Framebuffer Color Clock (C version)

Created by: https://github.com/will-tam/framebuffer-color_clock-C

Modified for use with Candle to show a clock on an attached display if the kiosk-mode is disabled, and the Photo-Frame addon is also not installed

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A colored clock just in test of framebuffer library. I confess this test/exercice idea comes from "Le Vortex" https://www.youtube.com/@LeVortexARTE/videos and their clock.

/!\ Assume FB is in 32bpp mode. /!\

The best way to test :

• Create a Linux virtual machine (VM) with an X server.
• In console mode:
  • Check and configure network between VM and your physical machine (PM).
  • install, configure and run the ssh server.
  • Log off or not, but the VM still active.
• Open a terminal on your PM.
  • Open a ssh connection with the VM.
  • Install and configure the C development kit (gcc + make + lib in debug/dev).
  • Install git.
  • Clone this repository.
  • Go to the newly created directory.
  • Just type make.
  • If all is ok, the VM console shows you nice arts, while the ssh terminal shows some information.

Of course, you can try directly in your PM (in TTY1 for example - CTRL-ALT-F1 if you use X interface). BUT if something wrong, prepare to reboot your PM.

Great thanks to

• HSL and HSV color :

  • https://en.wikipedia.org/wiki/HSL_and_HSV
  • https://www.niwa.nu/2013/05/math-behind-colorspace-conversions-rgb-hsl/

• Framebuffer :

  • https://github.com/roddehugo/linuxfb?tab=readme-ov-file
  • https://wiki.osdev.org/Drawing_In_a_Linear_Framebuffer
  • https://github.com/DirectFB/directfb/tree/master/systems/fbdev

• Key events :

  • https://www.flipcode.com/archives/_kbhit_for_Linux.shtml

• Line and circle algorithmes :

  • https://en.wikipedia.org/wiki/Bresenham%27s_line_algorithm
  • https://fr.wikipedia.org/wiki/Algorithme_de_trac%C3%A9_de_cercle_d'Andres
  • https://gist.github.com/bert/1085538

• Tranforming HSV color format into GB color format :

  • https://www.rapidtables.com/convert/color/hsv-to-rgb.html
  • https://en.wikipedia.org/w/index.php?title=HSL_and_HSV

ENJOY