Function py_sub_image

tools/python/src/image2.cpp:522–553

// ----------------------------------------------------------------------------------------

py::array py_sub_image (
    const py::array& img,
    const rectangle& win
)
{
    DLIB_CASSERT(img.ndim() >= 2);

    auto width_step = img.strides(0);

    const long nr = img.shape(0);
    const long nc = img.shape(1);
    rectangle rect(0,0,nc-1,nr-1);
    rect = rect.intersect(win);

    std::vector<size_t> shape(img.ndim()), strides(img.ndim());
    for (size_t i = 0; i < shape.size(); ++i)
    {
        shape[i] = img.shape(i);
        strides[i] = img.strides(i);
    }

    shape[0] = rect.height();
    shape[1] = rect.width();

    size_t col_stride = 1;
    for (size_t i = 1; i < strides.size(); ++i)
        col_stride *= strides[i];

    const void* data = (char*)img.data() + col_stride*rect.left() + rect.top()*strides[0];

    return py::array(img.dtype(), shape, strides, data, img);
}

py::array py_sub_image2 (
    const py::tuple& image_and_rect_tuple