chrome/browser/ui/views/frame/minimize_button_metrics_win.h

   1 // Copyright (c) 2012 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 CHROME_BROWSER_UI_VIEWS_FRAME_MINIMIZE_BUTTON_METRICS_WIN_H_
   6 #define CHROME_BROWSER_UI_VIEWS_FRAME_MINIMIZE_BUTTON_METRICS_WIN_H_
   7
   8 #include <windows.h>
   9
  10 #include "base/basictypes.h"
  11
  12 // Class that implements obtaining the X coordinate of the native minimize
  13 // button for the native frame on Windows.
  14 // This is a separate class because obtaining it is somewhat tricky and this
  15 // code is shared between BrowserDesktopWindowTreeHostWin and BrowserFrameWin.
  16 class MinimizeButtonMetrics {
  17  public:
  18   MinimizeButtonMetrics();
  19   ~MinimizeButtonMetrics();
  20
  21   void Init(HWND hwnd);
  22
  23   // Obtain the X offset of the native minimize button. Since Windows can lie
  24   // to us if we call this at the wrong moment, this might come from a cached
  25   // value rather than read when called.
  26   int GetMinimizeButtonOffsetX() const;
  27
  28   // Must be called when hwnd_ is activated to update the minimize button
  29   // position cache.
  30   void OnHWNDActivated();
  31
  32  private:
  33   // Gets the value for GetMinimizeButtonOffsetX(), caching if found.
  34   int GetAndCacheMinimizeButtonOffsetX() const;
  35
  36   HWND hwnd_;
  37
  38   // Cached offset of the minimize button. If RTL this is the location of the
  39   // minimize button, if LTR this is the offset from the right edge of the
  40   // client area to the minimize button.
  41   mutable int cached_minimize_button_x_delta_;
  42
  43   // Static cache of |cached_minimize_button_x_delta_|.
  44   static int last_cached_minimize_button_x_delta_;
  45
  46   // Has OnHWNDActivated() been invoked?
  47   bool was_activated_;
  48
  49   DISALLOW_COPY_AND_ASSIGN(MinimizeButtonMetrics);
  50 };
  51
  52 #endif  // CHROME_BROWSER_UI_VIEWS_FRAME_MINIMIZE_BUTTON_METRICS_WIN_H_