Pango
Pango (stylized as Παν語) is a text layout engine library which works with HarfBuzz shaping engine for displaying multi-language text. Full-function rendering of text and cross-platform support is had when Pango is used with platform APIs or 3rd party libraries, such as Uniscribe and FreeType, as text rendering backends. Pango-processed text will appear similar under different operating systems.
Pango is a special-purpose library for text and not a general-purpose graphics rendering library such as Cairo, with which Pango can be used. Indeed, the Cairo documentation recommends Pango be used to "render" text rather than Cairo for all but the simplest text "rendering".
The name pango comes from Greek pan (παν, "all") and Japanese go (語, "language").
Support for OpenType features
Pango 1.17 and newer support the locl feature tag that allows alternate glyphs to be used for the same Unicode code point. Assuming you have Verdana version 5.01 installed, which supports the locl feature for the latn/ROM (Romanian) script, a quick demonstration (on Linux) is: