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