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test1.html
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test1.html
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<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>DeltaImg Test 1</title>
<link rel="stylesheet" type="text/css" href="style/main.css">
</head>
<body>
<section class="c bodywidth">
<a href="http://hacks.philingrey.com/2012/03/deltaimg-resolution-and-bandwidth-responsive-images/"><- Back to blog</a>
<h2>Select a Kitty!</h2>
<ul class="c" style="width:150px;" id="kittyselector">
<li class="s2">1</li>
<li class="s2">2</li>
<li class="s2">3</li>
</ul>
<h2 class="cb">Delta Image:</h2>
<p id="upgradeButton" class="s1 c" style="width:200px;margin:0 auto;">Upgrade</p>
<img id="responsive" class="c" width="1024p×" height="512px" src="images/test1/place_kitty_1_low.jpg" data-stage="0" data-kitty="1">
<h2>Original:</h2>
<img id="full" class="c" width="1024p×" height="512px" src="images/test1/place_kitty_1.jpg">
</section>
<script>
/*
This is the important function
*/
upgrade = function(el, dsrc, cb){
var canvas = document.createElement('canvas')
, ctx = canvas.getContext('2d')
, img2 = new Image()
, data1
, data2;
img2.onload = function(){
canvas.width = img2.width;
canvas.height = img2.height;
ctx.drawImage(el,0,0,img2.width,img2.height);
data1 = ctx.getImageData(0,0,img2.width,img2.height);
ctx.drawImage(img2,0,0,img2.width,img2.height);
data2 = ctx.getImageData(0,0,img2.width,img2.height);
// Use the diff
for(var i=0;i<img2.width*img2.height;i++){
for(var j=0;j<3;j++){
data1.data[4*i+j] = Math.min(255,Math.max(0,(data1.data[4*i+j]+((data2.data[4*i+j]-127) || 0))));
}
}
ctx.putImageData(data1,0,0);
el.src = ctx.canvas.toDataURL();
if(cb) cb();
};
img2.src = dsrc;
};
/*
This stuff is not important, feel very free to ignore it
*/
upgrader = function(){
switch(++stage){
case 1: upgrade(document.getElementById('responsive'),'images/test1/place_kitty_3_low_to_med_diff.jpg');
document.getElementById('upgradeButton').innerHTML = "Upgrade (again)";
break;
case 2: upgrade(document.getElementById('responsive'),'images/test1/place_kitty_3_med_to_full_diff.jpg');
document.getElementById('upgradeButton').innerHTML = "Done!";
break;
default: break;
}
}
window.onload = function(){
document.getElementById("upgradeButton").addEventListener("click",function(e){
var el = document.getElementById('responsive');
switch(++el.dataset['stage']){
case 1: upgrade(document.getElementById('responsive'),'images/test1/place_kitty_'+el.dataset['kitty']+'_low_to_med_diff.jpg');
this.innerHTML = "Upgrade (again)";
break;
case 2: upgrade(document.getElementById('responsive'),'images/test1/place_kitty_'+el.dataset['kitty']+'_med_to_full_diff.jpg');
this.innerHTML = "Done!";
break;
default: break;
}
});
document.getElementById("kittyselector").addEventListener("click",function(e){
document.getElementById('responsive').src = "images/test1/place_kitty_"+e.target.innerHTML+"_low.jpg";
document.getElementById('responsive').dataset['stage'] = 0;
document.getElementById('responsive').dataset['kitty'] = e.target.innerHTML;
document.getElementById("upgradeButton").innerHTML = "Upgrade";
document.getElementById('full').src = "images/test1/place_kitty_"+e.target.innerHTML+".jpg";
});
}
</script>
</body>
</html>