layout/base/nsIReflowCallback.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5 #ifndef nsIReflowCallback_h___
   6 #define nsIReflowCallback_h___
   7
   8 /**
   9  * Reflow callback interface.
  10  * These are not refcounted. Objects must be removed from the presshell
  11  * callback list before they die.
  12  * Protocol: objects will either get a ReflowFinished() call when a reflow
  13  * has finished or a ReflowCallbackCanceled() call if the shell is destroyed,
  14  * whichever happens first. If the object is explicitly removed from the shell
  15  * (using nsIPresShell::CancelReflowCallback()) before that occurs then neither
  16  * of the callback methods are called.
  17  */
  18 class nsIReflowCallback {
  19 public:
  20   /**
  21    * The presshell calls this when reflow has finished. Return true if
  22    * you need a Flush_Layout to happen after this.
  23    */
  24   virtual bool ReflowFinished() = 0;
  25   /**
  26    * The presshell calls this on outstanding callback requests in its
  27    * Destroy() method. The shell removes the request after calling
  28    * ReflowCallbackCanceled().
  29    */
  30   virtual void ReflowCallbackCanceled() = 0;
  31 };
  32
  33 #endif /* nsIReflowCallback_h___ */