Index: trunk/src/conf_core.h
===================================================================
--- trunk/src/conf_core.h	(revision 713)
+++ trunk/src/conf_core.h	(revision 714)
@@ -11,6 +11,7 @@
 			RND_CFT_COLOR attached;
 		} color;
 		RND_CFT_STRING default_font;     /* OBSOLETE: used to be path to a ttf font; camv-rnd uses an embedded internal vector font now */
+		RND_CFT_BOOLEAN bbox_debug;      /* enable rendering bounding box of objects, for debugging */
 	} appearance;
 	const struct rc { /* rc */
 		RND_CFT_BOOLEAN error_on_bad_cli_files;
Index: trunk/src/conf_core_fields.h
===================================================================
--- trunk/src/conf_core_fields.h	(revision 713)
+++ trunk/src/conf_core_fields.h	(revision 714)
@@ -1,4 +1,5 @@
 conf_reg(appearance.default_font,             scalar, RND_CFN_STRING,  "appearance",             "default_font",           "OBSOLETE: used to be path to a ttf font; camv-rnd uses an embedded internal vector font now", 0)
+conf_reg(appearance.bbox_debug,               scalar, RND_CFN_BOOLEAN, "appearance",             "bbox_debug",             "enable rendering bounding box of objects, for debugging", 0)
 conf_reg(appearance.color.layer,              array,  RND_CFN_COLOR,   "appearance/color",       "layer",                  "default layer colors; when a new layer is created, a color from this list is assigned initially", 0)
 conf_reg(appearance.color.attached,           scalar, RND_CFN_COLOR,   "appearance/color",       "attached",               "<attached>", 0)
 conf_reg(rc.error_on_bad_cli_files,           scalar, RND_CFN_BOOLEAN, "rc",                     "error_on_bad_cli_files", "<error_on_bad_cli_files>", 0)
Index: trunk/src/draw.c
===================================================================
--- trunk/src/draw.c	(revision 713)
+++ trunk/src/draw.c	(revision 714)
@@ -2,7 +2,7 @@
  *                            COPYRIGHT
  *
  *  camv-rnd - electronics-related CAM viewer
- *  Copyright (C) 2019 Tibor 'Igor2' Palinkas
+ *  Copyright (C) 2019,2023 Tibor 'Igor2' Palinkas
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -25,7 +25,9 @@
  */
 
 #include <librnd/hid/hid.h>
+#include <librnd/hid/hid_inlines.h>
 #include "obj_any.h"
+#include "conf_core.h"
 
 /* based on https://math.stackexchange.com/questions/13150/extracting-rotation-scale-values-from-2d-transformation-matrix/13165#13165 */
 static double mx_extract_rot(rnd_xform_mx_t mx)
@@ -94,6 +96,25 @@
 	for(o = camv_rtree_first(&it, &ly->objs, view); o != NULL; o = camv_rtree_next(&it)) {
 		camv_any_obj_t *obj = o;
 		obj->proto.calls->draw(obj, gc, mx);
+		if (conf_core.appearance.bbox_debug) {
+			rnd_coord_t x1, y1, x2, y2;
+
+			if (mx != NULL) {
+				x1 = rnd_xform_x((*mx), obj->proto.bbox.x1, obj->proto.bbox.y1); y1 = rnd_xform_y((*mx), obj->proto.bbox.x1, obj->proto.bbox.y1);
+				x2 = rnd_xform_x((*mx), obj->proto.bbox.x2, obj->proto.bbox.y2); y2 = rnd_xform_y((*mx), obj->proto.bbox.x2, obj->proto.bbox.y2);
+			}
+			else {
+				x1 = obj->proto.bbox.x1; y1 = obj->proto.bbox.y1;
+				x2 = obj->proto.bbox.x2; y2 = obj->proto.bbox.y2;
+			}
+
+			rnd_hid_set_line_cap(gc, rnd_cap_round);
+			rnd_hid_set_line_width(gc, -1);
+			rnd_render->draw_line(gc, x1, y1, x2, y1);
+			rnd_render->draw_line(gc, x2, y1, x2, y2);
+			rnd_render->draw_line(gc, x2, y2, x1, y2);
+			rnd_render->draw_line(gc, x1, y2, x1, y1);
+		}
 	}
 }