QTableView draw custom lines
Is there any way to draw custom lines, like, say, every three rows, with a different thickness?
You can subclass QTreeView and override drawRow to draw anything you want - lines, shapes, text, pictures, whatever.
Sorry, I read tree view and you meant table view.
You can set an item delegate. Then you implement the delegate by subclassing QStyledItemDelegate and override the paint method in which you can draw whatever you need.