Dynamic kerning pair reduction for digital font rendering

• US 10,275,426 B1
• Filed: 09/22/2015
• Issued: 04/30/2019
• Est. Priority Date: 09/22/2015
• Status: Active Grant

• Current Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Original Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Inventors: Cao, Yushu, Ragavan, Sivarangini, Bacus, Michael Patrick
• Primary Examiner(s): Nguyen, Anh-Tuan V
• Application Number:
  US14/860,738
• Time in Patent Office: 1,316 Days
• Field of Search: None
• CPC Class Codes: G06F 3/14 Digital output to display device ; Cooperation and interconnection of the display device with other functional units
• CPC Class Codes: G06F 40/109 Font handling; Temporal or kinetic typography
• CPC Class Codes: G09G 2340/0471 Vertical positioning
• CPC Class Codes: G09G 2340/0478 Horizontal positioning
• CPC Class Codes: G09G 2340/14 Solving problems related to the presentation of information to be displayed
• CPC Class Codes: G09G 2360/121 using a cache memory
• CPC Class Codes: G09G 2370/022 Centralised management of display operation, e.g. in a server instead of locally
• CPC Class Codes: G09G 2380/14 Electronic books and readers
• CPC Class Codes: G09G 5/243 Circuits for displaying proportional spaced characters or for kerning
• CPC Class Codes: G09G 5/26 for modifying the character dimensions, e.g. double width, double height

Abstract

Systems, methods, and computer-readable media are disclosed for dynamic kerning pair reduction for digital font rendering. Example methods may include receiving a first font file comprising glyph data and a first set of kerning pairs, determining a first kerning pair of the first set of kerning pairs that comprises a kerning adjustment value below a kerning adjustment threshold, removing the first kerning pair from the first set of kerning pairs to generate a second set of kerning pairs, and generating a second font file comprising the glyph data and the second set of kerning pairs.

Claims

1. A method comprising:

determining, by a device comprising at least one processor and a display, a first font file for rendering text on the display, the first font file comprising glyph data and a first glyph positioning table, wherein the glyph data comprises a set of glyphs representing English characters, and the first glyph positioning table comprises a set of kerning pairs for the font file, wherein a first kerning pair of the set of kerning pairs comprises a first glyph identifier, a second glyph identifier, a horizontal kerning adjustment value, and a frequency of occurrence for the first kerning pair;

parsing the font file to determine the first glyph positioning table;

parsing the first glyph positioning table to determine a first number of kerning pairs in the set of kerning pairs for the font file;

determining that the first number of kerning pairs exceeds a target number of kerning pairs;

determining whether the horizontal kerning adjustment value is less than a kerning pair adjustment threshold;

determining whether the frequency of occurrence is less than a frequency of occurrence threshold;

in response to determining that the kerning adjustment value is greater than or equal to the kerning pair adjustment threshold, or that the frequency of occurrence is greater than or equal to the frequency of occurrence threshold, keeping the first kerning pair in the set of kerning pairs;

in response to determining that the horizontal kerning adjustment value is less than the kerning pair adjustment threshold, and that the frequency of occurrence is less than the frequency of occurrence threshold, deleting the second glyph identifier from the first kerning pair in the first glyph positioning table to remove the first kerning pair from the set of kerning pairs;

determining that a second number of kerning pairs remaining in the set of kerning pairs of the first glyph positioning table meets the target number of kerning pairs;

generating a second glyph positioning table with the second number of kerning pairs remaining in the set of kerning pairs;

serializing the second glyph positioning table such that the second glyph table comprises kerning pair information in sequential order;

generating a second font file for rendering text on the display, the second font file comprising the glyph data and the second glyph positioning table; and

rendering text on the display of the electronic reader device using the second font file.

2. The method of claim 1, further comprising:

determining a frequency of occurrence of a character pair comprising a first character and a second character in a corpus of English literature;

determining that the frequency of occurrence is below a frequency of occurrence threshold;

determining a third glyph identifier associated with the first character and a fourth glyph identifier associated with the second character;

determining a second kerning pair in the first glyph positioning table comprising the third glyph identifier and the fourth glyph identifier; and

deleting the fourth glyph identifier from the second kerning pair to remove the second kerning pair from the set of kerning pairs in the first glyph positioning table.

3. The method of claim 1, further comprising:

determining a content frequency of occurrence of a character pair comprising a first character and a second character in an electronic book;

determining that the content frequency of occurrence is below a content frequency of occurrence threshold;

determining a third glyph identifier associated with the first character and a fourth glyph identifier associated with the second character;

determining a second kerning pair in the first glyph positioning table comprising the third glyph identifier and the fourth glyph identifier; and

deleting the fourth glyph identifier from the second kerning pair to remove the second kerning pair from the set of kerning pairs in the first glyph positioning table.

4. The method of claim 1, further comprising:

determining a set of desired kerning pairs;

determining a second kerning pair in the first glyph positioning table comprising a third glyph identifier and a fourth glyph identifier;

comparing the second kerning pair to the set of desired kerning pairs;

determining that the set of desired kerning pairs does not include a desired kerning pair with the third glyph identifier and the fourth glyph identifier; and

deleting the fourth glyph identifier from the second kerning pair to remove the second kerning pair from the set of kerning pairs in the first glyph positioning table.

5. A method comprising:

receiving, by a device comprising at least one processor and a display, a first font file for rendering text on the display, the first font file comprising glyph data and a first set of kerning pairs, wherein a first kerning pair of the first set of kerning pairs comprises a kerning adjustment value and a frequency of occurrence for the first kerning pair;

determining whether the kerning adjustment value is below a kerning adjustment threshold;

determining whether the frequency of occurrence is below a frequency of occurrence threshold;

in response to determining that the kerning adjustment value is greater than or equal to the kerning adjustment threshold, or that the frequency of occurrence is greater than or equal to the frequency of occurrence threshold, keeping the first kerning pair in the first set of kerning pairs;

in response to determining that the kerning adjustment value is less than the kerning adjustment threshold, and that the frequency of occurrence is less than the frequency of occurrence threshold, removing the first kerning pair from the first set of kerning pairs to generate a second set of kerning pairs; and

generating a second font file for rendering text on the display, the second font file comprising the glyph data and the second set of kerning pairs.

6. The method of claim 5, further comprising:

determining that a first number of kerning pairs in the first set of kerning pairs exceeds a threshold number of kerning pairs; and

determining that a second number of kerning pairs in the second set of kerning pairs satisfies the threshold number of kerning pairs.

7. The method of claim 5, further comprising:

parsing the first font file; and

determining a table of the first font file that comprises the first set of kerning pairs;

wherein determining the table comprises determining a first glyph identifier associated with the first kerning pair, determining a second glyph identifier associated with the first kerning pair, and associating the kerning adjustment value with the first kerning pair; and

the kerning adjustment value comprises a horizontal adjustment, a vertical adjustment, or a diagonal adjustment.

8. The method of claim 7, wherein removing the first kerning pair comprises disassociating the first glyph identifier or the second glyph identifier with the first kerning pair in the table.

9. The method of claim 5, wherein the kerning adjustment value is a horizontal adjustment value, and further comprising determining that the horizontal kerning adjustment value is less than a kerning pair adjustment threshold.

10. The method of claim 5, wherein the frequency of occurrence threshold is a corpus frequency of occurrence threshold, the method further comprising:

determining a corpus frequency of occurrence of a character pair comprising a first character and a second character in a corpus of literature;

determining that the corpus frequency of occurrence is below the corpus frequency of occurrence threshold;

determining a first glyph identifier associated with the first character and a second glyph identifier associated with the second character;

determining a second kerning pair in the first set of kerning pairs comprises the third glyph identifier and the fourth glyph identifier; and

removing the second kerning pair from the first set of kerning pairs.

11. The method of claim 5, further comprising:

determining that the first kerning pair comprises a first glyph identifier and a second glyph identifier;

determining a second kerning pair in the first set of kerning pairs that comprises the first glyph identifier and the second glyph identifier; and

removing the second kerning pair from the first set of kerning pairs.

12. The method of claim 5, further comprising:

determining a set of desired kerning pairs;

determining a second kerning pair in the first set of kerning pairs that comprises a first glyph identifier and a second glyph identifier;

comparing the second kerning pair to the set of desired kerning pairs;

determining that the set of desired kerning pairs does not include a desired kerning pair comprising the first glyph identifier and the second glyph identifier; and

removing the second kerning pair from the first set of kerning pairs.

13. The method of claim 5, wherein the frequency of occurrence threshold is a content frequency of occurrence threshold, the method further comprising:

receiving an indication to render a source text;

determining a content frequency of occurrence of a character pair in the source text;

determining that the content frequency of occurrence of the character pair is below the content frequency of occurrence threshold;

determining a first glyph identifier associated with a first character of the character pair and a second glyph identifier associated with a second character of the character pair;

determining a second kerning pair in the first set of kerning pairs that comprises the first glyph identifier and the second glyph identifier;

removing the second kerning pair from the first set of kerning pairs; and

rendering the source text using the second font file.

14. The method of claim 5, further comprising:

receiving an indication to render a source text;

determining a second kerning pair of the first set of kerning pairs comprises a first glyph identifier and a second glyph identifier;

determining that the second kerning pair does not occur in the source text;

removing the second kerning pair from the first set of kerning pairs; and

rendering the source text using the second font file.

15. A device, comprising:

a display;

at least one memory storing computer-executable instructions; and

at least one processor communicatively coupled to the at least one memory and configured to access the at least one memory and execute the computer-executable instructions to;

receive a first font file for rendering text on the display, wherein the first font file comprises glyph data and a first set of kerning pairs, wherein a first kerning pair of the first set of kerning pairs comprises a kerning adjustment value and a frequency of occurrence for the first kerning pair;

determine whether the kerning adjustment value is below a kerning adjustment threshold;

determine whether the frequency of occurrence is below a frequency of occurrence threshold;

in response to a determination that the kerning adjustment value is greater than or equal to the kerning adjustment threshold, or that the frequency of occurrence is greater than or equal to the frequency of occurrence threshold, keep the first kerning pair in the first set of kerning pairs;

in response to a determination that the kerning adjustment value is less than the kerning adjustment threshold, and that the frequency of occurrence is less than the frequency of occurrence threshold, remove the first kerning pair from the first set of kerning pairs to generate a second set of kerning pairs; and

generate a second font file for rendering text on the display, wherein the second font file comprises the glyph data and the second set of kerning pairs.

16. The device of claim 15, wherein the at least one processor is further configured to execute the computer-executable instructions to:

determine that a first number of kerning pairs in the first set of kerning pairs exceeds a threshold number of kerning pairs; and

determine that a second number of kerning pairs in the second set of kerning pairs satisfies the threshold number of kerning pairs.

17. The device of claim 15, wherein the at least one processor is further configured to execute the computer-executable instructions to:

parse the first font file; and

determine a table of the first font file that comprises the first set of kerning pairs;

wherein the at least one processor is configured to determine the table by determining a first glyph identifier associated with the first kerning pair, determining a second glyph identifier associated with the first kerning pair, and associating the kerning adjustment value with the first kerning pair; and

wherein the kerning adjustment value comprises a horizontal adjustment, a vertical adjustment, or a diagonal adjustment.

18. The device of claim 17, wherein the at least one processor is further configured to execute the computer-executable instructions to remove the first kerning pair by disassociating the first glyph identifier or the second glyph identifier with the first kerning pair in the table.

19. The device of claim 15, wherein the frequency of occurrence threshold is a corpus frequency of occurrence threshold, and the at least one processor is further configured to execute the computer-executable instructions to:

determine a corpus frequency of occurrence of a character pair comprises a first character and a second character in a corpus of literature;

determine that the corpus frequency of occurrence is below the corpus frequency of occurrence threshold;

determine a first glyph identifier associated with the first character and a second glyph identifier associated with the second character;

determine a second kerning pair in the first set of kerning pairs comprises the third glyph identifier and the fourth glyph identifier; and

remove the second kerning pair from the first set of kerning pairs.

20. The device of claim 15, wherein the frequency of occurrence threshold is a content frequency of occurrence threshold, and the at least one processor is further configured to execute the computer-executable instructions to:

receive an indication to render a source text;

determine a content frequency of occurrence of a character pair in the source text;

determine that the content frequency of occurrence of the character pair is below the content frequency of occurrence threshold;

determine a first glyph identifier associated with a first character of the character pair and a second glyph identifier associated with a second character of the character pair;

determine a second kerning pair in the first set of kerning pairs that comprises the first glyph identifier and the second glyph identifier;

remove the second kerning pair from the first set of kerning pairs; and

render the source text using the second font file.