IM_BUILDLUT(3)
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