Programming Python, Second Edition

The PyDemos and PyGadgets Launchers

To close out this chapter, I want to show the implementations of the two GUIs used to run major book examples. The following GUIs, PyDemos and PyGadgets, are simply GUIs for launching other GUI programs. In fact, we’ve now come to the end of the demo launcher story: both of the programs here interact with modules that we met earlier in Chapter 8 and Chapter 3:

• launchmodes.py starts independent Python programs portably.

• Launcher.py finds programs, and ultimately runs both PyDemos and PyGadgets when used by the self-configuring top-level launcher scripts.

• LaunchBrowser.py spawns web browsers.

See Examples Example 3-24, Example 4-14, and Example 4-15 for the code for these modules. The programs listed here add the GUI components to the program launching system -- they simply provide easy-to-use pushbuttons that spawn most of the larger examples in this text when pressed.

Both these scripts also assume that they will be run with the current working directory set to their directory (they hardcode paths to other programs relative to that). Either click on their names in a file explorer, or run them from a command-line shell after a cd to the top-level PP2E examples root directory. These scripts could allow invocations from other directories by prepending the PP2EHOME environment variable’s value to program script paths, but they were really only designed to be run out of the PP2E root.

PyDemos Launcher Bar

The PyDemos script constructs a bar of buttons ...