[79637f]: devel / graphs / clipGraph.m Maximize Restore History

Download this file

clipGraph.m    233 lines (186 with data), 7.0 kB

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
## Copyright (C) 2004-2011 David Legland <david.legland@grignon.inra.fr>
## Copyright (C) 2004-2011 INRA - CEPIA Nantes - MIAJ (Jouy-en-Josas)
## Copyright (C) 2012 Adapted to Octave by Juan Pablo Carbajal <carbajal@ifi.uzh.ch>
## All rights reserved.
##
## Redistribution and use in source and binary forms, with or without
## modification, are permitted provided that the following conditions are met:
##
## 1 Redistributions of source code must retain the above copyright notice,
## this list of conditions and the following disclaimer.
## 2 Redistributions in binary form must reproduce the above copyright
## notice, this list of conditions and the following disclaimer in the
## documentation and/or other materials provided with the distribution.
##
## THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ''AS IS''
## AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
## IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
## ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
## ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
## DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
## SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
## CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
## OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
## OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
function varargout = clipGraph(nodes, edges, varargin)
#CLIPGRAPH Clip a graph with a rectangular area
#
# [N2 E2] = clipGraph(N, E, BOX);
# [N2 E2 F2] = clipGraph(N, E, F, BOX);
# N is an array ov vertices, E an array of edges, containing indices of
# first ans second vertices, and F (optional) is either a matrice or a
# cell array containing indices of vertices for each face.
# BOX is either a box given as a matrix: [XMIN XMAX;YMIN YMAX], or a row
# vector following matlab axis format: [XMIN XMAX YMIN YMAX].
#
# Example
# clipGraph
#
# See also
#
#
# ------
# Author: David Legland
# e-mail: david.legland@grignon.inra.fr
# Created: 2007-01-18
# Copyright 2007 INRA - BIA PV Nantes - MIAJ Jouy-en-Josas.
## Format inputs
# extract input arguments
faces = [];
if length(varargin)==1
box = varargin{1};
elseif length(varargin)==2
faces = varargin{1};
box = varargin{2};
else
error('Wrong number of arguments in clipGraph');
end
# uniformization of input for box.
box = box';
box = box(:);
# accuracy of numeric computations
ACC = 1e-14;
## Get bounding lines
# get bounds of the box
xmin = box(1);
xmax = box(2);
ymin = box(3);
ymax = box(4);
# create box corners
corners = [ ...
xmin ymin; ...
xmin ymax; ...
xmax ymin; ...
xmax ymax]; ...
## Clip the nodes
# find nodes inside clipping window
insideNodes = ...
nodes(:,1)-xmin>ACC & nodes(:,1)-xmax<ACC & ...
nodes(:,2)-ymin>ACC & nodes(:,2)-ymax<ACC;
# convert to indices
indNodes = find(insideNodes);
# create correspondance between original nodes and inside nodes
hashNodes = zeros(size(nodes, 1), 1);
for i=1:length(indNodes)
hashNodes(indNodes(i)) = i;
end
# select clipepd nodes
nodes2 = nodes(indNodes, :);
## Clip edges
# initialize empty array
edges2 = zeros([0 2]);
# create correspondance map between old edges and clipped edges.
hashEdges = zeros(size(edges, 1), 1);
# iterate over each edge
for e=1:size(edges, 1)
# current edge
edge = [nodes(edges(e, 1), :) nodes(edges(e, 2), :)];
# flags to indicate whether nodes are inside box or not
in1 = ismember(edges(e, 1), indNodes);
in2 = ismember(edges(e, 2), indNodes);
# check if edge is totally inside window -> no clip
if in1 && in2
edges2 = [edges2; hashNodes(edges(e, :))']; ##ok<AGROW>
hashEdges(e) = size(edges2, 1);
continue;
end
# check that edge is not totally clipped -> no edge
if edge(1)-xmin<ACC && edge(3)-xmin<ACC, continue; end
if edge(1)-xmax>ACC && edge(3)-xmax>ACC, continue; end
if edge(2)-ymin<ACC && edge(4)-ymin<ACC, continue; end
if edge(2)-ymax>ACC && edge(4)-ymax>ACC, continue; end
# otherwise, we have to clip the edge !
edge = clipEdge(edge, [box(1) box(2); box(3) box(4)]);
# display debug info
#disp(sprintf('clip edge n�%2d, from %2d to %2d', e, edges(e,1), edges(e,2)));
# Node for first vertex
if ~in1
nodes2 = [nodes2; edge([1 2])]; ##ok<AGROW>
indN1 = size(nodes2, 1);
else
indN1 = hashNodes(edges(e, 1));
end
# Node for second vertex
if ~in2
nodes2 = [nodes2; edge([3 4])]; ##ok<AGROW>
indN2 = size(nodes2, 1);
else
indN2 = hashNodes(edges(e, 2));
end
# add clipped edge to the list
edges2 = [edges2; indN1 indN2]; ##ok<AGROW>
hashEdges(e) = size(edges2, 1);
end
## Clip the faces
faces2 = {};
for f = 1:length(faces)
# indices of vertices of current face
face = faces{f};
# if the face is not clipped, use directly new indices of nodes
face2 = hashNodes(face)';
if ~ismember(0, face2)
faces2 = [faces2, {face2}]; ##ok<AGROW>
continue;
end
# At least one vertex is clipped. Here is some more special processing
# edges of current face
faceEdges = sort([face' face([2:end 1])'], 2);
# indices of face edges in edges array
indEdges = ismember(edges, faceEdges, 'rows');
# convert to indices of edges in clipped edges array. indEdges with
# value=0 correspond to totally clipped edges, and can be removed.
indEdges = hashEdges(indEdges);
indEdges = indEdges(indEdges~=0);
# case of face totally clipped: break and continuue with next face
if isempty(indEdges)
continue;
end
# extract indices of vertices of the clipped face
face2 = edges2(indEdges, :);
face2 = unique(face2(:));
# Test whether one should add one of the corner of the box.
poly = [nodes(face, 1) nodes(face, 2)];
ind = inpolygon(corners(:,1), corners(:,2), poly(:,1), poly(:,2));
if sum(ind)>0
nodes2 = [nodes2; corners(ind, :)]; ##ok<AGROW>
face2 = [face2; size(nodes2, 1)]; ##ok<AGROW>
end
# vertices of the face, as points
faceNodes = nodes2(face2, :);
# sort vertices according to their angle around the centroid
[faceNodes I] = angleSort(faceNodes, centroid(faceNodes)); ##ok<ASGLU>
# add current face to list of faces
faces2 = [faces2, {face2(I)'}]; ##ok<AGROW>
end
## Format output arguments
# clean up nodes to ensure coord correspond to clipping box.
nodes2(:,1) = min(max(nodes2(:,1), box(1)), box(2));
nodes2(:,2) = min(max(nodes2(:,2), box(3)), box(4));
if nargout==2
varargout{1} = nodes2;
varargout{2} = edges2;
elseif nargout==3
varargout{1} = nodes2;
varargout{2} = edges2;
varargout{3} = faces2;
end