fill.m: Overhaul input validation to be Matlab-compatible (bug #67535)

* NEWS.11.md: Announce changes in Matlab compatibility section.

* fill.m: Document that specifying one color per polygon can be done with any
vector (not just row vector).  Use numel() in preference to length().  Add
FIXME note about missing validation that inputs X, Y, and C are 2-D.  Replace
input logic for vector/matrix combinations with longer code that attempts to
match the length of the vector to one of the dimensions of the matrix data.
Replace use of isequal() (slow) with faster tests that don't require function
call.  Validate that RGB triplet data is in the range [0,1].

Author: Rik

etc/NEWS.11.md

@@ -79,6 +79,9 @@ Summary of important user-visible changes for version 11 (yyyy-mm-dd):
   invocations for each cell element.  In earlier versions, the elements were
   converted to a compatible type if possible.
 
+- The function `fill` now handles all input combination of vector and matrix
+  vertex data and color data in a Matlab-compatible way.
+
 ### Alphabetical list of new functions added in Octave 11
 
 * `corrcov`

scripts/plot/draw/fill.m

@@ -40,11 +40,11 @@
 ## is a single color specification such as a @code{plot} format or an
 ## RGB-triple.  In this case the polygon(s) will have one unique color.  If
 ## @var{c} is a vector or matrix then the color data is first scaled using
-## @code{clim} and then indexed into the current colormap.  A row vector will
-## color each polygon (a column from matrices @var{x} and @var{y}) with a
-## single computed color.  A matrix @var{c} of the same size as @var{x} and
-## @var{y} will compute the color of each vertex and then interpolate the face
-## color between the vertices.
+## @code{clim} and then indexed into the current colormap.  A vector will color
+## each polygon (a column from matrices @var{x} and @var{y}) with a single
+## computed color.  A matrix @var{c} of the same size as @var{x} and @var{y}
+## will compute the color of each vertex and then interpolate the face color
+## between the vertices.
 ##
 ## Multiple property/value pairs for the underlying patch object may be
 ## specified, but they must appear in pairs.  The full list of properties is
@@ -53,8 +53,8 @@
 ## If the first argument @var{hax} is an axes handle, then plot into this axes,
 ## rather than the current axes returned by @code{gca}.
 ##
-## The optional return value @var{h} is a vector of graphics handles to
-## the created patch objects.
+## The optional return value @var{h} is a vector of graphics handles to the
+## created patch objects.
 ##
 ## Example: red square
 ##
@@ -102,20 +102,12 @@
     unwind_protect
       set (hax, "nextplot", "add");
 
-      for i = 1 : length (iargs)
+      for i = 1 : numel (iargs)
         x = varargin{iargs(i)};
         y = varargin{iargs(i) + 1};
         cdata = varargin{iargs(i) + 2};
 
-        if (! size_equal (x, y))
-          if (iscolumn (y) && rows (y) == rows (x))
-            y = repmat (y, [1, columns(x)]);
-          elseif (iscolumn (x) && rows (x) == rows (y))
-            x = repmat (x, [1, columns(y)]);
-          else
-            error ("fill: X and Y must have same number of rows");
-          endif
-        endif
+        ## FIXME: Probably should validate that x, y, cdata are 2-D.
 
         if (isrow (x))
           x = x(:);
@@ -124,17 +116,52 @@
           y = y(:);
         endif
 
-        if (ischar (cdata) || isequal (size (cdata), [1, 3]))
+        if (! size_equal (x, y))
+          if (iscolumn (x))
+            rx = rows (x);
+            [ry, cy] = size (y);
+            if (rx == ry)
+              x = repmat (x, [1, cy]);
+            elseif (rx == cy)
+              y = y.';
+              x = repmat (x, [1, ry]);
+            else
+              error ("fill: vector X and matrix Y must have a length which matches along one dimension");
+            endif
+          elseif (iscolumn (y))
+            ry = rows (y);
+            [rx, cx] = size (x);
+            if (ry == rx)
+              y = repmat (y, [1, cx]);
+            elseif (ry == cx)
+              x = x.';
+              y = repmat (y, [1, rx]);
+            else
+              error ("fill: matrix X and vector Y must have a length which matches along one dimension");
+            endif
+          else
+            error ("fill: matrices X and Y must be the same size");
+          endif
+        endif
+
+        ## Test for color specification as text ('r') or RGB triple.
+        if (ischar (cdata) ||
+            (all (size (cdata) == [1, 3]) && all (cdata >= 0 & cdata <= 1)))
           one_color = true;
         else
           one_color = false;
         endif
 
-        ## For Matlab compatibility, replicate cdata to match size of data
-        if (! one_color && iscolumn (cdata))
-          sz = size (x);
-          if (all (sz > 1))
-            cdata = repmat (cdata, [1, sz(2)]);
+        ## Manage cdata to ensure for loop below works
+        if (! one_color && isvector (cdata))
+          if (numel (cdata) == columns (x))
+            ## One color per polygon
+            cdata = cdata(:).';
+          elseif (numel (cdata) == rows (x))
+            ## Vertex colors.  Replicate cdata to match size of data.
+            cdata = repmat (cdata(:), [1, columns(x)]);
+          else
+            error ("fill: invalid format for color data C");
           endif
         endif