xschem - 3.4.4-1 main

Xschem is a schematic capture program, it allows creation of hierarchical
representation of circuits with a top down approach. By focusing on
interfaces, hierarchy and instance properties a complex system can be
described in terms of simpler building blocks. A VHDL or Verilog or Spice
netlist can be generated from the drawn schematic, allowing the simulation
of the circuit. Key feature of the program is its drawing engine written in
C and using directly the Xlib drawing primitives; this gives very good speed
performance, even on very big circuits. The user interface is built with the
Tcl-Tk toolkit, tcl is also the extension language used.