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[Octave-cvsupdate] SF.net SVN: octave:[10204] trunk/octave-forge/main/geometry
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From: <jpi...@us...> - 2012-04-12 21:22:54
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Revision: 10204
http://octave.svn.sourceforge.net/octave/?rev=10204&view=rev
Author: jpicarbajal
Date: 2012-04-12 21:22:47 +0000 (Thu, 12 Apr 2012)
Log Message:
-----------
geometry: Adding curveval and cuve2polyline. functions to convert form polygonal curves to polylines.
Modified Paths:
--------------
trunk/octave-forge/main/geometry/DESCRIPTION
trunk/octave-forge/main/geometry/INDEX
trunk/octave-forge/main/geometry/NEWS
trunk/octave-forge/main/geometry/inst/shape2d/shape2polygon.m
Added Paths:
-----------
trunk/octave-forge/main/geometry/inst/shape2d/curve2polyline.m
trunk/octave-forge/main/geometry/inst/shape2d/curveval.m
Modified: trunk/octave-forge/main/geometry/DESCRIPTION
===================================================================
--- trunk/octave-forge/main/geometry/DESCRIPTION 2012-04-12 13:47:32 UTC (rev 10203)
+++ trunk/octave-forge/main/geometry/DESCRIPTION 2012-04-12 21:22:47 UTC (rev 10204)
@@ -1,11 +1,11 @@
Name: Geometry
-Version: 1.4.1
-Date: 2012-03-24
+Version: 1.4.2
+Date: 2012-XX-XX
Author: David Legland <dav...@gr...>, José Luis García Pallero <jgp...@gm...>, Juan Pablo Carbajal <car...@if...>
Maintainer: Juan Pablo Carbajal <car...@if...>
Title: Computational Geometry
Description: Library for geometric computing extending MatGeom functions. Useful to create, transform, manipulate and display geometric primitives.
-Depends: octave (>= 3.4.0)
+Depends: octave (>= 3.4.0), general (>= 1.3.0)
Autoload: yes
License: GPLv3+, FreeBSD
Url: http://octave.sf.net, http://matgeom.sf.net, http://davis.wpi.edu/~matt/courses/clipping/, https://bitbucket.org/jgpallero/octclip
Modified: trunk/octave-forge/main/geometry/INDEX
===================================================================
--- trunk/octave-forge/main/geometry/INDEX 2012-04-12 13:47:32 UTC (rev 10203)
+++ trunk/octave-forge/main/geometry/INDEX 2012-04-12 21:22:47 UTC (rev 10204)
@@ -124,6 +124,8 @@
shapecentroid
shapeplot
shapetransform
+ curvelval
+ curve2polyline
2D Others
bisector
crackPattern2
Modified: trunk/octave-forge/main/geometry/NEWS
===================================================================
--- trunk/octave-forge/main/geometry/NEWS 2012-04-12 13:47:32 UTC (rev 10203)
+++ trunk/octave-forge/main/geometry/NEWS 2012-04-12 21:22:47 UTC (rev 10204)
@@ -1,6 +1,19 @@
Summary of important user-visible changes for releases of the geometry package
===============================================================================
+geometry-1.4.2 Release Date: 2012-XX-XX Release Manager: Juan Pablo Carbajal
+===============================================================================
+
+* Added function
+ - curveval.m: Evaluates a polynomial curve defined as a 2-by-N matrix.
+ - curve2polyline.m: Converts a polynomial curve into a polyline by the adaptive
+ sampling method.
+
+* Known issues
+ - simplifypolygon.m returns empty polygons when points are repeated, i.e when
+ the polygon is not correctly formed.
+
+===============================================================================
geometry-1.4.1 Release Date: 2012-03-24 Release Manager: Juan Pablo Carbajal
===============================================================================
Added: trunk/octave-forge/main/geometry/inst/shape2d/curve2polyline.m
===================================================================
--- trunk/octave-forge/main/geometry/inst/shape2d/curve2polyline.m (rev 0)
+++ trunk/octave-forge/main/geometry/inst/shape2d/curve2polyline.m 2012-04-12 21:22:47 UTC (rev 10204)
@@ -0,0 +1,139 @@
+%% Copyright (c) 2012 Juan Pablo Carbajal <car...@if...>
+%%
+%% This program 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
+%% any later version.
+%%
+%% This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
+
+%% -*- texinfo -*-
+%% @deftypefn {Function File} {@var{polyline} = } curve2polyline (@var{curve})
+%% @deftypefnx {Function File} {@var{polyline} = } curve2polyline (@dots,@var{property},@var{value},@dots)
+%% Adaptive sampling of a parametric curve.
+%%
+%% The @var{curve} is described as a 2-by-N matrix. Rows correspond to the
+%% polynomial (compatible with @code{polyval}) describing the respective component
+%% of the curve. The curve must be parametrized in the interval [0,1].
+%% The vertices of the polyline are accumulated in regions of the curve where
+%% the curvature is higher.
+%%
+%% @strong{Parameters}
+%% @table @samp
+%% @item 'Nmax'
+%% Maximum number of vertices. Not used.
+%% @item 'Tol'
+%% Tolerance for the error criteria. Default value @code{1e-4}.
+%% @item 'MaxIter'
+%% Maximum number of iterations. Default value @code{10}.
+%% @item 'Method'
+%% Not implemented.
+%% @end table
+%%
+%% @seealso{shape2polygon, curveval}
+%% @end deftypefn
+
+%% This function is based on the algorithm described in
+%% L. H. de Figueiredo (1993). "Adaptive Sampling of Parametric Curves". Graphic Gems III.
+%% I had to remove the recursion so this version could be improved.
+%% Thursday, April 12 2012 -- JuanPi
+
+function [polyline t bump]= curve2polyline (curve, varargin)
+
+ # --- Parse arguments --- #
+ parser = inputParser ();
+ parser.FunctionName = "curve2polyline";
+ parser = addParamValue (parser,'Nmax', 32, @(x)x>0);
+ parser = addParamValue (parser,'Tol', 1e-4, @(x)x>0);
+ parser = addParamValue (parser,'MaxIter', 10, @(x)x>0);
+ parser = parse(parser,varargin{:});
+
+ Nmax = parser.Results.Nmax;
+ tol = parser.Results.Tol;
+ MaxIter = parser.Results.MaxIter;
+
+ clear parser
+ # ------ #
+
+ t = [0; 1];
+ tf = 1;
+ points = 1;
+ for iter = 1:MaxIter
+ % Add parameter values where error is still bigger than tol.
+ t = interleave(t, tf);
+ nt = length(t);
+
+ % Update error
+ polyline = curveval (curve,t);
+ bump = bumpyness(polyline);
+
+ % Check which intervals must be subdivided
+ idx = find(bump > tol);
+ % The position of the bumps mpas into intervals
+ % 1 -> 1 2
+ % 2 -> 3 4
+ % 3 -> 5 6
+ % and so on
+ idx = [2*(idx-1)+1; 2*idx](:);
+ tf = false (nt-1,1);
+ tf(idx) = true;
+
+ if all (!tf)
+ break;
+ end
+
+ end
+
+endfunction
+
+function f = bumpyness (p)
+%% Check for co-linearity
+%% TODO implement various method for this
+%% -- Area of the triangle close to zero (used currently).
+%% -- Angle close to pi.
+%% -- abs(p0-pt) + abs(pt-p1) - abs(p0-p1) almost zero.
+%% -- Curve's tange at 0,t,1 are almost parallel.
+%% -- pt is in chord p0 -> p1.
+
+ PL = p(1:2:end-2,:);
+ PC = p(2:2:end-1,:);
+ PR = p(3:2:end,:);
+
+ a = PL - PC;
+ b = PR - PC;
+
+ f = (a(:,1).*b(:,2) - a(:,2).*b(:,1)).^2;
+
+endfunction
+
+function tt = interleave (t,varargin)
+
+ nt = length(t);
+ ntt = 2 * nt -1;
+ tt = zeros(ntt,1);
+ tt(1:2:ntt) = t;
+ beta = 0.4 + 0.2*rand(nt-1, 1);
+ tt(2:2:ntt) = t(1:end-1) + beta.*(t(2:end)-t(1:end-1));
+
+ if nargin > 1
+ tf = true (ntt,1);
+ tf(2:2:ntt) = varargin{1};
+ tt(!tf) = [];
+ end
+
+endfunction
+
+%!demo
+%! curve = [0 0 1 0;1 -0.3-1 0.3 0];
+%! polyline = curve2polyline(curve,'tol',1e-8);
+%!
+%! t = linspace(0,1,100)';
+%! pc = curveval(curve,t);
+%!
+%! plot(p(:,1),p(:,2),'-o',pc(:,1),pc(:,2),'-r')
Added: trunk/octave-forge/main/geometry/inst/shape2d/curveval.m
===================================================================
--- trunk/octave-forge/main/geometry/inst/shape2d/curveval.m (rev 0)
+++ trunk/octave-forge/main/geometry/inst/shape2d/curveval.m 2012-04-12 21:22:47 UTC (rev 10204)
@@ -0,0 +1,30 @@
+%% Copyright (c) 2012 Juan Pablo Carbajal <car...@if...>
+%%
+%% This program 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
+%% any later version.
+%%
+%% This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
+
+%% -*- texinfo -*-
+%% @deftypefn {Function File} {@var{p} = } curveval (@var{curve}, @var{t})
+%% Evaluates parametric @var{curve} at @var{t}.
+%%
+%% @end deftypefn
+function p = curveval (curve, t)
+
+ dim = size (curve,1);
+ p = zeros (length(t), dim);
+
+ for i = 1:dim
+ p(:,i) = polyval (curve(i,:), t);
+ end
+
+endfunction
Modified: trunk/octave-forge/main/geometry/inst/shape2d/shape2polygon.m
===================================================================
--- trunk/octave-forge/main/geometry/inst/shape2d/shape2polygon.m 2012-04-12 13:47:32 UTC (rev 10203)
+++ trunk/octave-forge/main/geometry/inst/shape2d/shape2polygon.m 2012-04-12 21:22:47 UTC (rev 10204)
@@ -21,7 +21,7 @@
%% @var{shape} is a n-by-1 cell where each element is a pair of polynomials
%% compatible with polyval.
%% @var{polygon} is a k-by-2 matrix, where each row represents a vertex.
-%% @var{N} defines the number of points to be used in non-straigth edges.
+%% @var{N} defines the number of points to be used in non-straight edges.
%%
%% @seealso{polygon2shape, drawPolygon}
%% @end deftypefn
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