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## Copyright (C) 2007-2013 David Bateman
##
## This file is part of Octave.
##
## Octave is free software; you can redistribute it and/or modify it
## under the terms of the GNU General Public License as published by
## the Free Software Foundation; either version 3 of the License, or (at
## your option) any later version.
##
## Octave is distributed in the hope that it will be useful, but
## WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
## General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with Octave; see the file COPYING. If not, see
## <http://www.gnu.org/licenses/>.
function geometryimages (nm, typ)
graphics_toolkit ("gnuplot");
set_print_size ();
hide_output ();
if (strcmp (typ, "png"))
set (0, "defaulttextfontname", "*");
endif
if (strcmp (typ, "eps"))
d_typ = "-depsc2";
else
d_typ = ["-d" typ];
endif
if (! __have_feature__ ("QHULL")
&& any (strcmp (nm, {"voronoi", "griddata", "convhull", "delaunay", ...
"triplot"})))
sombreroimage (nm, typ, d_typ);
elseif (strcmp (typ, "txt"))
image_as_txt (nm);
elseif (strcmp (nm, "voronoi"))
rand ("state", 9);
x = rand (10, 1);
y = rand (10, 1);
tri = delaunay (x, y);
[vx, vy] = voronoi (x, y, tri);
triplot (tri, x, y, "b");
hold on;
plot (vx, vy, "r");
[r, c] = tri2circ (tri(end,:), x, y);
pc = [-1:0.01:1];
xc = r * sin (pi*pc) + c(1);
yc = r * cos (pi*pc) + c(2);
plot (xc, yc, "g-", "LineWidth", 3);
axis([0, 1, 0, 1]);
legend ("Delaunay Triangulation", "Voronoi Diagram");
print ([nm "." typ], d_typ);
elseif (strcmp (nm, "triplot"))
rand ("state", 2)
x = rand (20, 1);
y = rand (20, 1);
tri = delaunay (x, y);
triplot (tri, x, y);
print ([nm "." typ], d_typ);
elseif (strcmp (nm, "griddata"))
rand ("state", 1);
x = 2 * rand (1000,1) - 1;
y = 2 * rand (size (x)) - 1;
z = sin (2 * (x.^2 + y.^2));
[xx,yy] = meshgrid (linspace (-1,1,32));
griddata (x,y,z,xx,yy);
print ([nm "." typ], d_typ);
elseif (strcmp (nm, "convhull"))
x = -3:0.05:3;
y = abs (sin (x));
k = convhull (x, y);
plot (x(k),y(k),'r-', x,y,'b+');
axis ([-3.05, 3.05, -0.05, 1.05]);
print ([nm "." typ], d_typ);
elseif (strcmp (nm, "delaunay"))
rand ("state", 1);
x = rand (1, 10);
y = rand (1, 10);
T = delaunay (x, y);
X = [ x(T(:,1)); x(T(:,2)); x(T(:,3)); x(T(:,1)) ];
Y = [ y(T(:,1)); y(T(:,2)); y(T(:,3)); y(T(:,1)) ];
axis ([0, 1, 0, 1]);
plot (X,Y,"b", x,y,"r*");
print ([nm "." typ], d_typ);
elseif (strcmp (nm, "inpolygon"))
randn ("state", 2);
x = randn (100, 1);
y = randn (100, 1);
vx = cos (pi * [-1 : 0.1: 1]);
vy = sin (pi * [-1 : 0.1 : 1]);
in = inpolygon (x, y, vx, vy);
plot (vx, vy, x(in), y(in), "r+", x(!in), y(!in), "bo");
axis ([-2, 2, -2, 2]);
print ([nm "." typ], d_typ);
else
error ("unrecognized plot requested");
endif
hide_output ();
endfunction
function [r, c] = tri2circ (tri, xx, yy)
x = xx(tri);
y = yy(tri);
m = (y(1:end-1) - y(2:end)) ./ (x(1:end-1) - x(2:end));
xc = (prod(m) .* (y(1) - y(end)) + m(end)*(x(1)+x(2)) - m(1)*(x(2)+x(3))) ...
./ (2 * (m(end) - m(1)));
yc = - (xc - (x(2) + x(3))./2) ./ m(end) + (y(2) + y(3)) / 2;
c = [xc, yc];
r = sqrt ((xc - x(1)).^2 + (yc - y(1)).^2);
endfunction
function set_print_size ()
image_size = [5.0, 3.5]; # in inches, 16:9 format
border = 0; # For postscript use 50/72
set (0, "defaultfigurepapertype", "<custom>");
set (0, "defaultfigurepaperorientation", "landscape");
set (0, "defaultfigurepapersize", image_size + 2*border);
set (0, "defaultfigurepaperposition", [border, border, image_size]);
endfunction
## Use this function before plotting commands and after every call to
## print since print() resets output to stdout (unfortunately, gnpulot
## can't pop output as it can the terminal type).
function hide_output ()
f = figure (1);
set (f, "visible", "off");
endfunction
function sombreroimage (nm, typ, d_typ)
if (strcmp (typ, "txt"))
fid = fopen (sprintf ("%s.txt", nm), "wt");
fputs (fid, "+-----------------------------+\n");
fputs (fid, "| Image unavailable because |\n");
fputs (fid, "| of a missing QHULL library. |\n");
fputs (fid, "+-----------------------------+\n");
fclose (fid);
return;
else ## if (!strcmp (typ, "txt"))
hide_output ();
[x, y, z] = sombrero ();
unwind_protect
mesh (x, y, z);
title ("Sorry, graphics not available because octave was\\ncompiled without the QHULL library.");
unwind_protect_cleanup
print ([nm "." typ], d_typ);
hide_output ();
end_unwind_protect
endif
endfunction
## generate something for the texinfo @image command to process
function image_as_txt (nm)
fid = fopen (sprintf ("%s.txt", nm), "wt");
fputs (fid, "\n");
fputs (fid, "+---------------------------------+\n");
fputs (fid, "| Image unavailable in text mode. |\n");
fputs (fid, "+---------------------------------+\n");
fclose (fid);
endfunction
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