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 "spacer_widget.hpp"
#include "toolbar_tab_button_widget.hpp"
#include "../GUI/module.hpp"
#include "../layout/row_column_layout.hpp"
#include "../geometry/module.hpp"
#include <memory>
#include <ranges>
 
namespace hi { inline namespace v1 {
 
template<fixed_string Name = "">
class toolbar_widget final : public widget {
public:
    using super = widget;
    constexpr static auto prefix = Name / "toolbar";
 
    toolbar_widget(widget *parent) noexcept : super(parent)
    {
        hi_axiom(loop::main().on_thread());
 
        // The toolbar is a top level widget, which draws its background as the next level.
        semantic_layer = 0;
 
        _children.push_back(std::make_unique<spacer_widget>(this));
    }
 
    template<typename Widget, horizontal_alignment Alignment = horizontal_alignment::left, typename... Args>
    Widget& make_widget(Args&&...args)
    {
        auto widget = std::make_unique<Widget>(this, std::forward<Args>(args)...);
        return static_cast<Widget&>(add_widget(Alignment, std::move(widget)));
    }
 
    [[nodiscard]] generator<widget const&> children(bool include_invisible) const noexcept override
    {
        for (hilet& child : _children) {
            co_yield *child.value;
        }
    }
 
    [[nodiscard]] box_constraints update_constraints() noexcept override
    {
        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<prefix>.cap_height(this));
        }
 
        hilet overhang = context.redraw_overhang;
 
        for (hilet& child : _children) {
            hilet child_clipping_rectangle =
                aarectangle{child.shape.x() - overhang, 0.0f, child.shape.width() + overhang * 2.0f, context.height() + overhang * 2.0f};
 
            child.value->set_layout(context.transform(child.shape, 1.0f, child_clipping_rectangle));
        }
    }
 
    void draw(widget_draw_context& context) noexcept override
    {
        if (*mode > widget_mode::invisible) {
            if (overlaps(context, layout)) {
                context.draw_box(layout, layout.rectangle(), theme<prefix>.background_color(this));
 
                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.
                    hilet focus_rectangle =
                        aarectangle{0.0f, 0.0f, layout.rectangle().width(), theme<prefix>.border_width(this)};
                    context.draw_box(
                        layout,
                        translate3{0.0f, 0.0f, 1.5f} * narrow_cast<aarectangle>(focus_rectangle),
                        theme<prefix>.background_color(this));
                }
            }
 
            for (hilet& 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 (hilet& child : _children) {
                hi_assert_not_null(child.value);
                r = child.value->hitbox_test_from_parent(position, r);
            }
 
            return r;
        } else {
            return {};
        }
    }
private:
    mutable row_layout<std::unique_ptr<widget>> _children;
    mutable float _child_height_adjustment = 0;
    size_t _spacer_index = 0;
 
    void update_layout_for_child(widget& child, ssize_t index, widget_layout const& context) const noexcept;
 
    widget& add_widget(horizontal_alignment alignment, std::unique_ptr<widget> widget) noexcept
    {
        auto& ref = *widget;
        switch (alignment) {
            using enum horizontal_alignment;
        case left:
            _children.insert(_children.cbegin() + _spacer_index, std::move(widget));
            ++_spacer_index;
            break;
        case right:
            _children.insert(_children.cbegin() + _spacer_index + 1, std::move(widget));
            break;
        default:
            hi_no_default();
        }
 
        return ref;
    }
 
    [[nodiscard]] bool tab_button_has_focus() const noexcept
    {
        for (hilet& cell : _children) {
            hilet child = cell.value.get();
            hi_assert_not_null(child);
            if (child->is_tab_button()) {
                if (*child->focus and *child->state != hi::widget_state::off) {
                    return true;
                }
            }
        }
 
        return false;
    }
};
 
}} // namespace hi::v1