[XeTeX] New feature planned for xetex

[Philip Taylor]

Jonathan Kew wrote:

> When \XeTeXinterwordspaceshaping is greater than 0, XeTeX will attempt
> to support fonts where the width of inter-word spaces may vary
> contextually, depending on the preceding and following text. This is
> needed by fonts such as SIL's Awami Nastaliq (in development) where
> words are expected to kern together across spaces.

> These [other] cases are addressed with \XeTeXinterwordspaceshaping=2. With this
> value, not only are inter-word spaces measured in context, but also each
> run of text (words and intervening spaces) in a single font will be
> re-shaped as a unit at \shipout time. This allows full shaping
> (contextual swashes, ligatures, etc) to take effect across inter-word
> spaces.

I like these ideas, Jonathan, but wonder whether the two concepts should
be orthogonal (possible implementation :  treat the value of
\XeTeXinterwordspaceshaping as a bit mask, such that
\XeTeXinterwordspaceshaping = 1 would be for SIL's Awami Nastaliq, etc.,
\XeTeXinterwordspaceshaping = 2 would be for Hoefler Italic, etc., and
\XeTeXinterwordspaceshaping = 3 would be for both). This would also
allow future extensibility without compromising backward compatibility.

Philip Taylor