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In ter-Office l\,leInorand urn
To Alto users Date October 20, 1975
from Bob Sproull Location Palo Alto
Subject Changes to .AL format Organization CSL
)(EROX
One vital pIece of information is missing from the present .AL font format--the baseline of
the font. The format is redefined to accomodate a 7-bit field "baseline," which is the
distance (in bits) from the baseline to the top of the highest character. Basp.line=O means
that you are reading a font file created before this format change, and you must either.
guess at the baseline or suffer.
The format change only involves the first two words of the font:
structure AL :
[
Height word IIHeight of font
Proportional bi t IITrue if font is proportionally spaced
Baseline bit 7 IIHere is the new baseline info
Tvlax\Vidth byte II.Maximum character width
]
Note: The Height entry is the honest truth about the font: if the user allocates Height
scan-lines for a text line, no character will overflow either above or below the line of
text. Note that characters with 0 words of bit-map (e.g., space) may exceed the Height
num ber wi thou t trouble.
\ The MAXC directory incorporat.Cd. This directory is at present empty; I will build it up in time. Iv1att Heiler's
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