Re: Bug with patch

[Shai Ayal]

On 10/8/07, David Bateman <address@hidden> wrote:
> There is an issue with the patch command.. Firstly it should accept a
> handle as the first argument (consider the attached patch). However the
> more important issue is that it miss treats the case where more that a
> single patch is treated in one call to patch. Consider the code
>
> t = (1/16:1/8:1)'*2*pi;t2 = ((1/16:1/8:1)' + 1/32)*2*pi; x =sin(t); y =
> cos(t); x2 = sin(t2); y2=cos(t2); h = patch([x,x2],[y,y2],'r')
>
> The patches are drawn correctly, however the handle h that is returned
> is a handle to the last patch drawn and not a handle to a multi-element
> patch that includes all of the patches..
>
> Its easy enough to treat the data and get this part right. However,
> looking at the facecolor code I'm not sure what this was originally
> trying to achieve and so I don't see the fix for this immediately.
> Shai/Kai do you a what the facecolor code is trying to do and a way to
> fix it to accept the cdata for multiple facets at once correctly?

This is Kai's code, but I think he was trying to achieve the behaviour
documented in:
http://www.mathworks.com/access/helpdesk/help/techdoc/ref/patch.html?cmdname=patch
under the section "Color Data Interpretation"

Shai


>
> D.
>
> *** ./scripts/plot/patch.m.orig22       2007-10-08 18:14:05.623299538 +0200
> --- ./scripts/plot/patch.m      2007-10-08 18:13:48.114126966 +0200
> ***************
> *** 21,26 ****
> --- 21,27 ----
>   ## @deftypefn {Function File} {} patch ()
>   ## @deftypefnx {Function File} {} patch (@var{x}, @var{y}, @var{c})
>   ## @deftypefnx {Function File} {} patch (@var{x}, @var{y}, @var{c}, 
> @var{opts})
> + ## @deftypefnx {Function File} {} patch (@var{h}, @dots{})
>   ## Create patch object from @var{x} and @var{y} with color @var{c} and
>   ## insert in the current axes object.  Return handle to patch object.
>   ##
> ***************
> *** 33,41 ****
>
>   function h = patch (varargin)
>
> !   ## make a default patch object, and make it the current axes for
> !   ## the current figure.
> !   tmp = __patch__ (gca (), varargin{:});
>
>     if (nargout > 0)
>       h = tmp;
> --- 34,54 ----
>
>   function h = patch (varargin)
>
> !   if (isscalar (varargin{1}) && ishandle (varargin{1}))
> !     h = varargin {1};
> !     if (! strcmp (get (h, "type"), "axes"))
> !       error ("patch: expecting first argument to be an axes object");
> !     endif
> !     oldh = gca ();
> !     unwind_protect
> !       axes (h);
> !       tmp = __patch__ (h, varargin{:});
> !     unwind_protect_cleanup
> !       axes (oldh);
> !     end_unwind_protect
> !   else
> !     tmp = __patch__ (gca (), varargin{:});
> !   endif
>
>     if (nargout > 0)
>       h = tmp;
>
>