Methods and apparatus for efficiently implementing and modifying foreground and background color selections

• US 6,342,896 B1
• Filed: 03/19/1999
• Issued: 01/29/2002
• Est. Priority Date: 03/19/1999
• Status: Expired due to Term

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Hitchcock, Gregory C., Dresevic, Bodin, Shetter, Martin T.
• Primary Examiner(s): Luu, Matthew
• Assistant Examiner(s): Sajous, Wesner
• Application Number:
  US09/272,412
• Time in Patent Office: 1,047 Days
• Field of Search: G06/F 1.730, 345/147, 345/150, 345/153, 345/155, 345/199, 345/149, 345/152, 345/186, 345/192, 345/194, 345/196, 345/517, 345/589, 345/591, 345/593, 345/596, 345/597, 345/600, 345/601, 345/549, 345/605, 345/613, 345/551, 345/552, 345/83, 345/88-89, 707/528
• US Class Current: 345/589
• CPC Class Codes: G06T 11/001 Texturing; Colouring; Generation of texture or colour inpainting G06T5/77
• CPC Class Codes: G09G 2340/0457 Improvement of perceived resolution by subpixel rendering
• CPC Class Codes: G09G 5/02 characterised by the way in which colour is displayed details of colour display specific for CRTs G09G1/28; specific for flat matrix panels other than liquid crystal displays G09G3/2003; specific for liquid crystal displays G09G3/3607

Abstract

Methods and apparatus for utilizing pixel sub-components which form a pixel element of an LCD display as separate Red (R), Green (G), and Blue (B) luminous intensity values. R, G, and B luminous intensity level values are generated as part of a weighted scan conversion operation and are packed into 8 bit values thereby avoiding the need to store, transmit and process separate R, G and B luminous intensity values representing character glyphs. A look-up table including packed pixel values and processed pixel values is used to convert between glyphs represented by the packed pixel values and R, G, and B pixel sub-component values in a format used by the display. In various embodiments the processed pixel values represent the result of performing unpacking, gamma correction, color filtering and color palette selection operations using the packed pixel values as input.

Claims

1. In a computer system that includes a display device having pixels each including a plurality of separately controllable pixel sub-components of different colors, a method of displaying an image on the display device using a look-up table that converts packed pixel values to sets of pixel sub-component values for controlling the pixel sub-components of the display device, the method comprising the acts of:

storing a look-up table that includes an array of entries, each entry including a set of pixel sub-component values and a corresponding packed pixel value;

receiving, as part of an image rendering process, a packed pixel value, wherein the packed pixel value has been generated in a compression operation based on image data that is to be displayed on the display device;

using the received packed pixel value as an index to the look-up table and obtaining, from an entry of the look-up table that includes the received packed pixel value, a first set of pixel sub-component values, the first set of pixel sub-component values corresponding to the received packed pixel value; and

using each of the pixel sub-component values of the first set of pixel sub-component values to control the pixel sub-components of a first pixel of the display device so as to display the image on the display device, each of the pixel sub-components of the first pixel being separately controlled by a different one of the pixel sub-component values of the first set of pixel sub-component values such that each pixel sub-component of the first pixel represents a different portion of the image.

2. A method as defined in claim 1, wherein the packed pixel value and the first set of pixel sub-component values each comprise data bit values, and wherein the packed pixel value comprises fewer bits than the first set of pixel sub-component values.

3. A method as defined in claim 1, further comprising the acts of:

processing the received packed pixel value to generate a transformed packed pixel value; and

using the transformed packed pixel value as an index to the look-up table to obtain, from an entry of the look-up table that includes the transformed packed pixel value, a second set of pixel sub-component values, the second set of pixel sub-component values corresponding to the transformed packed pixel value.

4. A method as defined in claim 3, further comprising the acts of:

using the first set of pixel sub-component values to control foreground color of the image; and

using the second set of pixel sub-component values to control background color of the image.

5. A method as defined in claim 3, further comprising the acts of:

using the first set of pixel sub-component values to control background color of the image; and

using the second set of pixel sub-component values to control foreground color of the image.

6. A method as defined in claim 1, wherein each of the pixel sub-component values stored in the table comprises a processed pixel sub-component value, and wherein a processing operation is used to generate each of the processed pixel sub-component values.

7. A method as defined in claim 6, wherein the processing operation comprises gamma correction.

8. A method as defined in claim 6, wherein the processing operation comprises color compensation.

9. A method as defined in claim 6, wherein the processing operation comprises color palette selection.

10. A method as defined in claim 1, wherein each set of sub-component values stored in the table comprises a red, blue, and green pixel luminous intensity value.

11. A method of generating a look-up table that is capable of converting packed pixel values to sets of pixel sub-component values so that the sets of pixel sub-component values can be used to display an image on a display device having pixels each including a plurality of separately controllable pixel sub-components of different colors, the method comprising the acts of:

selecting a plurality of packed pixel values that are to be indices to a look-up table;

generating, for each of the plurality of packed pixel values, a set of corresponding pixel sub-component values;

generating the look-up table by storing each of the sets of pixel sub-component values in an array entry of the look-up table in a memory device at an array position associated with the corresponding packed pixel value, such that packed pixel values can be used as indices into the array entries of the look-up table to obtain the corresponding pixel sub-component values to be applied to pixel sub-components of the display device; and

making the look-up table available to a display system that includes the display device, wherein the display system, upon receiving a packed pixel value, is capable of;

using the received packed pixel value as an index to the look-up table to obtain the corresponding set of pixel sub-components; and

using each of the pixel sub-component values of the obtained set of pixel sub-component values to control the pixel sub-components of a pixel of the display device so as to display the image on the display device, each of the controlled pixel sub-components being separately controlled by a different one of the pixel sub-component values such that each pixel sub-component represents a different portion of the image.

12. A method as defined in claim 11, wherein the act of generating the look-up table by storing each of the sets of pixel sub-component values in an array entry includes the act of processing each of the pixel sub-component values with a processing operation.

13. A method as defined in claim 12, wherein the processing operation comprises at least one of gamma correction, color compensation, and palette selection.

14. A method as defined in claim 11, wherein each set of pixel sub-component values and each corresponding packed pixel value comprise data bit values, and wherein each of the corresponding packed pixel values comprise fewer bits than each of the sets of pixel sub-component values.

15. A method as defined in claim 11, wherein each set of pixel sub-component values comprises a first, second, and third sub-component luminous intensity value.

16. A method as defined in claim 15, wherein each set of sub-component values stored in the table comprises a red, blue, and green pixel luminous intensity value.

17. A method as defined in claim 16, wherein the possible number of first, second, and third sub-component luminous intensity values is 256.

18. A method as defined in claim 11, further comprising the act of generating, for each of the plurality of packed pixel values, a transformed packed pixel value, wherein each of the transformed packed pixel values comprises the total quantity of the plurality of packed pixel values minus the corresponding packed pixel value.

19. A method as defined in claim 18, wherein the act of generating the look-up table further comprises the act of storing each of the transformed packed pixel values in an array entry of the look-up table at an array position associated with the corresponding packed pixel value used to generate the transformed packed pixel value, such that transformed packed pixel values can also be used as indices into the array entries of the look-up table to obtain the corresponding pixel sub-component values to be applied to pixel sub-components of the display device.

20. In a computer system that transmits to a display system data for rendering an image, wherein the display system includes a display device having pixels each including a plurality of separately controllable pixel sub-components of different colors, a method for generating the data transmitted to the display system, the method comprising the acts of:

generating, from a scaled representation of an image, a set of pixel sub-component values, each of the pixel sub-component values corresponding to a different pixel sub-component of a pixel of the display device;

converting the plurality of pixel sub-component luminous intensity values to a single packed pixel value, wherein the set of pixel sub-component values comprises a number of bits, and wherein the single packed pixel value comprises fewer bits than the set of pixel sub-component values; and

transmitting the single packed pixel value to the display system, wherein the display system has access to a look-up table that correlates packed pixel values to corresponding sets of pixel sub-component values and wherein, the display system, upon receiving the single packed pixel, is capable of;

using the received single packed pixel value as an index to the look-up table to obtain the corresponding set of pixel sub-component values; and

using each of the pixel sub-component values of the obtained set of pixel sub-component values to control the pixel sub-components of a pixel of the display device so as to display the image on the display device, each of the controlled pixel sub-components being separately controlled by a different one of the pixel sub-component values such that each pixel sub-component represents a different portion of the image.

21. A method as defined in claim 20, wherein each of the pixel sub-component values stored in the table comprises a processed pixel sub-component value, and wherein a processing operation is used to generate each of the processed pixel sub-component values.

22. A method as defined in claim 21, wherein the processing operation comprises gamma correction.

23. A method as defined in claim 21, wherein the processing operation comprises color compensation.

24. A method as defined in claim 21, wherein the processing operation comprises color palette selection.

25. A method as defined in claim 21, wherein each set of sub-component values stored in the table comprises a red, blue, and green pixel luminous intensity value.