Method for matching colors of data displayed on connected computer systems

• US 5,696,539 A
• Filed: 01/11/1995
• Issued: 12/09/1997
• Est. Priority Date: 12/08/1993
• Status: Expired due to Term

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Company (HP Inc.)
• Inventors: Garfinkel, Daniel, Yip, Thomas W., Welti, Bruce C.
• Primary Examiner(s): NGUYEN, CHANH DUY
• Application Number:
  US08/371,673
• Time in Patent Office: 1,063 Days
• Field of Search: 345/115, 345/150, 345/153, 345/185, 345/186, 345/187, 345/199, 345/1, 345/2, 348/32, 348/422, 382/17, 382/162, 382/164, 382/165
• US Class Current: 345/603
• CPC Class Codes: G06F 3/14 Digital output to display device ; Cooperation and interconnection of the display device with other functional units
• CPC Class Codes: G09G 5/028 Circuits for converting colour display signals into monochrome display signals
• CPC Class Codes: G09G 5/06 using colour palettes, e.g. look-up tables

Abstract

A system that translates the color of a pixel being displayed in a first visual type into a comparably colored pixel for a second visual type. The system first allocates a ramp of colors evenly distributed over the color palette of the second visual type, with the ramp occupying half of the colormap in the second visual type. For each pixel displayed on the first visual type, the colors of the pixel are matched to the ramp and if a close color is in the ramp, it is displayed on the second visual type. If no ramp color is sufficiently close, a new color is allocated in the colormap of the second visual type, if possible. Color translations are retained and used again when possible. When read-only and read-write classes of colors are used, a corresponding class is defined in the second visual type'"'"'s colormap.

Claims

1. A computer implemented method for translating a color used in a first visual type to a color in a second visual type, said computer implemented method comprising the steps of:

(a) allocating a ramp of a plurality of colors in a colormap of said second visual type, wherein said allocated ramp colors are evenly spaced within a color palette of said second visual type, and wherein said allocated ramp colors comprise fewer than all available colors in said colormap of said second visual type;

(b) selecting one of said used colors from said first visual type;

(c) comparing said selected used color to each allocated ramp color and to all additional colors previously allocated in said colormap to select a one of said allocated colors close to said selected used color;

(d) determining a difference between said selected allocated color and said selected used color;

(e) when said difference is less than a predetermined amount, using said selected colormap color as a translated color;

(f) when said difference is more than said predetermined amount, allocating an additional color in said colormap of said second visual type, wherein said additional color has palette values related to said selected used color, and selecting said additional color as said translated color;

(g) sending said translated color to said second visual type; and

(h) repeating steps (b) through (g) for each color used in said first visual type.

2. The computer implemented method of claim 1 wherein step (f) further comprises the step of:

(f1) when all available additional colors in said second visual type have been allocated, using said selected allocated color as said translated color.

3. The computer implemented method of claim 1 wherein step (b) further comprises the following step (b1), step (f) further comprises the following step (f1), and step (g) further comprises the following step (g1):

(b1) selecting a used color of a first class from said first visual type;

(f1) allocating said additional color in said colormap of second visual type as being of a same class as said first class; and

(g1) repeating steps (b) through (f) for each color used within each class of colors in said first visual type.

4. The computer implemented method of claim 1 wherein said allocated ramp colors comprise substantially half of all available colors in said colormap of said second visual type.

5. A computer implemented method for translating a color used in a first visual type to a color in a second visual type, said computer implemented method comprising the steps of:

(a) allocating a ramp of a plurality of colors in a colormap of said second visual type, wherein said allocated ramp colors are evenly spaced within a color palette of said second visual type, wherein said allocated ramp colors comprises less than all available colors in a colormap of said second visual type;

(b) selecting one of said used colors from said first visual type;

(c) when said selected used color has been previously translated, selecting a previously translated color as a translated color;

(d) comparing said selected color to each color of said allocated ramp colors and to all additional colors previously allocated in said colormap to select one of said allocated colors close to said selected used color;

(e) determining a difference between said selected allocated color and said selected used color;

(f) when said difference is less than a predetermined amount, using said selected allocated color as said translated color;

(g) when said difference is more than said predetermined amount, allocating an additional color in said colormap of said second visual type, wherein said additional color has palette values related to said selected color, and selecting said additional color as said translated color;

(h) retaining said translated color as said previously translated color for said selected color;

(i) sending said translated color to said second visual type; and

(j) repeating steps (b) through (i) for all colors used in said first visual type.

6. The computer implemented method of claim 5 wherein step (g) further comprises the step of:

(g1) when all available additional colors in said colormap of said second visual type have been allocated, using said selected allocated color as said translated color.

7. The computer implemented method of claim 5 wherein step (b) further comprises the following step (b1), step (g) further comprises the following step (g1), and step (h) further comprises the following step (h1):

(b1) selecting a used color of a first class from said first visual type;

(g1) allocating said additional color in said colormap of said second visual type as being of a same class as said first class; and

(h1) repeating steps (b) through (g) for all used colors in all classes of colors in said first visual type.

8. The computer implemented method of claim 5 wherein said allocated ramp colors comprise substantially half of all available colors in said colormap of said second visual type.

9. A computer implemented method for translating a color used in a first visual type to a color in a second visual type, wherein said first visual type displays colors using red, green, and blue values each of at least 4 bits in width, said computer implemented method comprising the steps of:

(a) allocating a ramp of a plurality of colors in a colormap of said second visual type, wherein said allocated ramp colors are evenly spaced within a color palette of said second visual type, wherein said allocated ramp colors comprises less than all available colors in a colormap of said second visual type;

(b) defining a true-index of a plurality of values in said first visual type, wherein said true-index comprises a first predetermined number of values;

(c) selecting one of said used colors from said first visual type;

(d) determining red, green, and blue values for said selected used color;

(e) reducing each of said red, green, and blue values to a reduced value comprising one of said first predetermined number of values;

(f) when said selected used color has not been previously translated, transferring to step (j);

(g) indexing said true-index using said reduced value and retrieving a true-index color from said true-index;

(h) determining a difference between said true-index color and said selected used color;

(i) when said difference is less than a predetermined amount, using said true-index color as a translated color and transferring to step (k);

(j) allocating an additional color in said colormap of said second visual type, wherein said additional color has palette values related to said selected used color, selecting said additional color as said translated color, and storing said additional color in said true-index as a previously translated color;

(k) sending said translated color to said second visual type; and

(l) repeating steps (b) through (k) for each color used in said first visual type.

10. The computer implemented method of claim 9 wherein said first predetermined number of values is step (b) is 4096 and wherein step (e) further comprises reducing each of said red, green and blue values to 4 bits in width by removing low order values.

11. A computer implemented method for translating a color displayed in a first window of a first computer system using a first visual type into a color displayed in a second window of a second computer system using a second visual type, said computer implemented method comprising the steps of:

(a) upon connecting said first window to said second window, allocating a ramp of a plurality of colors in a colormap of said second visual type, wherein said allocated ramp colors are evenly spaced within a color palette of said second visual type, and wherein said allocated ramp colors comprise less than all available colors in said colormap of said second visual type;

(b) receiving a pixel for display in said first window, said pixel having a pixel color from said first visual type;

(c) when said pixel color has been previously translated, selecting a previously translated pixel color as a translated pixel color;

(d) comparing said pixel color to each allocated ramp color and to all additional colors previously allocated in said colormap to select a one of said allocated colors close to said pixel color;

(e) determining a difference between said selected allocated color and said pixel color;

(f) when said difference is less than a predetermined amount, using said selected allocated color as said translated pixel color;

(g) when said difference is more than said predetermined amount, allocating an additional color in said colormap of said second visual type in said second computer system, wherein said additional color has palette values related to said pixel color, and selecting said additional color as said translated pixel color;

(h) retaining said translated pixel color as said previously translated pixel color for said selected color;

(i) sending said translated color to said second visual type in said second computer system; and

(j) repeating steps (b) through (i) so long as said first window remains connected to said second window.

12. The computer implemented method of claim 11 wherein step (g) further comprises the step of:

(g1) when all available additional colors in said colormap of said second visual type have been allocated, using said selected allocated color as said translated pixel color.

13. The computer implemented method of claim 11 wherein step (b) further comprises the following step (b1), and step (g) further comprises the following step (g1):

(b1) receiving a color of a first class from said first visual type; and

(g1) allocating said additional color in said colormap of said second visual type as being of a same class as said first class.

14. The computer implemented method of claim 11 wherein said allocated ramp colors comprise substantially half of all available colors in said colormap of said second visual type.