The line drawing editor, an experiment in computer vision
SIGGRAPH '76 Proceedings of the 3rd annual conference on Computer graphics and interactive techniques
Increasing capabilities in interactive computer graphics terminals
DAC '72 Proceedings of the 9th Design Automation Workshop
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LOGIGRAF, an interactive graphics program to lay out and edit schematic drawings, is now being used in a production environment at Bell Telephone Laboratories. The program runs on a GRAPHIC-211 graphics terminal (fig.1 ) which consists of a Digital Equipment Corporation PDP-15 computer with 8K of memory, secondary storage disk, card reader, 9 track tape, display processor, refreshed 21 inch CRT display, keyboard, light pen, function buttons, storage CRT, and hard copy unit. The cost of this hardware assuming a one shift operation and including maintenance is around $25/user hour.2 A virtual memory operating system is used to optimize the use of the 8K of core memory. The operating system and graphical programming support were developd as part of a general interactive graphics system for Bell Laboratories. LOGIGRAF is one of about a half dozen major application programs which all use the same system software. LOGIGRAF itself required almost three man years to develop and presently contains about fifty thousand words of Instructions. Programming was done in a higher level macro language designed for graphic application programming. Many technical obstacles had to be overcome in the development of the program. The most important of these had to do with providing a satisfactory user interface. In addition, a number o f new algorithms for dealing with the graphical data base permitted more complete graphical editing functions to be made available to the user.