Video graphics controller with improved pattern capabilities
CA 2127369 C · Owner: Bresenham, Jack E. · Inventors: Fontenot, Darwin; Eberst, John Vernon; Welker, Mark William
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Circuitry for drawing lines includes a video memory for storing pixel data and circuitry for generating a sequence of addresses defining a line of pixels in the video memory. A first memory stores a sequence of pattern units corresponding to the generated sequence of addresses. A second memory stores a value indicating a current pattern unit. Writing circuitry writes to the video memory at a generated address responsive to a current pattern unit. A third memory stores a control value which is accessed by update circuitry for updating the second memory to indicate the next pattern unit. The update circuitry may selectively update the second memory to the sequential pattern unit or reset the …
Read the whole patent
Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed January 13, 1993 and granted February 23, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended January 13, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 13, 2015.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.