHost + "google-analytics.com/ga.js' type='text/javascript'%3E%3C/script%3E"));
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</script>
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<script>
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try {
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var pageTracker = _gat._getTracker("UA-1656750-18");
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pageTracker._trackPageview();
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} catch(err) {}</script>
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</body>
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</html> |