[ap draw] fix segfault when disp is off

skip set_initial_world when no display

Author: robluo

vpr/src/draw/draw.cpp

@@ -285,7 +285,7 @@ void update_screen(ScreenUpdatePriority priority, const char* msg, enum pic_type
      * value controls whether or not the Proceed button must be clicked to   *
      * continue.  Saves the pic_on_screen_val to allow pan and zoom redraws. */
     t_draw_state* draw_state = get_draw_state_vars();
-
+    
     strcpy(draw_state->default_message, msg);
 
     if (!draw_state->show_graphics)
@@ -301,10 +301,12 @@ void update_screen(ScreenUpdatePriority priority, const char* msg, enum pic_type
 
         state_change = true;
 
-        if (pic_on_screen_val == ANALYTICAL_PLACEMENT) {
-            set_initial_world_ap();
-        } else {
-            set_initial_world();
+        if (draw_state->show_graphics) {
+            if (pic_on_screen_val == ANALYTICAL_PLACEMENT) {
+                set_initial_world_ap();
+            } else {
+                set_initial_world();
+            }
         }
 
         if (draw_state->pic_on_screen == NO_PICTURE) {