Method and apparatus for updating a graphical display in a distributed processing environment using compression

• US 8,423,673 B2
• Filed: 03/14/2005
• Issued: 04/16/2013
• Est. Priority Date: 03/14/2005
• Status: Active Grant

• Current Assignee: Citrix Systems, Inc. (Cloud Software Group)
• Original Assignee: Citrix Systems, Inc. (Cloud Software Group)
• Inventors: Bullard, Justin, Opferman, Toby
• Primary Examiner(s): KIM, TAE K
• Application Number:
  US10/906,955
• Publication Number:
  US 20060203007A1
• Time in Patent Office: 2,955 Days
• Field of Search: 709/247, 709230-232, 709/235, 709/246, 715/749, 382/232, 382/238, 382/239, 382/240, 382/244
• US Class Current: 709/247
• CPC Class Codes: G06F 3/1454 involving copying of the display data of a local workstation or window to a remote workstation or window so that an actual copy of the data is displayed simultaneously on two or more displays, e.g. teledisplay
• CPC Class Codes: G06T 3/00 Geometric image transformations in the plane of the image
• CPC Class Codes: G09G 2340/02 Handling of images in compressed format, e.g. JPEG, MPEG
• CPC Class Codes: G09G 2350/00 Solving problems of bandwidth in display systems

Abstract

A system and method for updating a remote display unit that communicates with a computing system are described. The method includes accessing display update information from an update queue that stores drawing commands issued by an application executing on the computing system, caching the display update information, applying a lossy compression algorithm to the display update information to create a lossy display update, and transmitting the lossy update to the remote display. The method also includes applying a lossless compression algorithm to the display update information in the cache to create a lossless display update and transmitting the lossless display update a predetermined of time after transmitting the lossy update.

Claims

1. A method of updating a remote display unit in communication with a computing system, the method comprising:

(a) accessing, by a thread executing on a computing system, display update information from an update queue storing drawing commands issued by an application executing on the computing system, the display update information comprising an image;

(b) storing the display update information to a cache;

(c) applying, by the thread, a lossy compression algorithm to a portion of the image to create a lossy display update;

(d) transmitting, by a driver executing on the computing system, the lossy update to the remote display;

(e) waiting a predetermined period of time after the transmission of the lossy update;

(f) examining the update queue to determine whether new display update information has been added to the update queue and, if new display update information exists then

(f-1) applying, by the thread, a lossy compression algorithm to the new update information to create a second lossy display update; and

(f-2) transmitting, by the driver, the second lossy display update to the remote display, otherwise

(f-3) applying, by the thread, a lossless compression algorithm to the same portion of the image stored in the cache to create a lossless display update, the lossless display update comprising a lossless version of the portion of the image; and

(f-4) transmitting, by the driver, the lossless display update to the remote display.

2. The method of claim 1 further comprising setting the operational mode of the computing system.

3. The method of claim 1 further comprising determining if the image was previously transmitted to the remote display unit.

4. The method of claim 3 further comprising signaling the remote display unit to indicate that the image was previously transmitted.

13. The method of claim 1 further comprising determining the predetermined time period based on a time since a last update was sent to the remote display unit and an amount of free buffer space in the driver.

14. The method of claim 1 further comprising determining the predetermined time period based on a time since a last update was sent to the remote display unit and availability of storage space in the cache.

15. The method of claim 1 further comprising determining the predetermined time period based on a time since a last update was sent to the remote display unit and an amount of space available in the queue.

5. A system for updating a display unit remotely located from a computing system comprising:

a queue storing a display update representative of a graphical output of an application program executing on the computer system, the display update comprising an image;

a cache storing the display update;

a thread accessing the queue and applying a lossy compression algorithm to a portion of the image to generate a lossy display update, and accessing the cache and applying a lossless compression algorithm to the same-portion of the image stored in the cache to generate a lossless display update the lossless display update comprising a lossless version of the portion of the image; and

a driver transmitting the lossy display update to the remote display unit, waiting a predetermined time period, examining the queue to determine whether new display update information has been added to the queue and, if new display update information exists then applying, by the thread, a lossy compression algorithm to the new update information to create a second lossy display update; and

transmitting, by the driver, the second lossy display update to the remote display, otherwise transmitting the lossless display update to the remote display unit.

6. The system of claim 5 further comprising a flag for setting the operational mode of the computing system.

7. The system of claim 5 further comprising a cache for determining if the image was previously transmitted to the remote display unit.

8. The system of claim 7 further comprising a transmitter for signaling the remote display unit to indicate that the image was previously transmitted.

16. The system of claim 5, wherein the driver determines the predetermined time period based on a time since a last update was sent to the remote display unit and an amount of free buffer space in the driver.

17. The system of claim 5, wherein the driver determines the predetermined time period based on a time since a last update was sent to the remote display unit and availability of storage space in the cache.

18. The system of claim 5, wherein the driver determines the predetermined time period based on a time since a last update was sent to the remote display unit and an amount of space available in the queue.

9. A system for updating a display unit remotely located from a computing system, the system comprising:

a queue for storing a display update representative of a graphical output of an application program executing on the computer system, the display update comprising an image;

a cache for storing a copy of the display update;

means for accessing the queue and applying a lossy compression algorithm to a portion of the image to generate a lossy display update, and for accessing the cache and applying a lossless compression algorithm to the same-portion of the image stored in the cache, to generate a lossless display update, the lossless display update comprising a lossless version of the portion of the image; and

means for examining the queue to determine whether new display update information has been added to the queue and, if new display update information exists then applying a lossy compression algorithm to the new update information to create a second lossy display update; and

transmitting the second lossy display update to the remote display, otherwise transmitting the lossless display update.

10. The system of claim 9 further comprising means for setting the operational mode of the computing system.

11. The system of claim 9 further comprising means for determining if the image was previously transmitted to the remote display unit.

12. The system of claim 11 further comprising means for signaling the remote display unit to indicate that the image was previously transmitted.

19. The system of claim 9, wherein the means for examining determines the predetermined time period based on a time since a last update was sent to the remote display unit and an amount of space available in the queue.

20. The system of claim 9, wherein the means for examining determines the predetermined time period based on a time since a last update was sent to the remote display unit and availability of storage space in the cache.