Hi,

The CSS Fonts Module Level 3 draft proposes a way for web pages to specify capitalization variants
    http://www.w3.org/TR/css3-fonts/#font-variant-caps-prop
but in Pango none of the OpenType lookup tables that would enable these features are present:
    pcap, smcp
    c2pc, s2sc

To be complete, let me state here how these should work.

Small caps are replacements for lower-case letters that are of the general form up uppercase letters, but the height of lowercase letters.  Petite caps are similar, but they are typically half the height of uppercase letters.

Best results are obtained by making use of specially designed glyphs for these smaller versions, and many fonts contain such substitutions:  these substitution glyphs are specified by the lookup tables, which work just like other single-character substitutions.

Of course, these features only apply to alphabetic scripts with case distincion (bicameral scripts).

In case the tables for the current script are not available in the font, uppercase letters should simply be scaled.  (I see some comments in the Pango source that seem to indicate Pango could take this last measure.)

Thanks!