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Date:      Fri, 7 Feb 2014 22:27:58 +0100
From:      Ed Schouten <ed@80386.nl>
To:        Aleksandr Rybalko <ray@freebsd.org>
Cc:        svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org
Subject:   Re: svn commit: r261585 - head/sys/dev/vt/hw/vga
Message-ID:  <CAJOYFBC9S8FLjJxL%2BEHGiwvszuJG7CN-_d2SbqXUjB7VX%2Byf7Q@mail.gmail.com>
In-Reply-To: <20140207171025.d33b95770f6b0d7d00b4aab3@freebsd.org>
References:  <201402071239.s17CdwIH007683@svn.freebsd.org> <CAJOYFBAAmcfrob4LsBC2jz6TxfNPd%2Bh6Np_dn7toOgXRZHAiow@mail.gmail.com> <20140207171025.d33b95770f6b0d7d00b4aab3@freebsd.org>

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Hi Aleksandr,

On 7 February 2014 16:10, Aleksandr Rybalko <ray@freebsd.org> wrote:
> On Fri, 7 Feb 2014 15:04:47 +0100
> Ed Schouten <ed@80386.nl> wrote:
>> On 7 February 2014 13:39, Aleksandr Rybalko <ray@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@80386.nl>



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