Re: [Linux-fbdev-devel] fb_imageblit semantic

[Geert U. <ge...@li...>]

On 17 Mar 2003, Antonino Daplas wrote:
> On Mon, 2003-03-17 at 21:47, Geert Uytterhoeven wrote:
> > BTW, I just realized there's no need to distinguish between monochrome copy and
> > monochrome-to-color expansion. The monochrome logo code just has to write the
> > correct values to fb_image.[fb]gcolor. I.e. all zeroes or all ones (number of
> > bits = var.bits_per_pixel, so it works for 8-bit monochrome, too).
> > 
> 
> I remember mentioning this to you before, and you said that there might
> be rare cases that fgcolor can be equal to bgcolor.  However, using -1
> instead for bg_color/fg_color may work, at least for the current setup
> and only for monochrome, (except perhaps 32-bit monochrome, if there is
> such a thing)

No, you wanted to distinguish between monochrome expansion and color copy by
setting fb_image.[fb]gcolor to -1.

> I still prefer splitting fb_imageblit() into two though, and still keep
> image->depth for logo drawing only, to allow for future expansion.

OK.

> > > Do we still use the LUT?  
> > 
> > Yes. An alternative is to enlarge the pseudo palette to 256 entries (if there
> 
> Yes.  Which also means logo drawing will also work for quirky drivers,
> and the upper layer will be finally totally independent of the low level
> drivers.
> 
> > are enough number of colors). But since imageblit is done for the logo only,
> > doing the transform from LUT index to pixel value in imageblit is OK, I think.
> > 
> 
> Yes, I also prefer referring to the LUT whatever the format even for
> character drawing.  I don't expect any noticeable performance penalty
> except for logo drawing.  The way it's currently done is because,
> looking at all drivers, not one fills up the pseudo_palette when bpp <=
> 8.

There are some, that have RGB332 truecolor.

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ge...@li...

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds