toggle_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 "../GUI/module.hpp"
#include "toggle_delegate.hpp"
 
namespace hi { inline namespace v1 {
 
template<typename Context>
concept toggle_widget_attribute = label_widget_attribute<Context>;
 
template<fixed_string Name = "">
class toggle_widget final : public widget {
public:
    using super = widget;
    using delegate_type = toggle_delegate;
    constexpr static auto prefix = Name / "toggle";
 
    std::shared_ptr<delegate_type> delegate;
 
    observer<label> on_label = tr("on");
 
    observer<label> off_label = tr("off");
 
    observer<label> other_label = tr("other");
 
    observer<hi::alignment> alignment = alignment::top_left();
 
    toggle_widget(widget *parent, std::shared_ptr<delegate_type> delegate, toggle_widget_attribute auto&&...attributes) noexcept :
        super(parent), delegate(std::move(delegate))
    {
        hi_assert_not_null(this->delegate);
        this->set_attributes<0>(hi_forward(attributes)...);
 
        _on_label_widget = std::make_unique<label_widget<prefix / "on">>(this, on_label, alignment);
        _off_label_widget = std::make_unique<label_widget<prefix / "off">>(this, off_label, alignment);
        _other_label_widget = std::make_unique<label_widget<prefix / "other">>(this, other_label, alignment);
 
        _grid.add_cell(0, 0, cell_type::button);
        _grid.add_cell(1, 0, cell_type::label);
 
        _delegate_cbt = this->delegate->subscribe([&] {
            ++global_counter<"toggle_widget:delegate:redraw">;
            hi_assert_not_null(this->delegate);
            state = this->delegate->state(this);
 
            _on_label_widget->mode = *state == widget_state::on ? widget_mode::display : widget_mode::invisible;
            _off_label_widget->mode = *state == widget_state::off ? widget_mode::display : widget_mode::invisible;
            _other_label_widget->mode = *state == widget_state::other ? widget_mode::display : widget_mode::invisible;
 
            process_event({gui_event_type::window_redraw});
        });
        this->delegate->init(*this);
        (*_delegate_cbt)();
    }
 
    template<different_from<std::shared_ptr<delegate_type>> Value, toggle_widget_attribute... Attributes>
    toggle_widget(widget *parent, Value&& value, Attributes&&...attributes) noexcept
        requires requires { make_default_toggle_delegate(hi_forward(value)); }
        : toggle_widget(parent, make_default_toggle_delegate(hi_forward(value)), hi_forward(attributes)...)
    {
    }
 
    template<
        different_from<std::shared_ptr<delegate_type>> Value,
        forward_of<observer<observer_decay_t<Value>>> OnValue,
        toggle_widget_attribute... Attributes>
    toggle_widget(widget *parent, Value&& value, OnValue&& on_value, Attributes&&...attributes) noexcept
        requires requires { make_default_toggle_delegate(hi_forward(value), hi_forward(on_value)); }
        : toggle_widget(parent, make_default_toggle_delegate(hi_forward(value), hi_forward(on_value)), hi_forward(attributes)...)
    {
    }
 
    template<
        different_from<std::shared_ptr<delegate_type>> Value,
        forward_of<observer<observer_decay_t<Value>>> OnValue,
        forward_of<observer<observer_decay_t<Value>>> OffValue,
        toggle_widget_attribute... Attributes>
    toggle_widget(widget *parent, Value&& value, OnValue&& on_value, OffValue&& off_value, Attributes&&...attributes) noexcept
        requires requires { make_default_toggle_delegate(hi_forward(value), hi_forward(on_value), hi_forward(off_value)); }
        :
        toggle_widget(
            parent,
            make_default_toggle_delegate(hi_forward(value), hi_forward(on_value), hi_forward(off_value)),
            hi_forward(attributes)...)
    {
    }
 
    [[nodiscard]] box_constraints update_constraints() noexcept override
    {
        for (auto& cell : _grid) {
            if (cell.value == cell_type::button) {
                cell.set_constraints(box_constraints{
                    theme<prefix>.size(this),
                    theme<prefix>.size(this),
                    theme<prefix>.size(this),
                    *alignment,
                    theme<prefix>.margin(this),
                    -vector2::infinity()});
 
            } else if (cell.value == cell_type::label) {
                cell.set_constraints(
                    max(_on_label_widget->update_constraints(),
                        _off_label_widget->update_constraints(),
                        _other_label_widget->update_constraints()));
 
            } else {
                hi_no_default();
            }
        }
 
        return _grid.constraints(os_settings::left_to_right());
    }
 
    void set_layout(widget_layout const& context) noexcept override
    {
        if (compare_store(layout, context)) {
            _grid.set_layout(context.shape, theme<prefix>.cap_height(this));
        }
 
        for (hilet& cell : _grid) {
            if (cell.value == cell_type::button) {
                _button_rectangle = align(cell.shape.rectangle, theme<prefix>.size(this), *alignment);
 
                // The distance between bottom of the 'pip' and bottom of the 'button'
                // is equal to the distance between the left of the 'pip' and
                // the left of the 'button'.
                _pip_edge_distance = (_button_rectangle.height() - theme<prefix / "pip">.height(this)) / 2;
                _pip_move_range = _button_rectangle.width() - _pip_edge_distance * 2 - theme<prefix / "pip">.width(this);
 
            } else if (cell.value == cell_type::label) {
                _on_label_widget->set_layout(context.transform(cell.shape, 0.0f));
                _off_label_widget->set_layout(context.transform(cell.shape, 0.0f));
                _other_label_widget->set_layout(context.transform(cell.shape, 0.0f));
 
            } else {
                hi_no_default();
            }
        }
    }
 
    void draw(widget_draw_context& context) noexcept override
    {
        if (*mode > widget_mode::invisible and overlaps(context, layout)) {
            for (hilet& cell : _grid) {
                if (cell.value == cell_type::button) {
                    draw_button(context, _button_rectangle);
                    draw_pip(context, _button_rectangle);
 
                } else if (cell.value == cell_type::label) {
                    _on_label_widget->draw(context);
                    _off_label_widget->draw(context);
                    _other_label_widget->draw(context);
 
                } else {
                    hi_no_default();
                }
            }
        }
    }
 
    [[nodiscard]] generator<widget const&> children(bool include_invisible) const noexcept override
    {
        co_yield *_on_label_widget;
        co_yield *_off_label_widget;
        co_yield *_other_label_widget;
    }
 
    [[nodiscard]] hitbox hitbox_test(point2 position) const noexcept final
    {
        hi_axiom(loop::main().on_thread());
 
        if (*mode >= widget_mode::partial and layout.contains(position)) {
            return {id, layout.elevation, hitbox_type::button};
        } else {
            return {};
        }
    }
 
    [[nodiscard]] bool accepts_keyboard_focus(keyboard_focus_group group) const noexcept override
    {
        hi_axiom(loop::main().on_thread());
        return *mode >= widget_mode::partial and to_bool(group & hi::keyboard_focus_group::normal);
    }
 
    void activate() noexcept
    {
        hi_assert_not_null(delegate);
        delegate->activate(*this);
        _state_changed();
    }
 
    bool handle_event(gui_event const& event) noexcept override
    {
        hi_axiom(loop::main().on_thread());
 
        switch (event.type()) {
        case gui_event_type::gui_activate:
            if (*mode >= widget_mode::partial) {
                activate();
                return true;
            }
            break;
 
        case gui_event_type::mouse_down:
            if (*mode >= widget_mode::partial and event.mouse().cause.left_button) {
                clicked = true;
                request_redraw();
                return true;
            }
            break;
 
        case gui_event_type::mouse_up:
            if (*mode >= widget_mode::partial and event.mouse().cause.left_button) {
                clicked = false;
 
                if (layout.rectangle().contains(event.mouse().position)) {
                    handle_event(gui_event_type::gui_activate);
                }
                request_redraw();
                return true;
            }
            break;
 
        default:;
        }
 
        return super::handle_event(event);
    }
private:
    enum class cell_type { button, label };
 
    static constexpr std::chrono::nanoseconds _animation_duration = std::chrono::milliseconds(150);
 
    grid_layout<cell_type> _grid;
 
    std::unique_ptr<label_widget<prefix / "on">> _on_label_widget;
    std::unique_ptr<label_widget<prefix / "off">> _off_label_widget;
    std::unique_ptr<label_widget<prefix / "other">> _other_label_widget;
 
    notifier<>::callback_token _delegate_cbt;
 
    aarectangle _button_rectangle;
 
    animator<float> _animated_value = _animation_duration;
    float _pip_move_range;
    float _pip_edge_distance;
 
    void draw_button(widget_draw_context& context, aarectangle shape) noexcept
    {
        context.draw_box(
            layout,
            shape,
            theme<prefix>.background_color(this),
            theme<prefix>.border_color(this),
            theme<prefix>.border_width(this),
            border_side::outside,
            theme<prefix>.border_radius(this));
    }
 
    void draw_pip(widget_draw_context& context, aarectangle shape) noexcept
    {
        _animated_value.update(state != widget_state::off ? 1.0f : 0.0f, context.display_time_point);
        if (_animated_value.is_animating()) {
            request_redraw();
        }
 
        hilet move_offset = [&] {
            if (os_settings::left_to_right()) {
                return _pip_move_range * _animated_value.current_value();
            } else {
                return _pip_move_range * (1.0f - _animated_value.current_value());
            }
        }();
 
        hilet pip_translate = translate3{shape.x() + _pip_edge_distance + move_offset, shape.y() + _pip_edge_distance, 0.1f};
        hilet pip_rectangle = pip_translate *aarectangle{theme<prefix / "pip">.size(this)};
 
        context.draw_box(
            layout,
            pip_rectangle,
            theme<prefix / "pip">.background_color(this),
            theme<prefix / "pip">.border_color(this),
            theme<prefix / "pip">.border_width(this),
            border_side::inside,
            theme<prefix / "pip">.border_radius(this));
    }
 
    template<size_t LabelCount>
    void set_attributes() noexcept
    {
    }
 
    template<size_t LabelCount>
    void set_attributes(toggle_widget_attribute auto&& first, toggle_widget_attribute auto&&...rest) noexcept
    {
        if constexpr (forward_of<decltype(first), observer<hi::label>>) {
            if constexpr (LabelCount == 0) {
                on_label = first;
                off_label = first;
                other_label = hi_forward(first);
            } else if constexpr (LabelCount == 1) {
                other_label.reset();
                off_label.reset();
                off_label = hi_forward(first);
            } else if constexpr (LabelCount == 2) {
                other_label = hi_forward(first);
            } else {
                hi_static_no_default();
            }
            set_attributes<LabelCount + 1>(hi_forward(rest)...);
 
        } else if constexpr (forward_of<decltype(first), observer<hi::alignment>>) {
            alignment = hi_forward(first);
            set_attributes<LabelCount>(hi_forward(rest)...);
 
        } else {
            hi_static_no_default();
        }
    }
};
}} // namespace hi::v1