Hi All,
I am happy to "announce" the birth of my latest child, called SizerHack.
SizerHack is a small application I wrote while investigating random
generated interfaces. In my opinion, it could be useful to teach
wxPython newbies how to deal with sizers and interfaces layouts in a
more "visual" way.
Basic Concepts
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Hereafter I present some features of SizerHack, explaining the
terminology I use later on in this part of the documentation.
(a) Layout Generation
SizerHack generates randomly a layout in a separate frame. Using the
nesting level you provide (see next point), it creates a layout where
widgets types are chosen randomly from a stock of 10 different
standard wxPython controls, added to their sizers using a randomly
selected proportion (either 0 or 1) and a randomly selected flag
(either 0 or wx.EXPAND).
Selecting a nesting level greater than 1 (which is the default),
SizerHack will generate a random layout in which sizers are nested.
In order to avoid a too big separate frame (in term of wx.Size), the
proportion keyword has a probability distribution of 80% for 0 and 20%
for 1 (which means 80% of the times a widget or a sizer will be added
to their containing sizers with a proportion of 0).
In order to generate a new layout, just select the menu "Edit" =>
"Create New Layout" or hit "Ctrl+L".
(b) Nesting Levels
SizerHack allows the user to select the nesting level for sizers: this
means the randomly generated layout in the separate frame will have
sizers nested in sizers nested in sizers... and so on, depending on
the nesting level you have chosen.
In order to change the nesting level, just select the menu "Edit" =>
"Set Nesting Level" or hit "Ctrl+N".
(c) Sizer Exposure
There are some cases where being able to see the sizer is helpful,
such as at design time. SizerHack allows you to see the sizers/widgets
hierarchy on screen, by painting the sizers/widgets boundaries. Just
select the menu "Hints" => "Draw Sizers" or hit "Ctrl+D" to see them.
Sizers with the wx.HORIZONTAL orientation are painted in solid BLUE,
while their children widgets are surrounded by a dotted blue line.
Sizers with the wx.VERTICAL orientation are in RED.
Description Of Sample Usage
Once launched, SizerHack will show you a randomly generated layout in
a new separate frame (with wx.STAY_ON_TOP flag). By default, SizerHack
creates the initial layout using a nesting level of 1. You can change
this value by choosing the menu "Edit" => "Set Nesting Level" or hit
"Ctrl+N".
In the SizerHack TreeList control, you will see 2 items, namely the
start of the layout hierarchy in the separate frame. These 2 items
represent a wx.Frame and a wx.Panel, which are fixed for every layout
SizerHack generates.
Now, the panel has always a sizer associated with it: what you should
do, is right-click on the wxPanel item and choose "Add Sizer As Child"
from the popup menu.
A new line in the TreeList control appears: it contains 3 wx.Choices,
asking you to choose from them: these wx.Choices represent the sizer
orientation, proportion and flag that SizerHack has used to assign
this sizer to wxPanel.
If you choose the correct answer from the wx.Choices, the icon next to
them will be a green "Ok" bitmap, otherwise it will be a red "Wrong"
cross.
Now that you have added the main sizer, by looking at the separate
frame and playing with it (resize it to see), you should decide which
widgets (or sub-sizers) have been added to the main sizer. If you
think a widget is a direct child of the main sizer, simply Drag and
Drop the widget from the separate frame to the item that represents
the main sizer in the TreeList control. If your answer is correct, a
new line appears in the TreeList control, asking you to fill 2
wx.Choices representing the proportion and flag used to add this
window to the main sizer.
In case of nested sizers, once you decide a sub-sizer is a child of
the main sizer (or a sub-sub-sizer is a child of a sub-sizer), just
right click on the main sizer (or on the sub-sizer) and choose "Add
Sizer as Child" from the popup menu.
If you are lost, or you don't recognize at a glance which kind of
layout you are presented, you have 2 alternatives:
1) Select the menu "Hints" => "Draw Sizers" to see on screen how the
sizers and widgets are arranged;
2) Right click on any item in the TreeList control (except the
wxFrame) and, from the popup menu, choose "Give Help!". SizerHack will
either uncover one child of the selected item or will fill one of the
wx.Choices for you.
Once all the hierarchy is complete and the wx.Choices are filled
correctly, SizerHack will congratulate with you for your
wx.SizerSkills!
You can find the source code (which contains the demo) in the usual place:
SizerHack is based on an hacked version of HyperTreeList: as usual, I
can only test on Windows XP, so I would be grateful if someone could
try it on other platforms (but not necessarily, Windows users are
always welcome 
) and report possible problems/issues/bugs.
I will also appreciate criticisms/comments on the basic idea on which
SizerHack has been built.
Suggestions for improvements are always welcome: however, I will
depart from Norway and then ex-Jugoslavia in thursday, so please be
patient if I can not answer to (possible) questions/messages on this
list after thursday.
Sorry for the long post 
wxPython rules.
Andrea.
"Imagination Is The Only Weapon In The War Against Reality."
http://xoomer.virgilio.it/infinity77/