/Demo/turtle/demohelp.txt
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- ----------------------------------------------
- xturtleDemo - Help
- ----------------------------------------------
- This document has two sections:
- (1) How to use the demo viewer
- (2) How to add your own demos to the demo repository
- (1) How to use the demo viewer.
- Select a demoscript from the example menu.
- The (syntax coloured) source code appears in the left
- source code window. IT CANNOT BE EDITED, but ONLY VIEWED!
- - Press START button to start the demo.
- - Stop execution by pressing the STOP button.
- - Clear screen by pressing the CLEAR button.
- - Restart by pressing the START button again.
- SPECIAL demos are those which run EVENTDRIVEN.
- (For example clock.py - or oldTurtleDemo.py which
- in the end expects a mouse click.):
- Press START button to start the demo.
- - Until the EVENTLOOP is entered everything works
- as in an ordinary demo script.
- - When the EVENTLOOP is entered, you control the
- application by using the mouse and/or keys (or it's
- controlled by some timer events)
- To stop it you can and must press the STOP button.
- While the EVENTLOOP is running, the examples menu is disabled.
- - Only after having pressed the STOP button, you may
- restart it or choose another example script.
- * * * * * * * *
- In some rare situations there may occur interferences/conflicts
- between events concerning the demo script and those concerning the
- demo-viewer. (They run in the same process.) Strange behaviour may be
- the consequence and in the worst case you must close and restart the
- viewer.
- * * * * * * * *
- (2) How to add your own demos to the demo repository
- - scriptname: must begin with tdemo_ ,
- so it must have the form tdemo_<your-script-name>.py
- - place: same directory as xturtleDemo.py or some
- subdirectory, the name of which must also begin with
- tdemo_.....
- - requirements on source code:
- code must contain a main() function which will
- be executed by the viewer (see provided example scripts)
- main() may return a string which will be displayed
- in the Label below the source code window (when execution
- has finished.)
- !! For programs, which are EVENT DRIVEN, main must return
- !! the string "EVENTLOOP". This informs the viewer, that the
- !! script is still running and must be stopped by the user!