Method and system for the representation of color and other attributes in bitmap fonts
First Claim
1. A data structure stored in a computer-readable medium which defines a font having glyphs that contain multiple colors, comprising:
- a color table containing a plurality of entries which respectively define a plurality of different colors;
a plurality of index tables each of which corresponds to a subset of the colors defined in said color table and contains entries that map to corresponding entries in said color table; and
a plurality of bit maps that respectively correspond to said glyphs, each bit map containing data values which identify entries in an index table which is associated with said bit map, to thereby designate colors from said color table for an image of the corresponding glyph.
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Accused Products
Abstract
Colors are specified within the individual glyphs of a font by means of an indirect approach which employs multiple tables. The data values for individual pixels of a glyph identify entries in an index table, which pertains to a subset of all available colors. The entries in the index table map to a complete set of colors that are specified in a color table. As a result of this structure, the amount of data that is required to specify the individual pixels of a glyph can be minimized to the number of bits required to distinguish the colors within that glyph. The specification of all available colors within a single table permits that table to be shared among various resources, including bitmap fonts and outline fonts.
42 Citations
42 Claims
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1. A data structure stored in a computer-readable medium which defines a font having glyphs that contain multiple colors, comprising:
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a color table containing a plurality of entries which respectively define a plurality of different colors;
a plurality of index tables each of which corresponds to a subset of the colors defined in said color table and contains entries that map to corresponding entries in said color table; and
a plurality of bit maps that respectively correspond to said glyphs, each bit map containing data values which identify entries in an index table which is associated with said bit map, to thereby designate colors from said color table for an image of the corresponding glyph. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for representing a bitmap font comprised of glyphs which contain multiple colors, comprising the steps of:
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generating a color table containing a plurality of entries which respectively define a plurality of different colors;
generating a plurality of bit maps each of which respectively corresponds to one of the glyphs of the bitmap font and which contains data values that designate a subset of the colors defined in said color table; and
mapping the data values in said bit maps to the entries in said color table, to thereby designate colors for the images of the glyphs which correspond to the bit maps, wherein said mapping step comprises the step of generating a plurality of mapping tables which contain entries corresponding to a subset of colors and which are indexed by the data values in said bit maps. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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19. A system for generating images of glyphs which have at least one multi-level attribute, comprising:
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a font memory storing;
a table containing a plurality of entries which respectively define different values for said attribute, a plurality of bit maps each of which respectively corresponds to one of said glyphs and which contains data values that designate some of the attribute values defined in said table, and an index which maps the data values in said bit maps to entries in said table;
a font subsystem responsive to the designation of a glyph to be imaged for accessing the bit map corresponding to the designated glyph and retrieving attribute values from said table that are mapped to the data values in the accessed bit map; and
an imaging system for generating an image of the glyph having the retrieved attribute values. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. A computer-readable medium having stored therein:
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a first table containing a plurality of entries which respectively define different values for an attribute of a bitmap font;
a plurality of bit maps that respectively define glyph images of the bitmap font, each bit map containing data values which designate values of said attribute for an image of the corresponding glyph; and
a plurality of index tables each of which map the data values in said bit maps to corresponding entries in said first table, wherein at least two of said corresponding glyphs are respectively associated with different ones of said index tables. - View Dependent Claims (30, 31, 32, 33, 34, 35)
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36. A method for generating images of glyphs of a bitmap font which have at least one multi-level attribute, comprising the steps of:
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receiving a designation of a glyph of the bitmap font to be imaged;
accessing a bit map which contains data values that designate values for said attribute;
mapping the data values in the bit map to entries in a table which respectively define different values for said attribute, wherein for each glyph to be imaged, said step of mapping comprises accessing a map table associated with the glyph from a plurality of map tables, wherein each of said map tables contains entries which collectively correspond to a subset of the entries in the table of attribute values, and wherein at least two of the glyphs of the bitmap font are respectively associated with different ones of said map tables; and
generating an image of the glyph having the attribute values to which said data values are mapped. - View Dependent Claims (37, 38, 39, 40, 41, 42)
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Specification