widget.hpp

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// Copyright Take Vos 2019-2022.
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at https://www.boost.org/LICENSE_1_0.txt)
 
#pragma once
 
#include "../GFX/draw_context.hpp"
#include "../GUI/theme.hpp"
#include "../GUI/hitbox.hpp"
#include "../GUI/keyboard_focus_direction.hpp"
#include "../GUI/keyboard_focus_group.hpp"
#include "../GUI/gui_event.hpp"
#include "../geometry/extent.hpp"
#include "../geometry/axis_aligned_rectangle.hpp"
#include "../geometry/transform.hpp"
#include "../observer.hpp"
#include "../chrono.hpp"
#include "../generator.hpp"
#include "set_constraints_context.hpp"
#include "widget_constraints.hpp"
#include "widget_layout.hpp"
#include "widget_mode.hpp"
#include <memory>
#include <vector>
#include <string>
#include <ranges>
 
namespace hi { inline namespace v1 {
class gui_window;
class font_book;
 
class widget {
public:
    widget *parent;
 
    std::string id;
 
    observer<widget_mode> mode = widget_mode::enabled;
 
    observer<bool> hover = false;
 
    observer<bool> focus = false;
 
    int semantic_layer;
 
    int logical_layer;
 
    widget(widget *parent) noexcept;
 
    virtual ~widget();
    widget(const widget&) = delete;
    widget& operator=(const widget&) = delete;
    widget(widget&&) = delete;
    widget& operator=(widget&&) = delete;
 
    [[nodiscard]] virtual hitbox hitbox_test(point3 position) const noexcept
    {
        return {};
    }
 
    [[nodiscard]] virtual hitbox hitbox_test_from_parent(point3 position) const noexcept
    {
        return hitbox_test(_layout.from_parent * position);
    }
 
    [[nodiscard]] virtual hitbox hitbox_test_from_parent(point3 position, hitbox sibling_hitbox) const noexcept
    {
        return std::max(sibling_hitbox, hitbox_test(_layout.from_parent * position));
    }
 
    [[nodiscard]] virtual bool accepts_keyboard_focus(keyboard_focus_group group) const noexcept
    {
        hi_axiom(loop::main().on_thread());
        return false;
    }
 
    virtual widget_constraints const& set_constraints(set_constraints_context const& context) noexcept = 0;
 
    widget_constraints const& constraints() const noexcept
    {
        return _constraints;
    }
 
    virtual void set_layout(widget_layout const& context) noexcept = 0;
 
    widget_layout const& layout() const noexcept
    {
        return _layout;
    }
 
    virtual void draw(draw_context const& context) noexcept = 0;
 
    virtual bool process_event(gui_event const& event) const noexcept
    {
        if (parent != nullptr) {
            return parent->process_event(event);
        } else {
            return true;
        }
    }
 
    void request_redraw() const noexcept
    {
        process_event({gui_event_type::window_redraw, layout().clipping_rectangle_on_window()});
    }
 
    virtual bool handle_event(gui_event const& event) noexcept;
 
    virtual bool handle_event_recursive(
        gui_event const& event,
        std::vector<widget const *> const& reject_list = std::vector<widget const *>{}) noexcept;
 
    [[nodiscard]] virtual widget const *find_next_widget(
        widget const *current_keyboard_widget,
        keyboard_focus_group group,
        keyboard_focus_direction direction) const noexcept;
 
    [[nodiscard]] widget const *find_first_widget(keyboard_focus_group group) const noexcept;
 
    [[nodiscard]] widget const *find_last_widget(keyboard_focus_group group) const noexcept;
 
    [[nodiscard]] bool is_first(keyboard_focus_group group) const noexcept;
 
    [[nodiscard]] bool is_last(keyboard_focus_group group) const noexcept;
 
    virtual void scroll_to_show(hi::aarectangle rectangle) noexcept;
 
    void scroll_to_show() noexcept
    {
        scroll_to_show(layout().rectangle());
    }
 
    [[nodiscard]] std::vector<widget const *> parent_chain() const noexcept;
 
    virtual [[nodiscard]] color background_color() const noexcept;
 
    virtual [[nodiscard]] color foreground_color() const noexcept;
 
    virtual [[nodiscard]] color focus_color() const noexcept;
 
    virtual [[nodiscard]] color accent_color() const noexcept;
 
    virtual [[nodiscard]] color label_color() const noexcept;
 
protected:
    widget_constraints _constraints;
    widget_layout _layout;
 
    decltype(mode)::callback_token _mode_cbt;
 
    [[nodiscard]] virtual generator<widget *> children() const noexcept
    {
        co_return;
    }
 
    [[nodiscard]] aarectangle make_overlay_rectangle(aarectangle requested_rectangle) const noexcept;
};
}} // namespace hi::v1