menu_button_widget.hpp

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// Copyright Take Vos 2021-2022.
// 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 "../macros.hpp"
#include "abstract_button_widget.hpp"
 
namespace hi { inline namespace v1 {
 
class menu_button_widget final : public abstract_button_widget {
public:
    using super = abstract_button_widget;
    using delegate_type = typename super::delegate_type;
 
    menu_button_widget(
        widget *parent,
        std::shared_ptr<delegate_type> delegate,
        button_widget_attribute auto&&...attributes) noexcept :
        super(parent, std::move(delegate))
    {
        alignment = alignment::middle_flush();
        set_attributes<0>(hi_forward(attributes)...);
    }
 
    template<
        different_from<std::shared_ptr<delegate_type>> Value,
        forward_of<observer<observer_decay_t<Value>>> OnValue,
        button_widget_attribute... Attributes>
    menu_button_widget(widget *parent, Value&& value, OnValue&& on_value, Attributes&&...attributes) noexcept
        requires requires
    {
        make_default_radio_button_delegate(hi_forward(value), hi_forward(on_value));
    } :
        menu_button_widget(
            parent,
            make_default_radio_button_delegate(hi_forward(value), hi_forward(on_value)),
            hi_forward(attributes)...)
    {
    }
 
    [[nodiscard]] box_constraints update_constraints() noexcept override
    {
        _label_constraints = super::update_constraints();
 
        // Make room for button and margin.
        _check_size = {theme().size(), theme().size()};
        _short_cut_size = {theme().size(), theme().size()};
 
        // On left side a check mark, on right side short-cut. Around the label extra margin.
        hilet extra_size = extent2{
            theme().margin<float>() * 4.0f + _check_size.width() + _short_cut_size.width(), theme().margin<float>() * 2.0f};
 
        auto constraints = _label_constraints + extra_size;
        constraints.margins = 0;
        return constraints;
    }
 
    void set_layout(widget_layout const& context) noexcept override
    {
        if (compare_store(_layout, context)) {
            hilet inside_rectangle = context.rectangle() - theme().margin<float>();
 
            if (os_settings::left_to_right()) {
                _check_rectangle = align(inside_rectangle, _check_size, alignment::middle_left());
                _short_cut_rectangle = align(inside_rectangle, _short_cut_size, alignment::middle_right());
                hilet label_rectangle = aarectangle{
                    point2{_check_rectangle.right() + theme().margin<float>(), 0.0f},
                    point2{_short_cut_rectangle.left() - theme().margin<float>(), context.height()}};
                _on_label_shape = _off_label_shape = _other_label_shape =
                    box_shape{_label_constraints, label_rectangle, theme().baseline_adjustment()};
 
            } else {
                _short_cut_rectangle = align(inside_rectangle, _short_cut_size, alignment::middle_left());
                _check_rectangle = align(inside_rectangle, _check_size, alignment::middle_right());
                hilet label_rectangle = aarectangle{
                    point2{_short_cut_rectangle.right() + theme().margin<float>(), 0.0f},
                    point2{_check_rectangle.left() - theme().margin<float>(), context.height()}};
                _on_label_shape = _off_label_shape = _other_label_shape =
                    box_shape{_label_constraints, label_rectangle, theme().baseline_adjustment()};
            }
 
            _check_glyph = find_glyph(elusive_icon::Ok);
            hilet check_glyph_bb = _check_glyph.get_metrics().bounding_rectangle * theme().icon_size();
            _check_glyph_rectangle = align(_check_rectangle, check_glyph_bb, alignment::middle_center());
        }
 
        super::set_layout(context);
    }
 
    void draw(draw_context const& context) noexcept override
    {
        if (*mode > widget_mode::invisible and overlaps(context, layout())) {
            draw_menu_button(context);
            draw_check_mark(context);
            draw_button(context);
        }
    }
 
    [[nodiscard]] bool accepts_keyboard_focus(keyboard_focus_group group) const noexcept override
    {
        return *mode >= widget_mode::partial and to_bool(group & hi::keyboard_focus_group::menu);
    }
 
    bool handle_event(gui_event const& event) noexcept override
    {
        using enum gui_event_type;
 
        switch (event.type()) {
        case gui_menu_next:
            if (*mode >= widget_mode::partial and not is_last(keyboard_focus_group::menu)) {
                process_event(gui_event::window_set_keyboard_target(
                    nullptr, keyboard_focus_group::menu, keyboard_focus_direction::forward));
                return true;
            }
            break;
 
        case gui_menu_prev:
            if (*mode >= widget_mode::partial and not is_first(keyboard_focus_group::menu)) {
                process_event(gui_event::window_set_keyboard_target(
                    nullptr, keyboard_focus_group::menu, keyboard_focus_direction::backward));
                return true;
            }
            break;
 
        case gui_activate:
            if (*mode >= widget_mode::partial) {
                activate();
                process_event(gui_event::window_set_keyboard_target(
                    nullptr, keyboard_focus_group::normal, keyboard_focus_direction::forward));
                process_event(gui_event::window_set_keyboard_target(
                    nullptr, keyboard_focus_group::normal, keyboard_focus_direction::backward));
                return true;
            }
            break;
 
        default:;
        }
 
        return super::handle_event(event);
    }
private:
    box_constraints _label_constraints;
 
    font_book::font_glyph_type _check_glyph;
    extent2 _check_size;
    aarectangle _check_rectangle;
    aarectangle _check_glyph_rectangle;
    extent2 _short_cut_size;
    aarectangle _short_cut_rectangle;
 
    void draw_menu_button(draw_context const& context) noexcept
    {
        hilet border_color = *focus ? focus_color() : color::transparent();
        context.draw_box(
            layout(), layout().rectangle(), background_color(), border_color, theme().border_width(), border_side::inside);
    }
    void draw_check_mark(draw_context const& context) noexcept
    {
        auto state_ = state();
 
        // Checkmark or tristate.
        if (state_ == hi::button_state::on) {
            context.draw_glyph(layout(), translate_z(0.1f) * _check_glyph_rectangle, _check_glyph, accent_color());
        }
    }
};
 
}} // namespace hi::v1