viewport_vis_byte_width  148 modules/histogram.c     static int viewport_vis_byte_width;
viewport_vis_byte_width  218 modules/histogram.c             viewport_vis_byte_width = (viewport_pix_width*3)/2;
viewport_vis_byte_width  221 modules/histogram.c             viewport_vis_byte_width = viewport_pix_width*2;
viewport_vis_byte_width  236 modules/histogram.c             histogram_sample_stage(img, histogram_stage, viewport_byte_width, viewport_vis_byte_width, viewport_height, xstep_bytes, ystep);