Allow plotting a single point in an ascii plot

(command .asciiplot)

src/frontend/plotting/agraf.c

@@ -86,12 +86,6 @@ ft_agraf(double *xlims, double *ylims, struct dvec *xscale, struct plot *plot, s
     yrange[0] = ylims[0];
     yrange[1] = ylims[1];
 
-    if (maxx < 2) {
-        fprintf(cp_err,
-                "Error: asciiplot can't handle scale with length < 2\n");
-        return;
-    }
-
     if (maxx <= 0) {
         fprintf(cp_err, "Note: no points to plot\n");
         return;
@@ -296,8 +290,14 @@ ft_agraf(double *xlims, double *ylims, struct dvec *xscale, struct plot *plot, s
             x = isreal(xscale) ? xscale->v_realdata[i] :
             realpart(xscale->v_compdata[i]);
         else if (xlog && xrange[0] > 0.0 && xrange[1] > 0.0)
+            if (maxx == 1)
+                x = (xrange[0] + xrange[1]) / 2.;
+            else
                 x = xrange[0] * pow(10.0, mylog10(xrange[1] / xrange[0])
                     * i / (maxx - 1));
+        else
+            if (maxx == 1)
+                x = (xrange[0] + xrange[1]) / 2.;
             else
                 x = xrange[0] + (xrange[1] - xrange[0]) * i / (maxx - 1);