A good talk on using the Linux Framebuffer (FOSDEM 2020)
lazarus / 39-Graphics

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WayneSherman · 2020-02-09 05:46

Back to the Linux Framebuffer!
Linux Framebuffer support in free software

https://fosdem.org/2020/schedule/event/fbdev/

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WayneSherman · 2020-02-09 05:53

Related:

Framebuffer Graphics routines for Freepascal.
An EXPERIMENTAL Pascal library for direct access to the Linux
Framebuffer

  https://github.com/JazzMaster/framebuffergraphics

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Thaddy · 2020-02-09 13:43

I have actually working framebuffer code and an fb.pas translation. I
will add that later today.
The code you refer to is incorrect and still contains untranslated C
code.

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Thaddy · 2020-02-09 15:50

As promised, fb.pas. Tested on Raspberry Pi.

And a simple example:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i program
fbinfo;{$mode delphi}{$H+}uses   BaseUnix,fb;var  fbfd:longint = 0;  
    // file handle  vinfo:fb_var_screeninfo; // variable screen
info.begin  // Open the framebuffer device file for reading and
writing  fbfd := fpopen('/dev/fb0', O_RDWR);  if fbfd = -1 then 
begin    writeln('Error: cannot open framebuffer device.');   
Halt(1)  end;  // get variable screen info  if fpioctl(fbfd,
FBIOGET_VSCREENINFO, @vinfo) <> 0 then   begin    writeln('Error
reading variable screen info.');    Halt(2);  end;  writeln('Display
info ',vinfo.xres,'x',vinfo.yres,' bpp ', vinfo.bits_per_pixel); 
fpclose(fbfd);  end.
I will add a wiki article with some real world examples later this
week. (code needs cleaning up)

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WayneSherman · 2020-02-09 16:25

Quote from: Thaddy on February 09, 2020, 04:50:56 pmAs promised,
fb.pas. Tested on Raspberry Pi.

And a simple example...

Love it.  Thanks for sharing.

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guest58172 · 2020-02-09 18:21

Quote from: WayneSherman on February 09, 2020, 06:46:03 amBack to the
Linux Framebuffer!
Linux Framebuffer support in free software

https://fosdem.org/2020/schedule/event/fbdev/

Is the FrameBuffer applicable for a "widgetset-agnostic" terminal
emulator component ? (think piping bash essentially)
I'd like to get rid of VTE so that I could use the QT5 interface
instead of GTK2. Only stopper for me right now is that I don't have an
easy solution to embbed a term with the QT5 widget set.

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Thaddy · 2020-02-09 19:30

In principle: yes. Things like font mapping, cursor etc are support by
the framebuffer interface, but it takes a *lot* of bolt-ons.
I am working on the reverse: make the owner drawn widgetset use a
frambuffer based canvas.
Note the framebuffer is actually legacy, but many - even new -
applications still use it.

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guest58172 · 2020-02-17 00:04

Looks like what I would need, to get a "desktop-environment-agnotisc
terminal emulator" is to use https://launchpad.net/libvterm and write
a GUI front end for it... No need for the FrameBuffer actually, just a
good old TWinControl class (and certainly some struggling ) should be
enough.