/usr/share/octave/packages/geometry-1.7.0/geom2d/clipEdge.m is in octave-geometry 1.7.0-1build1.
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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 | ## 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.
## -*- texinfo -*-
## @deftypefn {Function File} {@var{edge2} =} clipEdge (@var{edge}, @var{box})
## Clip an edge with a rectangular box.
##
## @var{edge}: [x1 y1 x2 y2],
## @var{box} : [xmin xmax ; ymin ymax] or [xmin xmax ymin ymax];
## return :
## @var{edge2} = [xc1 yc1 xc2 yc2];
##
## If clipping is null, return [0 0 0 0];
##
## if @var{edge} is a [nx4] array, return an [nx4] array, corresponding to each
## clipped edge.
##
## @seealso{edges2d, boxes2d, clipLine}
## @end deftypefn
function edge2 = clipEdge(edge, bb)
# process data input
if size(bb, 1)==2
bb = bb';
end
# get limits of window
xmin = bb(1);
xmax = bb(2);
ymin = bb(3);
ymax = bb(4);
# convert window limits into lines
lineX0 = [xmin ymin xmax-xmin 0];
lineX1 = [xmin ymax xmax-xmin 0];
lineY0 = [xmin ymin 0 ymax-ymin];
lineY1 = [xmax ymin 0 ymax-ymin];
# compute outcodes of each vertex
p11 = edge(:,1)<xmin; p21 = edge(:,3)<xmin;
p12 = edge(:,1)>xmax; p22 = edge(:,3)>xmax;
p13 = edge(:,2)<ymin; p23 = edge(:,4)<ymin;
p14 = edge(:,2)>ymax; p24 = edge(:,4)>ymax;
out1 = [p11 p12 p13 p14];
out2 = [p21 p22 p23 p24];
# detect edges totally inside window -> no clip.
inside = sum(out1 | out2, 2)==0;
# detect edges totally outside window
outside = sum(out1 & out2, 2)>0;
# select edges not totally outside, and process separately edges totally
# inside window
ind = find(~(inside | outside));
edge2 = zeros(size(edge));
edge2(inside, :) = edge(inside, :);
for i=1:length(ind)
# current edge
iedge = edge(ind(i), :);
# compute intersection points with each line of bounding window
px0 = intersectLineEdge(lineX0, iedge);
px1 = intersectLineEdge(lineX1, iedge);
py0 = intersectLineEdge(lineY0, iedge);
py1 = intersectLineEdge(lineY1, iedge);
# create array of points
points = [px0; px1; py0; py1; iedge(1:2); iedge(3:4)];
# remove infinite points (edges parallel to box edges)
points = points(all(isfinite(points), 2), :);
# sort points by x then y
points = sortrows(points);
# get center positions between consecutive points
centers = (points(2:end,:) + points(1:end-1,:))/2;
# find the centers (if any) inside window
inside = find( centers(:,1)>=xmin & centers(:,2)>=ymin & ...
centers(:,1)<=xmax & centers(:,2)<=ymax);
# if multiple segments are inside box, which can happen due to finite
# resolution, only take the longest segment
if length(inside)>1
# compute delta vectors of the segments
dv = points(inside+1,:) - points(inside,:);
# compute lengths of segments
len = hypot(dv(:,1), dv(:,2));
# find index of longest segment
[a, I] = max(len); ##ok<ASGLU>
inside = inside(I);
end
# if one of the center points is inside box, then the according edge
# segment is indide box
if length(inside)==1
# restore same direction of edge
if iedge(1)>iedge(3) || (iedge(1)==iedge(3) && iedge(2)>iedge(4))
edge2(i, :) = [points(inside+1,:) points(inside,:)];
else
edge2(i, :) = [points(inside,:) points(inside+1,:)];
end
end
end # end of loop of edges
endfunction
%!demo
%! bb = [0 100 0 100];
%! edge = [-10 10 90 110];
%! ec = clipEdge (edge, bb);
%!
%! drawBox(bb,'color','k');
%! line(edge([1 3]),edge([2 4]),'color','b');
%! line(ec([1 3]),ec([2 4]),'color','r','linewidth',2);
%! axis tight
%! v = axis ();
%! axis(v+[0 10 -10 0])
%!shared bb
%! bb = [0 100 0 100];
%!assert (clipEdge([20 30 80 60], bb), [20 30 80 60],1e-6);
%!assert (clipEdge([0 30 80 60], bb), [0 30 80 60],1e-6);
%!assert (clipEdge([0 30 100 60], bb), [0 30 100 60],1e-6);
%!assert (clipEdge([30 0 80 100], bb), [30 0 80 100],1e-6);
%!assert (clipEdge([0 0 100 100], bb), [0 0 100 100],1e-6);
%!assert (clipEdge([0 100 100 0], bb), [0 100 100 0],1e-6);
%!assert (clipEdge([20 60 120 60], bb), [20 60 100 60],1e-6);
%!assert (clipEdge([-20 60 80 60], bb), [0 60 80 60],1e-6);
%!assert (clipEdge([20 60 20 160], bb), [20 60 20 100],1e-6);
%!assert (clipEdge([20 -30 20 60], bb), [20 0 20 60],1e-6);
%!assert (clipEdge([120 30 180 60], bb), [0 0 0 0],1e-6);
%!assert (clipEdge([-20 30 -80 60], bb), [0 0 0 0],1e-6);
%!assert (clipEdge([30 120 60 180], bb), [0 0 0 0],1e-6);
%!assert (clipEdge([30 -20 60 -80], bb), [0 0 0 0],1e-6);
%!assert (clipEdge([-120 110 190 150], bb), [0 0 0 0],1e-6);
%!assert ([50 50 100 50], clipEdge([50 50 150 50], bb),1e-6);
%!assert ([50 50 0 50], clipEdge([50 50 -50 50], bb),1e-6);
%!assert ([50 50 50 100], clipEdge([50 50 50 150], bb),1e-6);
%!assert ([50 50 50 0], clipEdge([50 50 50 -50], bb),1e-6);
%!assert ([80 50 100 70], clipEdge([80 50 130 100], bb),1e-6);
%!assert ([80 50 100 30], clipEdge([80 50 130 0], bb),1e-6);
%!assert ([20 50 0 70], clipEdge([20 50 -30 100], bb),1e-6);
%!assert ([20 50 0 30], clipEdge([20 50 -30 0], bb),1e-6);
%!assert ([50 80 70 100], clipEdge([50 80 100 130], bb),1e-6);
%!assert ([50 80 30 100], clipEdge([50 80 0 130], bb),1e-6);
%!assert ([50 20 70 0], clipEdge([50 20 100 -30], bb),1e-6);
%!assert ([50 20 30 0], clipEdge([50 20 0 -30], bb),1e-6);
%!assert ([100 50 50 50], clipEdge([150 50 50 50], bb),1e-6);
%!assert ([0 50 50 50], clipEdge([-50 50 50 50], bb),1e-6);
%!assert ([50 100 50 50], clipEdge([50 150 50 50], bb),1e-6);
%!assert ([50 0 50 50], clipEdge([50 -50 50 50], bb),1e-6);
%!assert ([100 70 80 50], clipEdge([130 100 80 50], bb),1e-6);
%!assert ([100 30 80 50], clipEdge([130 0 80 50], bb),1e-6);
%!assert ([0 70 20 50], clipEdge([-30 100 20 50], bb),1e-6);
%!assert ([0 30 20 50], clipEdge([-30 0 20 50], bb),1e-6);
%!assert ([70 100 50 80], clipEdge([100 130 50 80], bb),1e-6);
%!assert ([30 100 50 80], clipEdge([0 130 50 80], bb),1e-6);
%!assert ([70 0 50 20], clipEdge([100 -30 50 20], bb),1e-6);
%!assert ([30 0 50 20], clipEdge([0 -30 50 20], bb),1e-6);
%!assert ([0 20 80 100], clipEdge([-10 10 90 110], bb),1e-6);
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