# HG changeset patch
# User Ben Abbott  <bpabbott@mac.com>
# Date 1316375754 14400
# Node ID da71f676e449a3be113ebdc570fed573d574538e
# Parent  62e710cea7f1aa8dd2b53224523c11d2b18b020e
Fix bug #34282. Fill holes in contours with the background colour

* scripts/plot/private/__contour__.m: Properly fill holes in contours.
* scripts/plot/contour.m: Add demo.

diff --git a/scripts/plot/contour.m b/scripts/plot/contour.m
--- a/scripts/plot/contour.m
+++ b/scripts/plot/contour.m
@@ -71,11 +71,22 @@
 endfunction
 
 %!demo
+%! clf ()
 %! [x, y, z] = peaks ();
 %! contour (x, y, z);
 
 %!demo
+%! clf ()
 %! [theta, r] = meshgrid (linspace (0, 2*pi, 64), linspace(0,1,64));
 %! [X, Y] = pol2cart (theta, r);
 %! Z = sin(2*theta).*(1-r);
 %! contour(X, Y, abs(Z), 10)
+
+%!demo
+%! clf ()
+%! x = linspace (-2, 2);
+%! [x, y] = meshgrid (x);
+%! z = sqrt (x.^2 + y.^2) ./ (x.^2 + y.^2+1);
+%! contourf (x, y, z, [0.4, 0.4])
+%! title ("The hole should be filled with the background color")
+
diff --git a/scripts/plot/private/__contour__.m b/scripts/plot/private/__contour__.m
--- a/scripts/plot/private/__contour__.m
+++ b/scripts/plot/private/__contour__.m
@@ -319,10 +319,18 @@
       else
         ## Special case unclosed contours
       endif
+      if (isnan(cont_lev(idx)))
+        fc = get (ca, "color");
+        if (strcmp (fc, "none"))
+          fc = get (ancestor (ca, "figure"), "color");
+        endif
+      else
+        fc = "flat";
+      endif
       h = [h; __go_patch__(ca, "xdata", ctmp(1, :)(:), "ydata", ctmp(2, :)(:),
                            "vertices", ctmp.', "faces", 1:(cont_len(idx)-1),
                            "facevertexcdata", cont_lev(idx),
-                           "facecolor", "flat", "cdata", cont_lev(idx),
+                           "facecolor", fc, "cdata", cont_lev(idx),
                            "edgecolor", lc, "linestyle", ls,
                            "linewidth", lw, "parent", hg)];
     endfor