Feature request: allow setting the FPACK dither seed

[dstndstn]

Hi,

I'm trying to make it so my code writes bit-identical outputs every time it runs, but I'm using the compression schemes that do the subtractive dither thing, so there is a seed chosen at run-time. It looks like CFITSIO has routines to set that seed -
fits_set_quantize_dither() or fits_set_dither_seed() etc
https://heasarc.gsfc.nasa.gov/docs/software/fitsio/c/c_user/node41.html

It looks like one place to add this feature would be here,

fitsio/fitsio/fitsio_pywrap.c

Line 1376 in c8f8d60

PyFITSObject_create_image_hdu(struct PyFITSObject* self, PyObject* args, PyObject* kwds) {

ie similar to how the quantization level can be set,

fitsio/fitsio/fitsio_pywrap.c

Line 1483 in c8f8d60

if (fits_set_quantize_level(self->fits, qlevel, &status)) {

thanks!
-dustin

[esheldon]

Good idea Dustin. Do you want to take a shot at it?

[dstndstn]

Maybe :) this isn't at the top of the priority stack at the moment though...