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<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
</head>
<style type=''>
html {
font-family: helvetica, sans-serif;
}
canvas {
padding: 15px;
margin: 10px;
}
.example {
display: inline-block;
width: 280px;
margin-top: 50px;
margin-right: 50px;
}
.title {
text-align: center;
}
.description {
width: 100%;
}
.description div {
display: inline-block;
text-align: center;
font-size: 13px;
}
.description .source {
width: 100px;
}
.description .target {
width: 100px;
}
.example-title {
text-align: center;
font-size: 16px;
}
.error {
color: red;
}
</style>
<body>
<h1 class="title">Timed DrawImage canvas to canvas</h1>
<h4 class="title", id="Test Result">This text is where the timing result will go...</h4>
</body>
<script type="text/javascript">
var smoothingEnabled = false;
var examplesNum = 0;
var imageSource = {
width: 50,
height: 50
};
var destCanvas = {
width: 100,
height: 100
};
var t0 = performance.now(); //save starting time
drawImage(25, 25); // The source canvas will copied to the 25,25 position of the destination canvas
var t1 = performance.now(); //save ending time
document.getElementById('Test Result').innerHTML = "DrawImage took " + (t1 - t0) + " milliseconds."; //print to browser
console.log("DrawImage took " + (t1 - t0) + " milliseconds."); //print to console
function renderExample(title) {
var container = document.createElement('div');
container.id = 'example' + examplesNum++;
container.setAttribute('class', 'example');
var h2 = document.createElement('h2');
h2.textContent = title;
h2.setAttribute('class', 'example-title');
container.appendChild(h2);
var div1 = document.createElement('div');
var canvas1 = document.createElement('canvas');
var canvas2 = document.createElement('canvas');
div1.appendChild(canvas1);
div1.appendChild(canvas2);
container.appendChild(div1);
var div2 = document.createElement('div');
div2.setAttribute('class', 'description');
var source = document.createElement('div');
source.textContent = ' Source (' + imageSource.width + ',' + imageSource.height + ')';
source.setAttribute('class', 'source');
var arrow = document.createElement('div');
arrow.textContent = ' -> ';
arrow.setAttribute('class', 'arrow');
var target = document.createElement('div');
target.textContent = 'Target (' + destCanvas.width + ',' + destCanvas.height + ')';
target.setAttribute('class', 'target');
div2.appendChild(source);
div2.appendChild(arrow);
div2.appendChild(target);
container.appendChild(div2);
return container;
}
function drawImage() {
var args = Array.prototype.slice.call(arguments);
var div = renderExample('drawImage(' + args.toString() + ')');
var canvasEls = div.querySelectorAll('canvas');
var canvas1 = canvasEls[0];
var canvas2 = canvasEls[1];
canvas1.width = imageSource.width;
canvas1.height = imageSource.height;
var ctx1 = canvas1.getContext('2d');
ctx1.fillStyle = "#00FFFF";
ctx1.fillRect(0, 0, imageSource.width, imageSource.height);
ctx1.fillStyle = "#000000";
ctx1.fillRect(5,5,40,40);
ctx1.clearRect(10,10,30,30);
ctx1.strokeRect(15,15,20,20);
canvas2.width = destCanvas.width;
canvas2.height = destCanvas.height;
var ctx2 = canvas2.getContext('2d');
ctx2.fillStyle = "#FF0000";
ctx2.fillRect(0, 0, destCanvas.width, destCanvas.height);
ctx2.imageSmoothingEnabled = smoothingEnabled;
args.unshift(canvas1);
try {
ctx2.drawImage.apply(ctx2, args);
}
catch(err) {
var title = div.querySelector('.example-title');
var error = document.createElement('h2');
error.setAttribute('class', 'example-title error');
div.insertBefore(error, title);
error.textContent += "Call Failed: " + err.message;
}
document.body.appendChild(div);
};
</script>
</body>
</html>
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