novnc/include/ui.js

/*
 * noVNC: HTML5 VNC client
 * Copyright (C) 2012 Joel Martin
 * Copyright (C) 2013 Samuel Mannehed for Cendio AB
 * Licensed under MPL 2.0 (see LICENSE.txt)
 *
 * See README.md for usage and integration instructions.
 */

/* jslint white: false, browser: true */
/* global window, $D, Util, WebUtil, RFB, Display */

var UI;

(function () {
    "use strict";

    var resizeTimeout;

    // Load supporting scripts
    window.onscriptsload = function () { UI.load(); };
    Util.load_scripts(["webutil.js", "base64.js", "websock.js", "des.js",
                       "keysymdef.js", "keyboard.js", "input.js", "display.js",
                       "jsunzip.js", "rfb.js", "keysym.js"]);

    UI = {

        rfb_state : 'loaded',
        settingsOpen : false,
        connSettingsOpen : false,
        popupStatusOpen : false,
        clipboardOpen: false,
        keyboardVisible: false,
        hideKeyboardTimeout: null,
        lastKeyboardinput: null,
        defaultKeyboardinputLen: 100,
        extraKeysVisible: false,
        ctrlOn: false,
        altOn: false,
        isTouchDevice: false,

        // Setup rfb object, load settings from browser storage, then call
        // UI.init to setup the UI/menus
        load: function (callback) {
            WebUtil.initSettings(UI.start, callback);
        },

        onresize: function (callback) {
            if (UI.getSetting('resize')) {
                var innerW = window.innerWidth;
                var innerH = window.innerHeight;
                var controlbarH = $D('noVNC-control-bar').offsetHeight;
                // For some unknown reason the container is higher than the canvas,
                // 5px higher in Firefox and 4px higher in Chrome
                var padding = 5;
                if (innerW !== undefined && innerH !== undefined)
                    UI.rfb.setDesktopSize(innerW, innerH - controlbarH - padding);
            }
        },

        // Render default UI and initialize settings menu
        start: function(callback) {
            UI.isTouchDevice = 'ontouchstart' in document.documentElement;

            // Stylesheet selection dropdown
            var sheet = WebUtil.selectStylesheet();
            var sheets = WebUtil.getStylesheets();
            var i;
            for (i = 0; i < sheets.length; i += 1) {
                UI.addOption($D('noVNC_stylesheet'),sheets[i].title, sheets[i].title);
            }

            // Logging selection dropdown
            var llevels = ['error', 'warn', 'info', 'debug'];
            for (i = 0; i < llevels.length; i += 1) {
                UI.addOption($D('noVNC_logging'),llevels[i], llevels[i]);
            }

            // Settings with immediate effects
            UI.initSetting('logging', 'warn');
            WebUtil.init_logging(UI.getSetting('logging'));

            UI.initSetting('stylesheet', 'default');
            WebUtil.selectStylesheet(null);
            // call twice to get around webkit bug
            WebUtil.selectStylesheet(UI.getSetting('stylesheet'));

            // if port == 80 (or 443) then it won't be present and should be
            // set manually
            var port = window.location.port;
            if (!port) {
                if (window.location.protocol.substring(0,5) == 'https') {
                    port = 443;
                }
                else if (window.location.protocol.substring(0,4) == 'http') {
                    port = 80;
                }
            }

            /* Populate the controls if defaults are provided in the URL */
            UI.initSetting('host', window.location.hostname);
            UI.initSetting('port', port);
            UI.initSetting('password', '');
            UI.initSetting('encrypt', (window.location.protocol === "https:"));
            UI.initSetting('true_color', true);
            UI.initSetting('cursor', !UI.isTouchDevice);
            UI.initSetting('resize', false);
            UI.initSetting('shared', true);
            UI.initSetting('view_only', false);
            UI.initSetting('path', 'websockify');
            UI.initSetting('repeaterID', '');

            UI.rfb = new RFB({'target': $D('noVNC_canvas'),
                              'onUpdateState': UI.updateState,
                              'onXvpInit': UI.updateXvpVisualState,
                              'onClipboard': UI.clipReceive,
                              'onFBUComplete': UI.FBUComplete,
                              'onFBResize': UI.updateViewDragButton,
                              'onDesktopName': UI.updateDocumentTitle});

            var autoconnect = WebUtil.getQueryVar('autoconnect', false);
            if (autoconnect === 'true' || autoconnect == '1') {
                autoconnect = true;
                UI.connect();
            } else {
                autoconnect = false;
            }

            UI.updateVisualState();

            // Show mouse selector buttons on touch screen devices
            if (UI.isTouchDevice) {
                // Show mobile buttons
                $D('noVNC_mobile_buttons').style.display = "inline";
                UI.setMouseButton();
                // Remove the address bar
                setTimeout(function() { window.scrollTo(0, 1); }, 100);
                UI.forceSetting('clip', true);
            } else {
                UI.initSetting('clip', false);
            }

            //iOS Safari does not support CSS position:fixed.
            //This detects iOS devices and enables javascript workaround.
            if ((navigator.userAgent.match(/iPhone/i)) ||
                (navigator.userAgent.match(/iPod/i)) ||
                (navigator.userAgent.match(/iPad/i))) {
                //UI.setOnscroll();
                //UI.setResize();
            }
            UI.setBarPosition();

            $D('noVNC_host').focus();

            UI.setViewClip();

            Util.addEvent(window, 'resize', function () {
                UI.setViewClip();
                // When the window has been resized, wait until the size remains
                // the same for 0.5 seconds before sending the request for changing
                // the resolution of the session
                clearTimeout(resizeTimeout);
                resizeTimeout = setTimeout(function(){
                    UI.onresize();
                }, 500);
            } );

            Util.addEvent(window, 'load', UI.keyboardinputReset);

            Util.addEvent(window, 'beforeunload', function () {
                if (UI.rfb_state === 'normal') {
                    return "You are currently connected.";
                }
            } );

            // Show description by default when hosted at for kanaka.github.com
            if (location.host === "kanaka.github.io") {
                // Open the description dialog
                $D('noVNC_description').style.display = "block";
            } else {
                // Show the connect panel on first load unless autoconnecting
                if (autoconnect === UI.connSettingsOpen) {
                    UI.toggleConnectPanel();
                }
            }

            // Add mouse event click/focus/blur event handlers to the UI
            UI.addMouseHandlers();

            if (typeof callback === "function") {
                callback(UI.rfb);
            }
        },

        addMouseHandlers: function() {
            // Setup interface handlers that can't be inline
            $D("noVNC_view_drag_button").onclick = UI.setViewDrag;
            $D("noVNC_mouse_button0").onclick = function () { UI.setMouseButton(1); };
            $D("noVNC_mouse_button1").onclick = function () { UI.setMouseButton(2); };
            $D("noVNC_mouse_button2").onclick = function () { UI.setMouseButton(4); };
            $D("noVNC_mouse_button4").onclick = function () { UI.setMouseButton(0); };
            $D("showKeyboard").onclick = UI.showKeyboard;

            $D("keyboardinput").oninput = UI.keyInput;
            $D("keyboardinput").onblur = UI.keyInputBlur;

            $D("showExtraKeysButton").onclick = UI.showExtraKeys;
            $D("toggleCtrlButton").onclick = UI.toggleCtrl;
            $D("toggleAltButton").onclick = UI.toggleAlt;
            $D("sendTabButton").onclick = UI.sendTab;
            $D("sendEscButton").onclick = UI.sendEsc;

            $D("sendCtrlAltDelButton").onclick = UI.sendCtrlAltDel;
            $D("xvpShutdownButton").onclick = UI.xvpShutdown;
            $D("xvpRebootButton").onclick = UI.xvpReboot;
            $D("xvpResetButton").onclick = UI.xvpReset;
            $D("noVNC_status").onclick = UI.togglePopupStatusPanel;
            $D("noVNC_popup_status_panel").onclick = UI.togglePopupStatusPanel;
            $D("xvpButton").onclick = UI.toggleXvpPanel;
            $D("clipboardButton").onclick = UI.toggleClipboardPanel;
            $D("settingsButton").onclick = UI.toggleSettingsPanel;
            $D("connectButton").onclick = UI.toggleConnectPanel;
            $D("disconnectButton").onclick = UI.disconnect;
            $D("descriptionButton").onclick = UI.toggleConnectPanel;

            $D("noVNC_clipboard_text").onfocus = UI.displayBlur;
            $D("noVNC_clipboard_text").onblur = UI.displayFocus;
            $D("noVNC_clipboard_text").onchange = UI.clipSend;
            $D("noVNC_clipboard_clear_button").onclick = UI.clipClear;

            $D("noVNC_settings_menu").onmouseover = UI.displayBlur;
            $D("noVNC_settings_menu").onmouseover = UI.displayFocus;
            $D("noVNC_apply").onclick = UI.settingsApply;

            $D("noVNC_connect_button").onclick = UI.connect;
        },

        // Read form control compatible setting from cookie
        getSetting: function(name) {
            var ctrl = $D('noVNC_' + name);
            var val = WebUtil.readSetting(name);
            if (typeof val !== 'undefined' && val !== null && ctrl.type === 'checkbox') {
                if (val.toString().toLowerCase() in {'0':1, 'no':1, 'false':1}) {
                    val = false;
                } else {
                    val = true;
                }
            }
            return val;
        },

        // Update cookie and form control setting. If value is not set, then
        // updates from control to current cookie setting.
        updateSetting: function(name, value) {

            // Save the cookie for this session
            if (typeof value !== 'undefined') {
                WebUtil.writeSetting(name, value);
            }

            // Update the settings control
            value = UI.getSetting(name);

            var ctrl = $D('noVNC_' + name);
            if (ctrl.type === 'checkbox') {
                ctrl.checked = value;

            } else if (typeof ctrl.options !== 'undefined') {
                for (var i = 0; i < ctrl.options.length; i += 1) {
                    if (ctrl.options[i].value === value) {
                        ctrl.selectedIndex = i;
                        break;
                    }
                }
            } else {
                /*Weird IE9 error leads to 'null' appearring
                in textboxes instead of ''.*/
                if (value === null) {
                    value = "";
                }
                ctrl.value = value;
            }
        },

        // Save control setting to cookie
        saveSetting: function(name) {
            var val, ctrl = $D('noVNC_' + name);
            if (ctrl.type === 'checkbox') {
                val = ctrl.checked;
            } else if (typeof ctrl.options !== 'undefined') {
                val = ctrl.options[ctrl.selectedIndex].value;
            } else {
                val = ctrl.value;
            }
            WebUtil.writeSetting(name, val);
            //Util.Debug("Setting saved '" + name + "=" + val + "'");
            return val;
        },

        // Initial page load read/initialization of settings
        initSetting: function(name, defVal) {
            // Check Query string followed by cookie
            var val = WebUtil.getQueryVar(name);
            if (val === null) {
                val = WebUtil.readSetting(name, defVal);
            }
            UI.updateSetting(name, val);
            return val;
        },

        // Force a setting to be a certain value
        forceSetting: function(name, val) {
            UI.updateSetting(name, val);
            return val;
        },


        // Show the popup status panel
        togglePopupStatusPanel: function() {
            var psp = $D('noVNC_popup_status_panel');
            if (UI.popupStatusOpen === true) {
                psp.style.display = "none";
                UI.popupStatusOpen = false;
            } else {
                psp.innerHTML = $D('noVNC_status').innerHTML;
                psp.style.display = "block";
                psp.style.left = window.innerWidth/2 -
                    parseInt(window.getComputedStyle(psp, false).width)/2 -30 + "px";
                UI.popupStatusOpen = true;
            }
        },

        // Show the XVP panel
        toggleXvpPanel: function() {
            // Close the description panel
            $D('noVNC_description').style.display = "none";
            // Close settings if open
            if (UI.settingsOpen === true) {
                UI.settingsApply();
                UI.closeSettingsMenu();
            }
            // Close connection settings if open
            if (UI.connSettingsOpen === true) {
                UI.toggleConnectPanel();
            }
            // Close popup status panel if open
            if (UI.popupStatusOpen === true) {
                UI.togglePopupStatusPanel();
            }
            // Close clipboard panel if open
            if (UI.clipboardOpen === true) {
                UI.toggleClipboardPanel();
            }
            // Toggle XVP panel
            if (UI.xvpOpen === true) {
                $D('noVNC_xvp').style.display = "none";
                $D('xvpButton').className = "noVNC_status_button";
                UI.xvpOpen = false;
            } else {
                $D('noVNC_xvp').style.display = "block";
                $D('xvpButton').className = "noVNC_status_button_selected";
                UI.xvpOpen = true;
            }
        },

        // Show the clipboard panel
        toggleClipboardPanel: function() {
            // Close the description panel
            $D('noVNC_description').style.display = "none";
            // Close settings if open
            if (UI.settingsOpen === true) {
                UI.settingsApply();
                UI.closeSettingsMenu();
            }
            // Close connection settings if open
            if (UI.connSettingsOpen === true) {
                UI.toggleConnectPanel();
            }
            // Close popup status panel if open
            if (UI.popupStatusOpen === true) {
                UI.togglePopupStatusPanel();
            }
            // Close XVP panel if open
            if (UI.xvpOpen === true) {
                UI.toggleXvpPanel();
            }
            // Toggle Clipboard Panel
            if (UI.clipboardOpen === true) {
                $D('noVNC_clipboard').style.display = "none";
                $D('clipboardButton').className = "noVNC_status_button";
                UI.clipboardOpen = false;
            } else {
                $D('noVNC_clipboard').style.display = "block";
                $D('clipboardButton').className = "noVNC_status_button_selected";
                UI.clipboardOpen = true;
            }
        },

        // Show the connection settings panel/menu
        toggleConnectPanel: function() {
            // Close the description panel
            $D('noVNC_description').style.display = "none";
            // Close connection settings if open
            if (UI.settingsOpen === true) {
                UI.settingsApply();
                UI.closeSettingsMenu();
                $D('connectButton').className = "noVNC_status_button";
            }
            // Close clipboard panel if open
            if (UI.clipboardOpen === true) {
                UI.toggleClipboardPanel();
            }
            // Close popup status panel if open
            if (UI.popupStatusOpen === true) {
                UI.togglePopupStatusPanel();
            }
            // Close XVP panel if open
            if (UI.xvpOpen === true) {
                UI.toggleXvpPanel();
            }

            // Toggle Connection Panel
            if (UI.connSettingsOpen === true) {
                $D('noVNC_controls').style.display = "none";
                $D('connectButton').className = "noVNC_status_button";
                UI.connSettingsOpen = false;
                UI.saveSetting('host');
                UI.saveSetting('port');
                //UI.saveSetting('password');
            } else {
                $D('noVNC_controls').style.display = "block";
                $D('connectButton').className = "noVNC_status_button_selected";
                UI.connSettingsOpen = true;
                $D('noVNC_host').focus();
            }
        },

        // Toggle the settings menu:
        //   On open, settings are refreshed from saved cookies.
        //   On close, settings are applied
        toggleSettingsPanel: function() {
            // Close the description panel
            $D('noVNC_description').style.display = "none";
            if (UI.settingsOpen) {
                UI.settingsApply();
                UI.closeSettingsMenu();
            } else {
                UI.updateSetting('encrypt');
                UI.updateSetting('true_color');
                if (UI.rfb.get_display().get_cursor_uri()) {
                    UI.updateSetting('cursor');
                } else {
                    UI.updateSetting('cursor', !UI.isTouchDevice);
                    $D('noVNC_cursor').disabled = true;
                }
                UI.updateSetting('clip');
                UI.updateSetting('resize');
                UI.updateSetting('shared');
                UI.updateSetting('view_only');
                UI.updateSetting('path');
                UI.updateSetting('repeaterID');
                UI.updateSetting('stylesheet');
                UI.updateSetting('logging');

                UI.openSettingsMenu();
            }
        },

        // Open menu
        openSettingsMenu: function() {
            // Close the description panel
            $D('noVNC_description').style.display = "none";
            // Close clipboard panel if open
            if (UI.clipboardOpen === true) {
                UI.toggleClipboardPanel();
            }
            // Close connection settings if open
            if (UI.connSettingsOpen === true) {
                UI.toggleConnectPanel();
            }
            // Close popup status panel if open
            if (UI.popupStatusOpen === true) {
                UI.togglePopupStatusPanel();
            }
            // Close XVP panel if open
            if (UI.xvpOpen === true) {
                UI.toggleXvpPanel();
            }
            $D('noVNC_settings').style.display = "block";
            $D('settingsButton').className = "noVNC_status_button_selected";
            UI.settingsOpen = true;
        },

        // Close menu (without applying settings)
        closeSettingsMenu: function() {
            $D('noVNC_settings').style.display = "none";
            $D('settingsButton').className = "noVNC_status_button";
            UI.settingsOpen = false;
        },

        // Save/apply settings when 'Apply' button is pressed
        settingsApply: function() {
            //Util.Debug(">> settingsApply");
            UI.saveSetting('encrypt');
            UI.saveSetting('true_color');
            if (UI.rfb.get_display().get_cursor_uri()) {
                UI.saveSetting('cursor');
            }
            UI.saveSetting('clip');
            UI.saveSetting('resize');
            UI.saveSetting('shared');
            UI.saveSetting('view_only');
            UI.saveSetting('path');
            UI.saveSetting('repeaterID');
            UI.saveSetting('stylesheet');
            UI.saveSetting('logging');

            // Settings with immediate (non-connected related) effect
            WebUtil.selectStylesheet(UI.getSetting('stylesheet'));
            WebUtil.init_logging(UI.getSetting('logging'));
            UI.setViewClip();
            UI.setViewDrag(UI.rfb.get_viewportDrag());
            //Util.Debug("<< settingsApply");
        },



        setPassword: function() {
            UI.rfb.sendPassword($D('noVNC_password').value);
            //Reset connect button.
            $D('noVNC_connect_button').value = "Connect";
            $D('noVNC_connect_button').onclick = UI.Connect;
            //Hide connection panel.
            UI.toggleConnectPanel();
            return false;
        },

        sendCtrlAltDel: function() {
            UI.rfb.sendCtrlAltDel();
        },

        xvpShutdown: function() {
            UI.rfb.xvpShutdown();
        },

        xvpReboot: function() {
            UI.rfb.xvpReboot();
        },

        xvpReset: function() {
            UI.rfb.xvpReset();
        },

        setMouseButton: function(num) {
            if (typeof num === 'undefined') {
                // Disable mouse buttons
                num = -1;
            }
            if (UI.rfb) {
                UI.rfb.get_mouse().set_touchButton(num);
            }

            var blist = [0, 1,2,4];
            for (var b = 0; b < blist.length; b++) {
                var button = $D('noVNC_mouse_button' + blist[b]);
                if (blist[b] === num) {
                    button.style.display = "";
                } else {
                    button.style.display = "none";
                }
            }
        },

        updateState: function(rfb, state, oldstate, msg) {
            UI.rfb_state = state;
            var klass;
            switch (state) {
                case 'failed':
                case 'fatal':
                    klass = "noVNC_status_error";
                    break;
                case 'normal':
                    klass = "noVNC_status_normal";
                    break;
                case 'disconnected':
                    $D('noVNC_logo').style.display = "block";
                    /* falls through */
                case 'loaded':
                    klass = "noVNC_status_normal";
                    break;
                case 'password':
                    UI.toggleConnectPanel();

                    $D('noVNC_connect_button').value = "Send Password";
                    $D('noVNC_connect_button').onclick = UI.setPassword;
                    $D('noVNC_password').focus();

                    klass = "noVNC_status_warn";
                    break;
                default:
                    klass = "noVNC_status_warn";
                    break;
            }

            if (typeof(msg) !== 'undefined') {
                $D('noVNC-control-bar').setAttribute("class", klass);
                $D('noVNC_status').innerHTML = msg;
            }

            UI.updateVisualState();
        },

        // Disable/enable controls depending on connection state
        updateVisualState: function() {
            var connected = UI.rfb_state === 'normal' ? true : false;

            //Util.Debug(">> updateVisualState");
            $D('noVNC_encrypt').disabled = connected;
            $D('noVNC_true_color').disabled = connected;
            if (UI.rfb && UI.rfb.get_display() &&
                UI.rfb.get_display().get_cursor_uri()) {
                $D('noVNC_cursor').disabled = connected;
            } else {
                UI.updateSetting('cursor', !UI.isTouchDevice);
                $D('noVNC_cursor').disabled = true;
            }
            $D('noVNC_clip').disabled = connected || UI.isTouchDevice;
            $D('noVNC_resize').disabled = connected;
            $D('noVNC_shared').disabled = connected;
            $D('noVNC_view_only').disabled = connected;
            $D('noVNC_path').disabled = connected;
            $D('noVNC_repeaterID').disabled = connected;

            if (connected) {
                UI.setViewClip();
                UI.setMouseButton(1);
                $D('clipboardButton').style.display = "inline";
                $D('showKeyboard').style.display = "inline";
                $D('noVNC_extra_keys').style.display = "";
                $D('sendCtrlAltDelButton').style.display = "inline";
            } else {
                UI.setMouseButton();
                $D('clipboardButton').style.display = "none";
                $D('showKeyboard').style.display = "none";
                $D('noVNC_extra_keys').style.display = "none";
                $D('sendCtrlAltDelButton').style.display = "none";
                UI.updateXvpVisualState(0);
            }

            // State change disables viewport dragging.
            // It is enabled (toggled) by direct click on the button
            UI.setViewDrag(false);

            switch (UI.rfb_state) {
                case 'fatal':
                case 'failed':
                case 'loaded':
                case 'disconnected':
                    $D('connectButton').style.display = "";
                    $D('disconnectButton').style.display = "none";
                    break;
                default:
                    $D('connectButton').style.display = "none";
                    $D('disconnectButton').style.display = "";
                    break;
            }

            //Util.Debug("<< updateVisualState");
        },

        // Disable/enable XVP button
        updateXvpVisualState: function(ver) {
            if (ver >= 1) {
                $D('xvpButton').style.display = 'inline';
            } else {
                $D('xvpButton').style.display = 'none';
                // Close XVP panel if open
                if (UI.xvpOpen === true) {
                    UI.toggleXvpPanel();
                }
            }
        },

        // This resize can not be done until we know from the first Frame Buffer Update
        // if it is supported or not.
        // The resize is needed to make sure the server desktop size is updated to the
        // corresponding size of the current local window when reconnecting to an
        // existing session.
        FBUComplete: function(rfb, fbu) {
            UI.onresize();
            UI.rfb.set_onFBUComplete(function() { });
        },

        // Display the desktop name in the document title
        updateDocumentTitle: function(rfb, name) {
            document.title = name + " - noVNC";
        },

        clipReceive: function(rfb, text) {
            Util.Debug(">> UI.clipReceive: " + text.substr(0,40) + "...");
            $D('noVNC_clipboard_text').value = text;
            Util.Debug("<< UI.clipReceive");
        },

        connect: function() {
            UI.closeSettingsMenu();
            UI.toggleConnectPanel();

            var host = $D('noVNC_host').value;
            var port = $D('noVNC_port').value;
            var password = $D('noVNC_password').value;
            var path = $D('noVNC_path').value;
            if ((!host) || (!port)) {
                throw new Error("Must set host and port");
            }

            UI.rfb.set_encrypt(UI.getSetting('encrypt'));
            UI.rfb.set_true_color(UI.getSetting('true_color'));
            UI.rfb.set_local_cursor(UI.getSetting('cursor'));
            UI.rfb.set_shared(UI.getSetting('shared'));
            UI.rfb.set_view_only(UI.getSetting('view_only'));
            UI.rfb.set_repeaterID(UI.getSetting('repeaterID'));

            UI.rfb.connect(host, port, password, path);

            //Close dialog.
            setTimeout(UI.setBarPosition, 100);
            $D('noVNC_logo').style.display = "none";
        },

        disconnect: function() {
            UI.closeSettingsMenu();
            UI.rfb.disconnect();

            // Restore the callback used for initial resize
            UI.rfb.set_onFBUComplete(UI.FBUComplete);

            $D('noVNC_logo').style.display = "block";
            UI.connSettingsOpen = false;
            UI.toggleConnectPanel();
        },

        displayBlur: function() {
            UI.rfb.get_keyboard().set_focused(false);
            UI.rfb.get_mouse().set_focused(false);
        },

        displayFocus: function() {
            UI.rfb.get_keyboard().set_focused(true);
            UI.rfb.get_mouse().set_focused(true);
        },

        clipClear: function() {
            $D('noVNC_clipboard_text').value = "";
            UI.rfb.clipboardPasteFrom("");
        },

        clipSend: function() {
            var text = $D('noVNC_clipboard_text').value;
            Util.Debug(">> UI.clipSend: " + text.substr(0,40) + "...");
            UI.rfb.clipboardPasteFrom(text);
            Util.Debug("<< UI.clipSend");
        },

        // Enable/disable and configure viewport clipping
        setViewClip: function(clip) {
            var display;
            if (UI.rfb) {
                display = UI.rfb.get_display();
            } else {
                return;
            }

            var cur_clip = display.get_viewport();

            if (typeof(clip) !== 'boolean') {
                // Use current setting
                clip = UI.getSetting('clip');
            }

            if (clip && !cur_clip) {
                // Turn clipping on
                UI.updateSetting('clip', true);
            } else if (!clip && cur_clip) {
                // Turn clipping off
                UI.updateSetting('clip', false);
                display.set_viewport(false);
                $D('noVNC_canvas').style.position = 'static';
                display.viewportChangeSize();
            }
            if (UI.getSetting('clip')) {
                // If clipping, update clipping settings
                $D('noVNC_canvas').style.position = 'absolute';
                var pos = Util.getPosition($D('noVNC_canvas'));
                var new_w = window.innerWidth - pos.x;
                var new_h = window.innerHeight - pos.y;
                display.set_viewport(true);
                display.viewportChangeSize(new_w, new_h);
            }
        },

        // Toggle/set/unset the viewport drag/move button
        setViewDrag: function(drag) {
            if (!UI.rfb) { return; }

            UI.updateViewDragButton();

            if (typeof(drag) === "undefined" ||
                typeof(drag) === "object") {
                // If not specified, then toggle
                drag = !UI.rfb.get_viewportDrag();
            }
            var vmb = $D('noVNC_view_drag_button');
            if (drag) {
                vmb.className = "noVNC_status_button_selected";
                UI.rfb.set_viewportDrag(true);
            } else {
                vmb.className = "noVNC_status_button";
                UI.rfb.set_viewportDrag(false);
            }
        },

        updateViewDragButton: function() {
            var vmb = $D('noVNC_view_drag_button');
            if (UI.rfb_state === 'normal' &&
                UI.rfb.get_display().get_viewport() &&
                UI.rfb.get_display().fbuClip()) {
                vmb.style.display = "inline";
            } else {
                vmb.style.display = "none";
            }
        },

        // On touch devices, show the OS keyboard
        showKeyboard: function() {
            var kbi = $D('keyboardinput');
            var skb = $D('showKeyboard');
            var l = kbi.value.length;
            if(UI.keyboardVisible === false) {
                kbi.focus();
                try { kbi.setSelectionRange(l, l); } // Move the caret to the end
                catch (err) {} // setSelectionRange is undefined in Google Chrome
                UI.keyboardVisible = true;
                skb.className = "noVNC_status_button_selected";
            } else if(UI.keyboardVisible === true) {
                kbi.blur();
                skb.className = "noVNC_status_button";
                UI.keyboardVisible = false;
            }
        },

        keepKeyboard: function() {
            clearTimeout(UI.hideKeyboardTimeout);
            if(UI.keyboardVisible === true) {
                $D('keyboardinput').focus();
                $D('showKeyboard').className = "noVNC_status_button_selected";
            } else if(UI.keyboardVisible === false) {
                $D('keyboardinput').blur();
                $D('showKeyboard').className = "noVNC_status_button";
            }
        },

        keyboardinputReset: function() {
            var kbi = $D('keyboardinput');
            kbi.value = new Array(UI.defaultKeyboardinputLen).join("_");
            UI.lastKeyboardinput = kbi.value;
        },

        // When normal keyboard events are left uncought, use the input events from
        // the keyboardinput element instead and generate the corresponding key events.
        // This code is required since some browsers on Android are inconsistent in
        // sending keyCodes in the normal keyboard events when using on screen keyboards.
        keyInput: function(event) {
            var newValue = event.target.value;
            var oldValue = UI.lastKeyboardinput;

            var newLen;
            try {
                // Try to check caret position since whitespace at the end
                // will not be considered by value.length in some browsers
                newLen = Math.max(event.target.selectionStart, newValue.length);
            } catch (err) {
                // selectionStart is undefined in Google Chrome
                newLen = newValue.length;
            }
            var oldLen = oldValue.length;

            var backspaces;
            var inputs = newLen - oldLen;
            if (inputs < 0) {
                backspaces = -inputs;
            } else {
                backspaces = 0;
            }

            // Compare the old string with the new to account for
            // text-corrections or other input that modify existing text
            var i;
            for (i = 0; i < Math.min(oldLen, newLen); i++) {
                if (newValue.charAt(i) != oldValue.charAt(i)) {
                    inputs = newLen - i;
                    backspaces = oldLen - i;
                    break;
                }
            }

            // Send the key events
            for (i = 0; i < backspaces; i++) {
                UI.rfb.sendKey(XK_BackSpace);
            }
            for (i = newLen - inputs; i < newLen; i++) {
                UI.rfb.sendKey(newValue.charCodeAt(i));
            }

            // Control the text content length in the keyboardinput element
            if (newLen > 2 * UI.defaultKeyboardinputLen) {
                UI.keyboardinputReset();
            } else if (newLen < 1) {
                // There always have to be some text in the keyboardinput
                // element with which backspace can interact.
                UI.keyboardinputReset();
                // This sometimes causes the keyboard to disappear for a second
                // but it is required for the android keyboard to recognize that
                // text has been added to the field
                event.target.blur();
                // This has to be ran outside of the input handler in order to work
                setTimeout(function() { UI.keepKeyboard(); }, 0);
            } else {
                UI.lastKeyboardinput = newValue;
            }
        },

        keyInputBlur: function() {
            $D('showKeyboard').className = "noVNC_status_button";
            //Weird bug in iOS if you change keyboardVisible
            //here it does not actually occur so next time
            //you click keyboard icon it doesnt work.
            UI.hideKeyboardTimeout = setTimeout(function() { UI.setKeyboard(); },100);
        },

        showExtraKeys: function() {
            UI.keepKeyboard();
            if(UI.extraKeysVisible === false) {
                $D('toggleCtrlButton').style.display = "inline";
                $D('toggleAltButton').style.display = "inline";
                $D('sendTabButton').style.display = "inline";
                $D('sendEscButton').style.display = "inline";
                $D('showExtraKeysButton').className = "noVNC_status_button_selected";
                UI.extraKeysVisible = true;
            } else if(UI.extraKeysVisible === true) {
                $D('toggleCtrlButton').style.display = "";
                $D('toggleAltButton').style.display = "";
                $D('sendTabButton').style.display = "";
                $D('sendEscButton').style.display = "";
                $D('showExtraKeysButton').className = "noVNC_status_button";
                UI.extraKeysVisible = false;
            }
        },

        toggleCtrl: function() {
            UI.keepKeyboard();
            if(UI.ctrlOn === false) {
                UI.rfb.sendKey(XK_Control_L, true);
                $D('toggleCtrlButton').className = "noVNC_status_button_selected";
                UI.ctrlOn = true;
            } else if(UI.ctrlOn === true) {
                UI.rfb.sendKey(XK_Control_L, false);
                $D('toggleCtrlButton').className = "noVNC_status_button";
                UI.ctrlOn = false;
            }
        },

        toggleAlt: function() {
            UI.keepKeyboard();
            if(UI.altOn === false) {
                UI.rfb.sendKey(XK_Alt_L, true);
                $D('toggleAltButton').className = "noVNC_status_button_selected";
                UI.altOn = true;
            } else if(UI.altOn === true) {
                UI.rfb.sendKey(XK_Alt_L, false);
                $D('toggleAltButton').className = "noVNC_status_button";
                UI.altOn = false;
            }
        },

        sendTab: function() {
            UI.keepKeyboard();
            UI.rfb.sendKey(XK_Tab);
        },

        sendEsc: function() {
            UI.keepKeyboard();
            UI.rfb.sendKey(XK_Escape);
        },

        setKeyboard: function() {
            UI.keyboardVisible = false;
        },

        // iOS < Version 5 does not support position fixed. Javascript workaround:
        setOnscroll: function() {
            window.onscroll = function() {
                UI.setBarPosition();
            };
        },

        setResize: function () {
            window.onResize = function() {
                UI.setBarPosition();
            };
        },

        //Helper to add options to dropdown.
        addOption: function(selectbox, text, value) {
            var optn = document.createElement("OPTION");
            optn.text = text;
            optn.value = value;
            selectbox.options.add(optn);
        },

        setBarPosition: function() {
            $D('noVNC-control-bar').style.top = (window.pageYOffset) + 'px';
            $D('noVNC_mobile_buttons').style.left = (window.pageXOffset) + 'px';

            var vncwidth = $D('noVNC_screen').style.offsetWidth;
            $D('noVNC-control-bar').style.width = vncwidth + 'px';
        }

    };
})();