Re: [9fans] Understanding /dev/draw

[Lucio De Re <lucio.dere@gmail.com>]

Whatever you do, do not start with Linux-type assumptions, or MIT-X
assumptions. They will cripple your understanding.

Everything is in the man pages, except the actual device driver,
/dev/draw. VGA, if I understand your interest, you will be spared.

I never quite understood everything involved in the Plan 9 graphics,
but it all looked quite manageable.

Lucio.


On 4/18/19, Chris McGee <newton688@gmail.com> wrote:
> Hi All,
>
> I'm looking at creating an alternate filesystem for /dev/draw, /dev/mouse
> and /dev/kbd that hooks up to a web server providing HTML interfaces (e.g.
> canvas) for Plan 9 UI. I've been reading over the manual pages, which are
> quite detailed, which is great, but there are some points of confusion for
> me.
>
> In particular, /dev/draw's interface and documentation keep referring to
> the concept of a "window" indirectly. It seems that in some cases the
> server providing /dev/draw needs to track windows and refresh them. But,
> what defines a window in this protocol? Is every image a window or only
> some of them?
>
> Also, I'm trying to understand how off-screen images, such as fonts are
> loaded. It seems that every image must be associated with a screen and be
> given a position within the screen. So, how do you prevent the image from
> being visible to the user?
>
> Hopefully, if I can understand some of the high-level concepts here then
> the manual page will be all that I need. Does anyone have experience with
> this area or could point me to information that might help clarify it?
>
> My next step will probably be to figure out how libmemdraw does all of this
> on top of a frame buffer.
>
> Thanks,
> Chris
>


--
Lucio De Re
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