Anisotropic anti-aliasing

• US 20040227770A1
• Filed: 05/16/2003
• Published: 11/18/2004
• Est. Priority Date: 05/16/2003
• Status: Active Grant

• Current Assignee: Adobe Inc.
• Original Assignee: Adobe Systems Incorporated (Adobe Inc.)
• Inventors: Arnold, R. David, Dowling, Terence S.
• Granted Patent: US 7,006,107 B2
• Time in Patent Office: Days
• US Class Current: 345/611
• CPC Class Codes: G06T 11/203 Drawing of straight lines or curves

Abstract

Methods, apparatus, including computer program products, and systems implement and use techniques for rendering glyphs. A representation of a glyph is generated, the glyph to be rendered at a size on an output device having a device resolution. A bitmap representation of the glyph is generated using a first anti-aliasing process in a first direction and using a different second anti-aliasing process in a second direction.

Claims

1. A computer-implemented method for generating a representation of a glyph, the glyph to be rendered at a size on an output device having a device resolution, comprising:

generating a bitmap representation of the glyph using a first anti-aliasing process in a first direction and using a different second anti-aliasing process in a second direction.

2. The method of claim 1, wherein generating a bitmap representation of the glyph includes:

generating a representation of an outline of the glyph at the size; and

scan converting the representation of the outline to generate the bitmap representation of the glyph at a high resolution, where a ratio of the high resolution to the device resolution is m to 1 in the first direction and (n*p) to 1 in the second direction and where m and (n*p) have values greater than 1, m is not equal to (n*p), and p has a value greater than or equal to one.

3. The method of claim 2, wherein generating a representation of the outline of the glyph includes:

generating a representation of a hinted outline of the glyph, wherein hinting in the first direction adjusts the outline representation to the nearest 1/m of a device pixel and hinting in the second direction adjusts the outline representation to the nearest 1/n of a device pixel.

4. The method of claim 3, wherein generating a representation of the outline of the glyph further includes:

scaling the representation of the hinted outline of the glyph by a factor of p in the second direction.

5. The method of claim 2, wherein m has a value of 8, n has a value of 1 and p has a value of 2.

6. The method of claim 2, wherein m has a value of 8, n has a value of 2 and p has a value of 1.

7. The method of claim 2, wherein m has a value of 6, n has a value of 1, and p has a value of 2.

8. The method of claim 2, wherein the first direction is the x direction and the second direction is the y direction in an x-y plane.

9. The method of claim 2, wherein the first direction is the y direction and the second direction is the x direction in an x-y plane.

10. The method of claim 2, wherein the glyph is included in a TrueType font.

11. The method of claim 1, wherein generating a bitmap representation of the glyph includes:

generating a representation of an outline of the glyph at a size that is larger than the size at which the glyph is to be rendered by a factor m in the first direction and by a factor (n*p) in the second direction, where m and (n*p) are not equal to one another and are greater than one and where p is greater than or equal to one; and

scan converting the representation of the outline to generate the bitmap representation of the glyph at a high resolution, where a ratio of the high resolution to the device resolution is m to 1 in the first direction and (n*p) to 1 in the second direction.

12. The method of claim 11, wherein generating a representation of the outline of the glyph includes:

generating a representation of a hinted outline of the glyph.

13. The method of claim 12, wherein generating a representation of the outline of the glyph further includes:

scaling the representation of the hinted outline of the glyph by a factor of p in the second direction.

14. The method of claim 11, wherein m has a value of 8, n has a value of 1 and p has a value of 2.

15. The method of claim 11, wherein m has a value of 8, n has a value of 2 and p has a value of 1.

16. The method of claim 11, wherein m has a value of 6, n has a value of 1, and p has a value of 2.

17. The method of claim 11, wherein the first direction is the x direction and the second direction is the y direction in an x-y plane.

18. The method of claim 11, wherein the first direction is the y direction and the second direction is the x direction in an x-y plane.

19. The method of claim 11, wherein the glyph is included in a Type 1 font.

20. A computer program product, tangibly stored on a computer-readable medium, for generating a representation of a glyph, the glyph to be rendered at a size on an output device having a device resolution, comprising instructions operable to cause a programmable processor to:

generate a bitmap representation of the glyph using a first anti-aliasing process in a first direction and using a different second anti-aliasing process in a second direction.

21. The computer program product of claim 20, wherein instructions operable to generate a bitmap representation of the glyph include instructions operable to:

generate a representation of an outline of the glyph at the size; and

scan convert the representation of the outline to generate the bitmap representation of the glyph at a high resolution, where a ratio of the high resolution to the device resolution is m to 1 in the first direction and (n*p) to 1 in the second direction and where m and (n*p) have values greater than 1, m is not equal to (n*p), and p has a value greater than or equal to one.

22. The computer program product of claim 21, wherein instructions operable to generate a representation of the outline of the glyph include instructions operable to:

generate a representation of a hinted outline of the glyph, wherein hinting in the first direction adjusts the outline representation to the nearest 1/m of a device pixel and hinting in the second direction adjusts the outline representation to the nearest 1/n of a device pixel.

23. The computer program product of claim 22, wherein instructions operable to generate a representation of the outline of the glyph further include instructions operable to:

scale the representation of the hinted outline of the glyph by a factor of p in the second direction.

24. The computer program product of claim 21, wherein m has a value of 8, n has a value of 1 and p has a value of 2.

25. The computer program product of claim 21, wherein m has a value of 8, n has a value of 2 and p has a value of 1.

26. The computer program product of claim 21, wherein m has a value of 6, n has a value of 1, and p has a value of 2.

27. The computer program product of claim 21, wherein the first direction is the x direction and the second direction is the y direction in an x-y plane.

28. The computer program product of claim 21, wherein the first direction is the y direction and the second direction is the x direction in an x-y plane.

29. The computer program product of claim 21, wherein the glyph is included in a TrueType font.

30. The computer program product of claim 20, wherein instructions operable to generate a bitmap representation of the glyph include instructions operable to:

generate a representation of an outline of the glyph at a size that is larger than the size at which the glyph is to be rendered by a factor m in the first direction and by a factor (n*p) in the second direction, where m and (n*p) are not equal to one another and are greater than one and where p is greater than or equal to one; and

scan convert the representation of the outline to generate the bitmap representation of the glyph at a high resolution, where a ratio of the high resolution to the device resolution is m to 1 in the first direction and (n*p) to 1 in the second direction.

31. The computer program product of claim 30, wherein instructions operable to generate a representation of the outline of the glyph include instructions operable to:

generate a representation of a hinted outline of the glyph.

32. The computer program product of claim 31, wherein instructions operable to generate a representation of the outline of the glyph further include instructions operable to:

scale the representation of the hinted outline of the glyph by a factor of p in the second direction.

33. The computer program product of claim 30, wherein m has a value of 8, n has a value of 1 and p has a value of 2.

34. The computer program product of claim 30, wherein m has a value of 8, n has a value of 2 and p has a value of 1.

35. The computer program product of claim 30, wherein m has a value of 6, n has a value of 1, and p has a value of 2.

36. The computer program product of claim 30, wherein the first direction is the x direction and the second direction is the y direction in an x-y plane.

37. The computer program product of claim 30, wherein the first direction is the y direction and the second direction is the x direction in an x-y plane.

38. The computer program product of claim 30, wherein the glyph is included in a Type 1 font.