Efficient portable document

• US 8,397,155 B1
• Filed: 09/30/2011
• Issued: 03/12/2013
• Est. Priority Date: 07/31/2009
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Google Inc. (Alphabet Inc.)
• Inventors: Szabo, Peter
• Primary Examiner(s): Paula, Cesar
• Assistant Examiner(s): Tran, Quoc A
• Application Number:
  US13/249,722
• Time in Patent Office: 529 Days
• Field of Search: 715/209
• US Class Current: 715/209
• CPC Class Codes: G06F 40/103 Formatting, i.e. changing of presentation of documents automatic justification G06F40/189; automatic line break hyphenation G06F40/191

Abstract

A computer-implemented method for formatting electronic documents involves obtaining, at a computer system, an electronic document in a source format. The process also involves processing the electronic document by optimizing sizes of one or more images embedded in the electronic document, optimizing sizes of one or more Type 1 fonts in the electronic document, and removing object duplicates in the electronic document. In addition, the process involves generating the document in a target format based on the processing.

Claims

1. A computer-implemented method for formatting electronic documents, comprising:

receiving, at a computer system, a source version of an electronic document in a source format;

processing the source version of the electronic document to generate a target version of the electronic document in a target format, the processing comprising

compressing one or more images embedded in the source version of the electronic document,

compressing one or more Type 1 fonts embedded in the source version of the electronic document, and

unifying object duplicates embedded in the source version of the electronic document,

the target version of the electronic document in the target format including both the compressed one or more images and the compressed one or more Type 1 fonts and excluding one of each of the object duplicates; and

outputting the target version of the electronic document in the target.

2. The method of claim 1, wherein the target format is a compressed version of the source format.

3. The method of claim 1, wherein the source format and the target format are both portable document format (PDF).

4. The method of claim 1, where the received source version of the electronic document is a previously compressed electronic document.

5. The method of claim 1, wherein the received source version of the document is in a TEX format and the target version of the electronic document is output in a portable document format (PDF) format.

6. The method of claim 1, wherein processing the source version of the electronic document comprises performing two or more operations selected from a group consisting of generating object streams and cross-reference streams based on the source version of the electronic document, encoding Type 1 fonts from the source version of the electronic document as CFF, creating graphics based on font subsetting factors and the source version of the electronic document, disabling font subsetting before concatenation of the source version of the electronic document, and embedding each graphics file from the source version of the electronic document once.

7. The method of claim 1, wherein processing the source version of the electronic document comprises further applying to the electronic document a plurality of publicly available applications in a predetermined sequence, and supplying an output from one of the plurality of publicly available applications to a next of the plurality of publicly available applications.

8. A non-transitory computer-readable, tangible data storage memory device having recorded thereon instructions that, when executed, cause a processor to perform operations that comprise:

receiving, at a computer system, a source version of an electronic document in a source format;

processing the electronic document to generate a target version of the electronic document in a target format, the processing comprising

compressing of one or more images embedded in the source version of the electronic document,

compressing one or more Type 1 fonts embedded in the source version of the electronic document, and

unifying object duplicates embedded in the source version of the electronic document,

the target version of the electronic document in the target format including both the compressed one or more images and the compressed one or more Type 1 fonts and excluding one of each of the object duplicates; and

outputting the target version of the electronic document in the target.

9. The non-transitory computer-readable, tangible data storage memory device of claim 8, wherein the target format is a compressed version of the source format.

10. The non-transitory computer-readable, tangible data storage memory device of claim 8, wherein the source format and the target format are both portable document format (PDF).

11. The non-transitory computer-readable, tangible data storage memory device of claim 8, where the received source version of the electronic document is a previously compressed electronic document.

12. The non-transitory computer-readable, tangible data storage memory device of claim 8, wherein the source version of the document is in a TEX format and the target version of the document is in a portable document format (PDF) format.

13. The non-transitory computer-readable, tangible data storage memory device of claim 8, wherein processing the source version of the electronic document comprises performing two or more operations selected from a group consisting of generating object streams and cross-reference streams based on the source version of the electronic document, encoding Type 1 fonts from the source version of the electronic document as CFF, creating graphics based on font subsetting factors and the source version of the electronic document, disabling font subsetting before concatenation of the source version of the electronic document, and embedding each graphics file from the source version of the electronic document once.

14. The non-transitory computer-readable, tangible data storage memory device of claim 8, wherein processing the source version of the electronic document comprises applying to the electronic document a plurality of publicly available applications in a predetermined sequence, and supplying an output from one of the plurality of publicly available applications to a next of the plurality of publicly available applications.

15. A computer-implemented system, comprising:

one or more computer processors;

a tangible memory device storing instructions that are accessible to the one or more processors, the instructions, when executed, causing the one or more processors to perform operations that comprise;

receiving, at a computer system, a source version of an electronic document in a source format;

processing the electronic document to generate a target version of the electronic document in a target format, the processing comprising

compressing one or more images embedded in the electronic document,

compressing one or more Type 1 fonts embedded in the source version of the electronic document, and

unifying object duplicates embedded in the source version of the electronic document,

the target version of the electronic document in the target format including both the compressed one or more images and the compressed one or more Type 1 fonts and excluding one of each of the object duplicates; and

outputting the target version of the electronic document in the target format.

16. The computer-implemented system of claim 15, wherein unifying object duplicates comprises unifying subsets of a same font.

17. The computer-implemented system of claim 15, wherein unifying object duplicates comprises:

constructing equivalence classes of more than one object; and

unifying the more than one object into only one object per class.

18. The computer-implemented system of claim 15, wherein unifying object duplicates comprises:

identifying two different representations of a single image in the source version of the electronic document in the source format;

removing a larger of the two different representations of the single image; and

updating references to a smaller of the two different representations of the single image.

19. The computer-implemented system of claim 15, wherein unifying object duplicates comprises:

detecting content duplication at a sub-object level;

extracting the duplicated content to individual objects; and

unifying the individual objects.

20. The computer-implemented system of claim 15, wherein the operations further comprise excluding base 14 fonts from the output target version of the electronic document.

21. The computer-implemented system of claim 15, wherein the operations further comprise defining at least one graphic in the target version of the electronic document in a format that avoids duplicating fonts that are embedded in the main portion of the target version of the electronic document.

22. The computer-implemented system of claim 15, wherein the operations further comprise:

concatenating non-stream objects to an object stream; and

compressing the object stream.

23. The computer-implemented system of claim 22, wherein the operations further comprise sorting the non-stream objects by type prior to the concatenating and the compressing.

24. The computer-implemented system of claim 15, wherein compressing the sizes of the one or more Type 1 fonts in the source version of the electronic document comprises embedding vector fonts rather than bitmap fonts into the target version of the electronic document.