Meet_the_Gimp_Videopodcast_Episode_038_Python

Meet the Gimp! is a weekly video podcast or tutorial about the Gimp graphics software from the viewpoint of a digital photographer. More information at http://meetthegimp.org

This work is licensed under a
Creative Commons Attribution-Share Alike 2.0 Germany License.


Episode 038: A Phython in a Barrel

March 25th, 2008

Will this title scare more people away than catch by curiosity? Who knows?..

The barrel distortion that gave me such problems last week is removed by using a built in filter for correcting (or simulating) lens distortions. You can find it in the image menu at Filters/Distorts/Lens Distortion.

As I have a lot of images with this error, I go out and write a special Python plugin to do this task. It?s not as complicated as it seems - I have a good template and the Web and Gimp give a lot of useful information. You can find the scripts used in this episode here on the Download Page

This is the finished Python program:

#!/usr/bin/env python

import math
from gimpfu import *

def remove_barrel_distortion(img, drw):

img.disable_undo()

layer_corr = drw.copy(True)
layer_corr.mode = NORMAL_MODE
layer_corr.name = "Barrel corrected"
img.add_layer(layer_corr, -1)

pdb.plug_in_lens_distortion(img, layer_corr, 0.0, 0.0, -12.0, 0.0, 0.0, 0.0)

img.enable_undo()
gimp.displays_flush

register(
"remove_barrel_distortion",
"Removes the barrel distortion of a Sanyo CA65",
"",
"Rolf Steinort <info @meetgimp.org>",
"public domain",
"2008",
"<image>/Filters/Distorts/B_arrel distortion removal CA65",
"RGB*, GRAY*",
[],
[],
remove_barrel_distortion)

main()

You find a similar program in this posting. There I have torn it apart and described all the parts. The Python for GIMP documentation and this website can be helpful.