Index: trunk/src/draw.c
===================================================================
--- trunk/src/draw.c	(revision 764)
+++ trunk/src/draw.c	(revision 765)
@@ -118,6 +118,8 @@
 	}
 }
 
+rnd_cardinal_t camv_draw_inhibit = 0;
+
 void camv_expose_main(rnd_hid_t *hid, const rnd_hid_expose_ctx_t *region, rnd_xform_t *xform_caller)
 {
 	rnd_cardinal_t lid;
@@ -124,7 +126,10 @@
 	rnd_hid_gc_t gc;
 	int clearing = -1, direct = 1, need_flush = 0;
 	rnd_hid_t *save = rnd_render;
-	
+
+	if (camv_draw_inhibit)
+		return;
+
 	if ((rnd_render != NULL) && (!rnd_render->override_render))
 		rnd_render = hid;
 
Index: trunk/src/draw.h
===================================================================
--- trunk/src/draw.h	(revision 764)
+++ trunk/src/draw.h	(revision 765)
@@ -8,4 +8,18 @@
 void camv_expose_main(rnd_hid_t *hid, const rnd_hid_expose_ctx_t *region, rnd_xform_t *xform_caller);
 void camv_expose_preview(rnd_hid_t *hid, rnd_hid_expose_ctx_t *e);
 
+/* Temporarily inhibid drawing if this is non-zero. A function that calls a
+   lot of other functions that would call camv_draw() a lot in turn may increase
+   this value before the calls, then decrease it at the end and call camv_draw().
+   This makes sure the whole block is redrawn only once at the end. */
+extern rnd_cardinal_t camv_draw_inhibit;
+
+#define camv_draw_inhibit_inc() camv_draw_inhibit++
+#define camv_draw_inhibit_dec() \
+do { \
+	if (camv_draw_inhibit > 0) \
+		camv_draw_inhibit--; \
+} while(0) \
+
+
 #endif