Rectangle Fitting

rectangle_fitting.cpp

#include <iostream>

struct rect_t
{
    float top_m;
    float left_m;
    float bottom_m;
    float right_m;

    float height() const { return bottom_m - top_m; }
    float width() const { return right_m - left_m; }
};

rect_t operator*(const rect_t& src, float scale)
{
    return rect_t{src.top_m * scale,
                  src.left_m * scale,
                  src.bottom_m * scale,
                  src.right_m * scale};
}

rect_t operator/(const rect_t& src, float scale)
{
    return rect_t{src.top_m / scale,
                  src.left_m / scale,
                  src.bottom_m / scale,
                  src.right_m / scale};
}

std::ostream& operator<<(std::ostream& s, const rect_t& src)
{
    return s << "{"
             << " t: " << src.top_m
             << ", l: " << src.left_m
             << ", b: " << src.bottom_m
             << ", r: " << src.right_m << ','
             << " h: " << src.height()
             << ", w: " << src.width()
             << " }";
}

rect_t scale_to_fit(const rect_t& src, const rect_t& dst)
{
    float  v_scale(src.height() / dst.height());
    float  h_scale(src.width() / dst.width());
    float  scale(std::max(v_scale, h_scale));
    rect_t scale_rect(src / scale);
    float  v_offset((dst.width() - scale_rect.width()) / 2);
    float  h_offset((dst.height() - scale_rect.height()) / 2);
    float  new_top(dst.top_m + v_offset);
    float  new_left(dst.left_m + h_offset);

    return rect_t{new_top,
                  new_left,
                  new_top + scale_rect.height(),
                  new_left + scale_rect.width()};
}

int main(int, char**)
{
    std::cout << "Hello, world!\n";

    rect_t dst{0, 0, 65, 120};
    rect_t wide{0, 0, 75, 150};
    rect_t tall{0, 0, 150, 75};

    std::cout << "dst: " << dst << "\n";
    std::cout << "wide: " << wide << "\n";
    std::cout << "tall: " << tall << "\n";

    rect_t wide_fit(scale_to_fit(wide, dst));

    std::cout << "wide_fit: " << wide_fit << "\n";

    rect_t tall_fit(scale_to_fit(tall, dst));

    std::cout << "tall_fit: " << tall_fit << "\n";

    return 0;
}