Video font cache
First Claim
1. A video controller for receiving alphanumeric character data and generating alphanumeric characters for a video display said video controller comprising:
- a video memory for storing alphanumeric character data, each of said alphanumeric character data representing at least one character of a character set, character attribute data including at least font selection data, and at least two character font bit maps, each of said at least two character font bit maps representing a display font;
a video font cache for storing said at least two character font bit maps in a page mode; and
a video memory controller, coupled to said video memory and said video font cache, for receiving said at least two character font bit maps from said video memory and reformatting said at least two character font bit maps in said font cache;
wherein each page of said paged character font bit maps comprises one scan line for each display font of each character of said character set.
2 Assignments
0 Petitions
Accused Products
Abstract
A video controller receives character data, attribute data and font data, each of which are stored in different planes of a video memory. The font data comprises bit maps of at least two character fonts, which may be user fonts or default fonts loaded from a controller BIOS. The video controller retrieves the font data, translates the font data into a page mode, and stores the font data in a hidden font cache in an unused portion of the video memory. The paged font data is divided into a number of pages equal to the number of scan lines per character. Each page contains a number of words, and each word contains at least two bytes. Each byte represents one scan line of a character in a different font. The video controller retrieves the paged fonts in page mode and assembles the scan lines for the characters to be displayed into one video scan line. The use of the page mode increases refresh rate and allows simultaneous display of two fonts.
36 Citations
21 Claims
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1. A video controller for receiving alphanumeric character data and generating alphanumeric characters for a video display said video controller comprising:
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a video memory for storing alphanumeric character data, each of said alphanumeric character data representing at least one character of a character set, character attribute data including at least font selection data, and at least two character font bit maps, each of said at least two character font bit maps representing a display font; a video font cache for storing said at least two character font bit maps in a page mode; and a video memory controller, coupled to said video memory and said video font cache, for receiving said at least two character font bit maps from said video memory and reformatting said at least two character font bit maps in said font cache; wherein each page of said paged character font bit maps comprises one scan line for each display font of each character of said character set. - View Dependent Claims (2)
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3. A method of generating alphanumeric characters in a video controller comprising the steps of:
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retrieving at least two character font bit maps, each representing a character font, from a video memory, each of said character font bit maps comprising a scan line bit map for each character of a character set; and reformatting said character font bit maps into a page mode to produce paged character font bit maps such that each page of said paged character font bit maps comprises one scan line for each character of a character set in each character font. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. An apparatus for storing, generating and displaying alphanumeric characters comprising:
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a processor for generating alphanumeric character data, each of said alphanumeric character data representing one character of a character set, attribute data including at least font selection data corresponding to each of said alphanumeric character data; and
font data representing pixel data for a font for each alphanumeric character;a video controller, coupled to said processor, for receiving said alphanumeric character data, said attribute data, and said font data and storing said alphanumeric data, attribute data and font data in a video memory and converting said font data into a page mode to produce paged font data; and a font cache, coupled to said video controller, for receiving and storing said font data in a page mode such that each page of said paged font data comprises pixel data for one scan line for each character in a character set. - View Dependent Claims (17, 18, 19)
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20. A video controller for receiving alphanumeric character data and generating alphanumeric characters of a video display, said video controller comprising:
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a video memory, comprising; a first memory plane for storing alphanumeric character data, each of said alphanumeric character data representing at least one character of a character set, a second memory plane for storing character attribute data including at least font selection data, a third memory plane for storing at least two character font bit maps, each of said at least two character font bit maps representing a display font, and a video font cache for storing said at least two character font bit maps in a page mode; and a video memory controller, coupled to said video memory, for receiving said at least two character font bit maps from said video memory and reformatting said at least two character font bit maps into a page mode to produce paged character font bit maps and storing said paged character font bit maps in said font cache; wherein each page of said paged character font bit maps comprises one scan line for each display font of each character of each character set, and said at least two character font bit maps are stored in said third memory plane by an external host processor in an unpaged mode.
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21. A method of displaying an alphanumeric character in a predetermined format on a display system comprising a plurality of scan lines, each scan line comprising a plurality of pixels, wherein a bit map corresponding to at least first and second fonts of the alphanumeric character is stored in a first memory such that the pixels corresponding to the first font are stored followed by pixels corresponding to the second font, the two fonts including the predetermined font;
- the method comprising the steps of;
rearranging the pixels by storing the pixels corresponding to the at least first and second fonts in a second memory such that pixels corresponding to one scan line of the at least first and second fonts are stored before pixels corresponding to a next scan line of the at least first and second fonts; retrieving a plurality of sequential pixels from the second memory such that pixels of at least one scan line corresponding to both the fonts are included in the retrieved pixels; selecting pixels corresponding to a predetermined font of the two fonts; and displaying a scan line in the predetermined font by displaying the selected pixels.
- the method comprising the steps of;
Specification