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webvirtcloud/static/js/novnc/core/util/events.js
2019-06-24 14:26:25 +03:00

139 lines
4.1 KiB
JavaScript
Executable file

/*
* noVNC: HTML5 VNC client
* Copyright (C) 2018 The noVNC Authors
* Licensed under MPL 2.0 (see LICENSE.txt)
*
* See README.md for usage and integration instructions.
*/
/*
* Cross-browser event and position routines
*/
export function getPointerEvent(e) {
return e.changedTouches ? e.changedTouches[0] : e.touches ? e.touches[0] : e;
}
export function stopEvent(e) {
e.stopPropagation();
e.preventDefault();
}
// Emulate Element.setCapture() when not supported
let _captureRecursion = false;
let _captureElem = null;
function _captureProxy(e) {
// Recursion protection as we'll see our own event
if (_captureRecursion) return;
// Clone the event as we cannot dispatch an already dispatched event
const newEv = new e.constructor(e.type, e);
_captureRecursion = true;
_captureElem.dispatchEvent(newEv);
_captureRecursion = false;
// Avoid double events
e.stopPropagation();
// Respect the wishes of the redirected event handlers
if (newEv.defaultPrevented) {
e.preventDefault();
}
// Implicitly release the capture on button release
if (e.type === "mouseup") {
releaseCapture();
}
}
// Follow cursor style of target element
function _captureElemChanged() {
const captureElem = document.getElementById("noVNC_mouse_capture_elem");
captureElem.style.cursor = window.getComputedStyle(_captureElem).cursor;
}
const _captureObserver = new MutationObserver(_captureElemChanged);
let _captureIndex = 0;
export function setCapture(elem) {
if (elem.setCapture) {
elem.setCapture();
// IE releases capture on 'click' events which might not trigger
elem.addEventListener('mouseup', releaseCapture);
} else {
// Release any existing capture in case this method is
// called multiple times without coordination
releaseCapture();
let captureElem = document.getElementById("noVNC_mouse_capture_elem");
if (captureElem === null) {
captureElem = document.createElement("div");
captureElem.id = "noVNC_mouse_capture_elem";
captureElem.style.position = "fixed";
captureElem.style.top = "0px";
captureElem.style.left = "0px";
captureElem.style.width = "100%";
captureElem.style.height = "100%";
captureElem.style.zIndex = 10000;
captureElem.style.display = "none";
document.body.appendChild(captureElem);
// This is to make sure callers don't get confused by having
// our blocking element as the target
captureElem.addEventListener('contextmenu', _captureProxy);
captureElem.addEventListener('mousemove', _captureProxy);
captureElem.addEventListener('mouseup', _captureProxy);
}
_captureElem = elem;
_captureIndex++;
// Track cursor and get initial cursor
_captureObserver.observe(elem, {attributes: true});
_captureElemChanged();
captureElem.style.display = "";
// We listen to events on window in order to keep tracking if it
// happens to leave the viewport
window.addEventListener('mousemove', _captureProxy);
window.addEventListener('mouseup', _captureProxy);
}
}
export function releaseCapture() {
if (document.releaseCapture) {
document.releaseCapture();
} else {
if (!_captureElem) {
return;
}
// There might be events already queued, so we need to wait for
// them to flush. E.g. contextmenu in Microsoft Edge
window.setTimeout((expected) => {
// Only clear it if it's the expected grab (i.e. no one
// else has initiated a new grab)
if (_captureIndex === expected) {
_captureElem = null;
}
}, 0, _captureIndex);
_captureObserver.disconnect();
const captureElem = document.getElementById("noVNC_mouse_capture_elem");
captureElem.style.display = "none";
window.removeEventListener('mousemove', _captureProxy);
window.removeEventListener('mouseup', _captureProxy);
}
}