<!DOCTYPE html>
<html>
<!--
Copyright The Closure Library Authors. All Rights Reserved.
Use of this source code is governed by the Apache License, Version 2.0.
See the COPYING file for details.
-->
<head>
<title>goog.events.WheelHandler</title>
<link rel="stylesheet" href="../css/checkbox.css">
<style>
#out {
background-color: #eee;
width: 500px;
height: 500px;
position: relative;
display: inline-block;
}
#h-line, #v-line {
position: absolute;
background: black;
}
#h-line {
width: 20px;
height: 1px;
}
#v-line {
width: 1px;
height: 20px;
}
#status {
position: absolute;
bottom: 0;
right: 0;
font: 70% sans-serif;
}
#debug {
font-family: monospace;
white-space: pre;
display: inline-block;
}
</style>
<script src="../base.js"></script>
<script>
goog.require('goog.events');
goog.require('goog.events.WheelHandler');
</script>
</head>
<body>
<h1>goog.events.WheelHandler</h1>
<p>Use your mousewheel on the gray box below to move the cross hair.
<div id=out>
<div id=h-line></div>
<div id=v-line></div>
<div id=status></div>
</div>
<div id=debug>
</div>
<script>
var WheelHandler = goog.events.WheelHandler;
var WheelEvent = goog.events.WheelEvent;
var WHEEL = WheelEvent.EventType.WHEEL;
function $(id) {
return document.getElementById(id)
}
var x = 250, y = 250;
var out = $('out');
var hLine= $('h-line');
var vLine = $('v-line');
var statusLine = $('status');
var debug = $('debug');
var availWidth = out.clientWidth - vLine.offsetWidth;
var availHeight = out.clientHeight - hLine.offsetHeight;
function handleWheel(e) {
x += e.pixelDeltaX;
x = Math.max(0, Math.min(availWidth, x));
y += e.pixelDeltaY;
y = Math.max(0, Math.min(availHeight, y));
updateLines();
e.preventDefault();
var deltaModeString = 'unknown';
var DeltaMode = WheelEvent.DeltaMode;
switch (e.deltaMode) {
case DeltaMode.PIXEL:
deltaModeString = 'DeltaMode.PIXEL';
break;
case DeltaMode.LINE:
deltaModeString = 'DeltaMode.LINE';
break;
case DeltaMode.PAGE:
deltaModeString = 'DeltaMode.PAGE';
break;
}
var debugObject = {
type: e.type,
deltaMode: deltaModeString,
deltaX: e.deltaX,
deltaY: e.deltaY,
deltaZ: e.deltaZ,
pixelDeltaX: e.pixelDeltaX,
pixelDeltaY: e.pixelDeltaY,
pixelDeltaZ: e.pixelDeltaZ,
};
debug.innerText = JSON.stringify(debugObject, undefined, 4);
}
function updateLines() {
vLine.style.left = x + 'px';
hLine.style.left = x - hLine.offsetWidth / 2 + 'px';
hLine.style.top = y + 'px';
vLine.style.top = y - vLine.offsetHeight / 2 + 'px';
statusLine.innerText = x + ', ' + y;
}
updateLines();
var mwh = new WheelHandler(out);
goog.events.listen(mwh, WHEEL, handleWheel);
goog.events.listen(window, 'unload', function(e) {
goog.events.unlisten(mwh, WHEEL, handleWheel);
});
</script>
</body>
</html>