Re: [Linux-fbdev-devel] 2 pm3fb questions/problesm ...

[Sven L. <lu...@dp...>]

On Tue, Jun 19, 2001 at 03:55:28PM +0200, Geert Uytterhoeven wrote:
> On Tue, 19 Jun 2001, Sven LUTHER wrote:
> > On Tue, Jun 19, 2001 at 02:08:11PM +0000, Petr Vandrovec wrote:
> > > for truecolor and 4bpp pseudocolor, 0x0f0f0f0f is correct for
> > > 8bpp pseudocolor, 0xXX0f0f0f (*) is for 24/32bpp directcolor,
> > > 0x3DEF3DEF for 15bpp, 0x79EF79EF for 16bpp, and you cannot
> > > use RGB332 truecolor without information loss.
> > 
> > mmm, truecolor is when the the rgb value is written directly to the pixel ?
> > and pseudo color is when you use a color index table.
> > 
> > What exactly is direct color ?
> 
> truecolor:
> 
>     red = (pixel & redmask) >> redshift
>     green = (pixel & greenmask) >> greenshift
>     blue = (pixel & bluemask) >> blueshift
> 
> pseudocolor:
> 
>     red = redtable[pixel]
>     green = greentable[pixel]
>     blue = bluetable[pixel]
> 
> directcolor:
> 
>     red = redtable[(pixel & redmask) >> redshift]
>     green = greentable[(pixel & greenmask) >> greenshift]
>     blue = bluetable[(pixel & bluemask) >> blueshift]
> 
> To make sure revc always does the correct thing, there should be a 17th entry
> in the display->dispsw_data telling the invertion mask.

And the correct thing to do is ?

Friendly,

Sven Luther