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FONT Format for All-Points-Addressable Devices

IP.com Disclosure Number: IPCOM000039415D
Original Publication Date: 1987-Jun-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 3 page(s) / 56K

Publishing Venue

IBM

Related People

DeGroot, JE: AUTHOR [+2]

Abstract

A method is described to reduce the amount of memory required to store a font by eliminating blank rows (rows with all 0's) from the top and bottom of all character boxes in the font. Fig. 1 shows a typical 5 columns and 10 rows. The top row is all zeros, and the bottom two rows are all zeros. Fig. 2 shows how the character is normally stored in memory. In accordance with the new method, a font data structure consists of three parts that is provided as shown in Fig. 3. (Image Omitted) 1. Descriptor Field This field describes the attributes of the font, e.g., font style (plain, bold, italic, etc., baseline, capline, mono/variable pitch indicator, total number of characters, width and height of each character, if monopitch). It also contains a pointer to the font lookup table.

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FONT Format for All-Points-Addressable Devices

A method is described to reduce the amount of memory required to store a font by eliminating blank rows (rows with all 0's) from the top and bottom of all character boxes in the font. Fig. 1 shows a typical 5 columns and 10 rows. The top row is all zeros, and the bottom two rows are all zeros. Fig. 2 shows how the character is normally stored in memory. In accordance with the new method, a font data structure consists of three parts that is provided as shown in Fig. 3.

(Image Omitted)

1. Descriptor Field

This field describes the attributes of the font, e.g., font

style (plain, bold, italic, etc., baseline, capline,

mono/variable pitch indicator, total number of characters,

width and height of each character, if monopitch). It also

contains a pointer to the font lookup table.

2. Font Data

This field contains the encoded representations of each

character in the font, minus the blank rows at the top and

bottom of each character box.

3. The Font Lookup Table contains one entry for every character

in the font.

Each entry in the font lookup table has four fields:

T. TOP: Contains the number of blank rows at the top of the

character box.

B. BOTTOM: Contains the number of blank rows at the bottom of

the character box.

W. WIDTH: Contains the number of columns in the character box

(this field permits fonts with variable-width character

boxes).

P. POINTER: Contains the address of the first non-blank row of a

character in the FONT DATA table. The advantages include a significan...