ui/base/win/mouse_wheel_util.h

   1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef UI_BASE_WIN_MOUSE_WHEEL_UTIL_H_
   6 #define UI_BASE_WIN_MOUSE_WHEEL_UTIL_H_
   7
   8 #include <windows.h>
   9
  10 #include "ui/base/ui_base_export.h"
  11
  12 namespace ui {
  13
  14 class ViewProp;
  15
  16 // Marks the passed |hwnd| as supporting mouse-wheel message rerouting.
  17 // We reroute the mouse wheel messages to such HWND when they are under the
  18 // mouse pointer (but are not the active window). Callers own the returned
  19 // object.
  20 UI_BASE_EXPORT ViewProp* SetWindowSupportsRerouteMouseWheel(HWND hwnd);
  21
  22 // Forwards mouse wheel messages to the window under it.
  23 // Windows sends mouse wheel messages to the currently active window.
  24 // This causes a window to scroll even if it is not currently under the mouse
  25 // wheel. The following code gives mouse wheel messages to the window under the
  26 // mouse wheel in order to scroll that window. This is arguably a better user
  27 // experience.  The returns value says whether the mouse wheel message was
  28 // successfully redirected.
  29 UI_BASE_EXPORT bool RerouteMouseWheel(HWND window,
  30                                       WPARAM w_param,
  31                                       LPARAM l_param);
  32
  33 }  // namespace ui
  34
  35 #endif  // UI_BASE_WIN_MOUSE_WHEEL_UTIL_H_