On Thu, Jun 21, 2001 at 12:28:30PM +0300, Tuomas Kuosmanen wrote:
> I personally have no clue what "Restart markers" or DCT method of "Fast
> integer" means in practice. So maybe someone who knows can look into this,
> and try to think what options are really necessary, and if there is really a
> point in showing some of them to the user, how to label it so you dont need
> to be a member of the Join Photographic Experts Group to know how to use the
> save dialog :-)

Education day!

Restart markers make JPEG data more robust -- asking for more frequent
restart markers will make less of the image corrupt if somehow the file
is damaged. For day-to-day web use set it to the minimum because of
course the markers increase size and small is beautiful.

DCT method is a libjpeg specific option which chooses an algorithm for
calculating the discrete cosine transform, depending on your hardware
the floating point might be faster or slower - for big images you might
try playing with this to decrease turn-around time. The default is OK
on most PCs.

> And yes, I am even a geek. There are users who are not. Gimp has a lot of
> these obscure things, for example the TIFF save dialog:


> Now, I dont even know if there are any cases when you want to use a certain
> setting, but if there is, it might be good to explain it a bit here somehow?

If you don't use the right setting <Proprietary Application> and/ or
<Code written by an Intern three years ago> will not load the TIFF,
usually making wild claims like "This is not a TIFF" or just crashing

<Proprietary Application> doesn't bother to tell you which setting to use
because they don't expect you to use any software except from <Proprietary
Vendor> and <Code written by Intern> doesn't tell you because the Intern
didn't finish documenting it.

Gimp cannot do anything about this, and all I can do is tell people to
avoid TIFF unless it is absolutely the only solution short of rolling
their own file format.

> Also, speaking of TIFF plugin, if the LZW saving is not supported anymore,
> it should be taken out as an option, instead have a small text label below
> the choices saying what the popup dialog says: "Note: LZW compression is not
> supported because of Unisys patent problems." or something.

The patent problem is in libtiff. At libtiff compile time users who have a
license from Unisys, or say that they don't need one will be given the
option of including a working LZW codec in their build.

It is not possible, right up until that dialog appears, to detect whether
the user's libtiff does or does not include LZW. To a libtiff using app
there is no difference between "Real LZW codec" and "LZW pseudo-codec
which displays an error" -- Gimp only knows that an error occurred.

Now - the material point of this thread. Yes, I would like to introduce
an "Advanced..." option or setting and some way to configure file
plug-ins without actually loading/ saving a file, like in PSP I think.

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