54 lines
1.5 KiB
Groff
54 lines
1.5 KiB
Groff
.TH IM_QUANTIM 3 "10 May 1991"
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.SH NAME
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im_quantim, im_quantlut, im_spatres \- quantise an image or a lut
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.SH SYNOPSIS
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.B #include <vips/vips.h>
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.B int im_quantim(in, out, no_of_bits)
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.br
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.B IMAGE *in, *out;
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.br
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.B int no_of_bits;
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.B int im_quantlut(lut, no_of_bits)
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.br
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.B IMAGE *lut;
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.br
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.B int no_of_bits;
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.B int im_spatres(in, out, step)
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.br
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.B IMAGE *in, *out;
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.br
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.B int step;
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.SH DESCRIPTION
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.B im_quantim()
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quantises the image file held by in using no_of_bits and writes the result to
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out. The no_of_bits should be between 1 and 7 inclusive. Input can have any
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number of bands. The function expects as input a valid unsigned char image.
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These functions are here for compatibility only. You should use the boolean
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operations im_andconst(3), im_orconst(3), im_shrink(3), im_zoom(3) and
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im_lowpass(3).
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.B im_quantlut()
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creates an one band unsigned char
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lookup table which is used by im_quantim(3).
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The no_of_bits should be between 1 and 7 inclusive.
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.B im_spatres()
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reduces the spatial resolution of in by averaging step*step pixels
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and replicating the result in out. The function can be used in
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order to show the effect of reducing the spatial resolution of a given image
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and the importance of post-filtering before displaying.
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Input can have any number of bands.
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.SH RETURN VALUE
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All functions returns 0 on success and -1 on error.
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.SH SEE ALSO
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im_andconst(3), im_orconst(3), im_shrink(3), im_zoom(3) im_lowpass(3).
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.SH COPYRIGHT
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.br
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N. Dessipris
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.SH AUTHOR
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N. Dessipris \- 10/05/1991
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