What to use when developing a graphical editor in C++/Qt?

Question

Qt

Hello.
I set myself an educational task - the development of a graphic editor. However, I'm not sure which tool I should use for this purpose.
First, I would like to define the result that I would like to get, namely something similar to the screenshot editor from the Greenshot program:

It is more likely to be called vector than raster.
Secondly, I would like to note that I would like to implement most of the functionality (work with objects) myself, since the task is educational and in the course I would like to master the more things, the better. Thus QGraphicsScene would not be desirable to use, due to the fact that the task becomes too simple in this case.
So I have QPainter and OpenGL in mind. However, again, I'm not sure how true it will be to use these tools in the development of such a graphical editor. What do you advise?
Thanks in advance.

Answer 1

I think Qt is a good choice for such a program. And I do not think that it makes sense for you to abandon QGraphicsScene just because otherwise the task seems too simple to you. I would rather assume that at some stage of the work, the capabilities of QGraphicsScene may not be enough for the tasks at hand (I once encountered a similar problem with her grandfather in Qt3), and then you really have to write all the code with pens. But to invent a job for yourself, abandoning existing classes - IMHO is wrong.
Don't get me wrong - learning how to create such classes yourself is a useful skill. But if you first learn how to use the existing ones, then when you decide to create something of your own, you will already have experience in using these classes, as well as an approximate understanding of what is good and what is not very good in them.
In my opinion, the task you have chosen is not as simple as it might seem, although it certainly depends on the number of features that you want to implement. But nevertheless, I would suggest that you first create a working program, thus realizing your goal, and only then if you still want to rewrite the internals to your own graphical containers.

Answer 2

for the lazy (if you just pass it, download it)
qt-apps.org/content/show.php/EasyPaint?content=140877
(ready "paint" on qt)
you can also see the source