slider.hpp

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/*
   Copyright (C) 2008 - 2016 by Mark de Wever <[email protected]>
   Part of the Battle for Wesnoth Project http://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.
*/

#ifndef GUI_WIDGETS_SLIDER_HPP_INCLUDED
#define GUI_WIDGETS_SLIDER_HPP_INCLUDED

#include "gui/widgets/integer_selector.hpp"
#include "gui/widgets/scrollbar.hpp"

#include "gui/core/widget_definition.hpp"
#include "gui/core/window_builder.hpp"

namespace gui2
{

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

/** A slider. */
class tslider : public tscrollbar_, public tinteger_selector_
{
public:
    tslider();

    /***** ***** ***** ***** layout functions ***** ***** ***** *****/

private:
    /** See @ref twidget::calculate_best_size. */
    virtual tpoint calculate_best_size() const override;

public:
    /***** ***** ***** ***** Inherited ***** ***** ***** *****/

    /** Inherited from tinteger_selector_. */
    void set_value(const int value);

    /** Inherited from tinteger_selector_. */
    int get_value() const
    {
        return minimum_value_ + get_item_position() * get_step_size();
    }

    /** Inherited from tinteger_selector_. */
    void set_minimum_value(const int minimum_value);

    /** Inherited from tinteger_selector_. */
    int get_minimum_value() const
    {
        return minimum_value_;
    }

    /** Inherited from tinteger_selector_. */
    void set_maximum_value(const int maximum_value);

    /** Inherited from tinteger_selector_. */
    int get_maximum_value() const
    // The number of items needs to include the begin and end so count - 1.
    {
        return minimum_value_ + get_item_count() - 1;
    }
    typedef std::function<t_string(int /*current position*/, int /*num positions*/)> tlabel_creator;
    /***** ***** ***** setters / getters for members ***** ****** *****/

    void set_best_slider_length(const unsigned length)
    {
        best_slider_length_ = length;
        set_is_dirty(true);
    }

    void set_minimum_value_label(const t_string& minimum_value_label)
    {
        minimum_value_label_ = minimum_value_label;
    }

    void set_maximum_value_label(const t_string& maximum_value_label)
    {
        maximum_value_label_ = maximum_value_label;
    }

    void set_value_labels(const std::vector<t_string>& value_labels);

    void set_value_labels(const tlabel_creator& value_labels)
    {
        value_labels_ = value_labels;
    }

    /**
     * Returns the label shown for the current value.
     *
     * @returns                   The label for the current value, if no label
     *                            for the current label is defined, it returns
     *                            the result of get_value().
     */
    t_string get_value_label() const;

protected:
    /** Inherited from tscrollbar. */
    void child_callback_positioner_moved();

private:
    /** The best size for the slider part itself, if 0 ignored. */
    unsigned best_slider_length_;

    /**
     * The minimum value the slider holds.
     *
     * The maximum value is minimum + item_count_.
     * The current value is minimum + item_position_.
     */
    int minimum_value_;

    /** Inherited from tscrollbar. */
    unsigned get_length() const
    {
        return get_width();
    }

    /** Inherited from tscrollbar. */
    unsigned minimum_positioner_length() const;

    /** Inherited from tscrollbar. */
    unsigned maximum_positioner_length() const;

    /** Inherited from tscrollbar. */
    unsigned offset_before() const;

    /** Inherited from tscrollbar. */
    unsigned offset_after() const;

    /** Inherited from tscrollbar. */
    bool on_positioner(const tpoint& coordinate) const;

    /** Inherited from tscrollbar. */
    int on_bar(const tpoint& coordinate) const;

    /** Inherited from tscrollbar. */
    bool in_orthogonal_range(const tpoint& coordinate) const;

    /** Inherited from tscrollbar. */
    int get_length_difference(const tpoint& original, const tpoint& current)
            const
    {
        return current.x - original.x;
    }

    /** See @ref tcontrol::update_canvas. */
    virtual void update_canvas() override;

    /**
     * When the slider shows the minimum value can show a special text.
     * If this text is not empty this text is shown else the minimum value.
     */
    t_string minimum_value_label_;

    /**
     * When the slider shows the maximum value can show a special text.
     * If this text is not empty this text is shown else the maximum value.
     */
    t_string maximum_value_label_;

    /**
     * This allows the slider to show custom texts instead of the values.
     * This vector should have the same amount of items as options for the
     * sliders. When set these texts are shown instead of the values. It also
     * overrides minimum_value_label_ and maximum_value_label_.
     */
    tlabel_creator value_labels_;

    /** See @ref tcontrol::get_control_type. */
    virtual const std::string& get_control_type() const override;

    /**
     * Handlers for keyboard input
     */
    void handle_key_decrease(bool& handled);
    void handle_key_increase(bool& handled);

    /**
     * Signal handlers:
     */
    void signal_handler_sdl_key_down(const event::tevent event,
                                     bool& handled,
                                     const SDLKey key);

    // In this subclass, only used to grab keyboard focus -
    // see tscrollbar class for more handling of this event.
    void signal_handler_left_button_up(const event::tevent event,
                                       bool& handled);
};

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

struct tslider_definition : public tcontrol_definition
{
    explicit tslider_definition(const config& cfg);

    struct tresolution : public tresolution_definition_
    {
        explicit tresolution(const config& cfg);

        unsigned minimum_positioner_length;
        unsigned maximum_positioner_length;

        unsigned left_offset;
        unsigned right_offset;
    };
};

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

namespace implementation
{

struct tbuilder_slider : public tbuilder_control
{
    explicit tbuilder_slider(const config& cfg);

    using tbuilder_control::build;

    twidget* build() const;

private:
    unsigned best_slider_length_;
    int minimum_value_;
    int maximum_value_;
    unsigned step_size_;
    int value_;

    t_string minimum_value_label_;
    t_string maximum_value_label_;

    std::vector<t_string> value_labels_;
};

} // namespace implementation

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

} // namespace gui2

#endif