Method and apparatus for providing a reformatted video image to a display

• US 5,555,460 A
• Filed: 03/09/1995
• Issued: 09/10/1996
• Est. Priority Date: 11/29/1989
• Status: Expired due to Term

• Current Assignee: Intel Corporation
• Original Assignee: Chips and Technologies, Inc. (Intel Corporation)
• Inventors: Ericsson, Bo E.
• Primary Examiner(s): Chin, Tommy P.
• Assistant Examiner(s): AU, AMELIA MEGAN
• Application Number:
  US08/402,159
• Time in Patent Office: 551 Days
• Field of Search: 345/154, 345/155, 345/153, 345/186, 345/187, 345/199, 345/200, 345/203, 345/147, 345/150, 345/3
• US Class Current: 345/545
• CPC Class Codes: G09G 5/028 Circuits for converting colour display signals into monochrome display signals

Abstract

A system which allows for the generation of grayscale video signals from color graphics images to grayscaling display devices receiving digital signals. The system is implemented advantageously in packed pixel color graphics modes of a video graphics array sysem utilized in a personal computer. The system is preferably implemented in a software program to decrease the number of hardware components, save circuit board space, consume less power and reduce complexity in the circuitry in the personal computer.

Claims

1. In a video graphics array (VGA) system, the VGA system includes a single memory for storing digital information, controller means for controlling the movement of the digital information and converter means for converting the digital information into video information in the form of a color value, a method for providing a grayscale equivalent of the color value to a display, the method comprising the steps of:

(a) configuring the VGA system for planar organization;

(b) drawing an image into a first portion of the single memory with a packed pixel arrangement;

(c) computing a grayscale value of the image in accordance with the color value;

(d) reformatting the grayscale value of the image;

(e) writing the reformatted grayscale value of the image to an unused portion of the single memory with a planar arrangement;

(f) generating the reformatted grayscale value from the unused portion of the single memory; and

(g) preventing the output of the video information of the image from the first portion of the single memory.

2. The method of claim 1 in which the converter means comprises a digital to analog converter wherein the color value is further translated to an analog output.

3. The method of claim 1 in which the single memory comprises a plurality of banks of random access memories that are coupled in parallel and have a common output.

4. The method of claim 1 in which the first portion is a first plane of the single memory.

5. The method of claim 1 wherein the unused portion comprises at least one other plane of the single memory.

6. The method of claim 1 wherein the unused portion comprises a plurality of other planes of the single memory.

7. The method of claim 1 wherein the unused portion comprises three other planes of the single memory.

8. The method of claim 5 in which the video graphics array system further includes means for receiving the generated reformatted grayscale value from the at least one other plane of the single memory means and displaying the image represented by the reformatted grayscale value.

9. The method of claim 6 in which the video graphics array system further includes means for receiving the reformatted grayscale value from the other planes of the single memory and displaying the image represented by the reformatted grayscale value.

10. The method of claim 1 wherein the color value is an RGB value.

11. In a video graphics array (VGA) system, the VGA system includes a single memory for storing digital information, controller means for controlling the movement of the digital information and converter means for converting the digital information into video information in the form of a color value, an apparatus for providing a grayscale value equivalent to the color value, the apparatus comprising:

means for configuring the VGA system in a planar organization;

means for drawing an image into a first portion of the single memory with a packed pixel arrangement;

means for computing the grayscale value of the image in accordance with the color value;

means for reformatting the grayscale value of the image;

means for writing the reformatted grayscale value of the image to an unused portion of the single memory with a planar arrangement;

means for generating the reformatted grayscale value from the unused portion of the single memory; and

means for preventing the output of the video information of the image from the first portion of the single memory.

12. The apparatus of claim 11 in which the converter comprises a digital to analog converter wherein the color value is further translated to an analog output.

13. The apparatus of claim 11 in which the single memory comprises four banks of random access memories that are coupled in parallel and have a common output.

14. The apparatus of claim 11 in which the first portion is a first plane of the single memory.

15. The apparatus of claim 11 wherein the unused portion comprises at least one other plane of the single memory.

16. The method of claim 11 wherein the unused portion comprises a plurality of other planes of the single memory.

17. The apparatus of claim 11 wherein the unused portion comprises three other planes of the single memory means.

18. The apparatus of claim 11 wherein the color value is an RGB value.

19. In a video graphics array (VGA) system, the system includes a single memory having a plurality of planes for storing digital information, means for controlling the movement of the digital information and means for converting the digital information into video information in the form of a color value, an apparatus for providing a grayscale equivalent to the color value to provide accurately an image to a display, the system comprising:

(a) means for configuring the planes of the single memory into a planar memory organization;

(b) means for drawing an image in a first plane with a packed pixel arrangement;

(c) means for computing a grayscale value of the image in accordance with the color value;

(d) means for reformatting the grayscale value of the image;

(e) means for storing the reformatted grayscale value in a second plane with a planar arrangement;

(f) means for generating a video output from the reformatted grayscale value; and

(g) means for preventing the generation of the video output from the first plane.

20. The apparatus of claim 19 in which the converter means comprises a digital to analog converter wherein the color value is further translated to an analog output.

21. The apparatus of claim 19 in which the single memory comprises four banks of random access memories that are coupled in parallel and have a common output.

22. The apparatus of claim 19 in which the color value is an RGB value.

23. The apparatus of claim 19 wherein at least one other plane of the plurality of planes is used to store the reformatted grayscale value for a generation of a video information.

24. The system of claim 19 wherein the color value is an RGB value.

25. In a video graphics array (VGA) system, the VGA system includes a single memory for storing digital information, controller means for controlling the movement of the digital information and converter means for converting the digital information into video information in the form of a color value, a method for providing a grayscale equivalent of the color value to a display, the method comprising the steps of:

(a) configuring the VGA system for planar organization;

(b) drawing an image into a first portion of the single memory with a packed pixel arrangement, the packed pixel arrangement having each pixel defined by a first plurality of bits;

(c) computing a grayscale value of the image in accordance with the color value;

(d) reformatting the grayscale value of the image;

(e) writing the reformatted grayscale value of the image to an unused portion of the single memory with a planar arrangement, the planar arrangement having each pixel defined by a second plurality of bits;

the first plurality of bits being larger than the second plurality of bits;

(f) generating the reformatted grayscale value from the unused portion of the single memory; and

(g) preventing the output of the video information of the image from the first portion of the single memory.

26. The video graphics array (VGA) system of claim 25 in which the first plurality of bits include 8 bits and the second plurality of bits include 4 bits.