widget/nsIScreen.idl

   1 /* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
   2  *
   3  * This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "nsISupports.idl"
   8
   9 %{C++
  10 /**
  11  * The display type of nsIScreen belongs to.
  12  */
  13 enum class DisplayType: int32_t {
  14   DISPLAY_PRIMARY,  // primary screen
  15   DISPLAY_EXTERNAL, // wired displays, such as HDMI, DisplayPort, etc.
  16   DISPLAY_VIRTUAL   // wireless displays, such as Chromecast, WiFi-Display, etc.
  17 };
  18 %}
  19
  20 [scriptable, uuid(826e80c8-d70f-42e2-8aa9-82c05f2a370a)]
  21 interface nsIScreen : nsISupports
  22 {
  23   /**
  24    * These report screen dimensions in (screen-specific) device pixels
  25    */
  26   void GetRect(out long left, out long top, out long width, out long height);
  27   void GetAvailRect(out long left, out long top, out long width, out long height);
  28
  29   /**
  30    * And these report in desktop pixels
  31    */
  32   void GetRectDisplayPix(out long left, out long top, out long width, out long height);
  33   void GetAvailRectDisplayPix(out long left, out long top, out long width, out long height);
  34
  35   readonly attribute long pixelDepth;
  36   readonly attribute long colorDepth;
  37
  38   /**
  39    * The number of device pixels per desktop pixel for this screen (for
  40    * hidpi configurations where there may be multiple device pixels per
  41    * desktop px and/or per CSS px).
  42    *
  43    * This seems poorly named (something like devicePixelsPerDesktopPixel
  44    * would be more accurate/explicit), but given that it is exposed to
  45    * front-end code and may also be used by add-ons, it's probably not
  46    * worth the disruption of changing it.
  47    *
  48    * Returns 1.0 if HiDPI mode is disabled or unsupported, or if the
  49    * host OS uses device pixels as its desktop pixel units (e.g. Windows 7 or
  50    * GTK/X11). Per-monitor DPI is available in Windows 8.1+, GTK/Wayland or
  51    * macOS.
  52    */
  53   readonly attribute double contentsScaleFactor;
  54
  55   /**
  56    * The default number of device pixels per unscaled CSS pixel for this
  57    * screen. This is probably what contentsScaleFactor originally meant
  58    * to be, prior to confusion between CSS pixels and desktop pixel units.
  59    */
  60   readonly attribute double defaultCSSScaleFactor;
  61
  62   /**
  63    * The DPI of the screen.
  64    */
  65   readonly attribute float dpi;
  66 };