Magic is an interactive system for creating and modifying VLSI circuit
layouts.  With Magic, you use a color graphics display and a mouse or
graphics tablet to design basic cells and to combine them
hierarchically into large structures.  Magic is different from other
layout editors you may have used.  The most important difference is
that Magic is more than just a color painting tool: it understands
quite a bit about the nature of circuits and uses this information to
provide you with additional operations.  For example, Magic has
built-in knowledge of layout rules; as you are editing, it
continuously checks for rule violations.  Magic also knows about
connectivity and transistors, and contains a built-in hierarchical
circuit extractor.  Magic also has a plow operation that
you can use to stretch or compact cells.  Lastly, Magic has routing
tools that you can use to make the global interconnections in your
circuits.

Magic is based on the Mead-Conway style of design.  This means that it
uses simplified design rules and circuit structures.  The
simplifications make it easier for you to design circuits and permit
Magic to provide powerful assistance that would not be possible
otherwise.  However, they result in slightly less dense circuits than
you could get with more complex rules and structures.  For example,
Magic permits only Manhattan designs (those whose edges are vertical
or horizontal).

Homepage:
http://opencircuitdesign.com/magic/index.html
