View source for Pango

{{short description|Library for text rendering}}
{{Other uses}}
{{use DMY dates|date=July 2025}}
{{Infobox software
| name         = Pango
| title        =
| logo         = Pango-name.svg
| logo size    = 200px
| logo caption = Pango name written as intended, Greek ''pan'' (παν, "all") and Japanese ''go'' (語, "language")
| collapsible  = 
| author       = Owen Taylor<ref>[https://www.osnews.com/story/5453 Interview: Red Hat's Owen Taylor on GTK+], '' also known for his contributions on Pango.'', by Eugenia Loli, 19th Dec 2003</ref><br />[[Raph Levien]]
| developer            = [[Behdad Esfahbod]]
| released             = {{Start date and age|1999|07|11|df=yes}}<ref>[https://people.redhat.com/otaylor/pango-mirror/download.shtml Pango], Made version 0.2, Owen Taylor, redhat.com</ref>
| latest release version = {{wikidata|property|edit|reference|P348}}
| latest release date    = {{start date and age|{{wikidata|qualifier|P348|P577}}}}
| programming language = [[C (programming language)|C]]
| operating system     = [[Unix-like]], [[Microsoft Windows]], Other
| platform             =
| size                 =
| language             =
| language count       =
| language footnote    = 
| genre                = [[Library (computing)|Software development library]]
| license              = [[LGPL]]
| alexa                =
| website              = {{URL|https://www.gtk.org/docs/architecture/pango}}
| standard             =
| AsOf                 =
}}

'''Pango''' (stylized as Παν語) is a text (i.e. [[glyph]]) layout engine [[library (computing)|library]] which works with the [[HarfBuzz]] shaping engine for displaying multi-language text.<ref>{{cite web|url=https://www.gtk.org/docs/architecture/pango|title=Pango website|access-date=19 July 2025}}</ref>

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 [[Front and back ends|backend]]s. Pango-processed text will appear similar under different operating systems.{{clarify|date=November 2012}}

Pango is a special-purpose library for text and not a general-purpose graphics rendering library such as [[Cairo (graphics)|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".<ref>{{cite web|url=https://cairographics.org/manual/cairo-text.html|title=Cairo: A Vector Graphics Library: text|access-date=27 November 2015}}</ref>

== History and naming ==
The name pango comes from Greek ''pan'' ([[wikt:παν|παν]], {{gloss|all}}) and Japanese ''go'' ([[wikt:語|語]], {{gloss|language}}).<ref>{{cite web|url=https://www.ibm.com/developerworks/library/l-u-pango1/|title=The Pango connection: Part 1|website=[[IBM]]|archive-url=https://web.archive.org/web/20090627223318/http://www.ibm.com/developerworks/library/l-u-pango1/|archive-date=27 June 2009|access-date=19 July 2025|url-status=dead}}</ref>

In January 2000, the merger of the GScript and GnomeText projects was named Pango.<ref>{{cite web|url=https://people.redhat.com/otaylor/pango-mirror/status-000114.shtml|title=Pango - Status - 2017-11-30|author=Owen Taylor|publisher=Redhat}}</ref><ref>{{cite web|url=https://linuxdevcenter.com/pub/a/linux/2000/03/21/guadec/guadec.html?page=2|title=GNOMEs in Paris: A Report from GUADEC|quote=''The most impressive part of their presentation was the discussion on Pango (the result of the GScript and GnomeText merger)''|date=21 March 2000|author=Chuck Toporek|publisher=O'Reilly Media|url-status=dead|access-date=19 July 2025|archive-date=1 December 2017|archive-url=https://web.archive.org/web/20171201031331/http://www.linuxdevcenter.com/pub/a/linux/2000/03/21/guadec/guadec.html?page=2}}</ref><ref>{{cite web|url=https://www.levien.com/gnome/pango-0.1.html|title=Pango proposal, rev 0.1|author=Raph Levien|date=28 July 1999|access-date=19 July 2025}}</ref><ref>{{cite web|url=https://people.redhat.com/otaylor/gscript/|archive-url=https://web.archive.org/web/20000815092557/http://people.redhat.com/otaylor/gscript/|url-status=live|archive-date=15 August 2000|access-date=21 July 2025|title=GScript - Unicode and Complex Text Processing|quote=''The GScript project has been merged with the GnomeText project. For information about the result, named Pango, see:https://www.pango.org If you have trouble accessing that site, there is a mirror here. By Owen Taylor''}}</ref><ref>{{cite web|url=https://www.levien.com/gnome/gnome-text.html|title=Gnome-Text API documentation|author=Raph Levien|date=10 Jul 1999|quote=''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.''}}</ref><ref>{{cite web|url=http://beast.testbit.eu/_mirror/gnome-news/946276088.html|title=GNOME Developer's Interview Follow-up|first=Ali|last=Abdin|date=1999|website=beast.testbit.eu|url-status=dead|archive-url=https://web.archive.org/web/20130602195924/http://beast.testbit.eu/_mirror/gnome-news/946276088.html|archive-date=2 June 2013|quote=''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.''}}</ref>

Pango version 1.0.0 was released 11 March 2002.<ref>{{cite web|url=http://gtk.org/pango-1.0.0-announce.html|title=Pango 1.0.0 released|access-date=20 February 2013|url-status=dead|archive-url=https://web.archive.org/web/20020402201452/http://gtk.org/pango-1.0.0-announce.html|archive-date=2 April 2002}}</ref><ref>{{cite web|url=https://mail.gnome.org/archives/gnome-announce-list/2002-March/msg00022.html|title=GTK user interface libraries, version 2.0|access-date= 19 July 2025}}</ref>

==Support for OpenType features==
[[Image:Pango locl demo.png|thumb|250px|Default rendering above, localized Romanian rendering below.]]

Pango 1.17 and newer support the '{{not a typo|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:
<syntaxhighlight lang="bash">
for lang in en ro
do
    pango-view \
        --font="Verdana 64" \
        --text "şţ vs. șț in $lang" \
        --language=$lang
done
</syntaxhighlight>

For an explanation of the substitutions rules for Romanian, see this [[Romanian alphabet#Comma-below .28.C8.99 and .C8.9B.29 versus cedilla .28.C5.9F and .C5.A3.29|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 [https://docs.gtk.org/Pango/pango_markup.html Pango markup], e.g.:
<syntaxhighlight lang="bash">
pango-view \
    --font="Verdana 24" \
    --markup \
    --text 'In the same text: şţ(en) and <span lang="ro">şţ(ro).</span>'
</syntaxhighlight>

Since 1.37.1, Pango added more attributes to provide complete support for processing OpenType feature.<ref>{{cite web
 | url        = https://ftp.gnome.org/pub/GNOME/sources/pango/1.37/pango-1.37.1.news
 | title      = Overview of changes between 1.37.0 and 1.37.1
 | access-date = 18 August 2015}}</ref><ref>{{cite web
 | url        = https://bugzilla.gnome.org/show_bug.cgi?id=738505
 | title      = Bug 738505 - Add fontfeatures support in PangoAttributes and markup
 | publisher  = GNOME Bugzilla
 | access-date = 18 August 2015}}</ref><ref>{{cite web
 | url        = http://tavmjong.free.fr/blog/?p=1442
 | title      = Font Features Land in Inkscape Trunk
 | publisher  = Tavmjong Bah's Blog
 | date       = 23 June 2015
 | access-date = 18 August 2015}}</ref>

The official showcase of Pango's script-aware features is [https://www.pango.org/ScriptGallery here].

==Major users==
[[File:GTK+ software architecture.svg|thumb|Simplified software architecture of [[GTK]]. Pango, [[GDK]], [[Accessibility Toolkit|ATK]], [[GIO (software)|GIO]], [[Cairo (graphics)|Cairo]] and [[GLib]].]]

Pango has been integrated into most Linux distributions. The [[GTK]] UI toolkit uses Pango for all of its text rendering.<ref>{{cite web|title=Download for GNU/Linux and Unix|url=http://www.gtk.org/download/linux.php|website=gtk.org|access-date=2017-11-30|url-status=dead|archive-url=https://web.archive.org/web/20160818111012/http://www.gtk.org/download/linux.php|archive-date=18 August 2016}}</ref> The [[Linux]] versions of the [[Mozilla Firefox]] web browser and [[Mozilla Thunderbird]] mail client use Pango for text rendering.<ref>{{cite web|title=Thunderbird 52.1.0 System Requirements|url=https://www.mozilla.org/en-US/thunderbird/52.1.0/system-requirements/|website=mozilla.org|access-date=31 July 2017|url-status=live|archive-url=https://web.archive.org/web/20170510012333/https://www.mozilla.org/en-US/thunderbird/52.1.0/system-requirements/|archive-date=10 May 2017}}</ref>

==See also==
{{Portal|Free and open-source software}}
* [[HarfBuzz]] (text shaping engine which is incorporated into Pango itself but can be also used stand-alone)
* [[Core Text]] (modern multilingual text rendering engine introduced in [[Mac OS X 10.5]])
* [[Graphite (smart font technology)|Graphite]] (multiplatform open source smart-font renderer)
* [[WorldScript]] (Old Macintosh multilingual text rendering engine)
* [[Typographic ligature]]
* [[Computer font]]

==References==
{{Reflist|30em}}

==External links==
* {{Official website}}
* [https://fishsoup.net/bib/PangoIuc25-paper.pdf Pango, an open-source Unicode text layout engine. by Owen Taylor in Twenty fifth Internationalization and unicode conference, April 2004] {{Webarchive|url=https://web.archive.org/web/20200706025551/http://fishsoup.net/bib/PangoIuc25-paper.pdf|date=2020-07-06}}
* [https://web.archive.org/web/20120227064838/http://ols.fedoraproject.org/OLS/Reprints-2001/taylor.pdf "Pango: internationalized text handling" Owen Taylor in Ottawa linux symposium 2001]
* [https://docs.gtk.org/Pango/ Pango Reference Manual]
* {{YouTube|Is4PW6f4Pk4|The journey of a word: how text ends up on a page}}, at [[linux.conf.au]] 2017 Simon Cozens explained the rendering of fonts

{{Free and open-source typography}}
{{Freedesktop.org}}

[[Category:1999 software]]
[[Category:C (programming language) libraries]]
[[Category:Free computer libraries]]
[[Category:Free software programmed in C]]
[[Category:Freedesktop.org libraries]]
[[Category:GNOME libraries]]
[[Category:GTK]]
[[Category:Software that uses Meson]]
[[Category:Text rendering libraries]]