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Diffstat (limited to 'webclients/novnc/core/util/events.js')
-rw-r--r-- | webclients/novnc/core/util/events.js | 138 |
1 files changed, 138 insertions, 0 deletions
diff --git a/webclients/novnc/core/util/events.js b/webclients/novnc/core/util/events.js new file mode 100644 index 0000000..8efd0c2 --- /dev/null +++ b/webclients/novnc/core/util/events.js @@ -0,0 +1,138 @@ +/* + * noVNC: HTML5 VNC client + * Copyright (C) 2012 Joel Martin + * 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 +var _captureRecursion = false; +var _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 + var 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() { + var captureElem = document.getElementById("noVNC_mouse_capture_elem"); + captureElem.style.cursor = window.getComputedStyle(_captureElem).cursor; +}; +var _captureObserver = new MutationObserver(_captureElemChanged); + +var _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(); + + var 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(function(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(); + + var captureElem = document.getElementById("noVNC_mouse_capture_elem"); + captureElem.style.display = "none"; + + window.removeEventListener('mousemove', _captureProxy); + window.removeEventListener('mouseup', _captureProxy); + } +}; |