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 "abstract_button_widget.hpp"
#include "../macros.hpp"
 
namespace hi { inline namespace v1 {
 
class toggle_widget final : public abstract_button_widget {
public:
    using super = abstract_button_widget;
    using delegate_type = typename super::delegate_type;
 
    toggle_widget(
        widget *parent,
        std::shared_ptr<delegate_type> delegate,
        button_widget_attribute auto&&...attributes) noexcept :
        super(parent, std::move(delegate))
    {
        alignment = alignment::top_left();
        set_attributes<0>(hi_forward(attributes)...);
    }
 
    template<different_from<std::shared_ptr<delegate_type>> Value, button_widget_attribute... Attributes>
    toggle_widget(widget *parent, Value&& value, Attributes&&...attributes) noexcept requires requires
    {
        make_default_toggle_button_delegate(hi_forward(value));
    } : toggle_widget(parent, make_default_toggle_button_delegate(hi_forward(value)), hi_forward(attributes)...) {}
 
    template<
        different_from<std::shared_ptr<delegate_type>> Value,
        forward_of<observer<observer_decay_t<Value>>> OnValue,
        button_widget_attribute... Attributes>
    toggle_widget(widget *parent, Value&& value, OnValue&& on_value, Attributes&&...attributes) noexcept
        requires requires
    {
        make_default_toggle_button_delegate(hi_forward(value), hi_forward(on_value));
    } :
        toggle_widget(
            parent,
            make_default_toggle_button_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,
        button_widget_attribute... Attributes>
    toggle_widget(
        widget *parent,
        Value&& value,
        OnValue&& on_value,
        OffValue&& off_value,
        Attributes&&...attributes) noexcept requires requires
    {
        make_default_toggle_button_delegate(hi_forward(value), hi_forward(on_value), hi_forward(off_value));
    } :
        toggle_widget(
            parent,
            make_default_toggle_button_delegate(hi_forward(value), hi_forward(on_value), hi_forward(off_value)),
            hi_forward(attributes)...)
    {
    }
 
    [[nodiscard]] box_constraints update_constraints() noexcept override
    {
        _label_constraints = super::update_constraints();
 
        // Make room for button and margin.
        _button_size = {theme().size() * 2.0f, theme().size()};
        hilet extra_size = extent2{theme().margin<float>() + _button_size.width(), 0.0f};
 
        auto r = max(_label_constraints + extra_size, _button_size);
        r.margins = theme().margin();
        r.alignment = *alignment;
        return r;
    }
 
    void set_layout(widget_layout const& context) noexcept override
    {
        if (compare_store(_layout, context)) {
            auto alignment_ = os_settings::left_to_right() ? *alignment : mirror(*alignment);
 
            if (alignment_ == horizontal_alignment::left or alignment_ == horizontal_alignment::right) {
                _button_rectangle = align(context.rectangle(), _button_size, alignment_);
            } else {
                hi_not_implemented();
            }
 
            hilet label_width = context.width() - (_button_rectangle.width() + theme().margin<float>());
            if (alignment_ == horizontal_alignment::left) {
                hilet label_left = _button_rectangle.right() + theme().margin<float>();
                hilet label_rectangle = aarectangle{label_left, 0.0f, label_width, context.height()};
                _on_label_shape = _off_label_shape = _other_label_shape =
                    box_shape{_label_constraints, label_rectangle, theme().baseline_adjustment()};
 
            } else if (alignment_ == horizontal_alignment::right) {
                hilet label_rectangle = aarectangle{0, 0, label_width, context.height()};
                _on_label_shape = _off_label_shape = _other_label_shape =
                    box_shape{_label_constraints, label_rectangle, theme().baseline_adjustment()};
 
            } else {
                hi_not_implemented();
            }
 
            hilet button_square =
                aarectangle{get<0>(_button_rectangle), extent2{_button_rectangle.height(), _button_rectangle.height()}};
 
            _pip_circle = align(button_square, circle{theme().size() * 0.5f - 3.0f}, alignment::middle_center());
 
            hilet pip_to_button_margin_x2 = _button_rectangle.height() - _pip_circle.diameter();
            _pip_move_range = _button_rectangle.width() - _pip_circle.diameter() - pip_to_button_margin_x2;
        }
        super::set_layout(context);
    }
 
    void draw(draw_context const& context) noexcept override
    {
        if (*mode > widget_mode::invisible and overlaps(context, layout())) {
            draw_toggle_button(context);
            draw_toggle_pip(context);
            draw_button(context);
        }
    }
 
private:
    constexpr static std::chrono::nanoseconds _animation_duration = std::chrono::milliseconds(150);
 
    box_constraints _label_constraints;
 
    extent2 _button_size;
    aarectangle _button_rectangle;
    animator<float> _animated_value = _animation_duration;
    circle _pip_circle;
    float _pip_move_range;
 
    void draw_toggle_button(draw_context const& context) noexcept
    {
        context.draw_box(
            layout(),
            _button_rectangle,
            background_color(),
            focus_color(),
            theme().border_width(),
            border_side::inside,
            corner_radii{_button_rectangle.height() * 0.5f});
    }
 
    void draw_toggle_pip(draw_context const& context) noexcept
    {
        _animated_value.update(state() == button_state::on ? 1.0f : 0.0f, context.display_time_point);
        if (_animated_value.is_animating()) {
            request_redraw();
        }
 
        hilet positioned_pip_circle = translate3{_pip_move_range * _animated_value.current_value(), 0.0f, 0.1f} * _pip_circle;
 
        hilet forground_color_ = state() == button_state::on ? accent_color() : foreground_color();
        context.draw_circle(layout(), positioned_pip_circle * 1.02f, forground_color_);
    }
};
 
}} // namespace hi::v1