Zooming in Sparky
From NMR Wiki
The following commands can be used for zooming in Sparky.
Before you can zoom - you will need to select a spectrum to zoom by clicking inside it's window.
zf - zoom full
zo - zoom out
zi - zoom in
zp - zoom previous
Related: vt - opens window where you can adjust width/height ratio
Also you can zoom with the mouse if zoom pointer mode is selected.