Re: drawing to a 1bpp aux display

[Michael <macallan%netbsd.org@localhost>]

Hello,

On Sun, 23 Oct 2016 14:25:49 +0200
Manuel Bouyer <bouyer%antioche.eu.org@localhost> wrote:

> I have a graphical application (opencpn, http://opencpn.org, FWIW)
> using wxWidgets (wxGTK on NetBSD). I want to write a plugin which can
> repeat some information to a second (or more), 1bpp display
> (a LCD display with resolution in the 128x64-240x128 range - this is not
> fixed yet). This display will be available as a genfb on NetBSD.
> It can be managed by a Xorg wsfb server, or by the plugin directly
> (whatever is more convenient).
> 
> So I will have to write a piece of code which will be dlopen()'ed
> by opencpn, so will have to coexists with wxGTK and dependancies,
> and will have to do rendering on a small 1bpp display/framebuffer
> of text (of various sizes) and graphics.
> 
> What would people familiar with X11 or graphics developement recomment ?

I assume there is no mappable framebuffer?
I'd just use a shadow framebuffer in memory, let wsdisplay / wsfb
scribble into it and periodically update the actual display. Depending
on the speed of the link to the display you may want to divide it up
and implement some scheme to update only parts that actually changed.
That would also take care of bitmap format / framebuffer organization
issues.

have fun
Michael