Re: [Linux-fbdev-devel] Re: [PATCH]: image.depth fix to accomodate monochrome cards

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

On 11 Jan 2003, Antonino Daplas wrote:
> On Sat, 2003-01-11 at 03:43, Geert Uytterhoeven wrote:
> > On Fri, 10 Jan 2003, James Simmons wrote:
> > >    I'm just not to crazy about the depth equal zero thing. I just pitcure 
> > > developers having a hard time with it.
> > 
> > Monochrome color expansion just works differently: it expands the zeroes and
> > ones in a bitmap based on fg_color and bg_color, while image drawing draws an
> > image containing colormap indices to the frame buffer.
> > 
> > Do you have a better suggestion?
> > 
> 
> If James is a bit skeptical about this, how about doing it this way:
> 
> If image.fg_color and image.bg_color == 0, then each byte of image.data
> is an index to the pseudo_palette, or the actual pixel, whatever the
> case may be.  Otherwise, image.data is a monochrome bitmap that should
> be expanded using fg_color and bg_color.
> 
> No other changes will be needed except that mono cards have to test for
> fg_color and bg_color, and we need to memset the fb_image structure to 0
> in fb_set_logo(). Non-mono cards will continue testing for image.depth.
> 
> Do you think this will work?  The only problem I can think of is a color
> expansion request where both bg and fg is 0.

And that can happen, try <ESC>[31m<ESC>[41m to set both to red.

> Or to totally eliminate the above possibility, add an extra field in
> struct fb_image to denote color expansion vs logo drawing.  Again, only
> mono cards will need to do this test.

Ugh, why invent a new field if we can use an existing field? depth == 0 is
invalid for image blitting anyway.

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