The cTurtle python package and turtle.py module contained within this directory provides a drop-in replacement for the original cTurtle.py module and turtle module respectively with the addition of providing a transparent ability to save PNG images of the final canvas state.

To use this either either of these replacements simply replace your existing cTurtle.py with the directory cTurtle. For turtle just drop the file turtle.py into the directory with your script. For either cTurtle or turtle, you will also need to copy the turtlecapture.py file into the same directory. You will also need to have the convert program provided by imagemagick on your system's path in order for the PNG to be saved.

By default, the modified module/package will behave exactly as before. However, when the environment variable SAVEIMAGE is set, an PNG image will be saved to the same location as whatever python program you run is contained. The image name will be whatever value you set to the SAVEIMAGE environment variable with .png appended.

For instance, if you want to save a snapshot as example_output.png of the window resulting from the program example.py, you need only set the environment variable SAVEIMAGE to example_output. The following is one method to accomplish that task:

SAVEIMAGE=example_output python example.py

Note that the image is saved to the same directory as the python script you are running; it is not always the current directory.

Running Headless

It's kind of annoying for the window to pop up for the brief period that it takes to process the entire program. On a Linux machine, the window can be avoided by using a virtual framebuffer. The xvfb program provides a convenient way to create and use a virtual framebuffer to handle such output. Assuming xvfb is installed the previous example can be run in a headless manor via:

SAVEIMAGE=example_output xvfb-run python example.py

Caveats

In order to automatically capture the end-of-program state, the mainloop and exitOnClick functions have been disabled. Additionally, to minimize the amount of time required to run the entire program, many functions that attempt to delay the rendering time have been disabled. Finally the onTimer function has been disabled. Any disabled function will produce a NOTICE message to the terminal. Note that it is common to see notices about _delay.