Adaptive compression of multi-level images

1. A method, comprising:

receiving, by a system including a processor, a color-mapped image of a physical rendering, and a color-table created based on a predefined discrete set of colors known prior to creation of the physical rendering, wherein the color-mapped image is generated from the physical rendering and the color-mapped image is represented by a subset of colors included in the predefined discrete set that are included in the physical rendering;

identifying background pixels and foreground pixels of the color-mapped image;

associating color index information with the foreground pixels of the color-mapped image;

compressing the color index information for the foreground pixels of the color-mapped image resulting in compressed color index information for the foreground pixels; and

generating an output file comprising:

the compressed color index information, and

one or more colors included in the color-table assigned to the foreground pixels.

2. The method of claim 1 , further comprising determining a compression scheme for the compressing of the color index information for the foreground pixels of the color-mapped image.

3. The method of claim 2 , wherein the determining the compression scheme includes determining whether to employ a lossless compression scheme or a lossy compression scheme.

4. The method of claim 1 , wherein the generating the output file comprises generating an encoded black and white representation of the color-mapped image.

5. The method of claim 4 , wherein the black and white representation of the color-mapped image comprises the background pixels and the foreground pixels.

6. The method of claim 1 , further comprising associating background flags for the background pixels of the color-mapped image and foreground flags for foreground pixels of the color-mapped image.

7. The method of claim 6 , further comprising compressing the background flags and the foreground flags.

8. The method of claim 1 , further comprising generating header data corresponding to a compressed file associated with the color-mapped image, wherein the header data comprises a value representative of a background color of the color-mapped image.

9. The method of claim 8 , further comprising setting the value representative of the background color equal or substantially equal to a color value of a surface on which the rendering is composed.

10. The method of claim 8 , further comprising mapping the color-mapped image into a black and white representation by setting values for respective pixels of the color-mapped image as a function of being either equal or not equal to the value representative of the background color.

11. A computer readable storage device comprising computer executable instructions that, in response to execution, cause a computing system including a processor to perform operations, comprising:

receiving a color-mapped image of a physical rendering, and a color-table created based on a predefined discrete set of colors known prior to creation of the physical rendering, wherein the color-mapped image is generated from the physical rendering and the color-mapped image is represented by a subset of colors included in the predefined discrete set that are included in the physical rendering;

identifying background pixels and foreground pixels of the color-mapped image;

associating color index information with the foreground pixels of the color-mapped image;

compressing the color index information for the foreground pixels of the color-mapped image; and

generating an output file comprising:

the color index information for the foreground pixels compressed in accordance with the compressing, and

one or more colors included in the color-table assigned to the foreground pixels.

12. The computer readable storage device of claim 11 , wherein the operations further comprise determining a compression scheme for the compressing of the color index information for the foreground pixels of the color-mapped image.

13. The computer readable storage device of claim 12 , wherein the determining the compression scheme further comprises determining whether to employ a lossless compression scheme or a lossy compression scheme.

14. The computer readable storage device of claim 11 , wherein the generating the output file further comprises generating an encoded black and white representation of the color-mapped image.

15. The computer readable storage device of claim 14 , wherein the black and white representation of the color-mapped image comprises the background pixels and the foreground pixels.

16. The computer readable storage device of claim 11 , wherein the operations further comprise associating background flags for the background pixels of the color-mapped image and foreground flags for foreground pixels of the color-mapped image.

17. A device, comprising:

a memory, coupled to a processor, that stores computer-executable instructions that, in response to execution, cause the device to at least:

receive a color-mapped image of a physical rendering, and a color-table created based on a predefined discrete set of colors known prior to creation of the physical rendering, wherein the color-mapped image is generated from the physical rendering and the color-mapped image is represented by a subset of colors included in the predefined discrete set that are included in the physical rendering;

identify background pixels and foreground pixels of the color-mapped image;

associate color index information with the foreground pixels of the color-mapped image;

compress the color index information for the foreground pixels of the color-mapped image; and

generate an output file comprising:

the color index information for the foreground pixels compressed in accordance with a compression scheme, and

one or more colors included in the color-table assigned to the foreground pixels.

18. The device of claim 17 , wherein the computer-executable instructions further cause the device to determine the compression scheme for compression of the color index information for the foreground pixels of the color-mapped image.

19. The device of claim 18 , wherein the compression scheme is a lossless compression scheme or a lossy compression scheme.

20. The device of claim 17 , wherein the computer-executable instructions further cause the device to generate the output file to include an encoded black and white representation of the color-mapped image.

21. The device of claim 20 , wherein the black and white representation of the color-mapped image comprises the background pixels and the foreground pixels.

22. The device of claim 17 , wherein the computer-executable instructions further cause the device to associate background flags for the background pixels of the color-mapped image and foreground flags for foreground pixels of the color-mapped image.

23. A system, comprising:

means for receiving a color-mapped image of a physical rendering, and a color-table created based on a predefined discrete set of colors known prior to creation of the physical rendering, wherein the color-mapped image is generated from the physical rendering and the color-mapped image is represented by a subset of colors included in the predefined discrete set that are included in the physical rendering;

means for identifying background pixels and foreground pixels of the color-mapped image;

means for associating color index information with the foreground pixels of the color-mapped image;

means for compressing the color index information for the foreground pixels of the color-mapped image; and

means for generating an output file comprising:

the color index information for the foreground pixels compressed in accordance with a determined compression scheme, and

one or more colors included in the color-table assigned to the foreground pixels.

24. The system of claim 23 , further comprising means for associating background flags for the background pixels of the color-mapped image and foreground flags for foreground pixels of the color-mapped image.

25. The system of claim 23 , further comprising means for generating header data corresponding to a compressed file associated with the color-mapped image, wherein the header data comprises a value representative of a background color of the color-mapped image, the value representative of the background color is a color value of a surface on which the rendering is composed.