Browse Prior Art Database

Dynamic Determination of Font Resolution when Storing/Locating Fonts

IP.com Disclosure Number: IPCOM000105561D
Original Publication Date: 1993-Aug-01
Included in the Prior Art Database: 2005-Mar-20
Document File: 2 page(s) / 58K

Publishing Venue

IBM

Related People

Goodson, B: AUTHOR [+4]

Abstract

Because character sets with the same name but different pel resolutions can exist on the same system, an identification mechanism is required that will ensure the correct pel resolution of the font used. In addition, it must also support the addition of other pel resolutions without any code changes.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 93% of the total text.

Dynamic Determination of Font Resolution when Storing/Locating Fonts

      Because character sets with the same name but different pel
resolutions can exist on the same system, an identification mechanism
is required that will ensure the correct pel resolution of the font
used.  In addition, it must also support the addition of other pel
resolutions without any code changes.

      The algorithm presented here dynamically determines the
resolution and the unit base metrics of the font so that future
resolution values are supported without code changes.

      When a character set is stored, a header record (Fig. 1) is
built which contains the font resolution.  The resolution is
determined by parsing the Font Control (FNC) AFPDS structured field
(Fig. 2) within the character set.  When parsing the FNC, the unit
base metrics is first determined by looking at byte 4.  If this byte
indicates a fixed metric font, the resolution value that is stored in
the header record is 240 pels resolution.  If byte 4 indicates a
relative metric font and the length of the FNC structured field is at
least 27 bytes, bytes 24 through 27 are stored in the header record
as the resolution.  Because character sets with the same name but
different pel resolutions may exist on the system, the header records
of these character sets are searched until one is found that matches
the pel density of the printer.  Once a character set is found with
the correct resolution, the FNC structured...