40 lines
1.1 KiB
Groff
40 lines
1.1 KiB
Groff
.TH IM_IFTHENELSE 3 "30 October 1992"
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.SH NAME
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im_ifthenelse \- use an unsigned char image to join two images together
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.SH SYNOPSIS
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.B #include <vips/vips.h>
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.B int im_ifthenelse(c, a, b, out)
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.br
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.B IMAGE *c, *a, *b, *out;
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.B int im_blend(c, a, b, out)
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.br
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.B IMAGE *c, *a, *b, *out;
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.SH DESCRIPTION
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.B im_ifthenelse
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builds an output image which uses some pels from a and some from b: if the
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conditional image c is non-zero at that point, the pel comes from a; if it
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is zero, the pel comes from b.
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The conditional image c can have either 1 band, in which case entire pels
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come either from a or b, or n bands, where n is the number of bands in both a
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and b, in which case individual band elements are chosen from a and b.
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Images a and b must match in size, type and number of bands.
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.B im_blend(3)
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works just as im_ifthenelse(3), except that instead of selecting between a and
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b, values in the condition image are used to softly blend between the two. 255
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means a only, 0 means b only, 128 means 50:50.
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.SH RETURN VALUE
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0 on success and -1 on error.
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.SH SEE ALSO
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im_equal(3), im_and(3).
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.SH COPYRIGHT
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National Gallery
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.SH AUTHOR
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J. Cupitt
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