Zooming image

[wysota]

I told you to subclass QAbstractScrollArea and implement the functionality from scratch, not to use a custom widget composed of a scroll area and a label. You will have to get your hands dirty here.

[MTK358]

OK, I looked but I don't understand what methods to reimplement and how to paint to the viewport.

[wysota]

OK, I looked but I don't understand what methods to reimplement and how to paint to the viewport.

Reimplement at least paintEvent() and optionally scrollContentsBy().

[MTK358]

OK, but how do I get a QPainter for the viewport widget?

[wysota]

You create it in the paint event like usual.

[MTK358]

Finally, I did it.

Anyway, it works great now, but I would really like it so that the user can scroll by dragging the mouse in the viewport. How would I do that?

[SixDegrees]

You're gradually reinventing QGraphicsView here. Just use that; you get all of the features you've brought up so far for free.

[MTK358]

You're gradually reinventing QGraphicsView here. Just use that; you get all of the features you've brought up so far for free.

I'm not very familiar with QGraphicsView but maybe...

Anyway, why didn't anyone else offer that?

[wysota]

Anyway, why didn't anyone else offer that?

I'm myself against using Graphics View for displaying a single image. In my opinion it gives too much overhead without giving anything else in return.