Caching fonts for improved bandwidth of transmitted text

• US 7,046,250 B1
• Filed: 07/17/2003
• Issued: 05/16/2006
• Est. Priority Date: 07/11/2002
• Status: Active Grant

• Current Assignee: Oracle America, Inc. (Oracle Corporation)
• Original Assignee: Sun Microsystems Incorporated (Oracle Corporation)
• Inventors: O'Neill, Thomas G., Slott, Jordan M.
• Primary Examiner(s): Tung, Kee M.
• Assistant Examiner(s): Hsu, Joni
• Application Number:
  US10/623,058
• Time in Patent Office: 1,034 Days
• Field of Search: 345/555, 345/557, 345/530, 345/543, 345/553, 345/531, 345/545, 382/232
• US Class Current: 345/555
• CPC Class Codes: G06F 12/0875 with dedicated cache, e.g. instruction or stack
• CPC Class Codes: G09G 2360/121 using a cache memory
• CPC Class Codes: G09G 5/225 comprising a loadable character generator character generators per se G09G5/24

Abstract

Caching fonts on a display computer may be performed in order to reduce network bandwidth utilization and/or to improve CPU usage. Text commands may be recorded when they are executed to create a portion of a graphics image. These text commands may be used to update a data structure with information, and this data structure may be used to more efficiently transmit the text portions of the graphics image. A caching mechanism may be used wherein the font utilized by the text command is stored in the cache if a compatible font does not already exist in the cache. Once the font has been cached, subsequent text commands utilizing the font may be executed with a dramatic reduction in network bandwidth.

Claims

1. A method for reducing the storage or bandwidth requirements of a graphics image or reducing CPU usage in a computer system, the method comprising:

recording a text command executed to create a portion of the graphics image;

using said text command to update a data structure with information;

compressing one or more sub-images of the graphics image using a compression scheme, each of said sub-images having a location, said location and said compression scheme for each of said sub-images chosen based on said information in said data structure, wherein;

said data structure identifies the portion of the graphics image that was created with a specific drawing command, further wherein;

said data structure includes a list specifying text regions, text strings, character set identifiers, and/or colors;

determining if a set of character images compatible with a set of character images utilized in the text command already exists in a cache;

adding the set of character images utilized in the text command to a display computer cache if the set of character images utilized in the text command does not already exist in a cache; and

utilizing said set of character images to display said one or more sub-images of the graphics image created using the text command, wherein said adding the set of character images utilized in the text command includes;

determining if there is enough room in said cache on said display computer for the set of character images;

removing cache entries until there is enough room in said cache, if there is not enough room in said cache on said display computer for the set of character images;

sending a request to said display computer to create one or more new cache entries for the set of character images; and

adding the set of character images to a list of sets of character images currently cached on said display computer.

2. The method of claim 1, where said removing cache entries includes taking into account the last time the cache entry was used.

3. The method of claim 1, wherein said removing cache entries includes:

removing one or more cache entries from a list of cache entries on a host computer; and

sending one or more requests to said display computer to remove said cache entries.

4. An apparatus for reducing the storage or bandwidth requirements of a graphics image or reducing CPU usage in a computer system, comprising:

a text command recorder;

a data structure updater coupled to said text command recorder;

an image compressor coupled to said data structure updater, said image compressor for compressing one or more sub-images of the graphics image using a compression scheme, said compression scheme for each of said sub-images chosen based on said information in said data structure;

a display computer cache compatible set of character images determiner coupled to said text command recorder;

a display computer cache set of character images adder coupled to said display computer cache compatible set of character images determiner; and

a display computer set of character images displayer coupled to said display computer cache set of character images adder, wherein said display computer cache set of character images adder includes;

a display computer cache room determiner;

a cache entry remover and cache entry remover request sender coupled to said display computer cache room determiner;

a new cache entry display computer request sender coupled to said display computer cache room determiner; and

a display computer cache set of character images list adder coupled to said new cache entry display computer request sender.

5. An apparatus for reducing the storage or bandwidth requirements of a graphics image or reducing CPU usage in a computer system, the apparatus comprising:

means for recording a text command executed to create a portion of the graphics image;

means for using said text command to update a data structure with information;

means for compressing one or more sub-images of the graphics image using a compression scheme, each of said sub-images having a location, said location and said compression scheme for each of said sub-images chosen based on said information in said data structure, wherein;

said data structure identifies the portion of the graphics image that was created with a specific drawing command, further wherein;

said data structure includes a list specifying text regions, text strings, character set identifiers, and/or colors;

means for determining if a set of character images compatible with a set of character images utilized in the text command already exists in a cache;

means for adding the set of character images utilized in the text command to a display computer cache if the set of character images utilized in the text command does not already exist in a cache; and

means for utilizing said set of character images to display said one or more sub-images of the graphics image created using the text command, wherein said means for adding the set of character images utilized in the text command includes;

means for determining if there is enough room in said cache on said display computer for the set of character images;

means for removing cache entries until there is enough room in said cache and sending one or more requests to said display computer to remove said cache entries, if there is not enough room in said cache on display computer for the set of character images;

means for sending a request to said display computer to create a new cache entry for the set of character images; and

means for adding the set of character images to a list of sets of character images currently cached on said display computer.

6. The apparatus of claim 5, where said means for removing cache entries includes means for taking into account the last time the cache entry was used.