DIRECTION_45DOWN  183 libavfilter/vf_edgedetect.c         if (gy >  tanpi8gx  && gy <  tan3pi8gx) return DIRECTION_45DOWN;
DIRECTION_45DOWN  235 libavfilter/vf_edgedetect.c             case DIRECTION_45DOWN:      COPY_MAXIMA(-1, -1,  1,  1); break;