Mercurial > octave-antonio

comparison scripts/geometry/rectint.m @ 7655:ea2344c4140b

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
rectint.m: vectorize and add tests
author bill@denney.ws
date Thu, 27 Mar 2008 14:48:36 -0400
parents 5ed0cb9e9584
children 836618fee9d6
comparison
equal deleted inserted replaced
7654:48edf48cd4dc 7655:ea2344c4140b
41 error ("rectint: expecting arguments to be 2-d arrays"); 41 error ("rectint: expecting arguments to be 2-d arrays");
42 elseif (columns (a) != 4) 42 elseif (columns (a) != 4)
43 error ("rectint: a must have 4 columns"); 43 error ("rectint: a must have 4 columns");
44 elseif (columns (b) != 4) 44 elseif (columns (b) != 4)
45 error ("rectint: b must have 4 columns"); 45 error ("rectint: b must have 4 columns");
46 elseif any ([a(:,3:4);b(:,3:4)](:) < 0)
47 error ("rectint: all widths and heights must be > 0")
48 endif
49
50 ## This runs faster if the number of rows of a is greater than the
51 ## number of rows of b. Swap them and transpose to make it run
52 ## faster.
53 swapinputs = false ();
54 if (rows (a) > rows (b))
55 tmp = a;
56 a = b;
57 b = tmp;
58 swapinputs = true ();
46 endif 59 endif
47 60
48 area = zeros (rows (a), rows (b)); 61 area = zeros (rows (a), rows (b));
49 for i = 1:rows (area) 62 r1 = [a(:,1:2) a(:,1:2)+a(:,3:4)];
50 r1 = a(i,:); 63 r2 = [b(:,1:2) b(:,1:2)+b(:,3:4)];
51 for j = 1:columns (area) 64 for i = 1:columns (area)
52 r2 = b(j,:); 65 ## Find the location of each point relative to the other points.
53 area(i,j) = (overlap (r1([1, 3]), r2([1, 3])) 66 r1x1small = r1(:,1) < r2(i,1);
54 * overlap (r1([2, 4]), r2([2, 4]))); 67 r1x1large = r1(:,1) > r2(i,3);
55 endfor 68 r1x1mid = (r1(:,1) >= r2(i,1)) & (r1(:,1) <= r2(i,3));
69 r1x2small = r1(:,3) < r2(i,1);
70 r1x2large = r1(:,3) > r2(i,3);
71 r1x2mid = (r1(:,3) >= r2(i,1)) & (r1(:,3) <= r2(i,3));
72
73 r1y1small = r1(:,2) < r2(i,2);
74 r1y1large = r1(:,2) > r2(i,4);
75 r1y1mid = (r1(:,2) >= r2(i,2)) & (r1(:,2) <= r2(i,4));
76 r1y2small = r1(:,4) < r2(i,2);
77 r1y2large = r1(:,4) > r2(i,4);
78 r1y2mid = (r1(:,4) >= r2(i,2)) & (r1(:,4) <= r2(i,4));
79
80 ## determine the width of the rectangle
81 ## r1 completely encloses r2
82 area(r1x1small & r1x2large,i) = r2(i,3) - r2(i,1);
83 ## the range goes from r2x min to r1x max
84 mask = r1x1small & r1x2mid;
85 area(mask,i) = r1(mask,3) - r2(i,1);
86 ## the range goes from r1x min to r2x max
87 mask = r1x1mid & r1x2large;
88 area(mask,i) = r2(i,3) - r1(mask,1);
89 ## the range goes from r1x min to r1x max
90 mask = r1x1mid & r1x2mid;
91 area(mask,i) = r1(mask,3) - r1(mask,1);
92
93 ## determine the height of the rectangle
94 ## r1 completely encloses r2
95 area(r1y1small & r1y2large,i) .*= r2(i,4) - r2(i,2);
96 ## the range goes from r2y min to r1y max
97 mask = r1y1small & r1y2mid;
98 area(mask,i) .*= r1(mask,4) - r2(i,2);
99 ## the range goes from r1y min to r2y max
100 mask = r1y1mid & r1y2large;
101 area(mask,i) .*= r2(i,4) - r1(mask,2);
102 ## the range goes from r1x min to r1x max
103 mask = r1y1mid & r1y2mid;
104 area(mask,i) .*= r1(mask,4) - r1(mask,2);
105
56 endfor 106 endfor
57 107
58 endfunction 108 if swapinputs
59 109 area = area';
60 function amt = overlap (r1, r2)
61
62 ## Determine whether two ranges overlap. Ranges are given as [value
63 ## offset]
64 amt = 0;
65
66 ## Make sure that the values are in order.
67 r1 = sort ([r1(1), r1(1)+r1(2)]);
68 r2 = sort ([r2(1), r2(1)+r2(2)]);
69
70 ## Is the first point in range 1 in the middle of range 2?
71 p1 = sum (r1(1) <= r2) == 1;
72 ## is the second?
73 p2 = sum (r1(2) <= r2) == 1;
74 if (p1)
75 if (p2)
76 amt = r1(2) - r1(1);
77 else
78 amt = r2(2) - r1(1);
79 endif
80 elseif (sum (r1(2) < r2) == 1)
81 amt = r1(2) - r2(1);
82 endif 110 endif
83 111
84 endfunction 112 endfunction
85 113
86 ## Tests 114 ## Tests
115 ## Exactly overlapping
116 %!assert(rectint([0 0 1 1], [0 0 1 1]), 1)
117 ## rect2 completely enclosed by rect1
118 %!assert(rectint([-1 -1 3 3], [0 0 1 1]), 1)
119 ## rect1 completely enclosed by rect2
120 %!assert(rectint([0 0 1 1], [-1 -1 3 3]), 1)
121 ## rect1 right and top in rect2
122 %!assert(rectint([-1 -1 1.5 1.5], [0 0 1 1]), 0.25)
123 ## rect2 right and top in rect1
124 %!assert(rectint([0 0 1 1], [-1 -1 1.5 1.5]), 0.25)
125 ## no overlap - shared corner
87 %!assert(rectint([0 0 1 1], [1 1 2 2]), 0) 126 %!assert(rectint([0 0 1 1], [1 1 2 2]), 0)
88 %!assert(rectint([0 0 1 1], [0.5 0.5 2 2]), 0.25) 127 ## no overlap - shared edge
89 %!assert(rectint([0 0 1 1;0.5 0.5 1 1], [1 1 2 2]), [0;0.25]) 128 %!assert(rectint([0 0 1 1], [0 1 2 2]), 0)
90 %!assert(rectint([1 1 2 2], [0 0 1 1;0.5 0.5 1 1]), [0 0.25]) 129 ## Correct orientation of output
91 130 %!assert(rectint([0 0 1 1;0.5 0.5 1 1;-1 -1 2 2], [1 1 2 2]), [0;0.25;0])
131 %!assert(rectint([1 1 2 2], [0 0 1 1;0.5 0.5 1 1;-1 -1 2 2]), [0 0.25 0])