Pango

For other uses, see Pango (disambiguation).

Pango

Παν語 Pango name written as intended
Original author(s)	Owen Taylor Raph Levien
Developer(s)	Behdad Esfahbod
Initial release	11 July 1999 (1999-07-11)
Stable release	1.40.1 (April 11, 2016 (2016-04-11)) [±]
Written in	C
Operating system	Unix-like, Microsoft Windows, Other
Type	Software development library
License	LGPL
Website	www.pango.org

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

File:Pango locl demo.png

Default rendering above, localized Romanian rendering below.

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:

for lang in en ro; do pango-view \
 --font="Verdana 64" \
 --text "şţ vs. șț in $lang" \
 --language=$lang; done

For an explanation of the substitutions rules for Romanian, see this discussion.

Setting the locale via the POSIX environment variable, e.g. LANG=ro_RO.UTF-8 will also cause Pango to use locl font feature. Finally, you can change the language on the fly in the same text using Pango markup, e.g.:

pango-view \
 --font="Verdana 24" \
 --markup \
 --text 'In the same text: <span lang="en">şţ</span>(en) and <span lang="ro">şţ</span>(ro).'

The official showcase of Pango's script-aware features is here.

Since 1.37.1, Pango added more attributes to provide completely support for processing OpenType feature.

Major users

Simplified software architecture of GTK+. Pango, GDK, ATK, GIO, Cairo and GLib.

Pango has been integrated into most Linux distributions. The GTK+ UI toolkit uses Pango for all of its text rendering. The Linux versions of the Mozilla Firefox web browser and Mozilla Thunderbird mail client use Pango for text rendering.

History

In January 2000 the merger of the GScript and GnomeText projects was named Pango.

Pango version 1.0.0 was released 11 March 2002.

See also

• Core Text (modern multilingual text rendering engine introduced in Mac OS X 10.5)
• Graphite (multiplatform open source smart-font renderer)
• WorldScript (Old Macintosh multilingual text rendering engine)

External links

• Official website
• Pango, an open-source Unicode text layout engine. by Owen Taylor in Twenty fifth Internationalization and unicode conference, April 2004
• The Pango Connection : Part 1, Tony Graham, 2001
• The Pango Connection : Part 2, Tony Graham, 2001
• "Pango: internationalized text handling" Owen Taylor in Ottawa linux symposium 2001
• "Implementation of Reverse Chaining Mechanism in Pango for Rendering Nastaliq Script" Wali, A., Rehman, S., In the Proceedings of Second Workshop of Computational Approaches to Arabic Script-based Languages (CAASL-2), Stanford University, US, 2007
• "Enhancing Contextual Substitution Support in Pango Using Opentype", Wali, A. MS Thesis, National University of Computer and Emerging Sciences, Lahore, Pakistan, 2004
• Pango Reference Manual