--- a/scripts/plot/draw/rose.m	Tue Sep 27 10:34:46 2016 +0200
+++ b/scripts/plot/draw/rose.m	Thu Sep 08 08:36:28 2016 -0700
@@ -31,7 +31,7 @@
 ##
 ## If @var{nbins} is given and is a scalar, then the histogram is produced with
 ## @var{nbin} bins.  If @var{bins} is a vector, then the center of each bin is
-## defined by the values of @var{bins} and the number of bins is
+## defined by the values in @var{bins} and the number of bins is
 ## given by the number of elements in @var{bins}.
 ##
 ## If the first argument @var{hax} is an axes handle, then plot into this axis,
@@ -43,6 +43,8 @@
 ## If two output arguments are requested then no plot is made and
 ## the polar vectors necessary to plot the histogram are returned instead.
 ##
+## Example
+##
 ## @example
 ## @group
 ## [th, r] = rose ([2*randn(1e5,1), pi + 2*randn(1e5,1)]);
@@ -50,6 +52,12 @@
 ## @end group
 ## @end example
 ##
+## Programming Note: When specifying bin centers with the @var{bins} input,
+## the edges for bins 2 to N-1 are spaced so that @code{@var{bins}(i)} is
+## centered between the edges.  The final edge is drawn halfway between bin N
+## and bin 1.  This guarantees that all input @var{th} will be placed into one
+## of the bins, but also means that for some combinations bin 1 and bin N may
+## not be centered on the user's given values.
 ## @seealso{hist, polar}
 ## @end deftypefn
 
@@ -66,38 +74,49 @@
   th = atan2 (sin (th), cos (th));
   th(th < 0) += 2*pi;
 
-  do_bin_check = false;
-  if (nargin > 1)
-    x = varargin{2};
-    if (isscalar (x))
-      do_bin_check = (x < 3); 
-      x = [0.5/x : 1/x : 1] * 2*pi;
+  custom_bins = false;
+  if (nargin == 1)
+    bins = [1/40 : 1/20 : 1] * 2*pi;
+  else
+    bins = varargin{2};
+    if (isscalar (bins))
+      bins = [0.5/bins : 1/bins : 1] * 2*pi;
     else
-      ## Force theta to [0,2*pi] range
-      x = atan2 (sin (x), cos (x));
-      x(x < 0) += 2*pi;
-      x = sort (x);
-      do_bin_check = true;
+      custom_bins = true;
+      ## Force angles to [0,2*pi] range
+      bins = atan2 (sin (bins), cos (bins));
+      bins(bins < 0) += 2*pi;
+      bins = unique (bins);
     endif
-  else
-    x = [1/40 : 1/20 : 1] * 2*pi;
   endif
-
-  [nn, xx] = hist (th, x);
-  xx = xx(:).';
-  if (isvector (nn))
-    nn = nn(:);
-  endif
-  x1 = xx(1:end-1) + diff (xx, 1) / 2;
-  x1 = [x1 ; x1; x1; x1](:);
-  th = [0; 0; x1; 2*pi ; 2*pi];
-  if (do_bin_check && any (diff (th) >= pi))
+  if (numel (bins) < 3)
     warning ("rose: bin sizes >= pi will not plot correctly");
   endif
 
-  r = zeros (4 * rows (nn), columns (nn));
-  r(2:4:end, :) = nn;
-  r(3:4:end, :) = nn;
+  [counts, binctr] = hist (th, bins);
+  binctr = binctr(:).';    # Force row vector
+  if (isvector (counts))
+    counts = counts(:);
+  endif
+  
+  binedge = binctr(1:end-1) + diff (binctr) / 2;
+  binedge = [binedge ; zeros(size(binedge)); zeros(size(binedge)); binedge];
+  binedge = binedge(:);
+  if (! custom_bins)
+    ## Add in implicit edges at 0 and 2*pi
+    th = [0; 0; binedge; 2*pi ; 0];
+  else
+    ## Add in final edge
+    last_bin_edge = binctr(end) + diff ([binctr(end), (2*pi+binctr(1))])/2;
+    if ((binedge(end) + last_bin_edge)/2 != binctr(end))
+      warning ("rose: bin 1 and bin %d are not centered", numel (binctr));
+    endif
+    th = [0; last_bin_edge; binedge; last_bin_edge; 0];
+  endif
+
+  r = zeros (4 * rows (counts), columns (counts));
+  r(2:4:end, :) = counts;
+  r(3:4:end, :) = counts;
 
   if (nargout < 2)
     oldfig = [];
@@ -134,8 +153,15 @@
 %! rose ([2*randn(1e5, 1), pi + 2*randn(1e5, 1)]);
 %! title ("rose() angular histogram plot with 2 data series");
 
+%!demo
+%! clf;
+%! rose ([0, 2, 3, 5], [0, pi/2, pi, 3*pi/2]);
+%! title ("rose() angular histogram plot with specified bins");
+
 ## Test input validation
 %!error rose ()
 %!warning <bin sizes .= pi will not plot correctly>
-%! [th, r] = rose ([1 2 2 4 4 4], [1 2 pi]);
+%! [th, r] = rose ([1 2 2 4 4 4], 2);
+%!warning <bin 1 and bin 3 are not centered>
+%! [th, r] = rose ([1 2 2 4 4 4], [1 2 3]);