Raph Levien

Raphael Linus Levien (also known as Raph Levien) (born 1961) is an influential member of the free software developer community, through his creation of the Advogato virtual community and his work with the free software branch of Ghostscript. From 2007 until 2018 he was employed at Google.[1][2] He holds a PhD in Computer Science from UC Berkeley.[3] He also made a computer-assisted proof system similar to Metamath: Ghilbert. In April 2016, Levien announced a text editor made as a "20% project" (Google allows some employees to spend 20% of their working hours developing their own projects): Xi.

Imaging and typography

The primary focus of Levien's work and research is in the varied areas regarding the theory of imaging—that is, rendering pictures and fonts for electronic display, which in addition to being aesthetically and mathematically important also contribute to the accessibility and search-openness of the web.

Levien has written several papers documenting his research in halftoning technology, which have been implemented in the Gimp-Print free software package, as well as by several commercial implementations. He also created Gill, the GNOME desktop illustration application which aimed at supporting the W3C SVG standard for Vector Graphics. He states it was named after Eric Gill, the English type designer responsible for the Gill Sans, Perpetua and Joanna fonts. Direct development on Gill ceased around the year 2000, but a fork of its codebase has evolved to Sodipodi, and through it to Inkscape.

In 2009, Levien completed a PhD thesis entitled 'From Spiral to Spline: Optimal Techniques in Interactive Curve Design'[4] and published a standalone essay on the mathematical history of Elastica.[3] He calls the Elastica "A beautiful family of curves based on beautiful mathematics and a rich and fascinating history."

Beginning in 2010, his work with Google largely focused on introducing high-quality, open licensed, well organized webfonts to the internet through Google's webfont API.[5] Here, his experience with typographical technology, history and industry[4] helped to shape the development of this growing resource, though he has since moved on from the project to work on Android fonts and text layout.[1]

One of his own fonts, Inconsolata (named in 2009 as one of the ten best programming fonts by Hivelogic,[6] and generally known for its clean lines and elegant design) is now available within the Google library.[7] Regarding this font and his curves work in general, Levien had to say, "And, in fact, I don't just use the Euler spirals, I use a mixture of curves (my package is called Spiro, which is kind of an abbreviation for polynomial spirals). Most of Inconsolata (the monospaced font mentioned above) is drawn using G4-continuous splines, which are a very close approximation to the Minimum Variation Curve of Henry Moreton. I now think that's overkill, and G2-continuous splines (the Euler spiral ones) are plenty, and could be done with fewer points." [1]


In November 1999, Levien founded Advogato, a social website for the free software community, to test his ideas of attack-resistant trust metrics and to provide a development-focused forum for the free software community that was free of the kind of commercial motivations of such sites as Sourceforge.

The site has been successful from the point of view of the first criterion, surviving many attacks aimed at subverting the attack metric, made both by developers trying out attacks, and by spammers. The site has needed only relatively minor changes to cope with these. The site's trust metric provides, alongside Epinions, one of the two most important datasets used in empirical analysis of trust metrics and reputation systems. Levien observed that Google's PageRank algorithm can be understood to be an attack resistant trust metric rather similar to that behind Advogato.[8]

The site has had a more rocky road as a forum for free software developers, and currently hosts less discussion than at its peak as developers have moved from forums to weblogs. Due to this, Advogato has added a syndication feature which includes the weblogs of its current certified developer base. It remains one of the earlier networking sites, and is still a place for active discussion on development of free software.

Activism in GPL-licensed software and encryption legislation

Levien played a small part in precipitating the relaxation of the US crypto export legislation, by filing for a Commodities Jurisdiction Request for a T-shirt containing an implementation of the RSA encryption algorithm, in four lines of Perl. At the time (1995), the code on the T-shirt would have been regarded as a munition by the United States and other NATO governments.

ZD-Net's Interactive week summarised the issue that patents pose to the free software community:[9]

Levien recognizes the paradox: On one hand, he made money from forcing everyone who used his patented ideas to give him royalties. On the other, he shared the source code of several programs and recognized how the cooperation helped him and others. The two models were in conflict.

As a resolution to this conflict, in March 2000, Levien made a patent grant of his patent portfolio to the GPL community. This step was considered by some to have set a good example, and it has been suggested that it has set a precedent for IBM's subsequent patent grant, which followed two years later.

Personal life

He is divorced, with two sons: Alan and Max, and a stepdaughter. He is a member of the Berkeley Monthly Meeting[10] of the Religious Society of Friends (Quakers).[11] In the book TeX People: Interviews from the world of TeX, Levien notes, "I was born in Enkhuizen, the Netherlands, and moved to Virginia when I was three, so I don't really speak Dutch or anything but I do find myself with a liking for herring."[12]


  1. ^ a b c Levien, Raphael. "Personal Webpage". Retrieved 7 April 2013.
  2. ^ Levien, Raphael (2018-08-28). "A New Adventure". Retrieved 28 August 2018.
  3. ^ a b "The elastica: a mathematical history" (PDF). 23 August 2008. Retrieved 2011-08-04.
  4. ^ a b Levien, Raphael. "From Spiral to Spline: Optimal Techniques in Interactive Curve Design". Retrieved 18 September 2011.
  5. ^ "Google I/O 2011 Webfonts Presentations". YouTube. Retrieved 18 September 2011.
  6. ^ Benjamin, Dan. "Top 10 Programming Fonts". Hivelogic. Retrieved 18 September 2011.
  7. ^ Levien, Raphael. "Inconsolata". Webfont API. Retrieved 18 September 2011.
  8. ^ Chapter six of (Levien 2006).
  9. ^ Peter Wayner, ZD-Net Interactive Weel, 8 November 2001. Levien provided an annotated summary of the article.
  10. ^ "Berkeley Monthly Meeting website". Quaker.org. 2013-09-11. Retrieved 2013-12-05.
  11. ^ "Personal website". Levien.com. Retrieved 2013-12-05.
  12. ^ Tex (2009). TeX People: Interviews from the world of TeX (PDF). TeX. ISBN 978-0982462607.


External links


Advogato was an online community and social networking site dedicated to free software development, and was created by Raph Levien. In 2007, Steve Rainwater took over maintenance and new development from Raph. In 2016, Rainwater's running instance has been shutdown and backed up to archive.org. In October 2017, S. Ye took over from a backup copy in 2016 to re-enact a running instance for other researchers still interested in mod_virgule.

Bram Cohen

Bram Cohen (born October 12, 1975) is an American computer programmer, best known as the author of the peer-to-peer (P2P) BitTorrent protocol, as well as the first file sharing program to use the protocol, also known as BitTorrent. He is also the co-founder of CodeCon and organizer of the San Francisco Bay Area P2P-hackers meeting, and was the co-author of Codeville.

Centaur (typeface)

Centaur is a serif typeface by book and typeface designer Bruce Rogers, based on the Renaissance-period printing of Nicolas Jenson around 1470. He used it for his design of the Oxford Lectern Bible. It was given widespread release by the British branch of Monotype, paired with an italic designed by calligrapher Frederic Warde and based on the slightly later work of calligrapher and printer Ludovico Vicentino degli Arrighi. The italic has sometimes been named separately as the "Arrighi" italic.

Centaur is an elegant and quite slender design, lighter on the page than Jenson's work and most other revivals, an effect possibly amplified in the digital release compared to the metal type. It has been popular in fine book printing and is often used both for printing body text and especially titles and headings. One of its most notable uses has been in the designs of Penguin Books, who have regularly used it for titling.

Constantia (typeface)

Constantia is a serif typeface designed by John Hudson and commissioned by Microsoft. It is a transitional serif design, influenced by Eric Gill's Perpetua design. Development of the typeface began in 2003 and it was released in 2006.

Constantia is part of the ClearType Font Collection, a suite of fonts from various designers released with Windows Vista. All start with the letter C to reflect that they were designed to work well with Microsoft's ClearType text rendering system, a text rendering engine designed to make text clearer to read on LCD monitors. The other fonts in the suite are Calibri, Cambria, Candara, Consolas and Corbel.

Corbel (typeface)

Corbel is a humanist sans-serif typeface designed by Jeremy Tankard for Microsoft and released in 2005. It is part of the ClearType Font Collection, a suite of fonts from various designers released with Windows Vista. All start with the letter C to reflect that they were designed to work well with Microsoft's ClearType text rendering system, a text rendering engine designed to make text clearer to read on LCD monitors. The other fonts in the same group are Calibri, Cambria, Candara, Consolas and Constantia.

Elastica theory

The elastica theory is a theory of mechanics of solid materials developed by Leonhard Euler that allows for very large scale elastic deflections of structures.

Euler (1744) and Jakob Bernoulli developed the theory for elastic lines (yielding the solution known as the elastica curve) and studied buckling. Certain situations can be solved exactly by elliptic functions. Later elastica theory was generalized by F. and E. Cosserat into a geometric theory with intrinsic directions at each point (1907).

Elastica theory is an example of bifurcation theory. For most boundary conditions several solutions exist simultaneously.

When small deflections of a structure are to be analyzed, elastica theory is not required and an approximate solution may be found using the simpler linear elasticity theory or (for 1-dimensional components) beam theory.

A modern treatise of the planar elastica with full account of bifurcation and instability has been recently presented by Bigoni.

Euler spiral

An Euler spiral is a curve whose curvature changes linearly with its curve length (the curvature of a circular curve is equal to the reciprocal of the radius). Euler spirals are also commonly referred to as spiros, clothoids, or Cornu spirals.

Euler spirals have applications to diffraction computations. They are also widely used as transition curves in railroad engineering/highway engineering for connecting and transitioning the geometry between a tangent and a circular curve. A similar application is also found in photonic integrated circuits. The principle of linear variation of the curvature of the transition curve between a tangent and a circular curve defines the geometry of the Euler spiral:

Its curvature begins with zero at the straight section (the tangent) and increases linearly with its curve length.

Where the Euler spiral meets the circular curve, its curvature becomes equal to that of the latter.

GNOME Foundation

The GNOME Foundation is a non-profit organization based in Orinda, California, United States, coordinating the efforts in the GNOME project.

IBM ThinkPad 600

The IBM ThinkPad 600 series was a series of notebook computers introduced in 1998 by IBM as the immediate predecessor to the T-series which still exists today under Lenovo ownership. Three models were produced, the 600, 600E, and 600X; the series was succeeded in 2000 by the ThinkPad T20 series.


Inconsolata is an open-source font created by Raph Levien and released under the SIL Open Font License. It is a humanist monospaced font designed for source code listing, terminal emulators, and similar uses. It was influenced by the proprietary Consolas monospaced font, designed by Lucas de Groot, the proportional Avenir and IBM's classic monospaced Letter Gothic.

Inconsolata has received favorable reviews from many programmers who consider it to be a highly readable and clear monospaced font.

A Hellenised version of Inconsolata, containing full support for monotonic Modern Greek, was released by Dimosthenis Kaponis in 2011 as Inconsolata Hellenic, under the same license.There was originally no bold variant of Inconsolata, which caused less than optimal display on systems that used a bold variant to display text. However, when Inconsolata was added to Google Fonts, it was fully hinted and a bold variant was added.

Inconsolata-LGC is a fork of Inconsolata Hellenic which adds bold, italic and cyrillic glyphs.


Levien is a surname. Notable people with the surname include:

David Levien (born 1967), American screenwriter, novelist, director and producer

Hannah Levien, Australian actress and writer

Jason Levien (born 1971), American sports executive

Jonas Levien (1840–1906), Australian politician

Julia Levien (1911–2006), American dancer, dance teacher and choreographer

Meredith Kopit Levien (born 1971), American media executive

Norman Joseph Levien (1871–1967), New Zealand army officer

Raph Levien, American software programmer

Robert Levien (1849–1938), Australian politician

Roy Levien, American inventor

Sonya Levien (1888–1960), Russian-born American screenwriter

List of monospaced typefaces

This list of monospaced typefaces details standard monospaced fonts used in classical typesetting and printing.


Metamath is a language for developing strictly formalized mathematical definitions and proofs accompanied by a proof checker for this language and a growing database of thousands of proved theorems covering conventional results in logic, set theory, number theory, group theory, algebra, analysis, and topology, as well as topics in Hilbert spaces and quantum logic.


MuPDF is a free and open-source software framework written in C that implements a PDF, XPS, and EPUB parsing and rendering engine. It is used primarily to render pages into bitmaps, but also provides support for other operations such as searching and listing the table of contents and hyperlinks.

The focus of MuPDF is on speed, small code size, and high-quality anti-aliased rendering. Since the 1.2 release, MuPDF has optional support for interactive features such as form filling, JavaScript and transitions.The library ships with a rudimentary X11 and Windows viewer, and a set of command-line tools for batch rendering (mutool draw), examining the file structure (mutool show), and rewriting files (mutool clean). Later versions also have a JavaScript interpreter (mutool run) that allows for running scripts to create and edit PDF files.

A number of free software applications use MuPDF to render PDF documents, the most notable being Sumatra PDF. MuPDF is also available as a package for most Unix-like operating system distributions.

Independent parties have ported the library to many platforms, including the

Amazon Kindle,HP TouchPad,PlayStation Portable,Wii, and



Pango (stylized as Παν語) is a text layout engine library which works with the HarfBuzz shaping engine for displaying multi-language text. 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".The name pango comes from Greek pan (παν, "all") and Japanese go (語, "language").

Rust (programming language)

Rust is a multi-paradigm systems programming language focused on safety, especially safe concurrency. Rust is syntactically similar to C++, but is designed to provide better memory safety while maintaining high performance.

Rust was originally designed by Graydon Hoare at Mozilla Research, with contributions from Dave Herman, Brendan Eich, and others. The designers refined the language while writing the Servo layout engine and the Rust compiler. The compiler is free and open-source software dual-licensed under the MIT License and Apache License 2.0.

Rust was the "most loved programming language" in the Stack Overflow Developer Survey for 2016, 2017, and 2018.


Sodipodi is an open-source vector graphics editor, discontinued in 2004, and is the predecessor to Inkscape.

Steal This Film

Steal This Film is a film series documenting the movement against intellectual property directed by Jamie King, produced by The League of Noble Peers and released via the BitTorrent peer-to-peer protocol.

Two parts, and one special The Pirate Bay trial edition of the first part, have been released so far, and The League of Noble Peers is working on "Steal this Film – The Movie" and a new project entitled "The Oil of the 21st Century".

Trust metric

In psychology and sociology, a trust metric is a measurement of the degree to which one social actor (an individual or a group) trusts another social actor. Trust metrics may be abstracted in a manner that can be implemented on computers, making them of interest for the study and engineering of virtual communities, such as Friendster and LiveJournal.

Trust escapes a simple measurement because its meaning is too subjective for universally reliable metrics, and the fact that it is a mental process, unavailable to instruments. There is a strong argument against the use of simplistic metrics to measure trust due to the complexity of the process and the 'embeddedness' of trust that makes it impossible to isolate trust from related factors.

There is no generally agreed set of properties that make a particular trust metric better than others, as each metric is designed to serve different purposes, e.g. provides certain classification scheme for trust metrics. Two groups of trust metrics can be identified:

Empirical metrics focusing on supporting the capture of values of trust in a reliable and standardized way;

Formal metrics that focus on formalization leading to the ease of manipulation, processing and reasoning about trust. Formal metrics can be further classified depending on their properties.Trust metrics enable trust modelling and reasoning about trust. They are closely related to reputation systems. Simple forms of binary trust metrics can be found e.g. in PGP. The first commercial forms of trust metrics in computer software were in applications like eBay's Feedback Rating. Slashdot introduced its notion of karma, earned for activities perceived to promote group effectiveness, an approach that has been very influential in later virtual communities.

This page is based on a Wikipedia article written by authors (here).
Text is available under the CC BY-SA 3.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.