svn commit: r261585 - head/sys/dev/vt/hw/vga

[Ed Schouten]

Hi Aleksandr,

On 7 February 2014 16:10, Aleksandr Rybalko <ray at freebsd.org> wrote:
> On Fri, 7 Feb 2014 15:04:47 +0100
> Ed Schouten <ed at 80386.nl> wrote:
>> On 7 February 2014 13:39, Aleksandr Rybalko <ray at freebsd.org> wrote:
> Also people asking me about advanced features of vt(9), like use
> multiple displays. I'm not sure, but signed coordinates may help with
> some things on that way (or makes more problems :) ).

But if you were to have multiple displays, you should have separate
coordinate systems per display. It should not be seen as a single
pane.

>> Furthermore, I think it's a bit weird that vga_bitbltchr() contains
>> explicit bounds checking. What happened there? I remember at one point
>> in time, we had the nice invariant that vt(9) never attempted to draw
>> outside of the display resolution. What caused us to give up on that?
>
> Mouse cursor allowed to partially go out of screen, so we have to check
> (or use special function for mouse cursor).

Well, that's a compelling argument. Still, it's a bit weird then that
the bitblt function itself does not take signed coordinates. Would it
make sense to bring that in sync then?

-- 
Ed Schouten <ed at 80386.nl>