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

6       im_quantim, im_quantlut, im_spatres - quantise an image or a lut
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SYNOPSIS

9       #include <vips/vips.h>
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11       int im_quantim(in, out, no_of_bits)
12       IMAGE *in, *out;
13       int no_of_bits;
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15       int im_quantlut(lut, no_of_bits)
16       IMAGE *lut;
17       int no_of_bits;
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19       int im_spatres(in, out, step)
20       IMAGE *in, *out;
21       int step;
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DESCRIPTION

24       im_quantim()  quantises  the image file held by in using no_of_bits and
25       writes the result to out.  The no_of_bits should be  between  1  and  7
26       inclusive.   Input  can have any number of bands.  The function expects
27       as input a valid unsigned char image.
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29       These functions are here for compatibility only.  You  should  use  the
30       boolean   operations   im_andconst(3),   im_orconst(3),   im_shrink(3),
31       im_zoom(3) and im_lowpass(3).
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33       im_quantlut() creates an one band unsigned char lookup table  which  is
34       used by im_quantim(3).  The no_of_bits should be between 1 and 7 inclu‐
35       sive.
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37       im_spatres()  reduces  the  spatial  resolution  of  in  by   averaging
38       step*step  pixels  and replicating the result in out.  The function can
39       be used in order to show the effect of reducing the spatial  resolution
40       of  a  given image and the importance of post-filtering before display‐
41       ing.  Input can have any number of bands.
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RETURN VALUE

44       All functions returns 0 on success and -1 on error.
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SEE ALSO

47       im_andconst(3), im_orconst(3), im_shrink(3), im_zoom(3) im_lowpass(3).
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50       N. Dessipris
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AUTHOR

53       N. Dessipris - 10/05/1991
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57                                  10 May 1991                    IM_QUANTIM(3)
Impressum