Always check for GUI events during simulation, if any graphs exist.

Previously this check was only made if an iplot window existed.
The 100W.sp example displayed frozen windows with X11-based plotting.

src/frontend/plotting/graf.c

@@ -868,7 +868,6 @@ static int iplot(struct plot *pl, struct dbcomm *db)
     bool           changed = FALSE;
     int            id, yt;
     double         xlims[2], ylims[2];
-    static REQUEST reqst = { checkup_option, NULL };
     int            inited = 0;
     int            n_vec_plot = 0;
 
@@ -958,16 +957,12 @@ static int iplot(struct plot *pl, struct dbcomm *db)
         inited = 1;
 
     } else {
-        /* plot the last points and resize if needed */
-
-        Input(&reqst, NULL);
-
-        /* Window was closed? */
-
-        if (!currentgraph)
+        if (!currentgraph)        /* Window was closed? */
             return 0;
 
-        /* First see if we have to make the screen bigger */
+        /* Plot the latest points and resize if needed.
+         * First see if we have to make the screen bigger.
+         */
 
         dy = (isreal(xs) ? xs->v_realdata[len - 1] :
               realpart(xs->v_compdata[len - 1]));
@@ -1194,10 +1189,17 @@ void reset_trace(void)
 
 void gr_iplot(struct plot *plot)
 {
-    struct dbcomm *db;
+    static REQUEST reqst = { checkup_option, NULL };
+    struct dbcomm *db, *dc;
     int            dontpop;        /* So we don't pop w/o push. */
     char           buf[30];
 
+    if (Have_graph) {
+        /* There is at least one graph.  Process input on graph windows. */
+
+        Input(&reqst, NULL);
+    }
+
     hit = 0;
     for (db = dbs; db; db = db->db_next) {
         if (db->db_type == DB_IPLOT || db->db_type == DB_IPLOTALL) {

src/frontend/plotting/graphdb.c

@@ -41,6 +41,10 @@ typedef struct gbucket {
 
 static GBUCKET GBucket[NUMGBUCKETS];
 
+/* Global variable to indicate that at least one graph exits. Ugly but fast. */
+
+bool Have_graph;
+
 /* note: Zero is not a valid id.  This is used in plot() in graf.c. */
 static int RunningId = 1;
 
@@ -81,7 +85,7 @@ GRAPH *NewGraph(void)
     }
 
     RunningId++;
-
+    Have_graph = TRUE;
     return pgraph;
 } /* end of function NewGraph */
 
@@ -108,7 +112,6 @@ GRAPH *FindGraph(int id)
 } /* end of function FindGraph */
 
 
-
 GRAPH *CopyGraph(GRAPH *graph)
 {
     GRAPH *ret;
@@ -235,7 +238,15 @@ int DestroyGraph(int id)
                 lastlist->next = list->next;
             }
             else { /* at front */
+                int i;
+
                 GBucket[index].list = list->next;
+                for (i = 0; i < NUMGBUCKETS; ++i) {
+                    if (GBucket[i].list)
+                        break;
+                }
+                if (i >= NUMGBUCKETS)
+                    Have_graph = FALSE;
             }
 
             /* Run through and de-allocate dynamically allocated keyed list */
@@ -307,6 +318,7 @@ void FreeGraphs(void)
             txfree(deadl);
         }
     }
+    Have_graph = FALSE;
 } /* end of functdion FreeGraphs */
 
 

src/frontend/plotting/graphdb.h

@@ -12,4 +12,7 @@ void SetGraphContext(int graphid);
 void PushGraphContext(GRAPH *graph);
 void PopGraphContext(void);
 
+/* Global variable to indicate that at least one graph exits. Ugly but fast. */
+
+extern bool Have_graph;
 #endif