Re: [Linux-fbdev-devel] fb_imageblit semantic

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

On Mon, 17 Mar 2003, Petr Vandrovec wrote:
> On 17 Mar 03 at 13:18, Geert Uytterhoeven wrote:
> > That depends... How do we draw the monochrome penguin? Using image->depth is 1
> > or 8? The latter (current method) is slower, since we need to expand the
> > monochrome logo to 8-bit first, and (usually) compress it to 1-bit in the fbdev
> > driver afterwards.
> 
> As far as I can see, it gets monochromatic logo and converts it to
> 8bpp format ;-) (fb_set_logo, needs_logo = 1 or ~1) And then imageblit
> converts it back to 1bpp.

Yes, that's what I wrote above (current method).

> > And perhaps we may want to draw 32-bit ARGB images later?
> > 
> > So I see the following possible valid values for image->depth:
> >   - 8 (logo with up to 256 colors and LUT)
> >   - optional 1 (monochrome logo, if we don't want to expand?)
> >   - optional 32 (ARGB image, dithering left to the driver?)
> 
> I still do not understand 'if we don't want to expand'. This forces too
> much knowledge on upper layer, as far as I can tell.

Color expansion => use fb_image.fg_color if bit == 1,
		   use fb_image.bg_color if bit == 0
No expansion => look up color in fb_image.cmap.

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