Reducing the amount of graphical line data transmitted via a low bandwidth transport protocol mechanism

• US 7,127,525 B2
• Filed: 05/25/2001
• Issued: 10/24/2006
• Est. Priority Date: 05/26/2000
• Status: Active Grant

• Current Assignee: Citrix Systems, Inc. (Cloud Software Group)
• Original Assignee: Citrix Systems, Inc. (Cloud Software Group)
• Inventors: Collins, Henry, Yang, Ruiguo, Coleman, Paul
• Primary Examiner(s): Vaughn, William C.
• Assistant Examiner(s): BENGZON, GREG C
• Application Number:
  US09/866,520
• Publication Number:
  US 20030046432A1
• Time in Patent Office: 1,978 Days
• Field of Search: 709246-247, 345/419
• US Class Current: 709/247
• CPC Class Codes: G06F 16/9577 Optimising the visualization of content, e.g. distillation of HTML documents
• 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: H04L 67/01 Protocols
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• CPC Class Codes: H04L 67/131 Protocols for games, networked simulations or virtual reality
• CPC Class Codes: H04L 67/2876 Pairs of inter-processing entities at each side of the network, e.g. split proxies
• CPC Class Codes: H04L 67/289 Intermediate processing functionally located close to the data consumer application, e.g. in same machine, in same home or in same sub-network
• CPC Class Codes: H04L 67/5651 Reducing the amount or size of exchanged application data
• CPC Class Codes: H04L 67/568 Storing data temporarily at an intermediate stage, e.g. caching
• CPC Class Codes: H04L 67/75 Indicating network or usage conditions on the user display
• CPC Class Codes: H04L 69/04 Protocols for data compression, e.g. ROHC
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]
• CPC Class Codes: Y10S 707/99932 Access augmentation or optimizing
• CPC Class Codes: Y10S 707/99933 Query processing, i.e. searching
• CPC Class Codes: Y10S 707/99945 Object-oriented database structure processing

Abstract

The performance of distributed systems can be improved by reducing the amount of graphical line data transmitted between a server and a client. The server separates the graphical line data into a plurality of strips. The server then determines a quantized angle and a strip length for each of the strips. The beginning coordinate of the graphical line data is packaged together with the quantized angle or indicia of the quantized angle and the strip length data into a protocol packet and compressed prior to transmission to the client. In one embodiment the strip data transmitted to the client includes a second indicia that a particular strip has been previously transmitted to the client and the client is instructed to form the strip using locally stored data.

Claims

1. A method of efficiently reducing the amount of graphical data transmitted from a server to a client via a communications network, the method comprising the steps of:

separating a path defined by at least one drawing command of an application into a first strip and a second strip the first and second strips represented as a plurality of consecutive pixels, and each having;

a beginning coordinate and an endpoint coordinate defined within a coordinate system, a strip length, and an absolute angle associated therewith, the coordinate system corresponding to a region of a display unit associated with the client;

determining for the second strip a quantized angle associated wit the absolute angle of the second strip;

the quantized angle measured with respect to the coordinate system at the endpoint of the first strip;

forming a protocol stream at the server, the protocol stream including a beginning coordinate of the path and the strip length and an indicia of the quantized angle of each of the plurality of strips; and

transmitting the protocol stream from the server to the client via the communications network.

2. The method of claim 1 further comprising the step of compressing to beginning coordinate of the path and the strip length and the indicia of the quantized angle of each of the plurality of strips prior to transmitting the protocol stream to the client.

3. The method of claim 1 wherein the protocol stream includes an indicia associated wit at least one of the plurality of strips, the indicia corresponding to an index identifying a location of the at least one of the plurality of strips within a cache memory coupled to the client.

4. The method of claim 1 wherein the protocol stream includes an indicia associated with at least one of the plurality of strips, the indicia corresponding to a fuzzy key identifying a location of the at least one of the plurality of strips within a persistent storage memory coupled to the client.

5. The method of claim 1 wherein the indicia of the quantized angle corresponds to a quantized angle delta.

6. A method of efficiently reducing the amount of graphical data transmitted from a server to a client via a communications network, the method comprising the steps of:

separating a path defined by at least one drawing command of an application into a plurality of strips, each of the plurality of strips represented as a plurality of consecutive pixels and having a beginning coordinate and an endpoint coordinate defined within a coordinate system, the coordinate system corresponding to a region of a display unit associated with the client;

quantizing the coordinate system into a plurality of quantized angles;

determining the endpoint coordinate of a first one of the plurality of strips;

normalizing the endpoint coordinate of the first strip to correspond to the origin of the coordinate system;

associating the endpoint coordinate of the first strip to a beginning coordinate of a second one of the plurality of strips;

selecting one of the plurality of quantized angles of the coordinate system, the selected quantized angle corresponding to an approximate angle of the second strip; and

transmitting a difference between the endpoint coordinates of the first and second strips and an indication of the quantized angle to the client.

7. A system for efficiently reducing the amount of graphical data transmitted from a server to a client via a communications network, the system comprising:

a server agent operating on the server and coupled to the client via the communications network, wherein the server agent

a) separates a path defined by at least one drawing command of an application into a first strip and a second strips, the first and second strips represented as a plurality of consecutive pixels, and each having a beginning coordinate and an endpoint coordinate defined within a coordinate system, a strip length and an absolute angle associated therewith, the coordinate system corresponding to a region of a display unit associated with the client;

b) determines for the second strip a quantized angle associated with the absolute angle of the second plurality of strips, the quantized angle measured with respect to the coordinate system at the endpoint of the first strip;

c) forms a protocol stream at the server, the protocol stream including a beginning coordinate of the path and the strip length and an indicia of the quantized angle of each of the plurality of strips; and

d) transmits the protocol stream from the server to the client via the communications network.

8. The system of claim 7 wherein the server agent compresses the beginning coordinate of the path and the strip length and the indicia of the quantized angle of each of the plurality of strips prior to transmitting the protocol stream to the client.

9. The system of claim 7 wherein the protocol stream includes an indicia associated with at least one of the plurality of strips, the indicia corresponding to en index identifying a location of the at least one of the plurality of strips within a cache memory coupled to the client.

10. The system of claim 7 wherein the protocol stream includes an indicia associated with at least one of the plurality of strips, the indicia corresponding to a fuzzy key identifying a location of the at least one of the plurality of strips within a persistent storage memory coupled to the client.

11. The system of claim 7 wherein the indicia of the quantized angle corresponds to a quantized angle delta.

12. A system for efficiently reducing the amount of graphical data transmitted from a server to a client via a communications network, the system comprising:

a server agent operating on the server and coupled to the client via the communications network wherein the server agent

a) separates a path defined by at least one drawing command of an application into a plurality of strips, each of the plurality of strips represented as a plurality of consecutive pixels and having a beginning coordinate and an endpoint coordinate defined within a coordinate system, the coordinate system corresponding to a region of a display unit associated with the client;

b) quantizes the coordinate system into a plurality of quantized angles;

c) determines the endpoint coordinate of a first one of the plurality of strips;

d) normalizes the endpoint coordinate of the first strip to correspond to the origin of the coordinate system;

e) associates the endpoint coordinate of the first strip to a beginning coordinate of a second one of the plurality of strips;

f) selects one of the plurality of quantized angles of the coordinate system, the selected quantized angle corresponding to an approximate angle of the second strip; and

g) transmits a difference between the endpoint coordinates of the first and second strips and an indication of the quantized angle to the client.