if you read the docs, it is stated:
bq. QAbstractScrollArea is a low-level abstraction of a scrolling area. The area provides a central widget called the viewport, in which the contents of the area is to be scrolled (i.e, the visible parts of the contents are rendered in the viewport).
Next to the viewport is a vertical scroll bar, and below is a horizontal scroll bar. When all of the area contents fits in the viewport, each scroll bar can be either visible or hidden depending on the scroll bar's Qt::ScrollBarPolicy. When a scroll bar is hidden, the viewport expands in order to cover all available space. When a scroll bar becomes visible again, the viewport shrinks in order to make room for the scroll bar.
"see QAbstractScrollArea Description":http://doc.qt.nokia.com/4.7/qabstractscrollarea.html#details
so in short:
QScrollArea is the outmost container widget, it contains scrollbars and viewport widget. --> correct
viewport is the area, the visible stuff is rendered to
widget() represents the content, you added. It might be bigger than the QScrollArea Widget.
Nokia Certified Qt Specialist.
Programming Is Like Sex: One mistake and you have to support it for the rest of your life. (Michael Sinz)