/* -*- 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"

interface imgIContainer;
interface nsIURI;
interface nsISVGPaintContext;

/**
 * Starting in Windows 7, applications can display an overlay on the icon in
 * the taskbar. This class wraps around the native functionality to do this.
 */
[scriptable, uuid(b1858889-a698-428a-a14b-b5d60cff6de2)]
interface nsITaskbarOverlayIconController : nsISupports
{
  /**
   * Sets the overlay icon and its corresponding alt text.
   *
   * @param statusIcon The handle to the overlay icon. The icon will be scaled
   *                   to the small icon size (16x16 at 96 dpi). Can be null, in
   *                   which case if the taskbar button represents a single window
   *                   the icon is removed.
   * @param statusDescription The alt text version of the information
   *                          conveyed by the overlay, for accessibility
   *                          purposes.
   * @param paintContext Optional context information used when passing an SVG
   *                     image. This allows the caller to set the context-fill
   *                     and context-stroke properties that would normally
   *                     be provided by CSS.
   *
   * @note The behavior for window groups is managed by Windows.
   * - If an overlay icon is set for any window in a window group and another
   *   overlay icon is already applied to the corresponding taskbar button, that
   *   existing overlay is replaced.
   * - If null is passed in to replace the overlay currently being displayed,
   *   and if a previous overlay set for a different window in the group is
   *   still available, then that previous overlay is displayed.
   */
  void setOverlayIcon(in imgIContainer statusIcon,
                      in AString statusDescription,
                      [optional] in nsISVGPaintContext paintContext);
};