=DEann 23-Sep-97 skrifar "John Prinos"r:
>=20
> I am currently running ver0.75 XForms on Redhat linux ver4.1 using 16 b=
it
> colour.
>=20
> I am trying, for proof of concept, to show an 8 bit greyscale image. I =
get an
> X-window error: BADMATCH when I try to show the image. It seems to work=
if
> Redhat is in 8 bit mode.
>=20
> [ snip ]
>=20
> Any comments would be appreciated, I apologize for the hacked code but =
i just
> wanted to see if this was possible.
>=20
An 8-bit image, has each pixel on the screen as 1-byte in memory. So,
before you can display that image on a 16-bit color depth, where each pix=
el
is 2-byte in memory, you have to do a conversion. There are probably man=
y
ways to do this and those that are far better than this one (xearth is on=
e
program that does this, it uses an 8-bit image and converts it to 1,15,16=
,
24 or 32 bits depending on the visual).
Basically you could take every byte in your source image...
10011010
and duplicate each bit
1100001111001100
Which I think would be reasonably accurate, and whereafter you would ha=
ve
a picture suitable for a 16 bit visual.
Hope that helps...
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Orn Einar Hansen oe.hansen@oehansen.pp.se
oehansen@daimi.aau.dk
voice+fax; +46 035 217194
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