公开(公告)号：DE3175685D1

公开(公告)日：1987-01-15

申请号：DE3175685

申请日：1981-08-28

Applicant: IBM

Inventor： BRESENHAM JACK ELTON ,  GRICE DONALD GEORGE ,  PI SHING-CHOU

IPC: G06F3/153 ,  G06K15/22 ,  G06T11/20 ,  G09G1/10 ,  G09G5/20 ,  G09G5/36

Abstract: A graphic output system generates circular arcs of lengths up to and including a full circle of 360 degrees. Nonsymmetrical closest points are located for noninteger radius and arc center values. Incremental move commands are generated for drawing an arc either in the clockwise or counter clockwise direction which is a distinct advantage when used to drive a pen type electromechanical plotter. By dividing the generation of a 360 degree arc into eight octants, only two of the original eight directions need to be considered as candidate directions toward the next integer display matrix value to be displayed. Initialization provides a simple stopping test for any circular arc of arbitrary length and direction. Only simple addition and sign testing is used to display the circular arc.