xdvi allows the previewing of dvi (DeVice Independent) files
produced by 
and 
.
To facilitate previewing, the file can be reduced in size,
the margins adjusted,
and the colours altered all by using a mouse and clicking buttons.
Pressing the mouse button on top of the document will cause that part of the window to be magnified. The left mouse button will cause a small part of the window to be magnified, while the middle and the right buttons will temporarily enlarge larger sections of the window.
xdvi has many options. Please consult the man pages for more information.