Method
VipsImagebuildlut
Declaration [src]
int
vips_buildlut (
VipsImage* in,
VipsImage** out,
...
)
Description [src]
This operation builds a lookup table from a set of points. Intermediate
values are generated by piecewise linear interpolation. The lookup table is
always of type #VIPS_FORMAT_DOUBLE, use vips_cast() to change it to the
type you need.
For example, consider this 2 x 2 matrix of (x, y) coordinates:
We then generate a 1 x 256 element LUT like this:
This is then written as the output image, with the left column giving the index in the image to place the value.
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. You don’t need to start at zero, any integer will do, including negatives.
See also: vips_identity(), vips_invertlut(), vips_cast(), vips_maplut().
This method is not directly available to language bindings.
Parameters
out-
Type:
VipsImageOutput image.
The argument will be set by the function. The caller of the method takes ownership of the returned data, and is responsible for freeing it. ...-
Type:
NULL-terminated list of optional named arguments.