1######################################################################## 2## 3## Copyright (C) 1993-2021 The Octave Project Developers 4## 5## See the file COPYRIGHT.md in the top-level directory of this 6## distribution or <https://octave.org/copyright/>. 7## 8## This file is part of Octave. 9## 10## Octave is free software: you can redistribute it and/or modify it 11## under the terms of the GNU General Public License as published by 12## the Free Software Foundation, either version 3 of the License, or 13## (at your option) any later version. 14## 15## Octave is distributed in the hope that it will be useful, but 16## WITHOUT ANY WARRANTY; without even the implied warranty of 17## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 18## GNU General Public License for more details. 19## 20## You should have received a copy of the GNU General Public License 21## along with Octave; see the file COPYING. If not, see 22## <https://www.gnu.org/licenses/>. 23## 24######################################################################## 25 26## -*- texinfo -*- 27## @deftypefn {} {} contour (@var{z}) 28## @deftypefnx {} {} contour (@var{z}, @var{vn}) 29## @deftypefnx {} {} contour (@var{x}, @var{y}, @var{z}) 30## @deftypefnx {} {} contour (@var{x}, @var{y}, @var{z}, @var{vn}) 31## @deftypefnx {} {} contour (@dots{}, @var{style}) 32## @deftypefnx {} {} contour (@var{hax}, @dots{}) 33## @deftypefnx {} {[@var{c}, @var{h}] =} contour (@dots{}) 34## Create a 2-D contour plot. 35## 36## Plot level curves (contour lines) of the matrix @var{z}, using the 37## contour matrix @var{c} computed by @code{contourc} from the same 38## arguments; see the latter for their interpretation. 39## 40## The appearance of contour lines can be defined with a line style @var{style} 41## in the same manner as @code{plot}. Only line style and color are used; 42## Any markers defined by @var{style} are ignored. 43## 44## If the first argument @var{hax} is an axes handle, then plot into this axes, 45## rather than the current axes returned by @code{gca}. 46## 47## The optional output @var{c} contains the contour levels in @code{contourc} 48## format. 49## 50## The optional return value @var{h} is a graphics handle to the hggroup 51## comprising the contour lines. 52## 53## Example: 54## 55## @example 56## @group 57## x = 0:3; 58## y = 0:2; 59## z = y' * x; 60## contour (x, y, z, 2:3) 61## @end group 62## @end example 63## 64## @seealso{ezcontour, contourc, contourf, contour3, clabel, meshc, surfc, caxis, colormap, plot} 65## 66## @end deftypefn 67 68function [c, h] = contour (varargin) 69 70 [hax, varargin] = __plt_get_axis_arg__ ("contour", varargin{:}); 71 72 oldfig = []; 73 if (! isempty (hax)) 74 oldfig = get (0, "currentfigure"); 75 endif 76 unwind_protect 77 hax = newplot (hax); 78 79 [ctmp, htmp] = __contour__ (hax, "none", varargin{:}); 80 81 if (! ishold ()) 82 set (hax, "box", "on"); 83 endif 84 85 unwind_protect_cleanup 86 if (! isempty (oldfig)) 87 set (0, "currentfigure", oldfig); 88 endif 89 end_unwind_protect 90 91 if (nargout > 0) 92 c = ctmp; 93 h = htmp; 94 endif 95 96endfunction 97 98 99%!demo 100%! clf; 101%! colormap ("default"); 102%! [x, y, z] = peaks (); 103%! contour (x, y, z); 104%! title ({"contour() plot (isolines of constant Z)"; "Z = peaks()"}); 105 106%!demo 107%! clf; 108%! colormap ("default"); 109%! [theta, r] = meshgrid (linspace (0,2*pi,64), linspace (0,1,64)); 110%! [X, Y] = pol2cart (theta, r); 111%! Z = sin (2*theta) .* (1-r); 112%! contour (X, Y, abs (Z), 10); 113%! title ({"contour() plot"; "polar fcn: Z = sin (2*theta) * (1-r)"}); 114 115%!demo 116%! clf; 117%! colormap ("default"); 118%! z = peaks (); 119%! contour (z, [0 0]); 120%! title ({"contour() plot with single isoline at Z == 0"; "Z = peaks()"}); 121 122%!test 123%! hf = figure ("visible", "off"); 124%! clf (hf); 125%! unwind_protect 126%! [x, y, z] = peaks (); 127%! [c, h] = contour (x, y, z); 128%! levellist = -6:6; 129%! set (h, "levellist", levellist); 130%! assert (get (h, "levellist"), levellist); 131%! assert (get (h, "levellistmode"), "manual"); 132%! unwind_protect_cleanup 133%! close (hf); 134%! end_unwind_protect 135 136%!test 137%! hf = figure ("visible", "off"); 138%! clf (hf); 139%! unwind_protect 140%! [x, y, z] = peaks (); 141%! [c, h] = contour (x, y, z); 142%! levelstep = 3; 143%! set (h, "levelstep", levelstep); 144%! assert (get (h, "levelstep"), levelstep); 145%! assert (get (h, "levelstepmode"), "manual"); 146%! assert (get (h, "levellist"), -6:levelstep:6); 147%! assert (get (h, "levellistmode"), "auto"); 148%! unwind_protect_cleanup 149%! close (hf); 150%! end_unwind_protect 151