Window-dependent buffer selection
US5001469A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 29, 1988 |
| Grant date | Mar 19, 1991 |
| Priority date | — |
| Expiry date | Jun 29, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09G2340/12
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An image generator (38) in a workstation draws its image data from a pair of frame buffers (32 and 34). The selection between the frame buffers is made by a multiplexer circuit (42) that can switch between frame buffers (32 and 34) on a pixel-by-pixel basis, i.e., different frame buffers can be used during different parts of the same scan frame of a monitor (18) in the image generator (38). A selection-signal source (46), which provides the selection signals for the multiplexer circuit (42), includes a window detector (56), which compares the outputs of counters (72 and 74) that represent the monitor scan position with the outputs of registers (62, 64, 66, and 68) that represent the boundaries of windows used by respective applications that the workstation is running. The source (46) thereby identifies the windows in which the pixel currently being displayed is located, and it employs a priority circuit (76) to identify the one such window having the highest priority. Each software application deposits in a buffer register (70) the identity of the frame buffer (32 or 34) from which the data for its display should currently be drawn, and a priority circuit generates a BUFSEL signal …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.