Gimp-Python

Gimp-Python is a package that allows people to write plug-ins for The Gimp in the Python programming language rather than Script-Fu (Scheme), Perl, Tcl or C.

The newest version, 0.4, has support for both gimp 1.0 and gimp 1.1. Unlike previous versions, this one does not use Tkinter, but instead uses the PyGTK package which is a set of bindings for the GTK+ widget set. The reason for changing over from Tkinter was to get a more consistent look and feel, and for the extra widgets (color and font selectors for instance).

Gimp-Python provides an almost complete wrapper for the libgimp plug-in library, including support for tiles and pixel regions. This means that you can use it to do just about everything that is possible in C, but you get all the benefits of python. You do not have to worry about freeing data structures, and there are some other benefits (such as tiles automatically having the dirty flag set when you modify them). As an example of this power, there is a translation of the whirl and pinch plug-in included with the package.

The gimp-python wrapper for libgimp is an object oriented one, where many of the operations on images, drawables, channels and layers become methods or attributes of those particular types.

Gimp-Python also offers the benefits of script-fu through the gimpfu module. With this module, you need only write the plug-in function, make a call to register(), and gimpfu takes care of the GUI (if the plug-in was called interactively), handle the run_mode parameter, and save parameter defaults between invocations. This makes writing plug-ins very easy, while not restricting what they can do.

Among the sample plug-ins, there is a console plug-in. This plug-in is similar to the script-fu console plug-in, and allows you to experiment with gimp-python interactively, and programatically modify your images.

Documentation

There is some documentation for gimp-python in docbook SGML format. The package contains an HTML conversion as well. Here is an online copy of the documentation:

Download

You can download the source for this package at ftp://ftp.daa.com.au/pub/james/pygimp/. There is also some older versions available in the GIMP plug-in registry, but I have fogotten the password I used there, so the version there is out of date.

Example

Here is an example of a gimp-python plug-in. It is a translation of the script-fu clothify plug-in. It is also included in the gimp-python package.

from gimpfu import *

have_gimp11 = gimp.major_version > 1 or \
	      gimp.major_version == 1 and gimp.minor_version >= 1

def python_clothify(timg, tdrawable, bx=9, by=9,
		    azimuth=135, elevation=45, depth=3):
	bx = 9 ; by = 9 ; azimuth = 135 ; elevation = 45 ; depth = 3
	width = tdrawable.width
	height = tdrawable.height
	img = gimp.image(width, height, RGB)
	layer_one = gimp.layer(img, "X Dots", width, height, RGB_IMAGE,
			       100, NORMAL_MODE)
	img.disable_undo()
	if have_gimp11:
		pdb.gimp_edit_fill(layer_one)
	else:
		pdb.gimp_edit_fill(img, layer_one)
	img.add_layer(layer_one, 0)
	pdb.plug_in_noisify(img, layer_one, 0, 0.7, 0.7, 0.7, 0.7)
	layer_two = layer_one.copy()
	layer_two.mode = MULTIPLY_MODE
	layer_two.name = "Y Dots"
	img.add_layer(layer_two, 0)
	pdb.plug_in_gauss_rle(img, layer_one, bx, 1, 0)
	pdb.plug_in_gauss_rle(img, layer_two, by, 0, 1)
	img.flatten()
	bump_layer = img.active_layer
	pdb.plug_in_c_astretch(img, bump_layer)
	pdb.plug_in_noisify(img, bump_layer, 0, 0.2, 0.2, 0.2, 0.2)
	pdb.plug_in_bump_map(img, tdrawable, bump_layer, azimuth,
			     elevation, depth, 0, 0, 0, 0, TRUE, FALSE, 0)
	gimp.delete(img)

register(
	"python_fu_clothify",
	"Make the specified layer look like it is printed on cloth",
	"Make the specified layer look like it is printed on cloth",
	"James Henstridge",
	"James Henstridge",
	"1997-1999",
	"<Image>/Python-Fu/Alchemy/Clothify",
	"RGB*, GRAY*",
	[
		(PF_INT, "x_blur", "X Blur", 9),
		(PF_INT, "y_blur", "Y Blur", 9),
		(PF_INT, "azimuth", "Azimuth", 135),
		(PF_INT, "elevation", "elevation", 45),
		(PF_INT, "depth", "Depth", 3)
	],
	[],
	python_clothify)

main()

In this simple example, the GUI is automatically generated by gimpfu module. Only the plug-in function and the call to register() needed to be written by the plug-in author.


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