[Qt-interest] Display non printable characters in a QTextEdit/QPlainTextEdit

[Timo Falk]

Hi!

I want to display non printable characters (eg. ASCII control chars  < 32)
like Notepad++ (the second step is to toggle the display...). After 
browsing the qt source for a while, I think I have to deal with two 
things:

1. the layout of (the) line
2. the rendering of the glyphs

But now I am totally lost in the darkness between QTextLayout, 
QAbstractDocumentLayout, QTextEngine, etc...

Can anybody help me to sun againt? I have no idea what is the right point 
to start.

Timo