Plot auto-scaling

[ccbaci]

I am using Qt+Qwt for real time signal plotting. I need to auto-scale the y-axis so that the canvas size covers the data.

I tried QwtScaleEngine::Attribute::Floating = true to achieve the cumulative min-max. But I want to auto-scale my plot such that the boundaries are not taken from the min-max of data starting from time zero, but starting from another time.

How can I obtain time based min-max? (i.e. the auto-scale of my plot between times 5-10). I know one way is to check out all data between these times to find the max and min, then scale accordingly.

Is there a faster method at Qwt library?