Skip to content

Instantly share code, notes, and snippets.

@bueltge

bueltge/gist:1038032

Created Jun 21, 2011
Embed
What would you like to do?
Transition form bw 2 color with canvas
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>untitled</title>
<style>
/* Setup...not important. */
.img-wrap {
width: 500px;
margin: 100px auto;
position: relative;
cursor: pointer;
}
/* Handles animation of b*w to color */
canvas {
position: absolute;
left: 0;
top: 0;
opacity: 1;
-webkit-transition: all 1s;
-moz-transition: all 1s;
-o-transition: all 1s;
-ms-transition: all 1s;
transition: all 1s;
}
canvas:hover {
opacity: 0;
}
/* If you MUST have IE support */
#cvs-src {
filter: progid:DXImageTransform.Microsoft.BasicImage(grayscale=1);
}
#cvs-src:hover {
filter: none;
}
</style>
</head>
<body>
<div class="img-wrap">
<img id="cvs-src" src="your-image.jpg" />
<canvas width=500 height=500></canvas>
</div>
<script>
(function() {
var supportsCanvas = !!document.createElement('canvas').getContext;
supportsCanvas && (window.onload = greyImages);
function greyImages() {
var ctx = document.getElementsByTagName("canvas")[0].getContext('2d'),
img = document.getElementById("cvs-src"),
imageData, px, length, i = 0,
grey;
ctx.drawImage(img, 0, 0);
// Set 500,500 to the width and height of your image.
imageData = ctx.getImageData(0, 0, 500, 500);
px = imageData.data;
length = px.length;
for ( ; i < length; i+= 4 ) {
grey = px[i] * .3 + px[i+1] * .59 + px[i+2] * .11;
px[i] = px[i+1] = px[i+2] = grey;
}
ctx.putImageData(imageData, 0, 0);
}
})();
</script>
</body>
</html>
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
You can’t perform that action at this time.