I use gimp. To script use FPI EditPad.
1. Click on new.
2. Click on OK because default is for fpi.
3. Click on insert.
4. Click on FPI Template to get fpi template.
5. Click on insert again.
6. Click on Hud Definition
7. Locate the hud you wish to use. It actually can be anywhere in one of the subfolders of the files folder.
8. Now you will be asked to enter the name of the hud. Also you need to indicate the position of the hud. Press Enter.
9. A hud definition will automatically be created for you.
10. Finish your script. Example in code snippet.
;Artificial Intelligence Script
;Header
desc = example hud
;Triggers
:state=0:hudreset,hudx=50,hudy=50,hudimagefine=blank_scroll.png,hudname=hudname,hudhide=1,hudmake=display,state=1
:state=1,plrdistwithin=50:hudshow=hudname,hudfadeout=hudname,state=2
;End of Script
state=0 is the line that is created by hud def. This will position the hud on the center of the screen. X and Y positions are by percentage.