System and method for generating and displaying complex graphic images at a constant frame rate

• US 5,889,529 A
• Filed: 03/22/1996
• Issued: 03/30/1999
• Est. Priority Date: 03/22/1996
• Status: Expired due to Term

• Current Assignee: RPX Corporation
• Original Assignee: Silicon Graphics Incorporated (Graphics Properties Holdings, Inc.)
• Inventors: Jones, Michael T., Dignam, David L., Eitzmann, Gregory M.
• Primary Examiner(s): Jankus, Almis R.
• Application Number:
  US08/620,215
• Time in Patent Office: 1,103 Days
• Field of Search: 395/139, 395/128, 395/133, 395/173, 395/174, 395/806, 395/807, 395/118, 345/439, 345/428, 345/433, 345/418, 345/302, 345/473, 345/474
• US Class Current: 345/660
• CPC Class Codes: G06T 3/40 Scaling of whole images or parts thereof, e.g. expanding or contracting

Abstract

A system and method for dynamically resizing graphic images of variable image complexity to generate display images at a constant frame rate for output to a display device. In one frame, an image resolution is determined and a graphic image is drawn to the determined image resolution. In the subsequent frame, the graphic image is magnified to a target resolution prior to being output to a display device. The synchronization of the drawing of the graphic image and its display is managed by a swap buffer signal. The present invention further provides for the double buffering of graphic images and their corresponding image resolutions. The present invention further provides for the independent dynamic resizing of multiple channels, such that, a plurality of display devices can independently resize graphic images of variable complexity at a constant frame rate.

Claims

1. A video graphics system for dynamically resizing graphic images of variable complexity, comprising:

determining means for determining a first image resolution for a first graphic image;

drawing means for drawing said first graphic image to said first image resolution thereby producing a drawn image; and

magnifying means for magnifying said drawn image to a target resolution thereby generating a display image;

wherein said drawing means and said determining means execute within a time period of a single frame, and said magnifying means executes within said time period of said single frame, and

wherein said determining means compares a computational time for drawing a second graphic image with said time period of said single frame, wherein said second graphic image precedes said first graphic image.

2. A video graphic system according to claim 1, wherein said magnifying means comprises means for performing bi-linear interpolation.

3. A video graphic system according to claim 1, wherein said magnifying means comprises means for performing linear interpolation.

4. A video graphic system according to claim 1, wherein said magnifying means comprises means for performing bi-cubic interpolation.

5. A video graphic system according to claim 1, wherein said magnifying means executes concurrently with said drawing and said determining means.

6. A video graphic system according to claim 1, further comprising double buffering means to double buffer said graphic image, wherein a first frame buffer receives said drawn image produced by said drawing means during a first frame, and a second frame buffer contains a previously drawn image produced by said drawing means during a second frame, wherein said previously drawn image is magnified by said magnifying means during said first frame, and wherein said second frame is a time period immediately preceding said first frame.

7. A video graphic system according to claim 6, wherein said drawing means and said magnifying means are synchronized by a swap buffer signal.

8. A video graphic system according to claim 1, further comprising:

a plurality of drawing means; and

a plurality of magnifying means;

wherein one said drawing means and one said magnifying means correspond to a channel of a display device, thereby providing independent dynamic resizing of graphic images of variable complexity across multiple channels.

9. A video graphic system for dynamically resizing graphic images of variable complexity, comprising:

determining means for determining a first image resolution for a first graphic image;

drawing means for drawing said first graphic image at said first image resolution, thereby producing a drawn image; and

magnifying means for magnifying said drawn image to a target resolution thereby generating a display image, wherein

said drawing means and said determining means execute within a time period of a single frame, and said magnifying means executes within said time period of said single frame,

said determining means further determines a computational time for drawing a second graphic image that precedes said first graphic image exceeds a high-water mark, and if said computational time exceeds said high-water mark, said first image resolution is determined to be less than a second image resolution at which said second graphic image was drawn; and

said determining means further determines if said computational time falls below a low-water mark, and if said computational time falls below said low-water mark and said second image resolution does not equal said target resolution, said first image resolution is determined to be greater than said second image resolution, otherwise said first image resolution is determined to be said target resolution.

10. A video graphic system according to claim 9, wherein said magnifying means comprises means for performing bi-linear interpolation.

11. A video graphic system according to claim 9, wherein said magnifying means comprises means for performing linear interpolation.

12. A video graphic system according to claim 9, wherein said magnifying means comprises means for performing bi-cubic interpolation.

13. A video graphic system according to claim 9, wherein said magnifying means executes concurrently with said drawing and said determining means.

14. A video graphic system according to claim 9, further comprising double buffering means to double buffer said first graphic image, wherein a first frame buffer receives said drawn image produced by said drawing means during a first frame, and a second frame buffer contains a previously drawn image produced by said drawing means during a second frame, wherein said previously drawn image is magnified by said magnifying means during said first frame, and wherein said second frame is a time period immediately preceding said first frame.

15. A video graphic system according to claim 14, wherein said drawing means and said magnifying means are synchronized by a swap buffer signal. 16. A video graphic system according to claim 7, further comprising:

a plurality of drawing means; and

a plurality of magnifying means;

wherein one said drawing means and one said magnifying means correspond to a channel of a display device, thereby providing independent dynamic resizing of graphic images of variable complexity across multiple channels.

16. A video graphic system according to claim 9, further comprising:

a plurality of drawing means; and

a plurality of magnifying means;

wherein one side drawing means and one said magnifying means correspond to a channel of a display device, thereby providing independent dynamic resizing of graphic images of variable complexity across multiple channels.

17. In a computer-based system having a computer graphics system, a method for dynamically resizing a graphic image of variable complexity to generate a display image of a target resolution at a constant frame rate, said steps comprising:

(a) drawing, within a time period of a single frame, the graphic image of variable complexity to a first image resolution, thereby producing a drawn image;

(b) determining, within said time period of said single frame, a second image resolution for a second graphic image of variable complexity by comparing a computational time for drawing the graphic image of variable complexity with said time period of said single frame, wherein the graphic image of variable complexity precedes said second graphic image; and

(c) if said first image resolution is less than the target resolution, magnifying said drawn image to the target resolution, thereby producing the display image.

18. A method according to claim 17, wherein said step (c) executes within a time period of one frame and executes concurrently with said steps (a) and (b) which also execute within said time period of one frame.

19. A method according to claim 17, further comprising the steps of:

(d) double buffering said drawn image, wherein a first frame buffer receives the graphic image being drawn in step (a) during a first frame, and a second frame buffer stores a previously drawn image produced during a second frame, wherein said second frame is a time period immediately preceding said first frame;

(e) double buffering said image resolution, wherein a buffered resolution coefficients register stores said image resolution coefficients corresponding to the graphic image being drawn in said first frame buffer, and a resolution coefficients register stores said image resolution coefficients corresponding to said drawn image stored in said second frame buffer; and

(f) synchronizing said double buffering of said drawn image with said double buffering of said image resolution, wherein said first frame buffer and said second frame buffer are swapped concurrent with the transfer of said image resolution coefficients from said buffered resolution coefficients register to said resolution coefficients register.

20. The method according to claim 17, further comprising the steps of:

(d) drawing, within a time period of a single frame, said second graphic image of variable complexity to said second image resolution, thereby producing a second drawn image; and

(e) if said second image resolution is less than the target resolution, magnifying said second drawn image to the target resolution, thereby producing a second display image.

21. A video graphics system, comprising:

a pair of frame buffers, denoted by a first frame buffer and a second frame buffer, each of which receives a graphic image drawn to an image resolution, thereby storing a drawn image, wherein said first frame buffer receives said graphic image during a first frame and said second frame buffer receives a second graphic image during a second frame;

a switch for pointing to said pair of frame buffers wherein said switch indicates whether said first frame buffer is receiving said graphic image or whether said second frame buffer is receiving said graphic image;

a buffered resolution coefficients register for storing resolution coefficients associated with said graphic image currently being drawn to either said first frame buffer or said second frame buffer during said second frame;

a resolution coefficients register for storing resolution coefficients associated with said drawn image currently stored in either said first frame buffer or said second frame buffer during said first frame;

a swap buffer signal connected to said switch and said buffered resolution coefficients register wherein said swap buffer signal causes said switch to swap said first frame buffer and said second frame buffer and said buffered resolution coefficients register to output its stored resolution coefficients into said resolution coefficients register; and

a video output controller for reading the contents of said first frame buffer, if said first frame buffer contains said drawn image, or said second frame buffer, if said second frame buffer contains said drawn image, and outputting said drawn image to a display device, wherein said drawn image is magnified by said resolution coefficients stored in said resolution coefficients register prior to said outputting of said drawn image.

22. A video graphics system connected to a plurality of display devices, wherein each said display device has a unique channel, each channel comprising:

a pair of frame buffers, denoted by a first frame buffer and a second frame buffer, each of which receives a graphic image drawn to an image resolution, thereby storing a drawn image, wherein said first frame buffer receives said graphic image during a first frame and said second frame buffer receives a second graphic image during a second frame;

a switch for pointing to said pair of frame buffers wherein said switch indicates whether said first frame buffer is receiving said graphic image or whether said second frame buffer is receiving said graphic image;

a buffered resolution coefficients register for storing resolution coefficients associated with said graphic image currently being drawn to either said first frame buffer or said second frame buffer during said second frame;

a resolution coefficients register for storing resolution coefficients associated with said drawn image currently stored in either said first frame buffer or said second frame buffer during said first frame;

a swap buffer signal connected to said switch and said buffered resolution coefficients register wherein said swap buffer signal causes said switch to swap said first frame buffer and said second frame buffer and said buffered resolution coefficients register to output its stored resolution coefficients into said resolution coefficients register; and

a video output controller for reading the contents of said first frame buffer, if said first frame buffer contains said drawn image, or said second frame buffer, if said second frame buffer contains said drawn image, and outputting said drawn image to a display device, wherein said drawn image is magnified by said resolution coefficients stored in said resolution coefficients register prior to said outputting of said drawn image.

23. A video graphic system for dynamically resizing graphic images of variable complexity, comprising:

a plurality of drawing means for drawing graphic images to an image resolution thereby producing drawn images;

determining means for determining an image resolution for at least one of said graphic images; and

a plurality of magnifying means for magnifying said drawn images to a target resolution, thereby generating display images;

wherein one of said plurality of drawing means and said determining means execute within a time period of a single frame, and each of said plurality of magnifying means executes within a time period of said single frame, and

wherein one said drawing means and one said magnifying means correspond to a channel of a display device, thereby providing independent dynamic resizing of graphic images of variable complexity across multiple channels.

24. A video graphic system according to claim 23, wherein each of said plurality of magnifying means comprises bi-linear interpolation.

25. A video graphic system according to claim 23, wherein each of said plurality of magnifying means comprises linear interpolation.

26. A video graphic system according to claim 23, wherein each of said plurality of magnifying means comprises bi-cubic interpolation.

27. A video graphic system according to claim 23, wherein at least one of said magnifying means executes concurrently with at least one of said drawing means.

28. A video graphic system according to claim 23, wherein said determining means compares the computational time for drawing a graphic image preceding said at least one of said graphic images with said time period of said single frame.

29. A video graphic system according to claim 28, further comprising:

first determining means for determining if said computational time exceeds a high-water mark, wherein if said high-water mark is exceeded, said image resolution for said at least one of said graphic images is determined to be less than the image resolution at which said graphic image preceding said at least one of said graphic images was drawn; and

second determining means for determining if said computational time falls below a low-water mark, wherein if said computational time falls below said low-water mark and the image resolution at which said graphic image preceding said at least one of said graphic images was drawn does not equal said target resolution, said image resolution for said at least one of said graphic images is determined to be greater than the image resolution at which said graphic image preceding said at least one of said graphic images was drawn, otherwise said image resolution for said at least one of said graphic images is determined to be said target resolution.

30. A video graphic system according to claim 23, further comprising double buffering means to double buffer said graphic images, wherein a first frame buffer receives one of said drawn images produced by one of said drawing means during a first frame, and a second frame buffer contains a previously drawn image produced by said one of said drawing means during a second frame, wherein said previously drawn image is magnified by one of said magnifying means during said first frame, and wherein said second frame is a time period immediately preceding said first frame.

31. A video graphic system according to claim 30, wherein said one of said drawing means and said one of said magnifying means are synchronized by a swap buffer signal.

32. In a computer-based system having a computer graphics system, a method for dynamically resizing a graphic image of variable complexity to generate a display image of a target resolution at a constant frame rate, comprising the steps of:

(a) drawing, within a time period of a single frame, the graphic image of variable complexity to a first image resolution, thereby producing a drawn image;

(b) determining, within said time period of said single frame, a second image resolution for a second graphic image of variable complexity, wherein the graphic image of variable complexity precedes said second graphic image, and wherein said determining step comprises the steps of;

comparing a computational time for drawing the graphic image of variable complexity to a high-water mark, wherein if said computational time exceeds said high-water mark, said second image resolution is determined to be less than said first image resolution; and

comparing said computational time to a low-water mark, wherein if said computational time is less than said low-water mark and said first image resolution does not equal the target resolution, said second image resolution is determined to be greater than said first image resolution, otherwise said second image resolution is determined to be said target resolution; and

(c) if said first image resolution is less than the target resolution, magnifying said drawn image to the target resolution, thereby producing the display image.

33. A method according to claim 32, wherein said step (c) executes within a time period of one frame and executes concurrently with said steps (a) and (b) which also execute within said time period of one frame.

34. A method according to claim 32, further comprising the steps of:

(d) double buffering said drawn image, wherein a first frame buffer receives the graphic image being drawn in step (a) during a first frame, and a second frame buffer stores a previously drawn image produced during a second frame, wherein said second frame is a time period immediately preceding said first frame;

(e) double buffering said image resolution, wherein a buffered resolution coefficients register stores said image resolution coefficients corresponding to the graphic image being drawn in said first frame buffer, and a resolution coefficients register stores said image resolution coefficients corresponding to said drawn image stored in said second frame buffer; and

(f) synchronizing said double buffering of said drawn image with said double buffering of said image resolution, wherein said first frame buffer and said second frame buffer are swapped concurrent with the transfer of said image resolution coefficients from said buffered resolution coefficients register to said resolution coefficients register.

35. In a computer-based system having a computer graphics system, a method for dynamically resizing a graphic image of variable complexity to generate a display image of a target resolution at a constant frame rate, said steps comprising:

(a) drawing the graphic image of variable complexity to a first image resolution, thereby producing a drawn image;

(b) determining a second image resolution for a subsequent graphic image of variable complexity of said drawn image;

(c) magnifying said drawn image to the target resolution, thereby producing the display image;

(d) double buffering said drawn image, wherein a first frame buffer receives the graphic image being drawn in step (a) during a first frame, and a second frame buffer stores a previously drawn image produced during a second frame, wherein said second frame is a time period immediately preceding said first frame;

(e) double buffering said image resolution, wherein a buffered resolution coefficients register stores said image resolution coefficients corresponding to the graphic image being drawn in said first frame buffer, and a resolution coefficients register stores said image resolution coefficients corresponding to said drawn image stored in said second frame buffer; and

(f) synchronizing said double buffering of said drawn image with said double buffering of said image resolution, wherein said first frame buffer and said second frame buffer are swapped concurrent with the transfer of said image resolution coefficients from said buffered resolution coefficients register to said resolution coefficients register.

36. A method according to claim 35, wherein said steps (a) and (b) execute within a time period of one frame.

37. A method according to claim 36, wherein said step (c) executes within a time period of one frame and executes concurrently with said steps (a) and (b) which also execute within said time period of one frame.

38. A method according to claim 36, wherein said step (b) comprises a comparison of a computational time for drawing the graphic image of variable complexity with said time period of said single frame.

39. A method according to claim 38, wherein said step (b) further comprises:

(d) comparing said computational time to a high-water mark, wherein if said high-water mark is exceeded, said second image resolution is determined to be less than said first image resolution; and

(e) comparing said computational time to a low-water mark, wherein if said computational time falls below said low-water mark and said first image resolution is less than said target resolution, said second image resolution is determined to be greater than said first image resolution, otherwise said second image resolution is determined to be said target resolution.