suggestion for touch screen

[Angus]

I was inspired by the wish to keep the plot values x-wise, that means I wanted to keep the functin plotted from, say, 0..5 but since the function gives small y-values I just wanted to change the y-scaling with the vertical zoom gesture.
To me it is not like zooming into a picture, you know. (btw some apps for android and iOS do this kind of zoom - I had to search for their names)

You prefer to modify the x-range with every zoom, correct? Interessting, I'll try to think about benefits of that.
Thanks for the answer!