views/controls/scrollbar/native_scroll_bar_win.h

// Copyright (c) 2010 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef VIEWS_CONTROLS_SCROLLBAR_NATIVE_SCROLL_BAR_WIN_H_
#define VIEWS_CONTROLS_SCROLLBAR_NATIVE_SCROLL_BAR_WIN_H_
#pragma once

#include "views/controls/native_control_win.h"
#include "views/controls/scrollbar/native_scroll_bar_wrapper.h"

namespace views {

class ScrollBarContainer;

/////////////////////////////////////////////////////////////////////////////
//
// NativeScrollBarWin
//
// A View subclass that wraps a Native Windows scrollbar control.
//
// A scrollbar is either horizontal or vertical.
//
/////////////////////////////////////////////////////////////////////////////
class NativeScrollBarWin : public NativeControlWin,
                           public NativeScrollBarWrapper {
 public:
  // Create new scrollbar, either horizontal or vertical.
  explicit NativeScrollBarWin(NativeScrollBar* native_scroll_bar);
  virtual ~NativeScrollBarWin();

 private:
  // Overridden from View for layout purpose.
  virtual void Layout();
  virtual gfx::Size GetPreferredSize();

  // Overridden from View for keyboard UI purpose.
  virtual bool OnKeyPressed(const KeyEvent& event);
  virtual bool OnMouseWheel(const MouseWheelEvent& e);

  // Overridden from NativeControlWin.
  virtual void CreateNativeControl();

  // Overridden from ScrollBarWrapper.
  virtual int GetPosition() const;
  virtual View* GetView();
  virtual void Update(int viewport_size, int content_size, int current_pos);

  // The NativeScrollBar we are bound to.
  NativeScrollBar* native_scroll_bar_;

  // sb_container_ is a custom hwnd that we use to wrap the real
  // windows scrollbar. We need to do this to get the scroll events
  // without having to do anything special in the high level hwnd.
  scoped_ptr<ScrollBarContainer> sb_container_;

  // Last scrollbar state we wrote to the scrollbar. We keep it here, so we can
  // reinitialize the scrollbar to its previous state in case it gets hidden and
  // recreated.
  SCROLLINFO scroll_info_;

  DISALLOW_COPY_AND_ASSIGN(NativeScrollBarWin);
};

}  // namespace views

#endif  // #ifndef VIEWS_CONTROLS_SCROLLBAR_NATIVE_SCROLL_BAR_WIN_H_