Granted Patent B2

US 7,719,537 · App. 11/507,456 · Granted May 18, 2010

Abstract

Claims (41)

1. A method for processing by a computer font data comprising font instruction to provide improved font rendering by said computer upon display or printing, said method comprising:

analyzing by a computer operating system a set of pixels-per-em values and fractional pixel shifts contained in the font instruction, which is present in a library script or computer program, for each glyph in a font data to construct a database of values;

converting by said computer operating system said pixels-per-em values and said fractional pixel shifts into shorthand notation having a form of operational codes and argument values for each glyph in the font data; and

compressing by said computer operating system the operational codes and the argument values into a compressed data stream comprising a series of multiple-bit words representing font instruction specifications for each glyph in the font data which were originally represented as said pixel-per-em values and said fractional pixel shifts;

setting by said computer operating system fixed values corresponding to environmental variable values for each glyph;

decompressing the multi-bit words representing font instruction specifications; and

executing the font instruction specifications decompressed in absence of said environmental variable values thereby executing a reduced amount of code to render font glyphs.

2. The method of claim 1 , wherein said font instruction is selected from the group consisting of DELTAP1, DELTAP2, DELTAP3, SDS, SDB, SVTCA, PUSHB, PUSHW, NPUSHB, and NPUSHW.

3. The method of claim 1 , wherein the operational codes and the argument values are variable length codes.

4. The method of claim 1 , wherein said multiple-bit words comprise 16-bit words.

5. The method of claim 3 , wherein the compressing of the variable length codes of the operational codes and the argument values results in at least 60 percent data compression of the font instruction.

6. The method of claim 1 , wherein said fixed values corresponding to said environmental variable values correspond to:

(1) a numerically lowest shift value present for any point-per-em for the glyph,

(2) a shift increment,

(3) a lowest point-per-em value for which hints in the font instruction are present, and

(4) a packed multiple-bit value comprising fields comprising a point-per-em value, a count and a phase for use when decompressing the font instruction.

7. A method of processing by a computer for rendering a glyph from font data having compressed font instruction data in a form of a series of multiple-bit word or words representing shorthand notation for pixels-per-em values and fractional pixel shifts forming font instruction specifications and fixed environmental values for respective glyphs in the font data to provide improved font rendering by said computer upon display or printing, said method comprising:

setting by a computer system fixed values corresponding to environmental variable values for a glyph for:

(1) a numerically lowest shift value present for any point-per-em for the glyph,

(2) a shift increment,

(3) a lowest point-per-em value for which hints in the font instruction data are present, and

(4) a packed multiple-bit value comprising fields comprising a point-per-em value, a count and a phase for use when decompressing the font instruction data;

decompressing by said computer system the multiple-bit word or words corresponding to font instruction; and

executing by said computer system only relevant font instruction specifications, which is in absence of said fixed values corresponding to said environmental variable values, for the glyph thereby executing a reduced amount of code to render font glyphs.

8. The method of claim 7 , wherein said font instruction is selected from the group consisting of DELTAP1, DELTAP2, DELTAP3, SDS, SDB, SVTCA, PUSHB, PUSHW, NPUSHB, and NPUSHW.

9. The method of claim 7 , further comprising rendering the glyph using the multiple-bit word or words provided following said decompressing.

10. A method for processing by a computer font data comprising font instruction to provide improved font rendering by said computer upon display or printing, said method comprising:

analyzing by a computer system a set of pixels-per-em values and fractional pixel shifts contained in the font instruction for each glyph in the font data to construct a database of values;

converting by said computer system said set of pixels-per-em values and fractional pixel shifts into shorthand notation having a form of operational codes and argument values for each glyph in the font data;

compressing by said operating system the operational codes and the argument values into a compressed data stream comprising a series of multiple-bit word or words representing font instruction specifications for each glyph in the font data which were originally represented as said pixels-per-em values and said fractional pixel shifts;

setting by said computer operating system fixed values corresponding to environmental variable values for each glyph for:

(1) a numerically lowest shift value present for any point-per-em for the glyph,

(2)a shift increment,

(3) a lowest point-per-em value for which hints in the font instruction are present, and

(4) a packed multiple-bit word comprising a point-per-em value, a count and a phase for use when decompressing the font instruction;

decompressing by said operating system the multiple-bit word or words corresponding to the font instruction; and

executing by said operating system only relevant font instruction specifications for a respective glyph and not multiple-bit words corresponding to the font instruction for the fixed values corresponding to said environmental variable values thereby executing a reduced amount of code to render font glyphs.

11. The method of claim 10 , wherein said font instruction is selected from the group consisting of DELTAP1, DELTAP2, DELTAP3, SDS, SDB, SVTCA, PUSHB, PUSHW, NPUSHB, and NPUSHW.

12. The method of claim 10 , further comprising rendering the glyph using the multiple-bit word or words provided following said decompressing.

13. The method of claim 10 , wherein the operational codes and the argument values are represented by variable length words.

14. The method of claim 10 , wherein the multiple-bit word or words are 16-bit words.

Assignments (17)