# Re: SANE V2 - again...

Milon Firikis (milonf@ariadne-t.gr)
Fri, 03 Sep 1999 14:12:20 +0300

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Oliver Rauch wrote:

> Hi Milon,
>
> please reread my mail at first: gamma and halftone tables are needed!
> color correction may be,

I usually do that. First read the mails then I say my opinion if I have
any.

> but what shall a frontend do with a calibration vector:
> what I know about such calibrations is:
> the scanner does scan a white area and sends calibration data
> to the backend, the backend calculates the calibration vector and
> sends it back to the scanner.
> There is nothing a frontend can do with it, because the calibration
> is done different for each scanner-model and vendor.
>

I don't want to argue with on what needs to be a "Well Known Option" and
what not. I was tried to raise the point that there are cases where the
options which control the quality of a scan are not scalars but vectors
or tables. Because SANE currently does not suggest a better way of
letting the user set this non scalar variables, I said that it would be
possible to have a FILE option that allows the backend to download the
required info to the scanner.

I admit that my wording may was not clear enough. I said:

#-reading files with array of numbers as information. This would be
#useful to read/save/store
# -Calibration vectors (3x256)
# -Color Correction tables (3x3 integer matrix)
# -Halftone patterns (4x4, or 8x8 PGM images)

What I meant was that the frontend opens up a browser and let the user
to select a file. In that way the frontend doesn't need to know what
calibration is, and how to do it. Backend knows, and the user knows (and
the README describes the available files :-).

I put the these 4 cases (calibration, halftone, gamma, CCT) together
because I think that they represent the same problem. I understood what
you said, that you can eliminate the need of FILE downloading for some
of them by making them "Well Known Option" but I never disagreed with
that. I just said that a universal downloading option for FILES as
argument, may prove handy, if not useful. I didn't want necessarily to
cover all 4 cases. I most certainly prefer a "Well Known Option" where
is possible.

MF

PS.

I think this Download File operation is the equivalent of the RAW
scanning. In both cases the frontend doesn't know what is carrying
from/to disk/scanner.

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