row_column_widget.hpp

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// Copyright Take Vos 2020.
// 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 "row_column_delegate.hpp"
#include "grid_layout.hpp"
#include "../GUI/theme.hpp"
#include "../geometry/axis.hpp"
#include <memory>
 
namespace hi::inline v1 {
 
template<axis Axis>
class row_column_widget final : public widget {
public:
    static_assert(Axis == axis::horizontal or Axis == axis::vertical);
 
    using super = widget;
    using delegate_type = row_column_delegate<Axis>;
    static constexpr hi::axis axis = Axis;
 
    ~row_column_widget()
    {
        if (auto delegate = _delegate.lock()) {
            delegate->deinit(*this);
        }
    }
 
    row_column_widget(gui_window &window, widget *parent, std::weak_ptr<delegate_type> delegate = {}) noexcept :
        super(window, parent), _delegate(std::move(delegate))
    {
        hi_axiom(is_gui_thread());
 
        if (parent) {
            semantic_layer = parent->semantic_layer;
        }
        if (auto d = _delegate.lock()) {
            d->init(*this);
        }
    }
 
    template<typename Widget, typename... Args>
    Widget &make_widget(Args &&...args)
    {
        auto tmp = std::make_unique<Widget>(window, this, std::forward<Args>(args)...);
        auto &ref = *tmp;
        _children.push_back(std::move(tmp));
        request_reconstrain();
        return ref;
    }
 
    void clear() noexcept
    {
        hi_axiom(is_gui_thread());
        _children.clear();
        request_reconstrain();
    }
 
    [[nodiscard]] generator<widget *> children() const noexcept override
    {
        for (hilet &child : _children) {
            co_yield child.get();
        }
    }
 
    widget_constraints const &set_constraints() noexcept override
    {
        _layout = {};
 
        ssize_t index = 0;
 
        auto minimum_thickness = 0.0f;
        auto preferred_thickness = 0.0f;
        auto maximum_thickness = 0.0f;
        float margin_before_thickness = 0.0f;
        float margin_after_thickness = 0.0f;
 
        _grid_layout.clear();
        for (hilet &child : _children) {
            update_constraints_for_child(*child, index++, minimum_thickness, preferred_thickness, maximum_thickness, margin_before_thickness, margin_after_thickness);
        }
        _grid_layout.commit_constraints();
 
        hi_axiom(index == ssize(_children));
 
        if constexpr (axis == axis::row) {
            return _constraints = {
               {_grid_layout.minimum(), minimum_thickness},
               {_grid_layout.preferred(), preferred_thickness},
               {_grid_layout.maximum(), maximum_thickness},
               {_grid_layout.margin_before(), margin_before_thickness, _grid_layout.margin_after(), margin_after_thickness}};
        } else {
            return _constraints = {
               {minimum_thickness, _grid_layout.minimum()},
               {preferred_thickness, _grid_layout.preferred()},
               {maximum_thickness, _grid_layout.maximum()},
               {margin_before_thickness, _grid_layout.margin_before(), margin_after_thickness, _grid_layout.margin_after()}};
        }
    }
 
    void set_layout(widget_layout const &layout) noexcept override
    {
        if (compare_store(_layout, layout)) {
            _grid_layout.layout(axis == axis::row ? layout.width() : layout.height());
        }
 
        ssize_t index = 0;
        for (hilet &child : _children) {
            update_layout_for_child(*child, index++, layout);
        }
 
        hi_axiom(index == ssize(_children));
    }
 
    void draw(draw_context const &context) noexcept override
    {
        if (*visible) {
            for (hilet &child : _children) {
                child->draw(context);
            }
        }
    }
 
    hitbox hitbox_test(point3 position) const noexcept override
    {
        hi_axiom(is_gui_thread());
 
        if (*visible and *enabled) {
            auto r = hitbox{};
            for (hilet &child : _children) {
                r = child->hitbox_test_from_parent(position, r);
            }
            return r;
        } else {
            return {};
        }
    }
private:
    std::vector<std::unique_ptr<widget>> _children;
    std::weak_ptr<delegate_type> _delegate;
    grid_layout _grid_layout;
 
    void update_constraints_for_child(
        widget &child,
        ssize_t index,
        float &minimum_thickness,
        float &preferred_thickness,
        float &maximum_thickness,
        float &margin_before_thickness,
        float &margin_after_thickness) noexcept
    {
        hi_axiom(is_gui_thread());
 
        hilet &child_constraints = child.set_constraints();
        if (axis == axis::row) {
            _grid_layout.add_constraint(
                index,
                child_constraints.minimum.width(),
                child_constraints.preferred.width(),
                child_constraints.maximum.width(),
                child_constraints.margins.left(),
                child_constraints.margins.right());
 
            inplace_max(minimum_thickness, child_constraints.minimum.height());
            inplace_max(preferred_thickness, child_constraints.preferred.height());
            inplace_max(maximum_thickness, child_constraints.maximum.height());
            inplace_max(margin_before_thickness, child_constraints.margins.top());
            inplace_max(margin_after_thickness, child_constraints.margins.bottom());
 
        } else {
            _grid_layout.add_constraint(
                index,
                child_constraints.minimum.height(),
                child_constraints.preferred.height(),
                child_constraints.maximum.height(),
                child_constraints.margins.top(),
                child_constraints.margins.bottom());
 
            inplace_max(minimum_thickness, child_constraints.minimum.width());
            inplace_max(preferred_thickness, child_constraints.preferred.width());
            inplace_max(maximum_thickness, child_constraints.maximum.width());
            inplace_max(margin_before_thickness, child_constraints.margins.left());
            inplace_max(margin_after_thickness, child_constraints.margins.right());
        }
    }
 
    void update_layout_for_child(widget &child, ssize_t index, widget_layout const &context) const noexcept
    {
        hi_axiom(is_gui_thread());
 
        hilet[child_position, child_length] = _grid_layout.get_position_and_size(index);
 
        hilet child_rectangle = axis == axis::row ?
            aarectangle{child_position, 0.0f, child_length, layout().height()} :
            aarectangle{0.0f, layout().height() - child_position - child_length, layout().width(), child_length};
 
        child.set_layout(context.transform(child_rectangle, 0.0f));
    }
};
 
using row_widget = row_column_widget<axis::row>;
 
using column_widget = row_column_widget<axis::column>;
 
} // namespace hi::inline v1