1 ## Copyright (C) 2007-2012 David Bateman
3 ## This file is part of Octave.
5 ## Octave is free software; you can redistribute it and/or modify it
6 ## under the terms of the GNU General Public License as published by
7 ## the Free Software Foundation; either version 3 of the License, or (at
8 ## your option) any later version.
10 ## Octave is distributed in the hope that it will be useful, but
11 ## WITHOUT ANY WARRANTY; without even the implied warranty of
12 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 ## General Public License for more details.
15 ## You should have received a copy of the GNU General Public License
16 ## along with Octave; see the file COPYING. If not, see
17 ## <http://www.gnu.org/licenses/>.
20 ## @deftypefn {Function File} {} feather (@var{u}, @var{v})
21 ## @deftypefnx {Function File} {} feather (@var{z})
22 ## @deftypefnx {Function File} {} feather (@dots{}, @var{style})
23 ## @deftypefnx {Function File} {} feather (@var{h}, @dots{})
24 ## @deftypefnx {Function File} {@var{h} =} feather (@dots{})
26 ## Plot the @code{(@var{u}, @var{v})} components of a vector field emanating
27 ## from equidistant points on the x-axis. If a single complex argument
28 ## @var{z} is given, then @code{@var{u} = real (@var{z})} and
29 ## @code{@var{v} = imag (@var{z})}.
31 ## The style to use for the plot can be defined with a line style @var{style}
32 ## in a similar manner to the line styles used with the @code{plot} command.
34 ## The optional return value @var{h} is a vector of graphics handles to the
35 ## line objects representing the drawn vectors.
39 ## phi = [0 : 15 : 360] * pi/180;
40 ## feather (sin (phi), cos (phi));
44 ## @seealso{plot, quiver, compass}
47 function retval = feather (varargin)
49 [h, varargin, nargin] = __plt_get_axis_arg__ ("feather", varargin{:});
55 elseif (nargin == 1 || (nargin == 2 && ! isnumeric (varargin{2})))
60 elseif (nargin > 1 && isnumeric (varargin{2}))
67 have_line_spec = false;
68 while (ioff <= nargin)
69 arg = varargin{ioff++};
70 if ((ischar (arg) || iscell (arg)) && ! have_line_spec)
71 [linespec, valid] = __pltopt__ ("feather", arg, false);
74 have_line_spec = false;
77 error ("feather: invalid linespec");
80 error ("feather: unrecognized argument");
84 ## Matlab draws feather plots, with the arrow head as one continous
85 ## line, and each arrow separately. This is completely different than
86 ## quiver and quite ugly.
89 xtmp = [1 : n] + u .* (1 - arrowsize);
91 ytmp = v .* (1 - arrowsize);
92 x = [[1 : n]; xend; xtmp - v * arrowsize; xend; ...
93 xtmp + v * arrowsize];
94 y = [zeros(1, n); yend; ytmp + u * arrowsize / 3; yend; ...
95 ytmp - u * arrowsize / 3];
101 hlist = plot (h, x, y, line_spec, [1, n], [0, 0], line_spec);
102 unwind_protect_cleanup
115 %! phi = [0 : 15 : 360] * pi / 180;
116 %! feather (sin (phi), cos (phi))