#From: Ian Kluft <ikluft@cisco.com>
#
#This is adapted (much more generalized now) from a script I wrote last
#Wednesday to put the weather radar images in my X root window when some
#thunderstorms from Hurricane Greg (off the coast of Mexico) overran the
#Bay Area.
#
#Yeah, yeah... I know... thunderstorms are not a big deal in Central
#Florida, where you get 300 days a year with at least one thunderstorm.
#But we get about 5-10 a year here so it's not supposed to look like
#Florida.
#But it did for one night.  About 10 hours after I wrote the script,
#lightning struck 100 feet from my house.  So use with caution.  :-)
#
#Anyway, to use this script to put the Hurricane Floyd advisories or weather
#radar in your X root window, run it in a separate shell window like this...
#
#   ./url-bg http://www.nhc.noaa.gov/ftp/graphics/AT08/AL0899W.GIF
#
#or use the URL for your favorite weather radar image as the storm
#approaches.
#--
#Ian Kluft  KO6YQ PP-ASEL                                  Cisco Systems,
#Inc.
#ikluft@cisco.com (work)  ikluft@thunder.sbay.org (home)          San Jose,
#CA
#
#---------------------------------------------------------------------------
#!/bin/sh
# url-bg - periodically download an image from a URL to the X root window
# by Ian Kluft

url_get()
{
     $lynx -source $url
}

to_root_win()
{
     xsetroot
     case "$suffix" in
          gif|GIF) giftopnm | ppmtoxpm | xpmroot $stdin ;;
          jpg|jpeg|JPG|JPEG) djpeg -pnm | ppmtoxpm | xpmroot $stdin ;;
          *) print "unrecognized image type $suffix" >&2; exit 1 ;;
     esac
}

# check if OS can access fds through filesystem
case `uname -sr` in
     "SunOS 5"*) stdin=/dev/fd/0 ;;
     Linux*)   stdin=/proc/self/fd/0 ;;
     *)        echo "Sorry `uname -sr` is not supported" >&2; exit 1 ;;
esac

# check command line
url=$1
if [ ! "$url" ]
then
     echo "usage: $0 url" >&2
     exit 1
fi
suffix=`echo $url | sed 's/^.*\.//'`

# look for necessary commands
for path in /usr/bin/lynx /usr/local/bin/lynx
do
     if [ -x $path ]
     then
          lynx=$path
          break
     fi
done
for path in /usr/bin/xv /usr/local/bin/xv
do
     if [ -x $path ]
     then
          lynx=$path
          break
     fi
done

# main display loop
while true
do
     url_get | to_root_win     # see functions above
     sleep ${BG_INTERVAL:-3600}
done