| 1 | /* |
| 2 | * noVNC: HTML5 VNC client |
| 3 | * Copyright (C) 2018 The noVNC Authors |
| 4 | * Licensed under MPL 2.0 (see LICENSE.txt) |
| 5 | * |
| 6 | * See README.md for usage and integration instructions. |
| 7 | */ |
| 8 | |
| 9 | /* |
| 10 | * Cross-browser event and position routines |
| 11 | */ |
| 12 | |
| 13 | export function getPointerEvent(e) { |
| 14 | return e.changedTouches ? e.changedTouches[0] : e.touches ? e.touches[0] : e; |
| 15 | } |
| 16 | |
| 17 | export function stopEvent(e) { |
| 18 | e.stopPropagation(); |
| 19 | e.preventDefault(); |
| 20 | } |
| 21 | |
| 22 | // Emulate Element.setCapture() when not supported |
| 23 | let _captureRecursion = false; |
| 24 | let _elementForUnflushedEvents = null; |
| 25 | document.captureElement = null; |
| 26 | function _captureProxy(e) { |
| 27 | // Recursion protection as we'll see our own event |
| 28 | if (_captureRecursion) return; |
| 29 | |
| 30 | // Clone the event as we cannot dispatch an already dispatched event |
| 31 | const newEv = new e.constructor(e.type, e); |
| 32 | |
| 33 | _captureRecursion = true; |
| 34 | if (document.captureElement) { |
| 35 | document.captureElement.dispatchEvent(newEv); |
| 36 | } else { |
| 37 | _elementForUnflushedEvents.dispatchEvent(newEv); |
| 38 | } |
| 39 | _captureRecursion = false; |
| 40 | |
| 41 | // Avoid double events |
| 42 | e.stopPropagation(); |
| 43 | |
| 44 | // Respect the wishes of the redirected event handlers |
| 45 | if (newEv.defaultPrevented) { |
| 46 | e.preventDefault(); |
| 47 | } |
| 48 | |
| 49 | // Implicitly release the capture on button release |
| 50 | if (e.type === "mouseup") { |
| 51 | releaseCapture(); |
| 52 | } |
| 53 | } |
| 54 | |
| 55 | // Follow cursor style of target element |
| 56 | function _capturedElemChanged() { |
| 57 | const proxyElem = document.getElementById("noVNC_mouse_capture_elem"); |
| 58 | proxyElem.style.cursor = window.getComputedStyle(document.captureElement).cursor; |
| 59 | } |
| 60 | |
| 61 | const _captureObserver = new MutationObserver(_capturedElemChanged); |
| 62 | |
| 63 | export function setCapture(target) { |
| 64 | if (target.setCapture) { |
| 65 | |
| 66 | target.setCapture(); |
| 67 | document.captureElement = target; |
| 68 | } else { |
| 69 | // Release any existing capture in case this method is |
| 70 | // called multiple times without coordination |
| 71 | releaseCapture(); |
| 72 | |
| 73 | let proxyElem = document.getElementById("noVNC_mouse_capture_elem"); |
| 74 | |
| 75 | if (proxyElem === null) { |
| 76 | proxyElem = document.createElement("div"); |
| 77 | proxyElem.id = "noVNC_mouse_capture_elem"; |
| 78 | proxyElem.style.position = "fixed"; |
| 79 | proxyElem.style.top = "0px"; |
| 80 | proxyElem.style.left = "0px"; |
| 81 | proxyElem.style.width = "100%"; |
| 82 | proxyElem.style.height = "100%"; |
| 83 | proxyElem.style.zIndex = 10000; |
| 84 | proxyElem.style.display = "none"; |
| 85 | document.body.appendChild(proxyElem); |
| 86 | |
| 87 | // This is to make sure callers don't get confused by having |
| 88 | // our blocking element as the target |
| 89 | proxyElem.addEventListener('contextmenu', _captureProxy); |
| 90 | |
| 91 | proxyElem.addEventListener('mousemove', _captureProxy); |
| 92 | proxyElem.addEventListener('mouseup', _captureProxy); |
| 93 | } |
| 94 | |
| 95 | document.captureElement = target; |
| 96 | |
| 97 | // Track cursor and get initial cursor |
| 98 | _captureObserver.observe(target, {attributes: true}); |
| 99 | _capturedElemChanged(); |
| 100 | |
| 101 | proxyElem.style.display = ""; |
| 102 | |
| 103 | // We listen to events on window in order to keep tracking if it |
| 104 | // happens to leave the viewport |
| 105 | window.addEventListener('mousemove', _captureProxy); |
| 106 | window.addEventListener('mouseup', _captureProxy); |
| 107 | } |
| 108 | } |
| 109 | |
| 110 | export function releaseCapture() { |
| 111 | if (document.releaseCapture) { |
| 112 | |
| 113 | document.releaseCapture(); |
| 114 | document.captureElement = null; |
| 115 | |
| 116 | } else { |
| 117 | if (!document.captureElement) { |
| 118 | return; |
| 119 | } |
| 120 | |
| 121 | // There might be events already queued. The event proxy needs |
| 122 | // access to the captured element for these queued events. |
| 123 | // E.g. contextmenu (right-click) in Microsoft Edge |
| 124 | // |
| 125 | // Before removing the capturedElem pointer we save it to a |
| 126 | // temporary variable that the unflushed events can use. |
| 127 | _elementForUnflushedEvents = document.captureElement; |
| 128 | document.captureElement = null; |
| 129 | |
| 130 | _captureObserver.disconnect(); |
| 131 | |
| 132 | const proxyElem = document.getElementById("noVNC_mouse_capture_elem"); |
| 133 | proxyElem.style.display = "none"; |
| 134 | |
| 135 | window.removeEventListener('mousemove', _captureProxy); |
| 136 | window.removeEventListener('mouseup', _captureProxy); |
| 137 | } |
| 138 | } |