256 color terminal "screen saver"/"seizure-inducer" in bash :P

Xyne · 2009-12-24 08:07:27

Here's another coding byproduct. I somehow ended up playing with terminal colors, wrote some Perl code to convert terminal colors to hexadecimal values and vice versa (I might post that later too), played with some ascii art in the terminal, then wrote this just for fun.

The color transitions correspond to random single steps within the 6x6x6 color cube of a 256-color terminal.

There are currently 3 modes:

mode 1

cascade_colors

Full lines of color.

mode 2

cascade_colors 1 x

Symmetric margins that vary randomly by steps of x.

mode 3

cascade_colors 2 x y

A wandering stream of width x that moves by steps of y. Try this with "cascade_colors 2 15 15" in a full-screen terminal. *edit* Try "15 10" too.

The code should be easy to tweak. If you come up with some interesting modes, post them.

function cascade_colors()
{
  _I=1
  _J=0
  _K=0
  _WIDTH=$COLUMNS
  _MARGIN=0
  while true; do
  _A=$(($RANDOM % 3))
  _B=$(($RANDOM % 2))
  _C=$(($RANDOM % 3))
  case $_A in
  0)
    case $_B in
    0)
      [ $_I -gt 1 ] && _I=$(($_I - 1))
    ;;
    1)
      [ $_I -lt 6 ] && _I=$(($_I + 1))
    ;;
    esac
  ;;
  1)
    case $_B in
    0)
      [ $_J -gt 0 ] && _J=$(($_J - 1))
    ;;
    1)
      [ $_J -lt 5 ] && _J=$(($_J + 1))
    ;;
    esac
  ;;
  2)
    case $_B in
    0)
      [ $_K -gt 0 ] && _K=$(($_K - 1))
    ;;
    1)
      [ $_K -lt 5 ] && _K=$(($_K + 1))
    ;;
    esac
  ;;
  esac
  case $1 in
    1)
      _DELTA=$2
      case $_C in
        0)
          [ $_WIDTH -lt $(($COLUMNS - 2*$_DELTA)) ] && _WIDTH=$(($_WIDTH + 2*$_DELTA))
        ;;
        1)
          [ $_WIDTH -gt $((1 + 2*$_DELTA)) ] && _WIDTH=$(($_WIDTH - 2*$_DELTA))
        ;;
      esac
      _MARGIN=$((($COLUMNS-$_WIDTH)/2))
    ;;
    2)
      _WIDTH=$2
      _DELTA=$3
      case $_C in
        0)
          [ $_MARGIN -le $(($COLUMNS - $_WIDTH - $_DELTA)) ] && _MARGIN=$(($_MARGIN + $_DELTA))
        ;;
        1)
          [ $_MARGIN -ge $_DELTA ] && _MARGIN=$(($_MARGIN - $_DELTA))
        ;;
      esac
    ;;
    *)
      _WIDTH=$COLUMNS
      _MARGIN=0
    ;;
  esac
  _NUMBER=$((15 + $_I + 6*$_J + 36*$_K))

  echo -en "\e[0;49m"
  if [ $_MARGIN -gt 0 ]; then
    for _FOO in $(seq $_MARGIN); do
      echo -en " "
    done
  fi

  printf "\e[0;48;5;${_NUMBER}m"
  for _FOO in $(seq $_WIDTH); do
    echo -en " "
  done

  echo -e "\e[0;49m"
  done
}

*edit*
Stop it with ^C. Feel free to add some other way to stop it (timer, external condition, etc)

Last edited by Xyne (2010-06-07 02:14:29)

jac · 2009-12-24 10:03:33

Wow, wonderful work again Xyne! I've seen something like this before, but it was a lot more seizure-y (it only had full lines of color) while yours is a lot more screen-saver-y (2 15 10 is really sweet). Is there any way to actually set this as a screen saver?

Last edited by jac (2009-12-24 10:04:18)

Xyne · 2009-12-24 10:09:36

Thanks for the feedback.

There's probably some way to invoke it after a set amount of time but I have no idea how.

Arch Linux

#1 2009-12-24 08:07:27

256 color terminal "screen saver"/"seizure-inducer" in bash :P

#2 2009-12-24 10:03:33

Re: 256 color terminal "screen saver"/"seizure-inducer" in bash :P

#3 2009-12-24 10:09:36

Re: 256 color terminal "screen saver"/"seizure-inducer" in bash :P

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