Weaving with simple math in terminal.

It's written intently to be used as a screensaver. To weave, you need to give it an evaluation code as first argument, e.g.

weave.sh '(((x + y) % 2))'

The script draws vertical lines first, then use the supplied code to decide if a horizontal line is weaved over the vertical line. Where x is between 1 and terminal width W (columns) and y is between 1 and terminal height H (rows). If it evaluates as true, meaning the final value == 0, then it does that; otherwise go under the vertical line. There is more examples in sample-screensaver.sh. You can even write a Bash function if it's too complicated as one-liner:

triangle() {
 (((x + y) % 2)) && ((x * H / W >= (y - 1)))
}
export -f triangle
weave.sh 'triangle'

The script has no options, it relies on environment variables entirely, the following is the default values:

# Characters and colors for vertical and horizontal lines
char_v='|' char_h='-'
color_v='\e[32;1m' color_h='\e[31;1m'
# Sleep delays
sleep_v=0.01 ${sleep_h=0.01
sleep_end=5

eval_h="1ドル" # Get evaluation code from '1ドル'
eval_h='(((x+y)%2))' # , or set to a default pattern
show_eval_h=no #"yes" to print out evaluation code

For example, if you want to change the characters, you can do

char_v='┃' char_h='━' weave.sh

Here is a video of sample-screensaver.sh.

weave.sh '(( $(echo "v=s(($x-1)24a(1)/$W);scale=0;$H-$H(v+1)/2 == $y" | bc -l) ))'

weave.sh '(( $(echo "v=s(($x-1)*2*4*a(1)/$W);scale=0;$H-$H*(v+1)/2 == $y" | bc -l) ))'

weave.sh '(((x % 5 + y % 11) % 2))

weave.sh '(((x % 5 + y % 11) % 2))

Feel free to create pull request. Whether make the code better or add some awesome examples to sample-screensaver.sh, they are all welcome.

Copyright (c) 2013 Yu-Jie Lin
weave.sh is licensed under the MIT License