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IM_BUILDLUT

IM_BUILDLUT

Section: C Library Functions (3) Updated: June 2006
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NAME

im_buildlut - build a LUT from a set of x/y points  

SYNOPSIS

#include <vips/vips.h>

int
im_buildlut( DOUBLEMASK *input, IMAGE *output )

 

DESCRIPTION

im_buildlut(3) constructs a LUT, interpolating a set of x/y points. Interpolation is strictly piecewise linear. For example, if the input is:


  0     0

  128   20

  255   100

we generate the values:


  index  value


  0      0

  1      0.01

  .. etc. linear interpolation
  128    20

  129    20.5

  .. etc. linear interpolation
  255    100

(we don't generate the index column, that's just there to show the position in the table)

The x/y points don't need to be sorted: we do that. You can have several Ys: each becomes a band in the output LUT. X can start at any integer value, including negatives.

 

RETURN VALUE

-1 on error, otherwise 0  

SEE ALSO

im_invertlut(3), im_identity(3).  

COPYRIGHT

2006, Imperial College


 

Index

NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
SEE ALSO
COPYRIGHT

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