Re: [Linux-fbdev-devel] question on _putc, _putcs, _bmove..

[Petr V. <VAN...@vc...>]

On 18 Jul 01 at 14:02, Romain Dolbeau wrote:
> In the above functions, are the various position
> parameters (sx, xx, sy, yy) in
> 
> 1) display coordinate
> 2) buffer coordinate
> 
> Before I commit my change to fix pm3fb, I'd
> like an authoritative answer on the subject.
> It just _feels_ wrong to me to use absolute
> coordinate.

It is buffer coordinate. You have framebuffer
xres_virtual * yres_virtual pixels, and all
coordinates for putc/clear/bmove are relative
to left upper corner of this buffer.

Then you have window xres * yres which specifies
what is visible on screen.

And while coordinates for painting characters
are in character cell, offset from buffer's
top left corner and window top left corner 
(xoffset, yoffset) is specified in pixels, not 
in character cells.

So you should take yoffset/xoffset into account
only for setting viewport position (and yres/xres
for setting viewport size), while accelerated
painting ops should not use these 4 values at all.
                        Best regards,
                                Petr Vandrovec
                                van...@vc...