Function bicubic_kernel

src/include/image_process_utils/imageproc.hpp:14–23

Keys bicubic kernel (a = -0.5) - matches PyTorch antialias=True

    // Keys bicubic kernel (a = -0.5) - matches PyTorch antialias=True
    inline float bicubic_kernel(float x) {
        const float a = -0.5f;
        x = std::fabs(x);
        if (x < 1.0f)
            return ((a + 2.0f) * x - (a + 3.0f)) * x * x + 1.0f;
        else if (x < 2.0f)
            return ((a * x - 5.0f * a) * x + 8.0f * a) * x - 4.0f * a;
        else
            return 0.0f;
    }

    inline int clamp(int x, int lo, int hi) {
        return std::max(lo, std::min(x, hi));