Quote Originally Posted by csvivek View Post
My requirement is i need to receive data from a socket, to be continuously drawn on the widget.
Continuity is a purely mathematical concept. Software is limited by the hardware it runs on and is thus, by essence, discrete...

Now you need to make a choice :
  • is your plot meant to be viewed in real time by the user with no possibility to look backward? Then skip some paint events, possibly caching the data if it does not overlap.
  • if this is not the case store everything and render on demand
As a side note you might consider updating only the part of your widget which need to be updated.

I also just wanted to point out the QPainter vs OpenGL does not make sense since QPainter can use OpenGL... Just use a QGLWidget as a viewport and QPainter will rely on OpenGL for all its drawing operations... That's the point of this class by the way : abstracting the drawing operations.