I tried to draw some curves using QwtPlot, the scale of plot may range from 100 to 100000 pixels. It is easy to obtain this goal, but this solution consumes too much memory cause the size of plot too big.

I think we can just draw part of curves, which display on screen. Now another problem arises, I don't know how to set scrollbar to control the display of curves.

Any suggestions? Thanks in advance!