ui/views/controls/scrollbar/native_scroll_bar_wrapper.h

// Copyright (c) 2011 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 UI_VIEWS_CONTROLS_SCROLLBAR_NATIVE_SCROLL_BAR_WRAPPER_H_
#define UI_VIEWS_CONTROLS_SCROLLBAR_NATIVE_SCROLL_BAR_WRAPPER_H_

#include "ui/views/views_export.h"

namespace ui {
class NativeTheme;
}

namespace views {

class NativeScrollBar;
class View;

// A specialization of NativeControlWrapper that hosts a platform-native
// scroll bar.
class VIEWS_EXPORT NativeScrollBarWrapper {
 public:
  virtual ~NativeScrollBarWrapper() {}

  // Updates the scroll bar appearance given a viewport size, content size and
  // current position.
  virtual void Update(int viewport_size, int content_size, int current_pos) = 0;

  // Retrieves the views::View that hosts the native control.
  virtual View* GetView() = 0;

  // Returns the position of the scrollbar.
  virtual int GetPosition() const = 0;

  // Creates an appropriate NativeScrollBarWrapper for the platform.
  static NativeScrollBarWrapper* CreateWrapper(NativeScrollBar* button);

  // Returns the system sizes of vertical/horizontal scroll bars.
  static int GetVerticalScrollBarWidth(const ui::NativeTheme* theme);
  static int GetHorizontalScrollBarHeight(const ui::NativeTheme* theme);
};

}  // namespace views

#endif  // UI_VIEWS_CONTROLS_SCROLLBAR_NATIVE_SCROLL_BAR_WRAPPER_H_