[XeTeX] Custom kerning

[Adam Twardoch (List)]

On 09-10-09 21:20, Peter Baker wrote:
> Thanks to Florian and John for planting a good idea. I am in the process
> of adding upright parens, brackets and braces to the italic versions of
> Junicode. These shapes will be selectable with ss16, and kerning (the
> whole point of the exercise, and the biggest job) will be correct. I'll
> mention it here when it's ready.

Peter,

I have proposed the following OpenType Layout feature to be added into 
the OpenType specification. Of course, if it's accepted, it will take 
quite a few years until it's actually implemented in any major 
applications, if at all. Nonetheless, I'll let you know once (and if) it 
gets accepted.

Best,
Adam

==

Tag: 'uprf'

Friendly name: Upright Forms

Registered by: Adam Twardoch

Function: Some italic fonts (such as ShinnType's Scotch Modern Italic or 
Peter Baker's Junicode Italic) will have both italic and upright forms 
of some characters in a single font: typically parentheses, other 
punctuation characters as well as other symbols such as mathematical 
characters or the © sign. This feature replaces the italic glyphs with 
the corresponding upright glyphs.

Example: The user would apply this feature to replace <i>)</i> with ). 
In some typesetting practice, when an italic phrase is enclosed in 
parentheses within text set in Roman type, the parentheses should remain 
upright rather than italic. When the user sets the parentheses using the 
Roman font, spacing problems may occur in pairs such as the italic "f" 
followed by the Roman ")". By including the upright alternate glyphs for 
parentheses in the italic font, the type designer can control the 
spacing and kerning behavior in such pairs.

Recommended implementation: The uprf table maps the italic forms in a 
font to the corresponding upright forms (GSUB lookup type 1).

Application interface: For GIDs found in the uprf coverage table, the 
application passes the GIDs to the table and gets back one new GID for each.

UI suggestion: This feature should be off by default. Note that not all 
italic fonts have italic style-linking in the family, so this feature 
should be accessible for any font that includes it.

Script/language sensitivity: Applies mostly to alphabets that have 
distinct upright and italic styles such as Latin, Cyrillic or Greek; 
note that many non-Latin fonts contain Latin as well.

Feature interaction: This feature is mutually exclusive with 'ital', 
which should be turned off when it's applied. It may be used in 
combination with other substitution (GSUB) features, whose results it 
may override.

== Revise feature description 'ital' ==

In the feature description for 'ital', in the "Feature interaction" 
section, add as a first sentence:

"This feature is mutually exclusive with 'uprf', which should be turned 
off when it's applied."

-- 

Adam Twardoch
| Language Typography Unicode Fonts OpenType
| twardoch.com | silesian.com | fontlab.net

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