widget.hpp

#ifndef LIBWTK_SDL2_WIDGET_HPP
#define LIBWTK_SDL2_WIDGET_HPP

#include <memory>
#include <optional>
#include <vector>

#include "context_info.hpp"
#include "draw_context.hpp"
#include "geometry.hpp"
#include "key_event.hpp"
#include "mouse_event.hpp"
#include "navigation_type.hpp"
#include "selection_context.hpp"
#include "swipe.hpp"

struct widget;

typedef std::shared_ptr<widget> widget_ptr;

enum class dirty_type
{
    CLEAN,
    CHILD_DIRTY,
    DIRTY
};

// This will choose the maximum dirty_type that is necessary such that a widget
// tree will be properly drawn.
dirty_type combine(dirty_type a, dirty_type b);

struct size_hint
{
    size_hint(vec min, vec nat);
    size_hint(vec min);

    vec minimal;
    vec natural;
};

struct widget
{

    widget();
    widget(widget const &) = delete;
    widget & operator=(widget const &) = delete;
    virtual ~widget();

    virtual void on_child_dirty(widget * child);

    virtual std::vector<widget *> get_visible_children();
    virtual std::vector<widget const *> get_visible_children() const;

    void clear_dirty();

    void mark_dirty();
    void mark_child_dirty(widget * child);

    void draw(draw_context & dc, selection_context const & sc) const;

    void draw_dirty(draw_context & dc, selection_context const & sc) const;

    virtual void on_draw(draw_context & dc, selection_context const & sc) const = 0;

    virtual void on_mouse_up_event(mouse_up_event const & e);
    virtual void on_mouse_down_event(mouse_down_event const & e);
    virtual void on_mouse_move_event(mouse_move_event const & e);
    virtual void on_key_event(key_event const & e);

    virtual void on_activate();

    SDL_Rect const & get_box() const;

    context_info const & get_context_info() const;

    void set_context_info(context_info const & ci);

    void set_parent(widget * parent);

    virtual std::vector<widget *> get_children();
    virtual std::vector<widget const *> get_children() const;

    void apply_layout(SDL_Rect box);

    virtual void on_box_allocated();

    // TODO change encoding: none(), height(int), width(int)
    virtual size_hint get_size_hint(int width = -1, int height = -1) const = 0;

    virtual bool can_use_intermediate_size() const;

    virtual widget * find_selectable(navigation_type nt, point center);

    virtual widget * navigate_selectable(navigation_type nt, point center);

    virtual widget * navigate_selectable_from_children(navigation_type nt, widget * w, point center);

    virtual void on_select();
    virtual void on_unselect();

    private:

    dirty_type _dirty;

    protected:

    std::optional<swipe_info> get_swipe_info_with_context_info(mouse_up_event const & e);

    widget * navigate_selectable_parent(navigation_type nt, point center);

    widget * _parent;

    private:

    void notify_parent_child_dirty();

    // cached for efficiency, may be replaced by just width and height
    SDL_Rect _box;

    context_info const * _context_info;
};

int opt_min(int opt_length, int length);
int opt_max(int opt_length, int length);
int opt_or_value(int opt_length, int length);
int opt_change(int opt_length, int length);

#endif