LEFTY. A two-view editor for technical pictures

This paper describes LEFTY, a two-view graphics editor for pictures in various contexts. This editor has no hardwired knowledge about specific picture layouts or editing operations. A picture is described by a program containing functions to draw the picture and functions to perform editing operations appropriate to the specific picture. Primitive user actions, like mouse and keyboard events, are bound to functions in this program. Besides the graphical view of the picture itself, the editor presents a textural view of the program that describes the picture. Programmability and the two-view interface allow the editor to handle a variety of pictures, but are particularly useful for pictures used in technical contexts, e.g., graphs and trees and VLSI layouts. LEFTY can communicate with other processes. This feature allows it to use existing tools to compute specific picture layouts and allows external processes to use the editor to display their data structures.