[sane-devel] uploading color transformation matrix on HP 4c/3c

[Michal Maruška]

is it implemented? (i need to modify only RGB->greyscale)
scanimage --help   seems to say so, but when i use it, i get

$ scanimage --mode Grayscale   --matrix-rgb 0,1,0,0,0,0,0,0,0 > sample
scanimage: attempted to set inactive option matrix-rgb


the sane-backends/backend/hp.TODO says
>  Find a way to set matrices in the frontend (gtk-table with sliders ?)