Glyph Outline Adjustment While Rendering

• US 20070030272A1
• Filed: 08/15/2006
• Published: 02/08/2007
• Est. Priority Date: 03/31/2004
• Status: Active Grant

• Current Assignee: Adobe Inc.
• Original Assignee: Adobe Systems Incorporated (Adobe Inc.)
• Inventors: Arnold, R., Dowling, Terence
• Granted Patent: US 7,580,039 B2
• Time in Patent Office: Days
• US Class Current: 345/467
• CPC Class Codes: G06T 11/20 Drawing from basic elements, e.g. lines or circles
• CPC Class Codes: G06T 11/203 Drawing of straight lines or curves

Abstract

Methods and apparatus, including computer program products, that implement a method for adjusting a glyph outline while rendering. In one aspect a method includes receiving a glyph to be rendered at a size; generating from the glyph an outline of line segments, each line segment having two endpoints; translating the line segments all in an outward or inward direction, each line segment being moved by a distance and then rejoining pairs of adjacent line segments by extending or trimming their endpoints until each pair of adjacent line segments join at an intersection point that is an endpoint of each the line segments of the pair; and determining an augmented scaled outline of the glyph from the translated and rejoined line segments.

Claims

1. A computer-implemented method comprising:

receiving a glyph to be rendered at a size;

generating from the glyph an outline of line segments, each line segment having two endpoints;

translating the line segments all in an outward or inward direction, each line segment being moved by a distance, and then rejoining pairs of adjacent line segments by extending or trimming their endpoints until each pair of adjacent line segments join at an intersection point that is an endpoint of each the line segments of the pair; and

determining an augmented scaled outline of the glyph from the translated and rejoined line segments.

2. The method of claim 1, wherein:

the outward or inward direction in which each line segment is translated is perpendicular to the line segment.

3. The method of claim 1, wherein:

inward or outward directions which a line segment can be translated is classified as one of a predetermined set of cardinal directions, and the distance which the line segment is moved is based on a classification of the direction in which the line segment is moved.

4. The method of claim 3, wherein:

the cardinal directions are up, down, left, right, between up and right, between up and left, between down and left, and between down and right.

5. The method of claim 1, wherein:

the distance which a line segment is moved is represented by a horizontal component and a vertical component, and the line segment is moved by moving each endpoint of the line segment by the horizontal component and by the vertical component.

6. The method of claim 1, wherein generating the outline of line segments includes:

generating from the glyph an initial outline;

scaling the initial outline in accordance with the size to generate a scaled outline; and

changing any curve of the scaled outline to one or more line segments.

7. The method of claim 6, wherein determining an augmented scaled outline includes:

changing each line segment in the translated and rejoined line segments that were previously converted from a curve back to the respective curve.

8. The method of claim 1, wherein:

the distance which a line segment is translated is based on a displacement number that is calculated as a function of scaled stem width or size.

9. The method of claim 8, wherein:

the function is for one of optical compensation, producing a bold appearance, or producing a light appearance.

10. The method of claim 8, wherein calculation of the adjustment number includes:

calculating an initial displacement number for producing a bold appearance or for producing a light appearance;

calculating an initial displacement number for optical compensation, the calculating of the initial displacement number for optical compensation accounting for the initial displacement number for producing a bold appearance or for producing a light appearance; and

combining the initial displacement number for producing a bold appearance or for producing a light appearance with the initial displacement number for optical compensation to obtain the displacement number.

11. The method of claim 1, further comprising:

determining whether a rejoining of two line segments has violated one or more constraints, wherein the rejoining produces an intersection point that is the intersection of the two line segments, the intersection being an endpoint for each of the line segment; and

when the rejoining is determined to have violated the one or more constraints, adjusting the position of the intersection point.

12. The method of claim 11, wherein:

the one or more constrains require that an endpoint of a translated line segment be within a predetermined distance from the endpoint'"'"'s pre-translated position.

13. The method of claim 11, wherein:

the one or more constraints are based on a miter limit.

14. The method of claim 1, further comprising:

generating a bitmap from the augmented scaled outline.

15. The method of claim 14, wherein:

determining of the augmented scaled outline of the glyph and generating the bitmap are performed by a rasterizer during rendering, the rasterizer being a component of a renderer.

16. The method of claim 15, further comprising:

using a downsampler to downsample the bitmap, the downsampler being a component of the renderer.

17. A computer-program product, tangibly stored on machine-readable medium, the product comprising instructions operable to cause a computing device to perform a method comprising:

receiving a glyph to be rendered at a size;

generating from the glyph an outline of line segments, each line segment having two endpoints;

translating the line segments all in an outward or inward direction, each line segment being moved by a distance, and then rejoining pairs of adjacent line segments by extending or trimming their endpoints until each pair of adjacent line segments join at an intersection point that is an endpoint of each the line segments of the pair; and

determining an augmented scaled outline of the glyph from the translated and rejoined line segments.

18. The product of claim 17, wherein:

the outward or inward direction in which each line segment is translated is perpendicular to the line segment.

19. The product of claim 17, wherein:

inward or outward directions which a line segment can be translated is classified as one of a predetermined set of cardinal directions, and the distance which the line segment is moved is based on a classification of the direction in which the line segment is moved.

20. The product of claim 19, wherein:

the cardinal directions are up, down, left, right, between up and right, between up and left, between down and left, and between down and right.

21. The product of claim 17, wherein:

the distance which a line segment is moved is represented by a horizontal component and a vertical component, and the line segment is moved by moving each endpoint of the line segment by the horizontal component and by the vertical component.

22. The product of claim 17, wherein generating the outline of line segments includes:

generating from the glyph an initial outline;

scaling the initial outline in accordance with the size to generate a scaled outline; and

changing any curve of the scaled outline to one or more line segments.

23. The product of claim 22, wherein determining an augmented scaled outline includes:

changing each line segment in the translated and rejoined line segments that were previously converted from a curve back to the respective curve.

24. The product of claim 17, wherein:

the distance which a line segment is translated is based on a displacement number that is calculated as a function of scaled stem width or size.

25. The product of claim 24, wherein:

the function is for one of optical compensation, producing a bold appearance, or producing a light appearance.

26. The product of claim 24, wherein calculation of the adjustment number includes:

calculating an initial displacement number for producing a bold appearance or for producing a light appearance;

calculating an initial displacement number for optical compensation, the calculating of the initial displacement number for optical compensation accounting for the initial displacement number for producing a bold appearance or for producing a light appearance; and

combining the initial displacement number for producing a bold appearance or for producing a light appearance with the initial displacement number for optical compensation to obtain the displacement number.

27. The product of claim 17, wherein the method further comprises:

determining whether a rejoining of two line segments has violated one or more constraints, wherein the rejoining produces an intersection point that is the intersection of the two line segments, the intersection being an endpoint for each of the line segment; and

when the rejoining is determined to have violated the one or more constraints, adjusting the position of the intersection point.

28. The product of claim 27, wherein:

the one or more constrains require that an endpoint of a translated line segment be within a predetermined distance from the endpoint'"'"'s pre-translated position.

29. The product of claim 27, wherein:

the one or more constraints are based on a miter limit.

30. The product of claim 17, wherein the method further comprises:

generating a bitmap from the augmented scaled outline.

31. The product of claim 30, wherein:

determining of the augmented scaled outline of the glyph and generating the bitmap are performed by a rasterizer during rendering, the rasterizer being a component of a renderer.

32. The product of claim 31, wherein the method further comprises:

using a downsampler to downsample the bitmap, the downsampler being a component of the renderer.