Added built-in noVNC support.

public/novnc/core/util/events.js

@@ -0,0 +1,139 @@
+/*
+ * 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);
+    }
+}