"Scratching an itch... by patching kmscon"


                                               or


                          "How OpenGL can lead to systems-programming"








-= 0/12 =-


   overview

     * what is kmscon?

     * who am I?

     * motivation

     * patch 1: output rotation

     * patch 2: mouse selection & 'clipboard'

     * patch 3: gyro support

     * patch 4: messing around...

     * upstream, future work

     * sourcecode, blog-posts, screencasts

     * q/a

-= 1/12 =-


   what is kmscon?

     * KMS-based system-console for Linux

     * plugin-infrastructure for features

     * Unicode-capable, e.g. cyrillic, japanese, farsi... no emojis yet

     * feature/plugin: Freetype fonts (mod-pango.so)

     * feature/plugin: OpenGL|ES render backend (mod-gltex.so)

     * libtsm: state machine for terminal-emulation (VT100..VT520)

     * 'old', ca. 2012, initial developer David Herrmann (https://dvdhrm.wordpress.com)

     * maintenance moved 'organically'? into other hands (https://github.com/aetf/kmscon)





-= 2/12 =-


   who am I?

     * homepage: macslow.org

     * blog: blog.macslow.org

     * eMail: macslow@gmail.com

     * mastodon: @MacSlow@floss.social

     * twitter: @MacSlow











-= 3/12 =-


   motivation

     * zen-moments 'in the zone'

     * non-typical (aka uncommon) monitor-setup

     * no system-console on Linux can rotate output a la xrandr

     * convenient: kmscon is OpenSource

     * even more convenient: knowing your way around OpenGL

     * peak-convenience: being a graphics-nerd with a tiny bit of spare-time

     * famous last words: "Ah, that's a piece of cake... it'll take an evening!"

     * start january/february 2023





-= 4/12 =-


   patch 1: output rotation (my main itch to scratch)

     * kmscon/src/text_gltex.c 

       * kmscon_text_gltex_ops

       * gltex_rotate

       * gltex_render_pointer (also see patch 2)

     * GL-transformation-matrix

     * height, width for number of characters has to be calculated

     * demo: UTF8-text, tmux, btop, cmatrix 







-= 5/12 =-


   patch 2: mouse selection & 'clipboard' (kind of TODO-item from David Herrmann)

     * kmscon structs: eloop, ev_timer

     * device-/kernel-interface: /dev/input/mice 

     * kmscon/src/kmscon_mouse.h

     * my added structs: kmscon_mouse_info, kmscon_selection_info

     * mouse, trackpoint, Apple Magic Mouse Pad... all at the same time

     * update-rate for device-query (busy polling at the moment still)

     * libtsm, https://blog.macslow.org/?p=407, wlterm

     * demo: tmux, cut&paste of filenames





-= 6/12 =-


   patch 3: gyro support (DBus service)

     * "It would be so cool, if the rotation happens automatically!"

     * laptop with gyro-sensor

     * DBus service "/net/hadess/SensorProxy" (Bastien 'hadess' Nocera)

     * #include <dbus/dbus.h> low-level, DBus-maintainer discourage its use :)

     * kmscon/src/kmscon_terminal.c

     * live-demo on separate laptop (with gyro) after the talk for interested folks 

     * -> screencasts







-= 7/12 =-


   patch 4: messing around... shader backgrounds (kind of TODO-item from David Herrmann)

     * since we are using OpenGL already, one could also...

     * ASCII-art vs real GLSL-shader :)

     * -> screencasts















-= 8/12 =-


   upstream

     * initial maintainer 'lost' somewhere within RedHat ;)

     * a debian-dev replied once, hinting me towards aetf's kmscon repo on github

     * new/current de-facto maintainer "aetf" does not seem to be very active

     * PRs against aetf's repo created on github... a few months ago

     * feedback really slow... or this is just too niche-specific of a patch

     * even planned a talk at FOSDEM in Bruessel 2024

     * future idea: use KMS' info of connected displays for real multi-head







-= 9/12 =-


   sourcecode, blog-posts, screencasts

     * https://github.com/MacSlow/kmscon

     * https://blog.macslow.org/?p=365

     * https://blog.macslow.org/?p=399

     * https://blog.macslow.org/?p=407

     * https://blog.macslow.org/?p=460

     * https://www.youtube.com/embed/ybjmUFIXfUU

     * https://www.youtube.com/embed/j21k9cbhDNQ

     * https://www.youtube.com/embed/b2F_jsfWvFY

     * https://www.youtube.com/embed/pRyEnU1hMXo



-= 10/12 =-


   Questions?





















-= 11/12 =-

 
   Thanks for your interest and attention everyone!





















-= 12/12 =-