Beautiful drop shadows now bow before me.

I got a lot of compliments on the design of the ignite session I did for Mil-OSS. Part of what made it work so well, I think, is the drop shadows, like you see here:

For a long time, I did these using the Gimp. It’s kind of a tedious process, especially if you are doing this for multiple images. Even if you automate it with a script, you have to start up the Gimp to get it to work. I wanted a way to do it from the command line, so I could convert a bunch of images at once.

So I wrote this quick script to use ImageMagick instead:

#!/bin/sh

if [ -z "$1" ]; then echo $0 '<filename>'; exit 1; fi;

filename=$(basename "$1")
extension=${filename##*.}
filename=${filename%.*}

convert -channel RGBA -colorspace RGB -background none "$1" 
( +clone -background none -shadow 60x5+10+10 ) 
+swap -layers merge +repage 
$filename-shadow.png

You’ll note that I always convert to PNG, because it’s important to preserve the transparency. If you convert to a JPG file, it’ll look terrible. So here’s an example. Notice that the shadow isn’t a square box — it actually follows the shape of the visible portion of the image. Shazam!