toolbar_widget.hpp

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// Copyright Take Vos 2020-2022.
// 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 "widget.hpp"
#include "../layout/layout.hpp"
#include "../geometry/geometry.hpp"
#include "../macros.hpp"
#include <memory>
#include <ranges>
#include <coroutine>
 
hi_export_module(hikogui.widgets.toolbar_widget);
 
hi_export namespace hi { inline namespace v1 {

class toolbar_widget : public widget {
public:
    using super = widget;

    toolbar_widget() noexcept : super()
    {
        hi_axiom(loop::main().on_thread());
 
        auto spacer = std::make_unique<spacer_widget>();
        spacer->set_parent(this);
 
        _children.push_back(std::move(spacer));
    }

    template<typename Widget, horizontal_alignment Alignment = horizontal_alignment::left, typename... Args>
    Widget& emplace(Args&&...args)
    {
        auto widget = std::make_unique<Widget>(std::forward<Args>(args)...);
        auto &ref = *widget;
        insert(Alignment, std::move(widget));
        return ref;
    }

    [[nodiscard]] generator<widget_intf &> children(bool include_invisible) noexcept override
    {
        for (auto const& child : _children) {
            co_yield *child.value;
        }
    }
 
    [[nodiscard]] box_constraints update_constraints() noexcept override
    {
        _layout = {};
 
        for (auto& child : _children) {
            child.set_constraints(child.value->update_constraints());
        }
 
        auto r = _children.constraints(os_settings::left_to_right());
        _child_height_adjustment = -r.margins.top();
 
        r.minimum.height() += r.margins.top();
        r.preferred.height() += r.margins.top();
        r.maximum.height() += r.margins.top();
        r.margins.top() = 0;
 
        return r;
    }
    void set_layout(widget_layout const& context) noexcept override
    {
        // Clip directly around the toolbar, so that tab buttons looks proper.
        if (compare_store(_layout, context)) {
            auto shape = context.shape;
            shape.rectangle = aarectangle{shape.x(), shape.y(), shape.width(), shape.height() + _child_height_adjustment};
            _children.set_layout(shape, theme().baseline_adjustment());
        }
 
        auto const overhang = context.redraw_overhang;
 
        for (auto const& child : _children) {
            auto const child_clipping_rectangle =
                aarectangle{child.shape.x() - overhang, 0, child.shape.width() + overhang * 2, context.height() + overhang * 2};
 
            child.value->set_layout(context.transform(child.shape, transform_command::menu_item, child_clipping_rectangle));
        }
    }
    void draw(draw_context const& context) noexcept override
    {
        if (mode() > widget_mode::invisible) {
            if (overlaps(context, layout())) {
                context.draw_box(layout(), layout().rectangle(), theme().fill_color(_layout.layer));
 
                if (tab_button_has_focus()) {
                    // Draw the line at a higher elevation, so that the tab buttons can draw above or below the focus
                    // line depending if that specific button is in focus or not.
                    auto const focus_rectangle = aarectangle{0.0f, 0.0f, layout().rectangle().width(), theme().border_width()};
                    context.draw_box(layout(), translate3{0.0f, 0.0f, 1.5f} * focus_rectangle, focus_color());
                }
            }
 
            for (auto const& child : _children) {
                hi_assert_not_null(child.value);
                child.value->draw(context);
            }
        }
    }
    hitbox hitbox_test(point2 position) const noexcept override
    {
        hi_axiom(loop::main().on_thread());
 
        // By default the toolbar is used for dragging the window.
        if (mode() >= widget_mode::partial) {
            auto r = layout().contains(position) ? hitbox{id, _layout.elevation, hitbox_type::move_area} : hitbox{};
 
            for (auto const& child : _children) {
                hi_assert_not_null(child.value);
                r = child.value->hitbox_test_from_parent(position, r);
            }
 
            return r;
        } else {
            return {};
        }
    }
    [[nodiscard]] color focus_color() const noexcept override
    {
        if (mode() >= widget_mode::partial) {
            return theme().accent_color();
        } else {
            return theme().border_color(_layout.layer - 1);
        }
    }
private:
    mutable row_layout<std::unique_ptr<widget>> _children;
    mutable float _child_height_adjustment = 0.0f;
    size_t _spacer_index = 0;
 
    void update_layout_for_child(widget& child, ssize_t index, widget_layout const& context) const noexcept;

    widget& insert(horizontal_alignment alignment, std::unique_ptr<widget> widget) noexcept
    {
        auto& ref = *widget;
        switch (alignment) {
            using enum horizontal_alignment;
        case left:
            widget->set_parent(this);
            _children.insert(_children.cbegin() + _spacer_index, std::move(widget));
            ++_spacer_index;
            break;
        case right:
            widget->set_parent(this);
            _children.insert(_children.cbegin() + _spacer_index + 1, std::move(widget));
            break;
        default:
            hi_no_default();
        }
 
        return ref;
    }

    bool tab_button_has_focus() const noexcept
    {
        for (auto const& cell : _children) {
            if (auto const *const c = dynamic_cast<toolbar_tab_button_widget *>(cell.value.get())) {
                if (c->focus() and c->value() == widget_value::on) {
                    return true;
                }
            }
        }
 
        return false;
    }
};
 
}} // namespace hi::v1