Graphics compression

• US 20030001868A1
• Filed: 06/24/2002
• Published: 01/02/2003
• Est. Priority Date: 06/28/2001
• Status: Active Grant

• Current Assignee: Ideaworks 3D Limited
• Original Assignee: Ideaworks 3D Limited
• Inventors: Sack, Adrian, Bandi, Srikanth
• Granted Patent: US 7,307,642 B2
• Time in Patent Office: Days
• US Class Current: 345/660
• CPC Class Codes: G06T 11/203 Drawing of straight lines or curves
• CPC Class Codes: G06T 9/001 Model-based coding, e.g. wire frame

Abstract

A method of manipulating a vector graphics data file representative of at least one graphics element defined by a set of co-ordinate values in a graphics image, the method comprising the step of scaling down the at least one graphics element by applying a scaling factor to the set of co-ordinate values defining the at least one graphics element. There is also disclosed a method of previewing a vector graphics image composed of a plurality of graphics elements comprising the steps of: parsing a vector graphics data file into individual graphics elements; selecting at least one graphics element; selecting and applying a scaling factor to a set of co-ordinate values defining the at least one selected graphics element; applying an inverse of the scaling factor to the set of co-ordinate values defining the at least one selected graphics element; displaying the graphics image including the graphics element having the scaling factor and inverse scaling factor applied thereto; and providing an indication of data file compression as a result of said scaling such that the effect of the scaling on image quality and data file size can be appreciated.

Claims

1. A method of manipulating a vector graphics data file representative of at least one graphics element defined by a set of co-ordinate values in a graphics image, the method comprising the step of scaling down the at least one graphics element by applying a scaling factor to the set of co-ordinate values defining the at least one graphics element.

2. A method according to claim 1, wherein each of the co-ordinate values is represented by a bit sequence and the step of applying the scaling factor comprises the step of eliminating at least the least significant bit from the co-ordinate values.

3. A method according to claim 2, wherein the scaling factor is 2ⁿ where n is an integer value of one or more and comprises the number of bits to be removed from the bit sequence.

4. A method according to claim 1, wherein the step of applying the scaling factor comprises the step of dividing the co-ordinate values by the scaling factor, the scaling factor having a value greater than 1.

5. A method according to claim 1, wherein each of the co-ordinate values is represented by a bit sequence and the scaling factor comprises a combined scaling factor having a value which lies between 2ⁿ and 2ⁿ⁺¹, where n and n+1 are integer values representing the number of bits to be removed from the bit sequence, the number of bits being dependent on the co-ordinate value being scaled.

6. A method according to claim 1, wherein the scaling factor is applied to all co-ordinate values used to define the at least one graphics element.

7. A method according to claim 1, wherein the vector graphics data file is representative of a plurality of graphics elements, at least one of which has a respective scaling factor applied thereto.

8. A method according to claim 7, wherein respective scaling factors are applied to respective ones of the graphics elements.

9. A method according to claim 1, comprising the further step of scaling up the at least one graphics element by applying an inverse of the scaling factor to the set of scaled co-ordinate values defining the at least one graphics element.

10. A method according to claim 9, wherein all the graphics elements are scaled up by an inverse of the scaling factor previously applied thereto.

11. A method according to claim 1, wherein a predetermined scaling factor is applied to the co-ordinate values in the vector graphics data file.

12. A method according to claim 11, comprising the step of applying a further scaling factor to the co-ordinate values in the vector graphics data file.

13. A method according to claim 1, comprising the further step of analysing the co-ordinate values in the vector graphics file and determining therefrom an appropriate scaling factor to be applied.

14. A method according to claim 1, wherein the vector graphics data file comprises a series of frames, each frame showing at least one graphics element to which a scaling factor can be applied.

15. A method according to claim 14, wherein the step of applying a scaling factor to the set of co-ordinate values defining the at least one graphics element is carried out selectively on a frame by frame basis.

16. A method according to claim 14, wherein the scaling factor applied to a particular graphics element is selectable on a frame by frame basis.

17. A method according to claim 16, wherein the scaling factor is applied to the at least one graphics element by setting a first scaling factor for the graphics element in one frame and setting a second scaling factor for the graphics element in another frame and applying a scaling factor between the first scaling factor and the second scaling factor to the graphics element for the frames between the one frame and the other frame.

18. A method according to claim 17, wherein the scaling factor is applied to the at least one graphics element in the intervening frames, as a linear function between the one frame and the other frame.

19. A method according to claim 1, comprising saving the vector graphics data file incorporating the scaled set of co-ordinate values and the respective scaling factors applied thereto.

20. A method according to claim 19, comprising the step of reading the re-saved file and scaling up the at least one graphics element by applying an inverse of the scaling factor to the set of scaled co-ordinate values defining the at least one graphics element;

and displaying the at least one graphics element.

21. A method according to claim 1, comprising the further steps of scaling up the at least one graphics element;

displaying the graphics image including the graphics element;

applying another scaling factor to the set of co-ordinate values defining the at least one graphics element;

applying an inverse of the scaling factor to the set of co-ordinate values defining the at least one graphics element; and

displaying the graphics image including the graphics element having the further scaling factor and inverse scaling factor applied thereto.

22. A method according to claim 21, comprising the further step of re-saving the data file incorporating the set of co-ordinate values scaled down by the further scaling factor.

23. A method according to claim 1, comprising the step of parsing a data file to extract vector graphics data representing individual graphics elements and then carrying out the scaling down step on one or more of the graphics elements.

24. A method according to claim 23, wherein the data file is a multimedia data file.

25. A method according to claim 23, wherein the data file is a SWF file.

26. A method according to claim 23, comprising the step of reconstituting the data file incorporating the scaled down co-ordinate values of the graphics elements.

27. A method according to claim 1, wherein a constituent of the graphics element defined by the set of co-ordinate values has a line weight assigned thereto, which line weight is scaled down and assigned a compensating line weight such that when the graphics element is scaled up for display the line weight of the graphics element appears to a user to be substantially as the uncompressed original line weight assigned thereto.

29. A method according to claim 28, comprising the further step of varying the scaling factor applied to the set of co-ordinate values for the at least one graphics element during display of the graphics element.

30. A method according to claim 28, wherein the step of applying a scaling factor to the set of co-ordinate values defining the at least one selected graphics element is carried out selectively on a frame by frame basis.

31. A method according to claim 28, wherein the scaling factor applied to a particular graphics element is selectable on a frame by frame basis.

32. A method according to claim 28, wherein said indication of data file compression to a user is graphical, numerical or audible.

33. A method according to claim 1 comprising the steps of reading the vector graphics data file and extracting therefrom the scaled down set of co-ordinate values defining the at least one graphics element and the respective scaling factor applied to the set of co-ordinate values;

applying an inverse of the respective scaling factors to the set of scaled co-ordinate values defining the at least one graphics element; and

displaying the at least one graphics element.

28. A method of previewing a vector graphics image composed of a plurality of graphics elements comprising the steps of:

parsing a vector graphics data file into individual graphics elements;

selecting at least one graphics element;

selecting and applying a scaling factor to a set of co-ordinate values defining the at least one selected graphics element;

applying an inverse of the scaling factor to the set of co-ordinate values defining the at least one selected graphics element;

displaying the graphics image including the graphics element having the scaling factor and inverse scaling factor applied thereto; and

providing an indication of data file compression as a result of said scaling such that the effect of the scaling on image quality and data file size can be appreciated.

34. A method of manipulating a vector graphics data file representative of at least one graphics element defined by a set of co-ordinate values in a graphics image, the method comprising the step of scaling down the at least one graphics element by eliminating at least a least significant bit from the co-ordinate values defining the at least one graphics element.

35. A computer-readable medium having instructions for performing steps of manipulating a vector graphics data file representative of at least one graphics element defined by a set of co-ordinate values in a graphics image, the method comprising scaling down the at least one graphics element by applying a scaling factor to the set of co-ordinate values defining the at least one graphics element.

36. A method of manipulating a vector graphics data file representative of at least one graphics element defined by a set of co-ordinate values in a graphics image, the method comprising the step of scaling down the at least one graphics element by applying a scaling factor to the set of co-ordinate values defining the at least one graphics element to produce a set of scaled co-ordinate values defining the at least one graphics element and subsequently scaling up the at least one graphics element by applying an inverse of the scaling factor to the set of scaled co-ordinate values defining the at least one graphics element.