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DRAWL 70: A COMPUTER GRAPHICS LANGUAGE

IP.com Disclosure Number: IPCOM000128412D
Original Publication Date: 1970-Jan-01
Included in the Prior Art Database: 2005-Sep-15

Publishing Venue

Software Patent Institute

Related People

Herzog, B.: AUTHOR [+4]

Abstract

The DRAWL language provides a simple means of defining a graphical composition and specifying operations on it. A catalog of parts is kept; any defined item may be re-used any number of times. Changes in viewing angle, scale, absolute location, and projection are easily affected in three dimensions via homogeneous coordinate projective geometry. Graphical output is available on cathode-ray tube-displays, digital-incremental plotters, and on-line computer line-printers and remote printing terminals.

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THIS DOCUMENT IS AN APPROXIMATE REPRESENTATION OF THE ORIGINAL.

DRAWL 70: A COMPUTER GRAPHICS LANGUAGE

B. Herzog THE UNIVERSITY OF MICHIGAN Technical Report 30 Fred Shadko

CONCOMP: Research in Conversational Use of Computers F. H. Westervelt, Director ORA Project 07449

Supported by:

ADVANCED RESEARCH PROJECTS AGENCY Department of Defense Washington, D.C.

Contract No. DA-49-083 OSA-3050 ARPA Order No. 716

Administered through:

OFFICE OF RESEARCH ADMINISTRATION Ann Arbor

August

ABSTRACT

The DRAWL language provides a simple means of defining a graphical composition and specifying operations on it. A catalog of parts is kept; any defined item may be re-used any number of times. Changes in viewing angle, scale, absolute location, and projection are easily affected in three dimensions via homogeneous coordinate projective geometry. Graphical output is available on cathode-ray tube-displays, digital-incremental plotters, and on-line computer line- printers and remote printing terminals.

TABLE OF CONTENTS

ABSTRACT.....iii
TABLE OF CONTENTS.....v
LIST OF FIGURES......vii
PREFACE.....ix
PROGRAMMER'S NOTE.....xi
INTRODUCTION.....2
DEFINITION OF POINTS.....4
NAMING AND DEFINING SEQUENCE FOR OBJECTS.....5
NAMING AND CREATING SEQUENCE FOR ASSEMBLIES.....6
TRANSFORMATIONS IN DRAWL.....8
PERFORMING A TRANSFORMATION.....10

University of Michigan Page 1 Jan 01, 1970

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DRAWL 70: A COMPUTER GRAPHICS LANGUAGE

EXECUTING THE DRAWING.....10
COMMENTS ON DRAWL NAMES AND OTHER PROGRAMMING CONVENTIONS.....11
APPENDIX A - HOMOGENEOUS COORDINATE PROJECTIVE GEOMETRY.....A1
APPENDIX B - DRAWL SUBROUTINE DESCRIPTIONS.....B1
APPENDIX C - DRAWL OUTPUT PARAMETERS.....C1

     Table C1 - Default settings for DRAWL RUN Parameters.....C1
APPENDIX D - SPECIAL DRAWL ROUTINES.....D1
APPENDIX E - DRAWL ERROR MESSAGES.....E1
APPENDIX F - SAMPLE DRAWL PROGRAMS.....F1
APPENDIX G - THE DRAWL 70 DATA STRUCTURE.....G1
APPENDIX H - DRAWL 70 FORTRAN SOURCE LISTING.....H1
APPENDIX I - ALPHABETICAL LIST OF DRAWL SUBROUTINES.....I1

LIST OF FIGURES

Figure 1. The DRAWL Sequence of Operations.....1
Figure 2. Specification of a Rectangular Parallelopiped.....3
Figure 3. DRAWL Hierarchy......3
Figure 4. Specifications of a Triangle.....7
Figure 5. DRAWL Transformation Matrix Breakdown.....9
Figure A-1. DRAWL Transformation Matrix Breakdown.....A-5
Figure A-2. Translation.....A-6
Figure A-3. β1--Rotation.....A-7
Figure A-4. β2--Rotation.....A-8
Figure A-5. β3--Rotation.....A-9
Figure A-6. The Perspective Transformation.....A-10
Figure A-7. Illustration of Perspective Transformation Matrix.....A-11
Figure F-1. DRAWL Output.....F-2
Figure F-2. DRAWL Output.....F-3
Figure F-3. DRAWL Output.....F-5
Figure G-1. DRAWL Data Structure.....G-2
Figure G-2. Internal Operation of TRANSF.....G-3

PREFACE

The DRAWL language was conceived in conjunction with a computer graphics course offered during the Fall term, 1966, by the Industrial Engineering Department, the University of Michigan. It was a...