seems very difficult onlywith painting...


but... maybe this idea could help you:

create a "bubble" widget

and after that...
create another widget (qtaglineedit -> not subclassing qlineedit!! is a new composition widget):
A Frame with white background...(to simulate a line edit)
inside the frame an empty "Widget" (in the left) and a qlineedit (in the right)... vertical layout ...

when you write a tag... you create a bubble... and add that bubble in the empty widget. of the left...
and so on...


I hope it helps