31 lines
1.0 KiB
Groff
31 lines
1.0 KiB
Groff
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.TH IM_RIGHTSHIFT_SIZE 3 "12 August 2006"
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.SH NAME
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im_rightshift_size \- Decrease size by a power-of-two factor
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.SH SYNOPSIS
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.nf
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.B #include <vips/vips.h>
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.sp
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.BI "int im_rightshift_size( IMAGE " "*in" ", IMAGE " "*out" ", int " "xshift" ", int " "yshift" ", int " "band_fmt" " );
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.fi
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.SH DESCRIPTION
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.B im_rightshift_size(3)
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decreases the size of an integer type image by a power-of-two factor, very quickly, by summing the values of
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adjacent pixels. The sum is shifted to produce output of the specified band format.
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.IR xshift " and "yshift
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are positive and give the base-two logarithms of the scale factors.
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.PP
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If the input image is a signed type, then
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.I band_fmt
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must be one of IM_BANDFMT_CHAR, IM_BANDFMT_SHORT or IM_BANDFMT_INT. If it is an unsigned type, then
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.I band_fmt
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must be one of IM_BANDFMT_UCHAR, IM_BANDFMT_USHORT or IM_BANDFMT_UINT.
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.SH RETURN VALUE
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The functions returns 0 on success and -1 on error.
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.SH SEE ALSO
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im_affine(3)
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.SH COPYRIGHT
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.br
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Copyright 2006, Tom Vajzovic.
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.SH AUTHOR
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Tom Vajzovic
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