Graph time range control

[titchy]

When looking at a graph on a small screen the data can be hard to see.
Having a range modifier below the time axis would allow easy zooming to a smaller time range within the graphs existing range.
I.e. no need to collect more data, just redraw with only the narrowed view range taking the whole graph.
Ui could be a slider with a grab point at each end.
Alternatively, or maybe additionally when the mouse is placed on the graph the mouse over could include values for all lines crossing that time stamp.