7120
|
1 ## Copyright (C) 2007 David Bateman |
|
2 ## |
|
3 ## This file is part of Octave. |
|
4 ## |
|
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. |
|
9 ## |
|
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. |
|
14 ## |
|
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/>. |
|
18 |
|
19 ## -*- texinfo -*- |
|
20 ## @deftypefn {Function File} {} quiver (@var{u}, @var{v}) |
|
21 ## @deftypefnx {Function File} {} quiver (@var{x}, @var{y}, @var{u}, @var{v}) |
|
22 ## @deftypefnx {Function File} {} quiver (@dots{}, @var{s}) |
|
23 ## @deftypefnx {Function File} {} quiver (@dots{}, @var{style}) |
|
24 ## @deftypefnx {Function File} {} quiver (@dots{}, 'filled') |
|
25 ## @deftypefnx {Function File} {} quiver (@var{h}, @dots{}) |
|
26 ## @deftypefnx {Function File} {@var{h} =} quiver (@dots{}) |
|
27 ## |
|
28 ## Plot the @code{(@var{u}, @var{v})} components of a vector field in |
|
29 ## an @code{(@var{x}, @var{y})} meshgrid. If the grid is uniform, you can |
|
30 ## specify @var{x} and @var{y} as vectors. |
|
31 ## |
|
32 ## If @var{x} and @var{y} are undefined they are assumed to be |
|
33 ## @code{(1:@var{m}, 1:@var{n})} where @code{[@var{m}, @var{n}] = |
|
34 ## size(@var{u})}. |
|
35 ## |
|
36 ## The variable @var{s} is a scalar defining a scaling factor to use for |
|
37 ## the arrows of the field relative to the mesh spacing. A value of 0 |
|
38 ## disables all scaling. The default value is 1. |
|
39 ## |
|
40 ## The style to use for the plot can be defined with a line style @var{style} |
|
41 ## in a similar manner to the line styles used with the @code{plot} command. |
|
42 ## If a marker is specified then markers at the grid points of the vectors are |
|
43 ## printed rather than arrows. If the argument 'filled' is given then the |
|
44 ## markers as filled. |
|
45 ## |
|
46 ## The optional return value @var{h} provides a list of handles to the |
|
47 ## the parts of the vector field (body, arrow and marker). |
|
48 ## |
7121
|
49 ## @example |
7120
|
50 ## @group |
7121
|
51 ## [x, y] = meshgrid (1:2:20); |
|
52 ## quiver (x, y, sin (2*pi*x/10), sin (2*pi*y/10)); |
|
53 ## @end group |
7120
|
54 ## @end example |
|
55 ## |
|
56 ## @seealso{plot} |
|
57 ## @end deftypefn |
|
58 |
|
59 function retval = quiver (varargin) |
7121
|
60 |
7215
|
61 [h, varargin, nargin] = __plt_get_axis_arg__ ("quiver", varargin{:}); |
|
62 |
7120
|
63 if (nargin < 2) |
|
64 print_usage (); |
7215
|
65 else |
7120
|
66 oldh = gca (); |
|
67 unwind_protect |
|
68 axes (h); |
|
69 newplot (); |
7215
|
70 tmp = __quiver__ (h, 0, varargin{:}); |
7120
|
71 unwind_protect_cleanup |
|
72 axes (oldh); |
|
73 end_unwind_protect |
|
74 endif |
|
75 |
|
76 if (nargout > 0) |
|
77 retval = tmp; |
|
78 endif |
7121
|
79 |
7120
|
80 endfunction |
|
81 |
|
82 %!demo |
|
83 %! [x,y] = meshgrid(1:2:20); |
|
84 %! quiver(x,y,sin(2*pi*x/10),sin(2*pi*y/10)) |
|
85 |
|
86 %!demo |
|
87 %! axis("equal"); |
|
88 %! x=linspace(0,3,80); y=sin(2*pi*x); theta=2*pi*x+pi/2; |
|
89 %! quiver(x,y,sin(theta)/10,cos(theta)/10); |
|
90 %! hold on; plot(x,y,"r"); hold off; |