The main difference for the user is that now it allows to auto adjust the face lower limit.
When you press space in the app, it will tell you to sit with your back straight for 5 seconds, during that time it will save your face position, calculate average position and size, and set the a lower limit for you, no manual input needed. And enforce it nicely :)
The code has also evolved a good deal, what started as basic functionality with initialisation of needed bits with a while(true) loop, moved towards being more modular via creating functions, and then pursuing further modularity using classes, and as last stage: expanding the user input towards a gui-event based paradigm.
What I'm finding is that more and more the user interface expands, the more complex the code becomes, losing part of its original orthogonality, that is, when I need to add a new handle for specific event, I usually need to touch other parts of the code to accommodate the new functionality.
What is happening?
The application is especially vulnerable to events that require different handling depending on the context... The code is littered with a multitude of global variables and flags that serve only one purpose -- handling the context.... With this representation, the context of the computation is represented ambiguously, so it is difficult to tell precisely in which mode the application is at any given time. Actually, the application has no notion of any single mode of operation, but rather tightly coupled and overlapping conditions of operation determined by values of the global variables and flags.
Found in Who moved my state, that reveals the weaknesses of event-driven programming and advocates the use of finite state machines.
As I see it, Behave's code should move from a main loop reacting to user keystrokes and mouse clicks, towards two separate modules with their respective loops in different threads. One would run the frame capturing and what to do with it, the other would create the gui and facilitate start/stop and interact/modify with the first.
I'll be digging into finite state machines in the next days and how to implement them with Behave.
Some reading done:
http://infohost.nmt.edu/tcc/help/pubs/tkinter/tkinter.pdf
http://www.astro.washington.edu/users/rowen/ROTKFolklore.html
http://www.astro.washington.edu/users/rowen/TkinterSummary.html#Resources
http://www.ferg.org/thinking_in_tkinter/all_programs.html
Tutorial on guis using Tkinter and Python:
http://www.alan-g.me.uk/l2p/tutevent.htm
http://www.alan-g.me.uk/l2p/tutgui.htm
Finite state machine implementation in Python:
http://www.python-course.eu/finite_state_machine.php
These guys have also a Tkinter tutorial:
http://www.python-course.eu/python_tkinter.php
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