viewport_image_offset  247 modules/zebra.c     int viewport_image_offset;  // for when viewport memory buffer is wider than viewport
viewport_image_offset  255 modules/zebra.c     viewport_image_offset = vid_get_viewport_image_offset(); 
viewport_image_offset  269 modules/zebra.c         for (y=viewport_yoffset, v=viewport_image_offset; y<viewport_yoffset+viewport_height; ++y) {