Compositing digital information on a display screen based on screen descriptor
US5745095A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 13, 1995 |
| Grant date | Apr 28, 1998 |
| Priority date | — |
| Expiry date | Dec 13, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09G2340/125
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method and system for producing a composite image of two or more graphic objects. In a set top box (44) designed to be used with a television receiver or video monitor (40), an application specific integrated circuit (ASIC) (76) is provided that includes a dynamic composition engine (DCE) (84), which generates a composite image for display on the screen of the television receiver. The composite image is based upon Screen Descriptor data that include a Line Descriptor defining each scan line using Span Descriptors. A Span Descriptor defines the portion of a line occupied by one of the objects that will comprise the composite image and specifies how that object will be combined with other objects on the line. A line buffer is filled with the pixels for the scan line next to be displayed while data in a second line buffer are written to the display screen. The two line buffers are then switched, enabling the next line to be composed in one line buffer while the data in the other line buffer are written to the screen. A new Screen Descriptor is produced if a change in the composite image occurs. When the last Line Descriptor in the current Screen Descriptor is processed, a pointer to…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.