I needed to generate custom font codes as well as some custom image codes for my current 40x8 dot matrix display driven via 74HC595 shift registers and CD4017 counter chips with Arduino. So I came up with this web based code generator. You can click on each segment to turn it on or off and the page will generate the code in arduino compatible binary array. I thought it might be useful for others too.
http://pial.net/page/tools.aspx
Enjoy!