set logscale will reset improper range limits to [.1:10] if autoscali…

…ng is active

ChangeLog

@@ -1,3 +1,9 @@
+2017-11-08  Ethan A Merritt  <merritt@u.washington.edu>
+
+	* src/set.c (set_logscale):  If the axis is currently autoscaled and
+	the range limits still hold non-positive values from a previous state,
+	reset them to [0.1 : 10.].
+
 2017-11-06  Ethan A Merritt  <merritt@u.washington.edu>
 
 	* term/lua.trm term/lua/gnuplot-tikz.lua:  Restore version information

src/set.c

@@ -2790,10 +2790,17 @@ set_logscale()
 		dummy = "x"; break;
 	    }
 
-	    /* Avoid a warning message trigger by default axis range [-10:10] */
+	    /* Avoid a warning message triggered by default axis range [-10:10] */
 	    if (axis_array[axis].set_min <= 0 && axis_array[axis].set_max > 0)
 		axis_array[axis].set_min = 0.1;
 
+	    /* Also forgive negative axis limits if we are currently autoscaling */
+	    if ((axis_array[axis].set_autoscale != AUTOSCALE_NONE)
+	    &&  (axis_array[axis].set_min <= 0 || axis_array[axis].set_max <= 0)) {
+		axis_array[axis].set_min = 0.1;
+		axis_array[axis].set_max = 10.;
+	    }
+
 	    if (newbase == 10.) {
 		sprintf(command, "set nonlinear %s via log10(%s) inv 10**%s",
 			axis_name(axis), dummy, dummy);