Decompressing run-length-encoded to transition-encoded font image information in an image generator
US4870498A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 15, 1987 |
| Grant date | Sep 26, 1989 |
| Priority date | — |
| Expiry date | Sep 15, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/419
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Transition-encoded information for a single scan line of a font image consists of flags at the addresses of all points of transition upon the scan line from black to white, and from white to black, in order to generate one scan line of the font image. This information is produced, scan line by scan line, in a system receiving the vertical position, the horizontal position, and a starting address within a font memory whereat a run-length-encoded description of a particular character font is stored. This information is developed by adding, in an adder, the initial horizontal displacement plus, in a cumulative fashion, the run-length-encoded font information for each character which appears, in some portion, upon an individual scan line. The transition-encoded information is used to control pixel by pixel image generation in an image generator equivalently to full bit-mapped control but with lower cost, higher speed of conversion, and greater flexibility in the images generated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.