Pango

Pango (stylized as Παν語) is a text (i.e. glyph) layout engine library which works with the HarfBuzz shaping engine for displaying multi-language text.[4]

For other uses, see Pango (disambiguation).
Original author(s)Owen Taylor[1]
Raph Levien
Developer(s)Behdad Esfahbod
Initial release11 July 1999 (1999-07-11)[2]
Stable release
1.51.1[3] Edit this on Wikidata / 11 August 2023 (11 August 2023)
Repository
Written inC
Operating systemUnix-like, Microsoft Windows, Other
TypeSoftware development library
LicenseLGPL
Websitewww.pango.org

Full-function rendering of text and cross-platform support is achieved when Pango is used with platform APIs or third-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. The Cairo documentation recommends Pango be used to "render" text rather than Cairo for all but the simplest text "rendering".[5]

History and naming

The name pango comes from Greek pan (παν, "all") and Japanese go (語, "language").[6]

In January 2000, the merger of the GScript and GnomeText projects was named Pango.[7][8][9][10][11][12]

Pango version 1.0.0 was released 11 March 2002.[13][14]

Support for OpenType features
Default rendering above, localized Romanian rendering below.

Pango 1.17 and newer support the locl feature tag that allows localized 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: şţ(en) and <span lang="ro">şţ(ro).</span>'

Since 1.37.1, Pango added more attributes to provide complete support for processing OpenType feature.[15][16][17]

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

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.[18] The Linux versions of the Mozilla Firefox web browser and Mozilla Thunderbird mail client use Pango for text rendering.[19]

See also

References
  1. Interview: Red Hat's Owen Taylor on GTK+, also known for his contributions on Pango., by Eugenia Loli, 19th Dec 2003
  2. Pango, Made version 0.2, Owen Taylor, redhat.com
  3. Error: Unable to display the reference properly. See the documentation for details.
  4. "Pango website". Retrieved 7 July 2011.
  5. "Cairo: A Vector Graphics Library: text". Retrieved 27 November 2015.
  6. "The Pango connection: Part 1". IBM. Archived from the original on 27 June 2009. Retrieved 7 July 2011.
  7. Pango - Status - 2017-11-30, Owen Taylor, Redhat
  8. GNOMEs in Paris: A Report from GUADEC, The most impressive part of their presentation was the discussion on Pango (the result of the GScript and GnomeText merger), 2000/03/21, By Chuck Toporek - O'Reilly Media
  9. Pango proposal, rev 0.1, Raph Levien, 28 July 1999
  10. GScript - Unicode and Complex Text Processing, The GScript project has been merged with the GnomeText project. For information about the result, named Pango, see: http://www.pango.org If you have trouble accessing that site, there is a mirror here. By Owen Taylor
  11. Gnome-Text API documentation, Raph Levien, 10 Jul 1999, Owen Taylor is working on gscript, which has some overlap with the functions described in this interface. We're working on unifying the two api's as much as possible.
  12. Abdin, Ali (1999). "GNOME Developer's Interview Follow-up". beast.testbit.eu. Archived from the original on 2013-06-02. Pango (which is the code name for a merger of my Gscript project and Raph Levien's GnomeText project) is a modular set of libraries for doing layout and rendering of international text. It's a bit similar to Microsoft's Uniscript or Apple's ATSUI.
  13. "Pango 1.0.0 released". Archived from the original on April 2, 2002. Retrieved 2013-02-20.
  14. GTK user interface libraries, version 2.0
  15. "Overview of changes between 1.37.0 and 1.37.1". Retrieved 18 August 2015.
  16. "Bug 738505 - Add fontfeatures support in PangoAttributes and markup". GNOME Bugzilla. Retrieved 18 August 2015.
  17. "Font Features Land in Inkscape Trunk". Tavmjong Bah's Blog. 23 June 2015. Retrieved 18 August 2015.
  18. "Download for GNU/Linux and Unix". gtk.org. Archived from the original on 18 August 2016. Retrieved 2017-11-30.
  19. "Thunderbird 52.1.0 System Requirements". mozilla.org. Archived from the original on 10 May 2017. Retrieved 31 July 2017.
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