59 lines
1.2 KiB
Groff
59 lines
1.2 KiB
Groff
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.TH IM_LINTRA 3 "24 April 1991"
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.SH NAME
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im_lintra, im_lintra_vec \- performs a linear transformation on an image
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.SH SYNOPSIS
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.B #include <vips/vips.h>
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.B int im_lintra_vec(n, a, in, b, out)
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.br
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.B int n;
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.br
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.B double *a, *b;
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.br
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.B IMAGE *in, *out;
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.B int im_lintra(a, in, b, out)
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.br
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.B double a, b;
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.br
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.B IMAGE *in, *out;
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.SH DESCRIPTION
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.B im_lintra_vec(3)
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performs a linear transform on image in, that is, it calculates
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out = a * in + b
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.B a
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and
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.B b
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are vectors, ie. arrays of constants of length
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.B n.
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If
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.B in
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has one band, then the vectors may be any length and the output image will
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have the same number of bands as the length of the vector. If
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.B in
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has many bands, then the vector must be length 1, or have the same length as
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the number of bands in the image.
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If the input format is one of the integer types
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then output is float. In all other cases the
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output is the same as the input.
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.B im_lintra(3)
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is a convenience function which calls
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.B im_lintra_vec(3)
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with a vector of length 1.
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.SH RETURN VALUE
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The function returns 0 on success and -1 on error.
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.SH BUGS
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The function does not check for under/overflow
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.SH SEE\ ALSO
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im_exptra(3), im_logtra(3)
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.SH AUTHOR
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N. Dessipris \- 24/04/1991
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.br
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J. Cupitt (rewrite) \- 21/7/93
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