Real time bit map capture and sharing for collaborative tools

• US 6,151,020 A
• Filed: 10/24/1997
• Issued: 11/21/2000
• Est. Priority Date: 10/24/1997
• Status: Expired due to Fees

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Compaq Computer Corporation (HP Inc.)
• Inventors: Palmer, Lawrence George, Palmer, Ricky Samuel
• Primary Examiner(s): SAX, STEVEN PAUL
• Application Number:
  US08/957,323
• Time in Patent Office: 1,124 Days
• Field of Search: 345/329, 345/2, 345/330, 345/346, 345/343, 345/356-357, 345/331-332
• US Class Current: 715/733
• CPC Class Codes: G06F 3/033 Pointing devices displaced or positioned by the user , e.g. mice, trackballs, pens or joysticks; Accessories therefor digitisers characterised by the transducing means G06F3/041
• 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: G09G 2320/103 Detection of image changes, e.g. determination of an index representative of the image change
• CPC Class Codes: G09G 2340/02 Handling of images in compressed format, e.g. JPEG, MPEG

Abstract

A new system and method for sharing graphical display information in a collaborative tool is disclosed which samples graphics display information regarding a shared display region on a server system. The disclosed system updates client systems regarding changes in the shared display region responsive to detection of a change in the shared display region contents. The disclosed system further modifies a polling rate used to sample the graphical display information on the server responsive to the frequency of changes to the shared display region. Specifically, in an example embodiment the disclosed system shares a display region among a plurality of users by selecting a first bit map from a series of bit maps used to display the shared display region on a server system. The server system then transmits said first bit map to a client system. The server system periodically selects a subsequent bit map from the series of bit maps at a polling rate. The server system later determines whether said shared display region on the server system has changed. If the shared display region has changed, then the server system transmits a representation of the subsequent bit map to said client system. The server system increases the polling rate responsive to determining that the shared display region on the server system has changed.

Claims

1. A method of providing a shared display region among a plurality of users across a computer network, comprising the steps of:

capturing a first bit map used to display said shared display region on a server system;

transmitting said first bit map to a client system;

capturing a second bit map from said series of bit maps at a polling rate, a polling rate initialized to a predetermined rate;

determining whether said shared display region on said server system has changed; and

transmitting a representation of said subsequent bit map to said client system if said shared display region on said server has changed; and

increasing said polling rate responsive to determining a change in said shared display region on said server system.

2. The method of claim 1 further comprising:

determining whether communications between said server system and said client system are blocked; and

leaving said polling rate unchanged if communications between said server system and said client system are blocked.

3. The method of claim 1 further comprising decreasing said polling rate upon detecting no change in said shared display region on said server system.

4. The method of claim 3 further comprising:

determining whether communications between said server system and said client system are blocked; and

leaving said polling rate unchanged responsive to determining said communications between said server system and said client system are blocked.

5. The method of claim 1 wherein said server system determines whether said shared display region has changed by performing an exclusive OR operation (XOR) between a first one of said subsequent bit maps and a second one of said subsequent bit maps, said shared display region having changed if the result of said XOR operation is non-zero.

6. The method of claim 2, wherein said step of determining whether said communications between said server system and said client system are blocked includes measuring a round trip delay of a message sent from said server system to said client system.

7. The method of claim 1, wherein said polling rate is increased responsive to determining a change in said shared display region on said server system by a predetermined percentage of the previous polling rate.

8. The method of claim 3 wherein said polling rate is decreased upon detecting no change in said shared display region on said server system by a predetermined percentage of the previous polling rate.

9. The method of claim 6 wherein said measuring of said round trip delay between said server system and said client system includes placing a time stamp into a message transmitted from said server system to said client system, and said client system returning said time stamp in an acknowledgement message associated with said transmitted message, said acknowledgement message transmitted from said client system to said server system.

10. A method of providing a shared display region among a plurality of users across a computer network, comprising the steps of:

executing at least one shared application on a server system forming at least one shared application window, said shared application window displaying at least partially within said shared display region;

capturing a first bit map used to display said shared display region on said server system;

transmitting said first bit map to a client system;

capturing a second bit map from said series of bit maps at a polling rate, a polling rate initialized to a predetermined rate; and

determining whether said shared display region on said server system has changed by performing an exclusive OR operation (XOR) between a first one of said subsequent bit maps and a second one of said subsequent bit maps, said shared display region having changed if the result of said XOR operation is non-zero, wherein said capturing of said first and second bitmaps are done independent from execution of said shared application.

11. The method of claim 10, further comprising the step of transmitting a representation of said subsequent bit map to said client system if said shared display region on said server has changed.

12. A system for providing a shared display region among a plurality of users across a computer network, comprising:

means for capturing a first bit map used to display said shared display region on a server system;

means for transmitting said first bit map to a client system;

means for capturing a second bit map from a series of bit maps at a polling rate, said polling rate initialized to a predetermined rate;

means for determining whether said shared display region on said server system has changed;

means for transmitting a representation of said subsequent bit map to said client system if said shared display region on said server has changed; and

means for increasing said polling rate responsive to determining a change in said shared display region on said server system.

13. The system of claim 12 further comprising:

determining whether communications between said server system and said client system are blocked; and

leaving said polling rate unchanged if communications between said server system and said client system are blocked.

14. The system of claim 12 further comprising decreasing said polling rate upon detecting no change in said shared display region on said server system.

15. The system of claim 14 further comprising:

means for determining whether communications between said server system and said client system are blocked; and

means for leaving said polling rate unchanged responsive to determining said communications between said server system and said client system are blocked.

16. The system of claim 12 wherein said server system determines whether said shared display region has changed by performing an exclusive OR operation (XOR) between a first one of said subsequent bit maps and a second one of said subsequent bit maps, said shared display region having changed if the result of said XOR operation is non-zero.

17. The system of claim 13, wherein said means for determining whether said communications between said server system and said client system are blocked includes means for measuring a round trip delay of a message sent from said server system to said client system.

18. The system of claim 12, wherein said polling rate is increased responsive to determining a change in said shared display region on said server system by a predetermined percentage of the previous polling rate.

19. The system of claim 14 wherein said polling rate is decreased upon detecting no change in said shared display region on said server system by a predetermined percentage of the previous polling rate.

20. The system of claim 17 wherein said measuring of said round trip delay between said server system and said client system includes placing a time stamp into a message transmitted from said server system to said client system, and said client system returning said time stamp in an acknowledgment message associated with said transmitted message, said acknowledgment message transmitted from said client system to said server system.

21. A system for providing a shared display region among a plurality of users across a computer network, comprising:

means for executing at least one shared application on a server system forming at least one shared application window said shared application window displaying at least partially within said shared display region;

means for capturing a first bit map used to display said shared display region on said server system;

means for transmitting said first bit map to a client system;

means for capturing a second bit map from a series of bit maps at a polling rate, said polling rate initialized to a predetermined rate; and

means for determining whether said shared display region on said server system has changed by performing an exclusive OR operation (XOR) between a first one of said subsequent bit maps and a second one of said subsequent bit maps, said shared display region having changed if the result of said XOR operation is non-zero, wherein said capturing of said first and second bitmaps are done independent from execution of said shared application.

22. The system of claim 21, further comprising means for transmitting a representation of said subsequent bit map to said client system if said shared display region on said server has changed.

23. A computer readable program storage device, having computer executable instructions encoded thereon, said computer executable instructions comprising program code, said program code for providing a shared display region among a plurality of users across a computer network, said program code comprising:

program code for capturing a first bit map used to display said shared display region on a server system;

program code for transmitting said first bit map to a client system;

program code for capturing a second bit map from a series of bit maps at a polling rate, said polling rate initialized to a predetermined rate;

program code for determining whether said shared display region on said server system has changed;

program code for transmitting a representation of said subsequent bit map to said client system if said shared display region on said server has changed; and

program code for increasing said polling rate responsive to determining a change in said shared display region on said server system.

24. The computer readable program storage device of claim 23 further comprising:

program code for determining whether communications between said server system and said client system are blocked; and

program code for leaving said polling rate unchanged if communications between said server system and said client system are blocked.

25. The computer readable program storage device of claim 23 further comprising program code for decreasing said polling rate upon detecting no change in said shared display region on said server system.

26. The computer readable program storage device of claim 25 further comprising:

program code for determining whether communications between said server system and said client system are blocked; and

program code for leaving said polling rate unchanged responsive to determining said communications between said server system and said client system are blocked.

27. The computer readable program storage device of claim 23 wherein said program code for determining whether said shared display region has changed performs an exclusive OR operation (XOR) between a first one of said subsequent bit maps and a second one of said subsequent bit maps, said shared display region having changed if the result of said XOR operation is non-zero.

28. The computer readable program storage device of claim 24, wherein said program code for determining whether said communications between said server system and said client system are blocked includes program code for measuring a round trip delay of a message sent from said server system to said client system.

29. The computer readable program storage device of claim 23, wherein said polling rate is increased responsive to determining a change in said shared display region on said server system by a predetermined percentage of the previous polling rate.

30. The computer readable program storage device of claim 25 wherein said polling rate is decreased upon detecting no change in said shared display region on said server system by a predetermined percentage of the previous polling rate.

31. The computer readable program storage device of claim 28 wherein said program code for measuring of said round trip delay between said server system and said client system includes program code for placing a time stamp into a message transmitted from said server system to said client system, and said client system returning said time stamp in an acknowledgment message associated with said transmitted message, said acknowledgment message transmitted from said client system to said server system.

32. A computer readable program storage device, having computer executable instructions encoded thereon, said computer executable instructions comprising program code, said program code for providing a shared display region among a plurality of users across a computer network, said program code comprising:

program code for executing at least one shared application on a server system forming at least one shared application window, said shared application window displaying at least partially within said shared display region;

program code for capturing a first bit map used to display said shared display region on said server system;

program code for transmitting said first bit map to a client system;

program code for capturing a second bit map from a series of bit maps at a polling rate, said polling rate initialized to a predetermined rate; and

program code for determining whether said shared display region on said server system has changed by performing an exclusive OR operation (XOR) between a first one of said subsequent bit maps and a second one of said subsequent bit maps, said shared display region having changed if the result of said XOR operation is non-zero, wherein said capturing of said first and second bitmaps are done independent from execution of said shared application.

33. The computer readable program storage device of claim 32, further comprising program code for transmitting a representation of said subsequent bit map to said client system if said shared display region on said server has changed.

34. The computer readable program storage device of either claim 32 or claim 33, wherein said computer program readable storage device is a magnetic disk ("floppy disk").

35. The computer readable program storage device of either claim 32 or claim 33, wherein said computer readable program storage device is a computer memory.

36. The computer readable program storage device of either claim 32 or claim 33, wherein said computer readable program storage device is an optical disk.