Toward a Composite Font format specification

Ken Lunde lunde at
Fri Aug 14 23:03:27 CEST 2009


In an effort to move the discussions forward, I would like to  
enumerate the primary functional tags, along with my initial ideas  
about what properties or attributes can be specified for each. I have  
already floated these ideas, but now that we're in basic agreement  
about some principles, I am able to condense this into a more readable  

Here we go:

Tag: <ComponentFont>
   Attribute: Target (required; a unique name for the font)
   Attribute: ScaleFactor (optional; scaling factor, expressed as a  
   Attribute: BaselineShift (optional; baseline shift, expressed as a  

Tag: <Language> (optional)
   Attribute: Target (required; an IETF language tag, as specified by  
RFC 4646)

Tag: <Encoding> (optional)
   Attribute: Target (required; the Unicode ranges to be used in the  
Composite Font)
   Attribute: Original (optional; the encoding ranges in the Component  
Font, if different than the "Target" attribute)

Of course, an appropriate XML namespace will need to be specified.

In looking at the Composite Font feature of Adobe InDesign, there are  
two types of scaling factors, both of which are independent from one  
another, meaning that both can be specified. One is a uniform scaling,  
applying to both the X- and Y-axis. The other is axis-independent  
scaling. While I am all for giving people enough rope to hang  
themselves, I consider this to be comparable to supplying the  
developer with razor-impregnated rope, and strongly suggest that the  
specification allows for only uniform scaling for the "ScaleFactor"  
attribute for the <ComponentFont> tag.

To everyone in this discussions, please think about additional  
attributes for these three functional tags.


-- Ken

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