Enlargement of font characters

• US 20070057949A1
• Filed: 09/15/2005
• Published: 03/15/2007
• Est. Priority Date: 09/15/2005
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Burago, Andrei, Genkin, Sergey, Kozyrev, Victor, Malkin, Sergey
• Granted Patent: US 7,242,404 B2
• Time in Patent Office: Days
• US Class Current: 345/467
• CPC Class Codes: G06T 11/203 Drawing of straight lines or curves

Abstract

A character within a font is enlarged to a desired size by first determining whether the font contains existing or predefined variants of the character having the desired size. If no appropriately sized variant exists, the enlarged character is assembled from a plurality of component glyphs that are stored with the font, wherein the component glyphs include an extender that may be duplicated within the assembled character in order to achieve the desired size. In one embodiment, the font includes tables containing records of the enlarged variants for a particular character, as well as part records for the component glyphs used to assemble the enlarged character.

Claims

1. A computer readable medium having computer-executable instructions for performing a method of enlarging a character within a document, wherein the character is a component of a predetermined font, the method comprising:

determining a desired size for the character;

determining whether the predetermined font includes existing variants of the character having the desired size;

upon determining that the predetermined font does include a variant of the character having the desired size, selecting the variant for insertion within the document; and

upon determining that the predetermined font does not include a variant of the character having the desired size, assembling a character of the desired size from a plurality of component glyphs stored within the predetermined font.

2. A computer readable medium as defined in claim 1, wherein:

each component glyph includes at least one straight line connector for overlapping a connector of an adjacent component glyph; and

initial assembly of the character utilizes a minimum number of component glyphs without including any extensions.

3. A computer readable medium as defined in claim 2, wherein assembling the character further comprises:

maximizing an amount of overlap between neighboring connectors at each end of adjacent component glyphs to minimize an overall size of the connector;

calculating a potential increase in character size resulting from reducing the amount of connector overlap from the maximum amount to a predetermined minimum amount of overlap, wherein the predetermined minimum amount is greater than zero; and

determining if the potential increase in character size is equal to or greater than the desired character size.

4. A computer readable medium as defined in claim 3, wherein assembling the character further comprises:

upon determining that the potential increase in character size is equal to or greater than the desired character size, reducing the overlap between adjacent connectors by a substantially equal amount until the desired character size is achieved.

5. A computer readable medium as defined in claim 3, wherein assembling the character further comprises:

upon determining that the potential increase in character size is not equal to or greater than the desired character size, adding at least one extender glyph to the character to increase the overall size of the character.

6. A computer readable medium as defined in claim 5, wherein the extender glyph comprises a straight line segment having a connector at each end.

7. A computer readable medium as defined in claim 6, wherein two extender glyphs are added to a character when the character is symmetrical about a center point, wherein one extender glyph is added on each side of the center point to maintain symmetry of the character.

8. A computer readable medium as defined in claim 5, further comprising:

repeating the steps of claims 3 and 5 until a determination is made that the potential increase in character size resulting from reducing the amount of connector overlap to the predetermined minimum amount is equal to or greater than the desired character size; and

reducing the overlap between adjacent connectors by a substantially equal amount until the desired character size is achieved.

9. A computer readable medium as defined in claim 8, wherein:

the character is a mathematical character; and

the predetermined font is one of an OpenType or a TrueType font.

10. A computer readable medium as defined in claim 9, wherein the character is enlarged in one of a vertical or horizontal direction.

11. A computer readable medium having computer-executable instructions for generating an enlarged version of a specified character within a predetermined font, wherein the specified character is enlarged in at least one of a vertical or horizontal direction, and wherein the computer-executable instructions define data structures within the predetermined font comprising:

a first data field containing a record of predefined enlarged variants for the specified character; and

a second data field containing a pointer to a glyph assembly table for the specified character, wherein the glyph assembly table contains information about a sequence of component glyphs used to assemble an enlarged version of the specified character.

12. A computer readable medium as defined in claim 11, wherein the data structures defined within the predetermined font further comprise:

a third data field containing a count of font characters that are capable of growing in a vertical direction; and

a fourth data field containing a count of font characters that are capable of growing in a horizontal direction;

13. A computer readable medium as defined in claim 11, wherein the record contained within the first data field includes an advance measurement in one of the vertical or horizontal directions for the predefined enlarged variant of the specified character.

14. A computer readable medium as defined in claim 11, wherein the glyph assembly table includes:

a count of component glyphs that are used to assemble the specified character; and

an array of component glyph records used to assemble the specified character.

15. A computer readable medium as defined in claim 14, wherein the array of component glyph records includes:

a first value representing a glyph identifier for each component glyph;

a second value representing a length of a connector at one end of the component glyph;

a third value representing a length of a connector at an opposite end of the component glyph, wherein the third value may be zero if the component glyph only includes a single connector;

a fourth value representing a full advance measurement for one of a height or length of the component glyph; and

a fifth value indicating whether the component glyph is an extender that can be repeated during assembly of the specified character, wherein the extender adds length or width in order to achieve a desired size of the specified character.

16. A computer readable medium as defined in claim 15, wherein the data structures defined within the predetermined font further include a value representing a minimum amount by which connectors of neighboring component glyphs must overlap during assembly of the specified character.

17. A computer readable medium as defined in claim 15, wherein:

the specified character is a mathematical character; and

the predetermined font is one of an OpenType or a TrueType font.

18. A computer readable medium having computer-executable instructions for generating an enlarged version of a specified character within a predetermined font, wherein the specified character is enlarged in at least one of a vertical or horizontal direction, and wherein the computer-executable instructions define a plurality of tables included with the predetermined font, the plurality of tables comprising:

a first table including a first count of font characters that are capable of growing in a vertical direction and a second count of font characters that are capable of growing in a horizontal direction;

a second table including a count of component glyphs that are used to assemble an enlarged version of the specified character, the second table further including an array of component glyph records describing each component glyph used to assemble the enlarged version of the specified character; and

a third table including a record of predefined enlarged variants for the specified character, the third table further including a pointer to the second table for the specified character; and

wherein the first, second and third tables enable a typesetting application utilizing the predetermined font to alternatively select a predefined enlarged variant of the specified character or assemble an enlarged version of the specified character from component glyphs, wherein the assembled version of the specified character has a desired size that is not represented within the predefined enlarged variants.

19. A computer readable medium as defined in claim 18, wherein the array of component glyph records includes:

a first value representing a glyph identifier for each component glyph;

a second value representing a length of a connector at one end of the component glyph;

a third value representing a length of a connector at an opposite end of the component glyph, wherein the third value may be zero if the component glyph only includes a single connector;

and a fourth value representing a full advance measurement for one of a height or length of the component glyph; and

a fifth value indicating whether the component glyph is an extender that can be repeated during assembly of the specified character, wherein the extender adds length or width in order to achieve a desired size of the specified character.

20. A computer readable medium as defined in claim 19 wherein:

the predetermined font is one of an OpenType or a TrueType font; and

the first table further includes a value representing a minimum amount by which connectors of neighboring component glyphs must overlap during assembly of the specified character.