TreeGraph allows you to view your tree with different zoom factors. You can specify the zoom factor by using the "Set zoom.."-option from the View menu or by turning the mouse wheel while holding the control-key.
Alternatively you could use one of the following special zoom functions.
The tree is displayed in a resolution of 100 % (which means about 2.83 pixels per millimeter (72 dpi)).
The size of the tree is changed so that it fits exactly the current size of the window. The aspect ratio remains unchanged. Depending on the original size of the tree it might be scaled up or down.
The size of the tree is changed so that its width equals the current width of the window. The aspect ratio remains unchanged, so that the tree may be higher than the window.
The size of the tree is changed so that its height equals the current height of the window. The aspect ratio remains unchanged, so that the tree may be wider than the window.