1RELATIONAL(3)              Library Functions Manual              RELATIONAL(3)
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NAME

6       im_equal,  im_notequal,  im_equalconst, im_equal_vec, im_notequalconst,
7       im_notequal_vec, im_less, im_lessconst, im_less_vec, im_more,  im_more‐
8       const,    im_more_vec,    im_lesseq,   im_lesseqconst,   im_lesseq_vec,
9       im_moreeq, im_moreeqconst, im_moreeq_vec - relational tests on images.
10

SYNOPSIS

12       #include <vips/vips.h>
13
14       int im_equal(a, b, out)
15       IMAGE *a, *b, *out;
16
17       int im_equalconst(a, out, c)
18       IMAGE *a, *out;
19       double c;
20
21       int im_equal_vec(a, out, n, v)
22       IMAGE *a, *out;
23       int n;
24       double *v;
25
26       int im_notequal(a, b, out)
27       IMAGE *a, *b, *out;
28
29       int im_notequalconst(a, out, c)
30       IMAGE *a, *out;
31       double c;
32
33       int im_notequal_vec(a, out, n, v)
34       IMAGE *a, *out;
35       int n;
36       double *v;
37
38       int im_less(a, b, out)
39       IMAGE *a, *b, *out;
40
41       int im_lessconst(a, out, c)
42       IMAGE *a, *out;
43       double c;
44
45       int im_less_vec(a, out, n, v)
46       IMAGE *a, *out;
47       int n;
48       double *v;
49
50       int im_more(a, b, out)
51       IMAGE *a, *b, *out;
52
53       int im_moreconst(a, out, c)
54       IMAGE *a, *out;
55       double c;
56
57       int im_more_vec(a, out, n, v)
58       IMAGE *a, *out;
59       int n;
60       double *v;
61
62       int im_lesseq(a, b, out)
63       IMAGE *a, *b, *out;
64
65       int im_lesseqconst(a, out, c)
66       IMAGE *a, *out;
67       double c;
68
69       int im_lesseq_vec(a, out, n)
70       IMAGE *a, *out;
71       int n;
72       double *v;
73
74       int im_moreeq(a, b, out)
75       IMAGE *a, *b, *out;
76
77       int im_moreeqconst(a, out, c)
78       IMAGE *a, *out;
79       double c;
80
81       int im_moreeq_vec(a, out, n, v)
82       IMAGE *a, *out;
83       int n;
84       double *v;
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86

DESCRIPTION

88       These functions perform a range of relational tests between images,  or
89       between  an  image  and  a constant. Functions which take two images as
90       arguments require that the two images be the same  size  and  have  the
91       same  number  of  bands.  They can be of mixed type: you may compare an
92       unsigned char image with a double image.
93
94       All functions return an unsigned char image, with the  same  number  of
95       bands  as the input images, in which band elements have been set to 255
96       for true and 0 for false.
97
98       The logical functions (im_andimage(3),  im_orimage(3),  im_eorimage(3))
99       may  be  used to combine boolean images to make more complex tests. The
100       selection function im_ifthenelse(3) may be used to take action  on  the
101       result of a test.
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103

RETURN VALUE

105       All functions return 0 on success and -1 on error.
106

SEE ALSO

108       im_ifthenelse(3), im_andimage(3).
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111       National Gallery, 1992
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AUTHOR

114       J. Cupitt
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118                                30 October 1992                  RELATIONAL(3)
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