当我在 Firefox 上时,canvas 调用 requestPointerLock
并且我按 F11 全屏 - 我看到事件 mousemove
被触发。这使得一些必须静止的东西移动,因为鼠标没有移动。
我尝试创建一个演示,但出现错误 Blocked pointer lock on an element because the element's frame is sandboxed and the 'allow-pointer-lock' permission is not set.
所以这是一个您至少可以阅读的代码示例。
HTML 部分:
<canvas id="canvas" width="800" height="600"></canvas>
JavaScript 部分:
canvas = document.getElementById('canvas');
document.addEventListener("click", function(e) {
canvas.requestPointerLock = canvas.requestPointerLock ||
canvas.mozRequestPointerLock ||
canvas.webkitRequestPointerLock;
if (canvas.requestPointerLock)
canvas.requestPointerLock();
}, false);
document.addEventListener("pointerlockchange", plChange, false);
document.addEventListener("mozpointerlockchange", plChange, false);
function plChange(e) {
var controlEnabled = (document.mozPointerLockElement === canvas ||
document.webkitPointerLockElement === canvas ||
document.pointerLockElement === canvas);
if (!controlEnabled) {
window.removeEventListener("mousemove", mouseMove);
} else {
window.addEventListener("mousemove", mouseMove, false);
}
}
function mouseMove(e) {
// This is being executed on window resize
console.log(e.movementY);
}
因此,当窗口全屏显示时(Firefox 会很慢地进行)- 我在控制台中打印了 e.movementY 并且值并不总是 0。
问题是我怎样才能阻止这个 Firefox“特性”,这样鼠标移动事件就不会被触发?
最佳答案
找到了缓解问题的解决方案。不幸的是,没有可行的解决方案可以真正解决这个问题,因为每当 Firefox 调整其窗口大小时,鼠标就会以某种方式被拖动,以便指针相对于左上角的位置保持不变。但是,由于它在屏幕上移动,因此会触发虚假的 mousemove
事件。
缓解这种情况的一种方法是向窗口对象添加一个 resize
处理程序以检查窗口是否正在调整大小 - 如果是,则设置一个标志并使用它来让鼠标移动处理程序摆脱困境。不幸的是,您不能在鼠标移动触发时重置此标志,因为您仍然会偶尔收到虚假的 mousemove
事件。相反,当您可以相对确定浏览器窗口已完全调整大小时,您必须设置一个最终重置标志的超时。
我设法用我的测试用例完成了它,看起来像这样:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml"
xml:lang="en">
<head>
<title>canvas Test Case</title>
<style type="text/css">
body {
background-color: silver;
}
canvas {
background-color: white;
}
</style>
<script type="application/javascript">
/* <![CDATA[ */
'use strict';
var canvas;
var this_timeout = null;
document.addEventListener('DOMContentLoaded', function (p_event) {
canvas = document.getElementById('canvas');
document.addEventListener("click", function (p_event) {
canvas.requestPointerLock = canvas.requestPointerLock ||
canvas.mozRequestPointerLock ||
canvas.webkitRequestPointerLock;
if (canvas.requestPointerLock)
canvas.requestPointerLock();
}, false);
document.addEventListener("pointerlockchange", plChange, false);
document.addEventListener("mozpointerlockchange", plChange, false);
window.addEventListener('resize', function (p_event) {
// Use this handler to set a flag that a resize event is taking place.
// Using the timeout ID actually hits two birds with one stone: It serves as a
// flag that a resize is actually taking place, plus it allows us to reset the
// timeout if it hasn't expired when another one fires.
if(this_timeout)
clearTimeout(this_timeout);
this_timeout = setTimeout(function () { this_timeout = null; }, 250);
console.log('Resizing...'); }, true);
}, false);
function stoppedResize() {
// If the timeout expires, reset the timeout id to show that we are done resizing.
this_timeout = null;
}
function plChange(p_event) {
var controlEnabled = (document.mozPointerLockElement === canvas ||
document.webkitPointerLockElement === canvas ||
document.pointerLockElement === canvas);
if (!controlEnabled) {
console.log('Disabling mouse tracker...');
window.removeEventListener("mousemove", mouseMove);
} else {
console.log('Enabling mouse tracker...');
window.addEventListener("mousemove", mouseMove, false);
}
}
function mouseMove(p_event) {
// Check whether there's a timeout running. If yes, just bail out...
if(this_timeout)
{
console.log('Skipping...');
return;
}
console.log('Mouse movement detected!');
}
/* ]]> */
</script>
</head>
<body>
<header><h1>canvas Test Case</h1></header>
<main>
<canvas id="canvas" width="800" height="600" />
</main>
</body>
</html>
通过这样做,您可以轻松缓解此问题。不幸的是,这不是我想要的干净解决方案,但考虑到情况,这是处理我能想到的问题的最佳方法。
至于你的其他问题,我想你想在这里发布一个关于 SO 的例子?如果是,我认为您遇到了对代码施加的一些限制。由于一切似乎都发生在 iframe
中,我猜某些操作已被禁止。附加某些事件处理程序显然会受到影响。
关于JavaScript:在 Firefox 上,调整窗口大小时触发 mousemove,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/52027484/