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<!DOCTYPE HTML>
<html class="reftest-wait">
<head>
<title>Image reftest wrapper</title>
<style type="text/css">
#image1 { background-color: rgb(10, 100, 250); }
</style>
<script>
var gImg;
function runAfterAsyncEvents(aCallback) {
function handlePostMessage(aEvent) {
if (aEvent.data == 'next') {
window.removeEventListener('message', handlePostMessage, false);
aCallback();
}
}
window.addEventListener('message', handlePostMessage, false);
// We'll receive the 'message' event after everything else that's currently in
// the event queue (which is a stronger guarantee than setTimeout, because
// setTimeout events may be coalesced). This lets us ensure that we run
// aCallback *after* any asynchronous events are delivered.
window.postMessage('next', '*');
}
// The image is loaded async after the page loads
// wait for it to finish loading
function onImageLoad() {
// Use a canvas to force the image to get sync decoded.
var canvas = document.createElement('canvas');
var ctx = canvas.getContext('2d');
try {
ctx.drawImage(gImg, 0, 0);
} catch (e) {
}
// Continue after pumping the event loop.
runAfterAsyncEvents(step2);
}
function step2() {
// Only now, once the image has already been sync decoded, do we load it in
// the <img> element we're going to snapshot. That's because for some of the
// tests that use wrapper.html, an error is only detected when decoding the
// actual image data - i.e., the error isn't detected in the header. The
// precise time when we detect the error, unfortunately, affects how we draw
// the image. This will be fixed in bug 1182531, and then we can simplify this
// code.
var finalImg = document.getElementById('image1');
finalImg.onload = finalImg.onerror = step3;
finalImg.src = gImg.src;
}
function step3() {
// We're ready to take the snapshot, but pump the event loop first just to
// be sure that everything has settled down.
runAfterAsyncEvents(takeSnapshot);
}
function takeSnapshot() {
document.documentElement.removeAttribute("class");
}
</script>
</head>
<body>
<!-- non-empty alt to avoid the broken image icon -->
<img id="image1" alt=" ">
<script>
// Use as "wrapper.html?image.png
gImg = document.createElement('img');
gImg.onload = gImg.onerror = onImageLoad;
gImg.src = document.location.search.substr(1);
</script>
</body>
</html>
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