layout.h

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#ifndef ASW_MODULES_UI_LAYOUT_H
#define ASW_MODULES_UI_LAYOUT_H
 
#include <cstddef>
#include <vector>
 
#include "context.h"
#include "widget.h"
 
namespace asw::ui {
 
enum class Direction {
    Vertical,
    Horizontal,
};
 
enum class Align {
    Start,
    Center,
    End,
    Stretch,
};
 
namespace detail {
 
class ForcedSizes {
public:
    float natural(const Widget& w, float current) const;
 
    void record(const Widget& w, float natural, float forced);
 
    void keep(const Widget& w);
 
    void finish();
 
private:
    struct Entry {
        WidgetId id;
        float natural;
        float forced;
    };
 
    // Find a child's record from last layout. Children come in the same
    // order each layout, so the search starts where the last one ended.
    const Entry* find(WidgetId id) const;
 
    // Vectors, not maps, and kept between layouts, so a layout does not
    // allocate
    std::vector<Entry> _last;
    std::vector<Entry> _next;
    mutable std::size_t _cursor = 0;
};
 
} // namespace detail
 
class Stack : public Widget {
public:
    Direction direction = Direction::Vertical;
 
    Align align = Align::Stretch;
 
    float gap = 8.0F;
 
    float padding = 0.0F;
 
    void layout(Context& ctx) override;
 
private:
    // Sizes across the stack forced by Align::Stretch
    detail::ForcedSizes _across;
};
 
class VBox : public Stack {
public:
    VBox()
    {
        padding = 10.0F;
    }
};
 
class Grid : public Widget {
public:
    std::size_t columns = 2;
 
    float gap = 8.0F;
 
    float padding = 0.0F;
 
    float row_height = 0.0F;
 
    void layout(Context& ctx) override;
 
private:
    // Heights forced by the row height
    detail::ForcedSizes _heights;
 
    // Kept between layouts so a layout does not allocate
    std::vector<Widget*> _shown;
    std::vector<float> _natural_h;
};
 
bool in_row_with_focusables(const Widget& w);
 
} // namespace asw::ui
 
#endif // ASW_MODULES_UI_LAYOUT_H