Re: [Groff] Patch for two grohtml bug fixes..

[Ralph Corderoy]

Hi Werner,

> But the X manual page also describes how to use fractions, e.g.
> 
>   rgbi:0.3/0.7/0.236
> 
> Do you say that it is the graphics device driver's job to convert
> this to 16-bit unsigned integers?

No, I was talking more about the interface between X client and server.
The `rgbi' notation above is converted in the client as part of the
Xcms (colour management system) library.  It has three look up tables
of intensity (that's the 0..1 part), one for each of red, green and
blue.  These map the intensity onto 0..0xffff in a non-linear manner.
If the table doesn't contain the exact intensity then Xcms interpolates
between the two table entries on either side.

The CIE colour space is device-independent IIRC.  And there may also be
some extra tinkering on the server side to cope with device
dependencies.

All in all it's pretty complex and I only know it a little having never
had cause to worry about with the X programming I've done.

Cheers,


Ralph.