--- a/libinterp/corefcn/gl-render.cc	Sat Jul 05 10:09:56 2014 +0200
+++ b/libinterp/corefcn/gl-render.cc	Sat Jun 21 13:07:57 2014 +0200
@@ -2208,6 +2208,14 @@
 void
 opengl_renderer::draw_patch (const patch::properties &props)
 {
+  // Do not render if the patch has incoherent data
+  std::string msg;
+  if (props.has_bad_data (msg))
+    {
+      warning ("opengl_renderer: %s. Not rendering.", msg.c_str ());
+      return;
+    }
+
   const Matrix f = props.get_faces ().matrix_value ();
   const Matrix v = xform.scale (props.get_vertices ().matrix_value ());
   Matrix c;

--- a/libinterp/corefcn/graphics.cc	Sat Jul 05 10:09:56 2014 +0200
+++ b/libinterp/corefcn/graphics.cc	Sat Jun 21 13:07:57 2014 +0200
@@ -327,6 +327,22 @@
 }
 
 static Matrix
+default_patch_xdata (void)
+{
+  Matrix m (3, 1, 0);
+  m(1) = 1.0;
+  return m;
+}
+
+static Matrix
+default_patch_ydata (void)
+{
+  Matrix m (3, 1, 1);
+  m(2) = 0;
+  return m;
+}
+
+static Matrix
 default_axes_position (void)
 {
   Matrix m (1, 4, 0.0);
@@ -7827,6 +7843,195 @@
     return convert_cdata (*this, fvc,cdatamapping_is ("scaled"), 2);
 }
 
+static bool updating_patch_data = false;
+
+void
+patch::properties::update_fvc (void)
+{
+  if (updating_patch_data)
+    return;
+
+  Matrix xd = get_xdata ().matrix_value ();
+  Matrix yd = get_ydata ().matrix_value ();
+  Matrix zd = get_zdata ().matrix_value ();
+  NDArray cd = get_cdata ().array_value ();
+
+  bad_data_msg = std::string ();
+  if (xd.dims () != yd.dims () || 
+      (xd.dims () != zd.dims () && ! zd.is_empty ()))
+    {
+      bad_data_msg = "x/y/zdata should have the same dimensions";
+      return;
+    }
+
+  // Faces and Vertices
+  dim_vector dv;
+  bool is3D = false;
+  octave_idx_type nr = xd.rows ();
+  octave_idx_type nc = xd.columns ();
+  if (nr == 1 && nc > 1)
+    {
+      nr = nc;
+      nc = 1;
+      xd = xd.transpose ();
+    }
+
+  dv(0) = nr * nc;
+  if (zd.is_empty ())
+    dv(1) = 2;
+  else
+    {
+      dv(1) = 3;
+      is3D = true;
+    }
+
+  Matrix vert (dv);
+  Matrix idx (nc, nr);
+
+  octave_idx_type kk = 0;
+  for (octave_idx_type jj = 0; jj < nc; jj++)
+    {
+      for (octave_idx_type ii = 0; ii < nr; ii++)
+        {
+          vert(kk,0) = xd(ii,jj);
+          vert(kk,1) = yd(ii,jj);
+          if (is3D)
+            vert(kk,2) = zd(ii,jj);
+
+          idx(jj,ii) = static_cast<double> (kk+1);
+
+          kk++;
+        }
+    }
+
+  // facevertexcdata
+  Matrix fvc;
+  if (cd.ndims () == 3)
+    {
+      dv(0) = cd.rows () * cd.columns ();
+      dv(1) = cd.dims ()(2);
+      fvc = cd.reshape (dv);
+    }
+  else
+    fvc = cd.as_column ();
+
+  // FIXME: shouldn't we update facevertexalphadata here ?
+
+  unwind_protect frame;
+  frame.protect_var (updating_patch_data);
+  updating_patch_data = true;
+
+  faces.set (idx);
+  vertices.set (vert);
+  facevertexcdata.set (fvc);
+}
+
+
+void
+patch::properties::update_data (void)
+{
+  if (updating_patch_data)
+    return;
+
+  Matrix idx = get_faces ().matrix_value ().transpose ();
+  Matrix vert = get_vertices ().matrix_value ();
+  NDArray fvc = get_facevertexcdata ().array_value ();
+
+  octave_idx_type nfaces = idx.columns ();
+  octave_idx_type nvert = vert.rows ();
+
+  // Check all vertices in faces are defined
+  bad_data_msg = std::string ();
+  if (static_cast<double> (nvert) < idx.row_max ().max ())
+    {
+      bad_data_msg = "some vertices in \"faces\" property are undefined";
+      return;
+    }
+
+  // Replace NaNs
+  if (idx.any_element_is_inf_or_nan ())
+    {
+      for (octave_idx_type jj = 0; jj < idx.columns (); jj++)
+        {
+          double valid_vert = idx(0,jj);
+          bool turn_valid = false;
+          for (octave_idx_type ii = 0; ii < idx.rows (); ii++)
+            {
+              if (xisnan (idx(ii,jj)) || turn_valid)
+                {
+                  idx(ii,jj) = valid_vert;
+                  turn_valid = true;
+                }
+              else
+                valid_vert = idx(ii,jj);
+            }
+        }
+    }
+  
+  // Build cdata
+  dim_vector dv = dim_vector::alloc (3);
+  NDArray cd;
+  bool pervertex = false;
+
+  if (fvc.rows () == nfaces || fvc.rows () == 1)
+    {
+      dv(0) = 1;
+      dv(1) = fvc.rows ();
+      dv(2) = fvc.columns ();
+      cd = fvc.reshape (dv);
+    }
+  else 
+    {
+      if (! fvc.is_empty ())
+        {
+          dv(0) = idx.rows ();
+          dv(1) = nfaces;
+          dv(2) = fvc.columns ();
+          cd.resize (dv);
+          pervertex = true;
+        }
+    }
+
+  // Build x,y,zdata and eventually per vertex cdata 
+  Matrix xd (idx.dims ()); 
+  Matrix yd (idx.dims ());
+  Matrix zd;
+  bool has_zd = false;
+  if (vert.columns () > 2)
+    {
+      zd = Matrix (idx.dims ());
+      has_zd = true;
+    }
+
+  
+  for (octave_idx_type jj = 0; jj < nfaces; jj++)
+    {
+      for (octave_idx_type ii = 0; ii < idx.rows (); ii++)
+        {
+          octave_idx_type row = static_cast<octave_idx_type> (idx(ii,jj)-1);
+          xd(ii,jj) = vert(row,0);
+          yd(ii,jj) = vert(row,1);
+
+          if (has_zd)
+            zd(ii,jj) = vert(row,2);
+          
+          if (pervertex)
+            for (int kk = 0; kk < fvc.columns (); kk++)
+              cd(ii,jj,kk) = fvc(row,kk);
+        }
+    }
+
+
+  unwind_protect frame;
+  frame.protect_var (updating_patch_data);
+  updating_patch_data = true;
+
+  set_xdata (xd);
+  set_ydata (yd);
+  set_zdata (zd);
+  set_cdata (cd);
+}
+
 // ---------------------------------------------------------------------
 
 octave_value

--- a/libinterp/corefcn/graphics.in.h	Sat Jul 05 10:09:56 2014 +0200
+++ b/libinterp/corefcn/graphics.in.h	Sat Jun 21 13:07:57 2014 +0200
@@ -4689,6 +4689,14 @@
   public:
     octave_value get_color_data (void) const;
 
+    // Matlab allows incoherent data to be stored into patch properties.
+    // The patch should then be ignored by the renderer. 
+    bool has_bad_data (std::string &msg) const 
+      { 
+        msg = bad_data_msg;
+        return ! msg.empty ();
+      }
+
     bool is_aliminclude (void) const
     { return (aliminclude.is_on () && alphadatamapping.is ("scaled")); }
     std::string get_aliminclude (void) const
@@ -4718,9 +4726,9 @@
       double_radio_property facealpha , double_radio_property (1.0, radio_values ("flat|interp"))
       color_property facecolor , color_property (color_values (0, 0, 0), radio_values ("none|flat|interp"))
       radio_property facelighting , "{none}|flat|gouraud|phong"
-      array_property faces , default_patch_faces ()
+      array_property faces u , default_patch_faces ()
       array_property facevertexalphadata , Matrix ()
-      array_property facevertexcdata , Matrix ()
+      array_property facevertexcdata u , Matrix ()
       // FIXME: interpreter is not a property of a Matlab patch.
       //        Octave uses this for legend() with the string displayname.
       radio_property interpreter , "{tex}|none|latex"
@@ -4735,9 +4743,9 @@
       double_property specularexponent , 10.0
       double_property specularstrength , 0.9
       array_property vertexnormals , Matrix ()
-      array_property vertices , default_patch_vertices ()
-      array_property xdata u , Matrix ()
-      array_property ydata u , Matrix ()
+      array_property vertices u , default_patch_vertices ()
+      array_property xdata u , default_patch_xdata ()
+      array_property ydata u , default_patch_ydata ()
       array_property zdata u , Matrix ()
 
       // hidden properties for limit computation
@@ -4771,17 +4779,67 @@
     }
 
   private:
-    void update_xdata (void) { set_xlim (xdata.get_limits ()); }
-    void update_ydata (void) { set_ylim (ydata.get_limits ()); }
-    void update_zdata (void) { set_zlim (zdata.get_limits ()); }
+    std::string bad_data_msg;
+
+    void update_faces (void) { update_data ();}
+
+    void update_vertices (void)  {  update_data ();}
+
+    void update_facevertexcdata (void) { update_data ();}
+
+    void update_fvc (void);
+
+    void update_xdata (void) 
+    { 
+      if (get_xdata ().is_empty ())
+        {
+          // For compatibility with matlab behavior, 
+          // if x/ydata are set empty, silently empty other *data and 
+          // faces properties while vertices remain unchanged. 
+          set_ydata (Matrix ());
+          set_zdata (Matrix ());
+          set_cdata (Matrix ());
+          set_faces (Matrix ());
+        }
+      else
+        update_fvc ();
+
+      set_xlim (xdata.get_limits ());
+    }
+
+    void update_ydata (void) 
+    { 
+      if (get_ydata ().is_empty ())
+        {
+          set_xdata (Matrix ());
+          set_zdata (Matrix ());
+          set_cdata (Matrix ());
+          set_faces (Matrix ());
+        }
+      else
+        update_fvc ();
+
+      set_ylim (ydata.get_limits ());
+    }
+
+    void update_zdata (void) 
+    { 
+      update_fvc ();
+      set_zlim (zdata.get_limits ());
+    }
 
     void update_cdata (void)
     {
+      update_fvc ();
+
       if (cdatamapping_is ("scaled"))
         set_clim (cdata.get_limits ());
       else
         clim = cdata.get_limits ();
     }
+
+
+    void update_data (void);
   };
 
 private:

--- a/scripts/plot/draw/patch.m	Sat Jul 05 10:09:56 2014 +0200
+++ b/scripts/plot/draw/patch.m	Sat Jun 21 13:07:57 2014 +0200
@@ -152,7 +152,8 @@
 %! y2 = cos (t2);
 %! vert = [x1, y1; x2, y2];
 %! fac = [1:8,NaN(1,8);9:24];
-%! patch ('Faces',fac, 'Vertices',vert, 'FaceVertexCData',[0, 1, 0; 0, 0, 1]);
+%! patch ('Faces',fac, 'Vertices',vert, ...
+%!        'FaceVertexCData',[0, 1, 0; 0, 0, 1], 'FaceColor', 'flat');
 
 %!demo
 %! %% Property change on multiple patches

--- a/scripts/plot/draw/private/__patch__.m	Sat Jul 05 10:09:56 2014 +0200
+++ b/scripts/plot/draw/private/__patch__.m	Sat Jun 21 13:07:57 2014 +0200
@@ -35,8 +35,7 @@
   is_numeric_arg = cellfun (@isnumeric, varargin);
 
   if (isempty (varargin))
-    args = {"xdata", [0; 1; 0], "ydata", [1; 1; 0], "facecolor", [0, 0, 0]};
-    args = setvertexdata (args);
+    args = varargin;
   elseif (isstruct (varargin{1}))
     if (isfield (varargin{1}, "vertices") && isfield (varargin{1}, "faces"))
       args{1} = "faces";
@@ -50,7 +49,6 @@
         args{6} = [];
       endif
       args = [args; varargin(2:end)];
-      args = setdata (args);
     else
       failed = true;
     endif
@@ -58,7 +56,6 @@
     if (nargin < 3 || ! is_numeric_arg(2))
       failed = true;
     else
-
       if (nargin > 4 && all (is_numeric_arg(1:4)))
         x = varargin{1};
         y = varargin{2};
@@ -182,188 +179,12 @@
       endif
 
       args = [args, varargin(iarg:end)];
-      args = setvertexdata (args);
     endif
   else
     args = varargin;
-    if (any (strcmpi (args, "faces") | strcmpi (args, "vertices")))
-      args = setdata (args);
-    else
-      args = setvertexdata (args);
-    endif
   endif
 
   if (!failed)
     h = __go_patch__ (p, args{:});
-
-    ## Setup listener functions
-    addlistener (h, "xdata", @update_data);
-    addlistener (h, "ydata", @update_data);
-    addlistener (h, "zdata", @update_data);
-    addlistener (h, "cdata", @update_data);
-
-    addlistener (h, "faces", @update_fvc);
-    addlistener (h, "vertices", @update_fvc);
-    addlistener (h, "facevertexcdata", @update_fvc);
   endif
 endfunction
-
-function args = delfields (args, flds)
-  idx = cellfun ("isclass", args, "char");
-  idx(idx) = ismember (args(idx), flds);
-  if (rows (idx) == 1)
-    idx |= [false, idx(1:end-1)];
-  else
-    idx |= [false; idx(1:end-1)];
-  endif
-  args(idx) = [];
-endfunction
-
-function args = setdata (args)
-  args = delfields (args, {"xdata", "ydata", "zdata", "cdata"});
-  ## Remove the readonly fields as well
-  args = delfields (args, {"type", "uicontextmenu"});
-  nargs = length (args);
-  idx = find (strcmpi (args, "faces"), 1, "last") + 1;
-  if (idx > nargs)
-    faces = [];
-  else
-    faces = args{idx};
-  endif
-  idx = find (strcmpi (args, "vertices"), 1, "last") + 1;
-  if (idx > nargs)
-    vert = [];
-  else
-    vert = args{idx};
-  endif
-  idx = find (strcmpi (args, "facevertexcdata"), 1, "last") + 1;
-  if (isempty (idx) || idx > nargs)
-    fvc = [];
-  else
-    fvc = args{idx};
-  endif
-  idx = find (strcmpi (args, "facecolor"), 1, "last") + 1;
-  if (isempty (idx) || idx > nargs)
-    if (!isempty (fvc))
-      fc = "flat";
-    else
-      fc = [0, 0, 0];
-    endif
-    args = {"facecolor", fc, args{:}};
-  endif
-
-  nc = rows (faces);
-  idx = faces.';
-  t1 = isnan (idx);
-  for i = find (any (t1))
-    first_idx_in_column = find (t1(:,i), 1);
-    idx(first_idx_in_column:end,i) = idx(first_idx_in_column-1,i);
-  endfor
-  x = reshape (vert(:,1)(idx), size (idx));
-  y = reshape (vert(:,2)(idx), size (idx));
-  if (columns (vert) > 2)
-    z = reshape (vert(:,3)(idx), size (idx));
-  else
-    z = [];
-  endif
-
-  if (rows (fvc) == nc || rows (fvc) == 1)
-    c = reshape (fvc, [1, size(fvc)]);
-  else
-    if (columns (fvc) == 3)
-      c = cat (3, reshape (fvc(idx, 1), size (idx)),
-                  reshape (fvc(idx, 2), size (idx)),
-                  reshape (fvc(idx, 3), size (idx)));
-    elseif (isempty (fvc))
-      c = [];
-    else  ## if (columnns (fvc) == 1)
-      c = permute (fvc(faces), [2, 1]);
-    endif
-  endif
-  args = {"xdata", x, "ydata", y, "zdata", z, "cdata", c, args{:}};
-endfunction
-
-function args = setvertexdata (args)
-  args = delfields (args, {"vertices", "faces", "facevertexcdata"});
-  ## Remove the readonly fields as well
-  args = delfields (args, {"type", "uicontextmenu"});
-  nargs = length (args);
-  idx = find (strcmpi (args, "xdata"), 1, "last") + 1;
-  if (idx > nargs)
-    x = [];
-  else
-    x = args{idx};
-  endif
-  idx = find (strcmpi (args, "ydata"), 1, "last") + 1;
-  if (idx > nargs)
-    y = [];
-  else
-    y = args{idx};
-  endif
-  idx = find (strcmpi (args, "zdata"), 1, "last") + 1;
-  if (isempty (idx) || idx > nargs)
-    z = [];
-  else
-    z = args{idx};
-  endif
-  idx = find (strcmpi (args, "cdata"), 1, "last") + 1;
-  if (isempty (idx) || idx > nargs)
-    c = [];
-  else
-    c = args{idx};
-  endif
-  idx = find (strcmpi (args, "facecolor"), 1, "last") + 1;
-  if (isempty (idx) || idx > nargs)
-    if (!isempty (c))
-      fc = "flat";
-    else
-      fc = [0, 0, 0];
-    endif
-    args = {"facecolor", fc, args{:}};
-  endif
-
-  [nr, nc] = size (x);
-  if (nr == 1 && nc > 1)
-    nr = nc;
-    nc = 1;
-  endif
-  if (isempty (z))
-    vert = [x(:), y(:)];
-  else
-    vert = [x(:), y(:), z(:)];
-  endif
-  faces = reshape (1:numel (x), nr, nc);
-  faces = faces.';
-
-  if (ndims (c) == 3)
-    fvc = reshape (c, rows (c) * columns (c), size (c, 3));
-  else
-    fvc = c(:);
-  endif
-
-  args = {"faces", faces, "vertices", vert, "facevertexcdata", fvc, args{:}};
-endfunction
-
-function update_data (h, d)
-  update_handle (h, false);
-endfunction
-
-function update_fvc (h, d)
-  update_handle (h, true);
-endfunction
-
-function update_handle (h, isfv)
-  persistent recursive = false;
-
-  if (! recursive)
-    recursive = true;
-    f = get (h);
-    if (isfv)
-      set (h, setdata ([fieldnames(f), struct2cell(f)].'(:)){:});
-    else
-      set (h, setvertexdata ([fieldnames(f), struct2cell(f)].'(:)){:});
-    endif
-    recursive = false;
-  endif
-endfunction
-