#!/bin/bash
# watermark -- add specified text as a watermark on the input image
#    saving the output as image+wm

setglobal wmfile = ""/tmp/watermark.$Pid.png""
setglobal fontsize = '"44'"		# should be a starting arg

trap "$[which rm] -f $wmfile" 0 1 15    # no temp file left behind

if test $Argc -ne 2  {
  echo "Usage: $[basename $0] imagefile "watermark text"" > !2 ; exit 1
}

if test ! -r $1  {
  echo "$[basename $0]: Can't read input image $1" > !2 ; exit 1
}

# to start, get the dimensions of the image

setglobal dimensions = $[identify -format "%G" $1]

# now let's create the temporary watermark overlay

convert -size $dimensions xc:none -pointsize $fontsize -gravity south \
  -draw "fill black text 1,1 '$2' text 0,0 '$2' fill white text 2,2 '$2'" \
  $wmfile

# echo "created watermark file with dimensions $dimensions"

# now let's composite the overlay and the original file

setglobal suffix = $[echo $1 | rev | cut -d. -f1 | rev]
setglobal prefix = $[echo $1 | rev | cut -d. -f2- | rev]

setglobal newfilename = ""$prefix+wm.$suffix""
composite -dissolve 75% -gravity south $wmfile $1 $newfilename

echo "Created new watermarked image file $newfilename"

exit 0