Displaying and storing an image having transparent and non-transparent pixels

• US 6,262,746 B1
• Filed: 02/25/1999
• Issued: 07/17/2001
• Est. Priority Date: 06/06/1995
• Status: Expired due to Term

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Compaq Computer Corporation (HP Inc.)
• Inventors: Collins, Roger S.
• Primary Examiner(s): Hong, Stephen S.
• Application Number:
  US09/258,094
• Time in Patent Office: 873 Days
• Field of Search: 345/302, 345/429, 345/433, 345/435, 345/440, 345/473, 345/474, 345/113, 345/114, 345/121, 345/123, 345/202, 345/523, 345/524, 345/525
• US Class Current: 345/629
• CPC Class Codes: G06T 13/80 2D [Two Dimensional] animation, e.g. using sprites

Abstract

An image is stored as data representing the values of non-transparent pixels, and stored instructions corresponding to some pixels, resulting in a data structure. The image may be displayed by executing two types of instructions. A first type of instruction includes a command to skip pixels in a destination image. A second type of instruction comprises a command to copy pixels from the source data to the destination image.

Claims

1. A method of displaying an image having a plurality of transparent pixels and a plurality of non-transparent pixels on a background, comprising the steps of:

retrieving a machine executable instruction in an instruction queue in a memory, the instruction queue including a plurality of copy instructions and a plurality of skip instructions, each copy instruction of the plurality of copy instructions being mapped from a set of non-transparent pixels of the plurality of non-transparent pixels and each skip instruction of the plurality of skip instructions being mapped from a set of transparent pixels of the plurality of transparent pixels, each skip instruction including a skip instruction count number;

when the machine executable instruction is a copy instruction, performing the following steps;

obtaining pixel data from a source pointer, the pixel data corresponding to non-transparent pixels of the plurality of non-transparent pixels;

replacing pixels in the background pointed to by a destination pointer with the pixel data from the source pointer;

incrementing both the source pointer and the destination pointer; and

returning to said step of retrieving; and

when the retrieved instruction is a skip instruction, performing the following steps;

incrementing the destination pointer to the background based on the skip instruction count number; and

returning to said step of retrieving.

2. The method of claim 1, wherein once each instruction in the instruction queue is executed the image overlays the corresponding portion of the background.

3. The method of claim 1, further comprising the steps of:

scanning the image a pixel at a time to detect a type of each pixel and a number of adjacent pixels of the same type;

adding a copy instruction to the instruction queue for each set of adjacent, non-transparent pixels detected; and

adding a skip instruction to the instruction queue for each set of adjacent, transparent pixels detected.

4. The method of claim 1, wherein the copy instruction is accompanied by a copy instruction count number corresponding to a size of the pixel data, and the source pointer and the destination pointer in response to the copy instruction are incremented based on the copy instruction count number.

5. The method of claim 1, wherein pixel color of each of the plurality of non-transparent pixels are added to a string of pixel values.

6. The method of claim 1, wherein a copy instruction provides an instruction for moving one byte from a memory location defined by the source pointer to another memory location defined by the destination pointer.

7. The method of claim 1, wherein a copy instruction provides an instruction for moving a word at a time from a memory location defined by the source pointer to another memory location defined by the destination pointer.

8. The method of claim 2, wherein non-transparent pixels replace pixels in the background and wherein transparent pixels leave the background unchanged.

13. The computer system of claim 1, wherein the transparent pixels are mapped into the skip instructions and the non-transparent pixels are mapped into the copy instructions.

14. The computer system of claim 1, wherein the memory storing the code executable by the processor, when executed, adds pixel color to a pixel value string.

15. The computer system of claim 1, wherein a copy instruction provides an instruction for moving one byte from a memory location defined by the source pointer to another memory location defined by the destination pointer.

16. The computer system of claim 1, wherein a copy instruction provides an instruction for moving a word at a time from a memory location defined by the source pointer to another memory location defined by the destination pointer.

17. The computer system of claim 1, wherein once each instruction in the instruction queue is executed, the image overlays the corresponding portion of the background, and wherein non-transparent pixels replace pixels in the background and transparent pixels leave the background unchanged.

9. A computer-readable medium encoded for storing an image including transparent pixels and non-transparent pixels, comprising:

a data structure stored in the computer-readable medium, the data structure including;

a string containing color codes for a plurality of non-transparent pixels; and

an instruction queue of machine-executable instructions comprising;

a plurality of copy instructions, each copy instruction of the plurality of copy instructions added to the instruction queue upon change from one of the non-transparent pixels to one transparent pixel of a plurality of transparent pixels of the image, and

a plurality of skip instructions, each skip instruction of the plurality of skip instructions added to the instruction queue upon change from one of the transparent pixels to one non-transparent pixel of the plurality of non-transparent pixels of the image, wherein each copy instruction corresponds to a set of successive non-transparent pixels of the image and each skip instruction corresponds to a set of successive transparent pixels of the image, and wherein execution of the machine-executable instructions along with the string enables display of the image.

10. The data structure of claim 9, wherein each copy instruction is accounted for by a copy instruction count number representing a number of non-transparent pixels to copy.

11. The data structure of claim 9, wherein a number of transparent pixels skipped by each skip instruction is the number of successive transparent pixels between non-transparent pixels in the image.

12. The data structure of claim 9, wherein each skip instruction is associated with a skip instruction count number representing a number of transparent pixels to skip.

18. A computer system for displaying on a background an image having transparent pixels and non-transparent pixels, comprising:

a processor for executing code; and

a display for displaying the image;

a memory storing a code executable by the processor and when executed, performing the steps of;

retrieving a machine executable instruction from an instruction queue in the memory, the instruction including a copy instruction corresponding to a plurality of non-transparent pixels and a skip instruction accompanied by a skip instruction count number associated with a plurality of transparent pixels;

when the machine executable instruction is a copy instruction, performing the following steps;

obtaining pixel data from a source pointer;

replacing pixels in the background pointed to by a destination pointer with the pixel data from a source pointer;

incrementing both the source pointer and the destination pointer; and

returning to said step of retrieving; and

when the retrieval instruction is a skip instruction, performing the following steps;

incrementing the destination pointer based on the skip instruction count number; and

returning to said step of retrieving.

19. The computer system of claim 18, wherein when each copy instruction in the instruction queue is executed the corresponding non-transparent pixels overlay the corresponding portion of the background.

20. The computer system of claim 18, wherein the copy instruction is accompanied by a copy instruction count number and when the machine executable instruction is a copy instruction incrementing the source pointer and the destination pointer by a number based on the copy instruction count number.

21. The computer system of claim 18, wherein the copy instruction is associated with a copy instruction count number corresponding to the size of the pixel data, and the source pointer and the destination pointer are incremented by a count established by the copy instruction count number.