/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "nsISupports.idl"
#include "nsIScreen.idl"

[scriptable, uuid(1C195990-FF9E-412B-AFE7-67D1C660BB27)]
interface nsIScreenManager : nsISupports
{
    //
    // Returns the screen that contains the rectangle. If the rect overlaps
    // multiple screens, it picks the screen with the greatest area of intersection.
    //
    // The coordinates are in pixels (not twips) and in screen coordinates.
    //
  nsIScreen screenForRect ( in long left, in long top, in long width, in long height ) ;
  
    // The screen with the menubar/taskbar. This shouldn't be needed very
    // often.
  readonly attribute nsIScreen primaryScreen;
  
    // Holds the number of screens that are available
  readonly attribute unsigned long numberOfScreens;

    // The default DPI scaling factor of the screen environment (number of
    // screen pixels corresponding to 1 CSS px, at the default zoom level).
    //
    // This is currently fixed at 1.0 on most platforms, but varies on Windows
    // if the "logical DPI" scaling option in the Display control panel is set
    // to a value other than 100% (e.g. 125% or 150% are increasingly common
    // defaults on laptops with high-dpi screens). See bug 851520.
    //
    // NOTE that on OS X, this does -not- reflect the "backing scale factor"
    // used to support Retina displays, which is a per-display property,
    // not a system-wide scaling factor. The default ratio of CSS pixels to
    // Cocoa points remains 1:1, even on a Retina screen where one Cocoa point
    // corresponds to two device pixels. (This is exposed via other APIs:
    // see window.devicePixelRatio).
    //
    // NOTE also that on Linux, this does -not- currently reflect changes
    // to the system-wide (X11 or Gtk2) DPI value, as Firefox does not yet
    // honor these settings. See bug 798362 and bug 712898.
  readonly attribute float systemDefaultScale;

    // Returns the nsIScreen instance for the given native widget pointer;
    // the pointer is specific to the particular widget implementation,
    // and is generally of the same type that NS_NATIVE_WINDOW is.
  [noscript] nsIScreen screenForNativeWidget ( in voidPtr nativeWidget );
};


%{ C++

%}