Zoom expands or shrinks the diagram horizontally, by changing the number of pixels per unit in the ruler.
Zoom Full to see the entire diagram within the window.
Menu: View | Zoom full Shortcut: Alt+F
Zoom In expands the diagram by increasing the number of pixels per unit in the ruler. Notice that the saved image is wider than in the above zoom-full example.
Menu: View | Zoom in Shortcut: Alt+I
Zoom Out shrinks the diagram by decreasing the number of pixels per unit in the ruler. Notice that the saved image is narrower than in the above zoom-full example.