Function af_skew

src/api/c/transform.cpp:259–294

}

af_err af_skew(af_array *out, const af_array in, const float skew0,
               const float skew1, const dim_t odim0, const dim_t odim1,
               const af_interp_type method, const bool inverse) {
    try {
        float tx = std::tan(skew0);
        float ty = std::tan(skew1);

        float trans_mat[6] = {1, 0, 0, 0, 1, 0};
        trans_mat[1]       = ty;
        trans_mat[3]       = tx;

        if (inverse) {
            if (tx == 0 || ty == 0) {
                trans_mat[1] = tx;
                trans_mat[3] = ty;
            } else {
                // calc_tranform_inverse(trans_mat);
                // short cut of calc_transform_inverse
                float d      = 1.0f / (1.0f - tx * ty);
                trans_mat[0] = d;
                trans_mat[1] = ty * d;
                trans_mat[3] = tx * d;
                trans_mat[4] = d;
            }
        }
        const dim4 tdims(3, 2, 1, 1);
        af_array t = 0;
        AF_CHECK(
            af_create_array(&t, trans_mat, tdims.ndims(), tdims.get(), f32));
        AF_CHECK(af_transform(out, in, t, odim0, odim1, method, true));
        AF_CHECK(af_release_array(t));
    }
    CATCHALL;

    return AF_SUCCESS;
}