vertical_scrollbar.hpp

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/*
    Copyright (C) 2008 - 2022
    by Mark de Wever <koraq@xs4all.nl>
    Part of the Battle for Wesnoth Project https://www.wesnoth.org/

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY.

    See the COPYING file for more details.
*/

#pragma once

#include "gui/widgets/scrollbar.hpp"

namespace gui2
{
namespace implementation
{
struct builder_vertical_scrollbar;
}

// ------------ WIDGET -----------{

/**
 * @ingroup GUIWidgetWML
 *
 * The definition of a vertical scrollbar.
 * This class is most of the time not used directly.
 * Instead it's used to build other items with scrollbars.
 *
 * The resolution for a vertical scrollbar also contains the following keys:
 * Key                      |Type                                |Default  |Description
 * -------------------------|------------------------------------|---------|-------------
 * minimum_positioner_length| @ref guivartype_unsigned "unsigned"|mandatory|The minimum size the positioner is allowed to be. The engine needs to know this in order to calculate the best size for the positioner.
 * maximum_positioner_length| @ref guivartype_unsigned "unsigned"|0        |The maximum size the positioner is allowed to be. If minimum and maximum are the same value the positioner is fixed size. If the maximum is 0 (and the minimum not) there's no maximum.
 * top_offset               | @ref guivartype_unsigned "unsigned"|0        |The number of pixels at the top which can't be used by the positioner.
 * bottom_offset            | @ref guivartype_unsigned "unsigned"|0        |The number of pixels at the bottom which can't be used by the positioner.
 * The following states exist:
 * * state_enabled - the vertical scrollbar is enabled.
 * * state_disabled - the vertical scrollbar is disabled.
 * * state_pressed - the left mouse button is down on the positioner of the vertical scrollbar.
 * * state_focussed - the mouse is over the positioner of the vertical scrollbar.
 */
class vertical_scrollbar : public scrollbar_base
{
    friend struct implementation::builder_vertical_scrollbar;

public:
    explicit vertical_scrollbar(const implementation::builder_vertical_scrollbar& builder);

private:
    /** Inherited from scrollbar_base. */
    virtual unsigned get_length() const override
    {
        return get_height();
    }

    /** Inherited from scrollbar_base. */
    virtual unsigned minimum_positioner_length() const override;

    /** Inherited from scrollbar_base. */
    virtual unsigned maximum_positioner_length() const override;

    /** Inherited from scrollbar_base. */
    virtual unsigned offset_before() const override;

    /** Inherited from scrollbar_base. */
    virtual unsigned offset_after() const override;

    /** Inherited from scrollbar_base. */
    virtual bool on_positioner(const point& coordinate) const override;

    /** Inherited from scrollbar_base. */
    virtual int on_bar(const point& coordinate) const override;

    /** Inherited from scrollbar_base. */
    virtual bool in_orthogonal_range(const point& coordinate) const override;

    /** Inherited from scrollbar_base. */
    virtual int get_length_difference(const point& original, const point& current) const override
    {
        return current.y - original.y;
    }

public:
    /** Static type getter that does not rely on the widget being constructed. */
    static const std::string& type();

private:
    /** Inherited from styled_widget, implemented by REGISTER_WIDGET. */
    virtual const std::string& get_control_type() const override;
};

// }---------- DEFINITION ---------{

struct vertical_scrollbar_definition : public styled_widget_definition
{
    explicit vertical_scrollbar_definition(const config& cfg);

    struct resolution : public resolution_definition
    {
        explicit resolution(const config& cfg);

        unsigned minimum_positioner_length;
        unsigned maximum_positioner_length;

        unsigned top_offset;
        unsigned bottom_offset;
    };
};

// }---------- BUILDER -----------{

namespace implementation
{

struct builder_vertical_scrollbar : public builder_styled_widget
{
    explicit builder_vertical_scrollbar(const config& cfg);

    using builder_styled_widget::build;

    virtual std::unique_ptr<widget> build() const override;
};

} // namespace implementation

// }------------ END --------------

} // namespace gui2