#! /bin/bash
#
# Assumes you have the following packages or files:
# - imagemagick
# - http://ms.unimelb.edu.au/~trice/xkcd-info
# - nitrogen
#
# The first time you run this script, you'll need to 
# manually set nitrogen to use the generated wallpaper.
set -e

# Change the following settings to whatever you feel like.
img_file=/tmp/xkcd-img.png
wp_file=$HOME/Pictures/Wallpapers/xkcd.png
col="#680000"
font="$HOME/.fonts/Humor-Sans.ttf"
scale="100%"

# Remove existing files.
for f in $wp_file $img_file; do
    [[ -e $f ]] && rm -v $f
done

# Get the image first. We need its dimensions to format the 
# title and alt-text.
convert -verbose $(xkcd-info img) -negate -background "$col" -alpha shape -resize "$scale" $img_file

# Wait.
while [ -n "$(ps auxc | grep convert)" ]; do
    sleep 0.25
done

# How wide is the image?
size=$(identify $img_file | awk '{print $3}' | awk -Fx '{print $1}')

# Create images based on the title and alt text.
convert -verbose \( -background transparent -fill "$col" -gravity center \
    -font "$font" -interline-spacing 8 -pointsize 32 \
    -size $size caption:"$(echo && xkcd-info title)" \) \
    \( -size "${size}x8" canvas:transparent \) \
    $img_file \
    \( -size "${size}x8" canvas:transparent \) \
    \( -background transparent -fill "$col" -gravity center \
    -font "$font" -interline-spacing 8 -pointsize 16 \
    -size $size caption:"$(xkcd-info alt)" \) \
    -gravity Center -append $wp_file

while [ -n "$(ps auxc | grep convert)" ]; do
    sleep 0.25
done

# Update the wallpaper.
[[ -e $wp_file ]] && nitrogen --restore

echo Done.