text: /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
  /* ***** BEGIN LICENSE BLOCK *****
   * Version: MPL 1.1/GPL 2.0/LGPL 2.1
   *
   * The contents of this file are subject to the Mozilla Public License Version
   * 1.1 (the "License"); you may not use this file except in compliance with
   * the License. You may obtain a copy of the License at
   * http://www.mozilla.org/MPL/
   *
   * Software distributed under the License is distributed on an "AS IS" basis,
   * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
   * for the specific language governing rights and limitations under the
   * License.
   *
   * The Original Code is mozilla.org code.
   *
   * The Initial Developer of the Original Code is
   * Netscape Communications Corporation.
   * Portions created by the Initial Developer are Copyright (C) 1998
   * the Initial Developer. All Rights Reserved.
   *
   * Contributor(s):
   *
   * Alternatively, the contents of this file may be used under the terms of
   * either of the GNU General Public License Version 2 or later (the "GPL"),
   * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
   * in which case the provisions of the GPL or the LGPL are applicable instead
   * of those above. If you wish to allow use of your version of this file only
   * under the terms of either the GPL or the LGPL, and not to allow others to
   * use your version of this file under the terms of the MPL, indicate your
   * decision by deleting the provisions above and replace them with the notice
   * and other provisions required by the GPL or the LGPL. If you do not delete
   * the provisions above, a recipient may use your version of this file under
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   *
   * ***** END LICENSE BLOCK ***** */
  
  #ifndef nsIComboboxControlFrame_h___
  #define nsIComboboxControlFrame_h___
  
  #include "nsISupports.h"
  #include "nsFont.h"
  
  class nsPresContext;
  class nsString;
  class nsIContent;
  class nsVoidArray;
  class nsCSSFrameConstructor;
  
  
  // IID for the nsIComboboxControlFrame class
  #define NS_ICOMBOBOXCONTROLFRAME_IID    \
    { 0x23f75e9c, 0x6850, 0x11da, \
        { 0x95, 0x2c, 0x0, 0xe0, 0x81, 0x61, 0x16, 0x5f } }
  
  /** 
    * nsIComboboxControlFrame is the common interface for frames of form controls. It
    * provides a uniform way of creating widgets, resizing, and painting.
    * @see nsLeafFrame and its base classes for more info
    */
  class nsIComboboxControlFrame : public nsISupports {
  
  public:
    NS_DECLARE_STATIC_IID_ACCESSOR(NS_ICOMBOBOXCONTROLFRAME_IID)
  
    /**
     * Indicates whether the list is dropped down
     */
    virtual PRBool IsDroppedDown() = 0;
  
    /**
     * Shows or hides the drop down
     */
    virtual void ShowDropDown(PRBool aDoDropDown) = 0;
  
    /**
     * Gets the Drop Down List
     */
    virtual nsIFrame* GetDropDown() = 0;
  
    /**
     * Sets the Drop Down List
     */
    virtual void SetDropDown(nsIFrame* aDropDownFrame) = 0;
  
    /**
     * Tells the combobox to roll up
     */
    virtual void RollupFromList() = 0;
  
    /**
     * Redisplay the selected text (will do nothing if text has not changed)
     */
    NS_IMETHOD RedisplaySelectedText() = 0;
  
    /**
     * Method for the listbox to set and get the recent index
     */
    virtual PRInt32 UpdateRecentIndex(PRInt32 aIndex) = 0;
  
    /**
     *
     */
    virtual void AbsolutelyPositionDropDown() = 0;
  
    /**
     * Notification that the content has been reset
     */
    virtual void OnContentReset() = 0;
    
    /**
     * This returns the index of the item that is currently being displayed
     * in the display area. It may differ from what the currently Selected index
     * is in in the dropdown.
     *
     * Detailed explanation: 
     * When the dropdown is dropped down via a mouse click and the user moves the mouse 
     * up and down without clicking, the currently selected item is being tracking inside 
     * the dropdown, but the combobox is not being updated. When the user selects items
     * with the arrow keys, the combobox is being updated. So when the user clicks outside
     * the dropdown and it needs to roll up it has to decide whether to keep the current 
     * selection or not. This method is used to get the current index in the combobox to
     * compare it to the current index in the dropdown to see if the combox has been updated
     * and that way it knows whether to "cancel" the current selection residing in the 
     * dropdown. Or whether to leave the selection alone.
     */
    virtual PRInt32 GetIndexOfDisplayArea() = 0;
  };
  
  NS_DEFINE_STATIC_IID_ACCESSOR(nsIComboboxControlFrame,
                                NS_ICOMBOBOXCONTROLFRAME_IID)
  
  #endif
  
  