core/util/browser.js

   1 /*
   2  * noVNC: HTML5 VNC client
   3  * Copyright (C) 2019 The noVNC Authors
   4  * Licensed under MPL 2.0 (see LICENSE.txt)
   5  *
   6  * See README.md for usage and integration instructions.
   7  *
   8  * Browser feature support detection
   9  */
  10
  11 import * as Log from './logging.js';
  12
  13 // Touch detection
  14 export let isTouchDevice = ('ontouchstart' in document.documentElement) ||
  15                                  // requried for Chrome debugger
  16                                  (document.ontouchstart !== undefined) ||
  17                                  // required for MS Surface
  18                                  (navigator.maxTouchPoints > 0) ||
  19                                  (navigator.msMaxTouchPoints > 0);
  20 window.addEventListener('touchstart', function onFirstTouch() {
  21     isTouchDevice = true;
  22     window.removeEventListener('touchstart', onFirstTouch, false);
  23 }, false);
  24
  25
  26 // The goal is to find a certain physical width, the devicePixelRatio
  27 // brings us a bit closer but is not optimal.
  28 export let dragThreshold = 10 * (window.devicePixelRatio || 1);
  29
  30 let _supportsCursorURIs = false;
  31
  32 try {
  33     const target = document.createElement('canvas');
  34     target.style.cursor = 'url("data:image/x-icon;base64,AAACAAEACAgAAAIAAgA4AQAAFgAAACgAAAAIAAAAEAAAAAEAIAAAAAAAEAAAAAAAAAAAAAAAAAAAAAAAAAD/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////AAAAAAAAAAAAAAAAAAAAAA==") 2 2, default';
  35
  36     if (target.style.cursor.indexOf("url") === 0) {
  37         Log.Info("Data URI scheme cursor supported");
  38         _supportsCursorURIs = true;
  39     } else {
  40         Log.Warn("Data URI scheme cursor not supported");
  41     }
  42 } catch (exc) {
  43     Log.Error("Data URI scheme cursor test exception: " + exc);
  44 }
  45
  46 export const supportsCursorURIs = _supportsCursorURIs;
  47
  48 let _supportsImageMetadata = false;
  49 try {
  50     new ImageData(new Uint8ClampedArray(4), 1, 1);
  51     _supportsImageMetadata = true;
  52 } catch (ex) {
  53     // ignore failure
  54 }
  55 export const supportsImageMetadata = _supportsImageMetadata;
  56
  57 let _hasScrollbarGutter = true;
  58 try {
  59     // Create invisible container
  60     const container = document.createElement('div');
  61     container.style.visibility = 'hidden';
  62     container.style.overflow = 'scroll'; // forcing scrollbars
  63     document.body.appendChild(container);
  64
  65     // Create a div and place it in the container
  66     const child = document.createElement('div');
  67     container.appendChild(child);
  68
  69     // Calculate the difference between the container's full width
  70     // and the child's width - the difference is the scrollbars
  71     const scrollbarWidth = (container.offsetWidth - child.offsetWidth);
  72
  73     // Clean up
  74     container.parentNode.removeChild(container);
  75
  76     _hasScrollbarGutter = scrollbarWidth != 0;
  77 } catch (exc) {
  78     Log.Error("Scrollbar test exception: " + exc);
  79 }
  80 export const hasScrollbarGutter = _hasScrollbarGutter;
  81
  82 /*
  83  * The functions for detection of platforms and browsers below are exported
  84  * but the use of these should be minimized as much as possible.
  85  *
  86  * It's better to use feature detection than platform detection.
  87  */
  88
  89 export function isMac() {
  90     return navigator && !!(/mac/i).exec(navigator.platform);
  91 }
  92
  93 export function isWindows() {
  94     return navigator && !!(/win/i).exec(navigator.platform);
  95 }
  96
  97 export function isIOS() {
  98     return navigator &&
  99            (!!(/ipad/i).exec(navigator.platform) ||
 100             !!(/iphone/i).exec(navigator.platform) ||
 101             !!(/ipod/i).exec(navigator.platform));
 102 }
 103
 104 export function isSafari() {
 105     return navigator && (navigator.userAgent.indexOf('Safari') !== -1 &&
 106                          navigator.userAgent.indexOf('Chrome') === -1);
 107 }
 108
 109 export function isIE() {
 110     return navigator && !!(/trident/i).exec(navigator.userAgent);
 111 }
 112
 113 export function isEdge() {
 114     return navigator && !!(/edge/i).exec(navigator.userAgent);
 115 }
 116
 117 export function isFirefox() {
 118     return navigator && !!(/firefox/i).exec(navigator.userAgent);
 119 }
 120