widget.hpp

// Copyright Take Vos 2019-2021.
// 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 "../GUI/theme.hpp"
#include "../GFX/draw_context.hpp"
#include "../GUI/hitbox.hpp"
#include "../GUI/keyboard_focus_direction.hpp"
#include "../GUI/keyboard_focus_group.hpp"
#include "../geometry/extent.hpp"
#include "../geometry/axis_aligned_rectangle.hpp"
#include "../geometry/transform.hpp"
#include "../observable.hpp"
#include "../command.hpp"
#include "../chrono.hpp"
#include <memory>
#include <vector>
#include <string>
 
namespace tt {
class gui_window;
struct mouse_event;
struct keyboard_event;
class font_book;
 
class widget {
public:
    gui_window &window;
 
    widget *const parent;
 
    std::string id;
 
    observable<bool> enabled = true;
 
    observable<bool> visible = true;
 
    float draw_layer;
 
    int semantic_layer;
 
    int logical_layer;
 
    widget(gui_window &window, widget *parent) noexcept;
 
    virtual ~widget();
    widget(const widget &) = delete;
    widget &operator=(const widget &) = delete;
    widget(widget &&) = delete;
    widget &operator=(widget &&) = delete;
 
    virtual void init() noexcept;
 
    virtual void deinit() noexcept;
 
    [[nodiscard]] bool is_gui_thread() const noexcept;
 
    tt::theme const &theme() const noexcept;
 
    tt::font_book &font_book() const noexcept;
 
    [[nodiscard]] virtual float margin() const noexcept;
 
    [[nodiscard]] extent2 minimum_size() const noexcept;
 
    [[nodiscard]] extent2 preferred_size() const noexcept;
 
    [[nodiscard]] extent2 maximum_size() const noexcept;
 
    void set_layout_parameters(
        geo::transformer auto const &local_to_parent,
        extent2 size,
        aarectangle const &clipping_rectangle) noexcept;
 
    void set_layout_parameters_from_parent(
        aarectangle child_rectangle,
        aarectangle parent_clipping_rectangle,
        float draw_layer_delta) noexcept;
 
    void set_layout_parameters_from_parent(aarectangle child_rectangle) noexcept;
 
    [[nodiscard]] matrix3 parent_to_local() const noexcept;
 
    [[nodiscard]] matrix3 local_to_parent() const noexcept;
 
    [[nodiscard]] matrix3 window_to_local() const noexcept;
 
    [[nodiscard]] matrix3 local_to_window() const noexcept;
 
    [[nodiscard]] extent2 size() const noexcept;
 
    [[nodiscard]] float width() const noexcept;
 
    [[nodiscard]] float height() const noexcept;
 
    [[nodiscard]] aarectangle rectangle() const noexcept;
 
    [[nodiscard]] virtual float base_line() const noexcept;
 
    [[nodiscard]] aarectangle clipping_rectangle() const noexcept;
 
    [[nodiscard]] virtual hitbox hitbox_test(point2 position) const noexcept;
 
    [[nodiscard]] virtual bool accepts_keyboard_focus(keyboard_focus_group group) const noexcept
    {
        tt_axiom(is_gui_thread());
        return false;
    }
 
    [[nodiscard]] virtual bool constrain(utc_nanoseconds display_time_point, bool need_reconstrain) noexcept;
 
    [[nodiscard]] virtual void layout(utc_nanoseconds display_time_point, bool need_layout) 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;
 
    virtual void draw(draw_context context, utc_nanoseconds display_time_point) noexcept;
 
    virtual void request_redraw() const noexcept;
 
    [[nodiscard]] virtual bool handle_event(command command) noexcept;
 
    [[nodiscard]] virtual bool handle_event(std::vector<command> const &commands) noexcept;
 
    [[nodiscard]] virtual bool handle_command_recursive(command command, std::vector<widget const *> const &reject_list) noexcept;
 
    [[nodiscard]] virtual bool handle_event(mouse_event const &event) noexcept;
 
    [[nodiscard]] virtual bool handle_event(keyboard_event const &event) 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(tt::rectangle rectangle) noexcept;
 
    [[nodiscard]] std::vector<widget const *> parent_chain() const noexcept;
 
    void clear() noexcept;
 
    widget &add_widget(std::unique_ptr<widget> widget) noexcept;
 
protected:
    std::vector<std::unique_ptr<widget>> _children;
 
    bool _hover = false;
 
    bool _focus = false;
 
    matrix3 _window_to_local;
 
    matrix3 _local_to_window;
 
    matrix3 _parent_to_local;
 
    matrix3 _local_to_parent;
 
    extent2 _size;
 
    aarectangle _clipping_rectangle;
 
    aarectangle _visible_rectangle;
 
    std::atomic<bool> _request_constrain = true;
 
    std::atomic<bool> _request_layout = true;
 
    extent2 _minimum_size;
    extent2 _preferred_size;
    extent2 _maximum_size;
 
    std::shared_ptr<std::function<void()>> _redraw_callback;
    std::shared_ptr<std::function<void()>> _relayout_callback;
    std::shared_ptr<std::function<void()>> _reconstrain_callback;
 
    template<typename T, typename... Args>
    T &make_widget(Args &&...args)
    {
        tt_axiom(is_gui_thread());
        auto tmp = std::make_unique<T>(window, this, std::forward<Args>(args)...);
        tmp->init();
        return static_cast<T &>(add_widget(std::move(tmp)));
    }
 
    [[nodiscard]] aarectangle make_overlay_rectangle(aarectangle requested_rectangle) const noexcept;
};
 
} // namespace tt