Error message on exceeding resolution limit

ChangeLog

@@ -1,3 +1,7 @@
+2011-09-11  Holger Vogt
+ * frontend/plotting/grid.c: Error message, if requested resolution
+   cannot be handled.
+
 2011-08-28  Dietmar Warning
  * /admst/ngspice.xml, ngspiceVersion.xml, psp102.va: psp102 module name change 
    according to model developer used naming convention (psp102 is now PSP102VA)

src/frontend/plotting/grid.c

@@ -294,6 +294,14 @@ lingrid(GRAPH *graph, double lo, double hi, double delta, int type, Axis axis)
     if (digits < 1)
 	digits = 0;
 
+    if (digits > 15) {
+        dd[0] = 1;
+        dd[1] = 1;
+        fprintf(cp_err, "Error: Plot resolution limit of 15 digits exceeded.\n");
+        fprintf(cp_err, "    Consider plotting with offset.\n");
+        return dd;
+    }
+
     if (axis == x_axis) {
       margin = graph->viewportxoff;
       /*max = graph->viewport.width + graph->viewportxoff;*/