bwidgets/inc/basic_widgets/core/math.hpp

#ifndef BWIDGETS_MATH_HPP
#define BWIDGETS_MATH_HPP

#include <SDL2/SDL_rect.h>

#include <basic_widgets/core/type/size.hpp>

namespace bwidgets::core
{
    static inline int center_rect(int container_size, int rect_size) noexcept
    {
        return (container_size - rect_size) / 2;
    }

    static inline float distance_sqrd(const SDL_Point& a, const SDL_Point& b) noexcept
    {
        return (a.x - b.x) * (a.x - b.x) + (a.y - b.y) * (a.y - b.y);
    }

    static inline float distance(const SDL_Point& a, const SDL_Point& b) noexcept
    {
        return std::sqrt(distance_sqrd(a, b));
    }

    static inline bool rect_in_rect(const SDL_Rect outer, const SDL_Rect inner) noexcept
    {
        SDL_Point top_left {inner.x, inner.y};
        SDL_Point bottom_right {inner.x + inner.w, inner.y + inner.h};

        return
            SDL_PointInRect(&top_left, &outer) &&
                SDL_PointInRect(&bottom_right, &outer);
    }

    static inline SDL_Rect rect_margin(const SDL_Rect& r, const Size& margin) noexcept
    {
        return {
            r.x + margin.w,
            r.y + margin.h,
            r.w - 2 * margin.w,
            r.h - 2 * margin.h
        };
    }

    static inline SDL_Rect rect_offset(const SDL_Rect& r, const SDL_Rect& offset) noexcept
    {
        return {
            r.x + offset.x,
            r.y + offset.y,
            r.w, r.h
        };
    }
}

#endif