Conformal plugin for the GIMP
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README.asciidoc rename README to match GitHub expectations Jul 9, 2012 use transparency in case of numerical exceptions Jul 18, 2012


Introduction is a plugin-in for The Gimp which allows visualisation of conformal maps.


You need gimp and the python scripting extension to Gimp. It is included in newer versions of Gimp, before it was available in packages named gimp-python or similar.


You can install as a local user or system wide:

Local User

Copy to the plug-ins subdirectory of your Gimp directory, usually $HOME/.gimp-2.*/plug-ins/ on Linux, and make sure that it is executable (chmod +x

System wide

Copy to the plug-ins subdirectory of your system Gimp directory, usually /usr/lib/gimp/2.*/plug-ins/ or (similar) on Linux, and make sure that it is executable (chmod a+rx


After starting The Gimp, you find the conformal plug-in in the Create submenu of the File menu. From the dialogue, you can adjust these parameters:

width, height

The dimensions of the new image.


The python code which is executed for every single pixel of the image. The code can use the value of the complex number z (which represents the current pixel) and should assign a value to w which will be considered the (mapping) image of z.

x left, x-right

The range of x-values (real parts) which is mapped to the horizontal image axis.

y top, y bottom

The range of y-values (imaginary parts) which is mapped to the vertical image axis.

grid spacing

The spacing of the generated coordinate grid.

checker board

Use a checker board instead of a grid.


The gradient representing the argument of the complex number.

The plugin-in then creates a new image with three layers:


This layer paints the conformally transformed coordinate grid.

Log. modulus

This layer adds a shading corresponding to the absolute value on a logarithmic scale, i.e. one cycle (from white to black) of the shading means doubling the modulus: the fractional part of lb |w| is used as an index into the default white-black gradient.


This layer is coloured using the value of the gradient at an index corresponding to arg w.

The two topmost layers have transparency and layer mode set appropriately, but feel free to experiment with these, as well as turning some layers off, depending on your goal: produce instructive illustrations, or simply beautiful pictures!

License is copy righted by Michael J. Gruber and is available under the GNU General Public License Version 2.