scroll_bar.h

// Aseprite UI Library
// Copyright (C) 2001-2017  David Capello
//
// This file is released under the terms of the MIT license.
// Read LICENSE.txt for more information.

#ifndef UI_SCROLL_BAR_H_INCLUDED
#define UI_SCROLL_BAR_H_INCLUDED
#pragma once

#include "ui/widget.h"

namespace ui {

  class ScrollableViewDelegate {
  public:
    virtual ~ScrollableViewDelegate() { }
    virtual gfx::Size visibleSize() const = 0;
    virtual gfx::Point viewScroll() const = 0;
    virtual void setViewScroll(const gfx::Point& pt) = 0;
  };

  class ScrollBar : public Widget {
  public:
    ScrollBar(int align, ScrollableViewDelegate* delegate);

    Style* thumbStyle() { return m_thumbStyle; }
    void setThumbStyle(Style* style) { m_thumbStyle = style; }

    int getBarWidth() const { return m_barWidth; }
    void setBarWidth(int barWidth) { m_barWidth = barWidth; }

    int getPos() const { return m_pos; }
    void setPos(int pos);

    int size() const { return m_size; }
    void setSize(int size);

    // For themes
    void getScrollBarThemeInfo(int* pos, int* len);

  protected:
    // Events
    bool onProcessMessage(Message* msg) override;
    void onPaint(PaintEvent& ev) override;

  private:
    void getScrollBarInfo(int* _pos, int* _len, int* _bar_size, int* _viewport_size);

    ScrollableViewDelegate* m_delegate;
    Style* m_thumbStyle;
    int m_barWidth;
    int m_pos;
    int m_size;

    static int m_wherepos;
    static int m_whereclick;
  };

} // namespace ui

#endif