Writing Plugins for GIMP in Python - page 2

Creating a Script

All GIMP plug-ins, regardless of language, need to call register to tell GIMP they exist. Here's a skeleton of a GIMP-Python plug-in showing how to register. Copy and paste this into pytest so you can see how it works:

def python_pytest(img, layer) :
    # Actual plug-in code will go here
    return

register(
       	"python_fu_pytest",
	"Does something",
	"Does something terribly useful",
	"Your name",
	"Your name",
	"2009",
	"Py Test...",
	"*",
	[
	],
	[],
	python_pytest,
        menu="/Filters/Distorts")

main()

What does all that mean? The first part, def python_pytest, is the routine that will do the real work ... but for now, it's just a placeholder. It takes two arguments, the image and layer to work on. Any plug-in that modifies an existing image must use at least these two arguments. Plug-ins that create new images don't need them.

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register is next. It takes quite a list of arguments:

• A python_fu name by which your function will be available to other GIMP scripts;
• Short and long descriptions of what the plug-in does;
• The name of the author and the copyright holder (usually the same person) and the copyright date;
• The name the plug-in should use in the menus;
• The types of images your plug-in can handle (RGB, greyscale, indexed or all). If it can work on any type of image, use "*"; if it creates a new image rather than operating on an existing one, use "";
• Any parameters the plug-in might show to the user -- I'll show how to use these in a future article;
• Any return values. Most python scripts leave this blank, or [];
• The name of the function that does the work, python_pytest;
• Where in the menus you want the function to show up.

Whew! Quite a lot of arguments, but usually you can copy most of them from some other plug-in and just change the values; you don't have to remember all of that.