Quote Originally Posted by karankumar1609 View Post
well graphicsView is the best API i have seen for drawing purpose.
It automatically update its child items which i dont want to handle.
You only have one item currently.

QWidget need to update manually on each small changes.. that will effect the performance.
Based on what you have now, changing location of one point in the plot requires all 100k points to be redrawn. That sounds to me like "each small changes requires manual update of the whole plot".

On Widget i have to mannually handle and draw each element.
That's what you do now too. Both QWidget and QGraphicsView use QPainter API for painting. Each time a piece of your data changes, you redraw the whole canvas which is exactly the situation with widgets. With graphics view, modifying one point should only redraw that one point (and possibly others that intersect with it).

like if i have to add a dynamic line element on graph i have to draw it and handle each and every moment.
That's what you do now.

In QGraphicsScene its easy.
Yes, I know. Unfortunately you're using QGraphicsView like it were a plain widget.