Charles L Bain

US Patent:

54448255, Aug 22, 1995

Filed:

Jun 14, 1994

Appl. No.:

8/259734

Inventors:

Charles L. Bain - Rhinebeck NY
Fai Chu - Kingston NY
Paul D. Dinicola - Kingston NY
John J. Lawless - Red Hook NY

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G06F 1540

US Classification:

395143

Abstract:

In a computer graphics system, a method and apparatus for scaling a line pattern having a predetermined first number of pixels to an actual line having a predetermined second number of pixels different from said first number. The total line length is divided by the line pattern length to obtain the number of line pattern repetitions and the number of remainder pixels in the actual line per line pattern repetition. An error term is incremented by the number of remainder pixels per repetition for each pixel of a given line pattern repetition that is processed. When the cumulative error term equals the line pattern length, the error term is decremented by the line pattern length and an extra pixel is generated. For lines that are shorter than the line pattern, a similar procedure is used except that when the cumulative error term equals the line pattern length, a pixel is deleted. Lines are drawn upon the completion of pattern segments rather than as successive pixel positions are generated to increase the drawing efficiency.