System and method for compressing color data using expandable color palette

1. A method of compressing color data, comprising:

providing an expandable color palette for storing a pre-established number of n-bit color codes, each of the n-bit color codes mapping to an m-bit color value, wherein m is an integer greater than n;

storing up to the pre-established number of n-bit color codes in a first palette table of the color palette;

expanding the color palette to include up to a specified number of additional palette tables for storing additional sets of the pre-established number of n-bit color codes; and

providing a link for associating the first palette table to one or more additional palette tables.

2. The method of claim 1 , wherein the pre-established number of n-bit color codes is characterized by 2 n −1 color codes.

3. The method of claim 1 , wherein expanding the color palette comprises expanding the color palette to include up to (m/n)−1 palette tables for storing sets of 2 n −1 color codes.

4. The method of claim 1 , wherein storing the color codes further comprises providing up to (m/n) pixel maps, the method further comprising using up to (m/n)−1 pixel maps to facilitate storing of the n-bit color codes in an associated palette table.

5. The method of claim 1 , wherein n=8 bits, m=32 bits, such that each palette table stores up to 255 8-bit color codes, and the color palette is expandable to up to 3 palette tables.

6. The method of claim 1 , further comprising:

providing a usage bitmap representative of the graphic drawing space, the usage bitmap comprising pixel values representative of a transparency state of a corresponding pixel in the graphic drawing space; and

writing a value indicative of a non-transparent state to pixel values in the usage bitmap having an associated color code in one of the palette tables.

7. The method of claim 1 , further comprising:

providing a first pixel map of the graphic drawing space, the first pixel map comprising palette values each representing an n-bit color code and a palette table identifier, the palette table identifier associating the first pixel map with the first palette table; and

generating up to a total of (m/n) pixel maps, each of (m/n)−1 pixel maps being associated with one of the additional palette tables.

8. The method of claim 7 , further comprising:

providing a usage bitmap representative of the graphic drawing space, the usage bitmap comprising pixel values representative of a transparency state of a corresponding pixel in the graphic drawing space, a non-transparent state for pixel values in the usage bitmap indicating usage of an associated color code in one of the palette tables;

after storing the pre-established number of n-bit color codes in each of (m/n)−1 palette tables, generating an (m/n th ) pixel map;

looking up a particular m-bit color value associated with non-transparent pixel locations in the usage bitmap; and

replacing palette values at the associated non-transparent pixel locations in the (m/n) pixel maps with m-bit color data, such that the m-bit color value is divided into (m/n) segments and each of the segments is respectively stored in the (m/n) pixel maps at the associated non-transparent pixel locations.

9. The method of claim 1 , further comprising reading color codes from the color palette.

10. The method of claim 1 , further comprising:

searching the first palette table for a particular m-bit color value and, if not located in the first palette table, searching the additional palette tables for the particular m-bit color value; and

reading the n-bit color code from the first or additional palette tables in which the m-bit color value is located.

11. A method of compressing color data, comprising:

providing an expandable color palette comprising n-bit color codes, each of the n-bit color codes mapping to an m-bit color value, wherein m is an integer greater than n;

providing a pixel map of a graphic drawing space, the pixel map comprising palette values each representing an n-bit color code and a palette table identifier;

searching, in response to an m-bit color value input, the color palette for a particular n-bit color code associated with the input m-bit color value, and writing the particular n-bit color code in the pixel map at each pixel map location in which the m-bit color value appears;

inserting, if the particular m-bit color value does not appear in a palette table of the color palette, the m-bit color value in an available location in the palette table and writing the particular n-bit color code in the pixel map at each pixel map location in which the m-bit color value appears;

generating, if no location is available in the palette table, an additional pixel map and an additional palette table, inserting the m-bit color value in the additional palette table, and writing the particular n-bit color code in the additional pixel map at each additional pixel map location in which the m-bit color value appears; and

providing a link for associating the palette table to the additional palette table.

12. The method of claim 11 , wherein up to (m/n)−1 palette tables are generated for storing sets of 2 n −1 n-bit color codes.

13. The method of claim 11 , wherein up to a total of (m/n)−1 pixel maps are generated for storing respective sets of 2 n −1 n-bit color codes.

14. The method of claim 11 , wherein n=8 bits, m=32 bits, such that each palette table stores up to 255 8-bit color codes, and the color palette is expandable to up to 3 generated palette tables.

15. The method of claim 11 , wherein the pixel maps comprises a pre-established number of palette values including a reserved palette value, the reserved palette value storing a linking value that associates the pixel map with the additional pixel map.

16. The method of claim 11 , further comprising reading m-bit color codes from the color palette.

17. The method of claim 11 , further comprising:

searching the first palette table for a particular m-bit color code and, if not located in the first palette table, searching the additional palette table for the particular m-bit color code; and

reading the n-bit color code from the first or additional palette table in which the m-bit color code is located.

18. The method of claim 11 , further comprising:

providing a usage bitmap representative of the graphic drawing space, the usage bitmap comprising pixel values representative of a transparency state of a corresponding pixel in the graphic drawing space, a non-transparent state for pixel values in the usage bitmap indicating usage of an associated color code in one of the palette tables;

after storing the pre-established number of n-bit color codes in each of (m/n)−1 palette tables, generating an (m/n th ) pixel map;

looking up a particular m-bit color value associated with non-transparent pixel locations in the usage bitmap; and

replacing palette values at the associated non-transparent pixel locations in the (m/n) pixel maps with m-bit color data, such that the m-bit color value is divided into (m/n) segments and each of the segments is respectively stored in the (m/n) pixel maps at the associated non-transparent pixel locations.

19. A system for compressing color data, comprising:

memory configured to support an expandable color palette for storing a pre-established number of n-bit color codes, each of the n-bit color codes mapping to an m-bit color value, wherein m is an integer greater than n; and

a processor, coupled to the memory, the processor storing up to the pre-established number of n-bit color codes in a first palette table of the color palette, expanding the color palette to include up to a specified number of additional palette tables for storing additional sets of the pre-established number of n-bit color codes, and storing a link value for associating the first palette table to one or more additional palette tables.

20. The system of claim 19 , wherein the pre-established number of n-bit color codes is characterized by 2 n −1 color codes.

21. The system of claim 19 , wherein the processor expands the color palette to include up to (m/n)−1 palette tables for storing sets of 2 n −1 color codes.

22. The system of claim 19 , wherein the processor generates up to (m/n) pixel maps and uses up to (m/n)−1 pixel maps to facilitate storing of the n-bit color codes in an associated palette table.

23. The system of claim 19 , wherein n=8 bits, m=32 bits, such that each palette table stores up to 255 8-bit color codes, and the color palette is expandable to up to 3 palette tables.

24. The system of claim 19 , further wherein the processor:

generates a first pixel map of the graphic drawing space, the first pixel map comprising palette values each representing an n-bit color code and a palette table identifier, the palette table identifier associating the first pixel map with the first palette table; and

generates up to a total of (m/n) pixel maps, each of (m/n)−1 pixel maps being associated with one of the additional palette tables.

25. The system of claim 24 , further wherein the processor:

generates a usage bitmap representative of the graphic drawing space, the usage bitmap comprising pixel values representative of a transparency state of a corresponding pixel in the graphic drawing space, a non-transparent state for pixel values in the usage bitmap indicating usage of an associated color code in one of the palette tables;

after storing the pre-established number of n-bit color codes in each of (m/n)−1 palette tables, generates an (m/n th ) pixel map;

performs a lookup of a particular m-bit color value associated with non-transparent pixel locations in the usage bitmap; and

replaces palette values at the associated non-transparent pixel locations in the (m/n) pixel maps with m-bit color data, such that the m-bit color value is divided into (m/n) segments and each of the segments is respectively stored in the (m/n) pixel maps at the associated non-transparent pixel locations.

26. The system of claim 19 , further wherein the processor:

provides a usage bitmap representative of the graphic drawing space, the usage bitmap comprising pixel values representative of a transparency state of a corresponding pixel in the graphic drawing space; and

writes a value indicative of a non-transparent state to pixel values in the usage bitmap having an associated color code in one of the palette tables.

27. The system of claim 19 , further wherein the processor reads color codes from the color palette.

28. The system of claim 19 , further wherein the processor:

searches the first palette table for a particular m-bit color value and, if not located in the first palette table, searches the additional palette tables for the particular m-bit color value; and

reads the n-bit color code from the first or additional palette tables in which the m-bit color value is located.

29. An information bearing medium comprising processor-readable instructions for compressing color data, the processor-readable instructions causing a processor to perform the steps of:

providing an expandable color palette for storing a pre-established number of n-bit color codes, each of the n-bit color codes mapping to an m-bit color value, wherein m is an integer greater than n;

storing up to the pre-established number of n-bit color codes in a first palette table of the color palette;

expanding the color palette to include up to a specified number of additional palette tables for storing additional sets of the pre-established number of n-bit color codes; and

providing a link for associating the first palette table to one or more additional palette tables.

30. The medium of claim 29 , wherein the pre-established number of n-bit color codes is characterized by 2 n −1 color codes.

31. The medium of claim 29 , wherein expanding the color palette comprises expanding the color palette to include up to (m/n)−1 palette tables for storing sets of 2 n −1 color codes.

32. The medium of claim 29 , wherein storing the color codes further comprises providing up to (m/n) pixel maps, the method further comprising using up to (m/n)−1 pixel maps to facilitate storing of the n-bit color codes in an associated palette table.

33. The medium of claim 29 , wherein n=8 bits, m=32 bits, such that each palette table stores up to 255 8-bit color codes, and the color palette is expandable to up to 3 palette tables.

34. The medium of claim 29 , further comprising:

providing a first pixel map of the graphic drawing space, the first pixel map comprising palette values each representing an n-bit color code and a palette table identifier, the palette table identifier associating the first pixel map with the first palette table; and

generating up to a total of (m/n) pixel maps, each of (m/n)−1 pixel maps being associated with one of the additional palette tables.

35. The medium of claim 34 , further comprising:

providing a usage bitmap representative of the graphic drawing space, the usage bitmap comprising pixel values representative of a transparency state of a corresponding pixel in the graphic drawing space, a non-transparent state for pixel values in the usage bitmap indicating usage of an associated color code in one of the palette tables;

after storing the pre-established number of n-bit color codes in each of (m/n)−1 palette tables, generating an (m/n th ) pixel map;

looking up a particular m-bit color value associated with non-transparent pixel locations in the usage bitmap; and

replacing palette values at the associated non-transparent pixel locations in the (m/n) pixel maps with m-bit color data, such that the m-bit color value is divided into (m/n) segments and each of the segments is respectively stored in the (m/n) pixel maps at the associated non-transparent pixel locations.

36. The medium of claim 29 , further comprising:

providing a usage bitmap representative of the graphic drawing space, the usage bitmap comprising pixel values representative of a transparency state of a corresponding pixel in the graphic drawing space; and

writing a value indicative of a non-transparent state to pixel values in the usage bitmap having an associated color code in one of the palette tables.

37. The medium of claim 29 , further comprising reading color is codes from the color palette.

38. The medium of claim 29 , further comprising:

searching the first palette table for a particular m-bit color value and, if not located in the first palette table, searching the additional palette tables for the particular m-bit color value; and

reading the n-bit color code from the first or additional palette tables in which the m-bit color value is located.