KLEPAS.ORG

In the pre­vi­ous post I hinted that the Tango Desktop Project icon set would be re-​licensed into the public domain. The news came through at the start of GUADEC 2008 over the tango-​artists mailing list. This some­what lengthy article should set straight what Tango is, what it’s goals are, some of the hiccups that we’ve encoun­tered along the way and the immi­nent future of a pos­si­ble re-​licensing into the public domain.

Fig. 1 Example of the 16×16 Tango icons

Tango?

The Tango icon theme was the first icon theme to follow the Tango style guide and use the freedesk​top.org icon naming spec­i­fi­ca­tion. The style guide was intro­duced to give artists a guide­line to work from so that icons across the free desktop would have a unified and clean look, but also adhere to a common and well-​defined set of visual metaphors. The naming spec­i­fi­ca­tion which was an attempt to create a stan­dard method of naming icons in an icon set such that various desktop envi­ron­ments and pro­grams (GNOME, Xfce and even KDE) could use them, bat­tling the oth­er­wise gra­tu­itous renam­ing of files.

The idea behind an icon set is to avoid redun­dancy. For example the “save” icon would be con­sis­tent across all appli­ca­tions that utilize the save func­tion, and would only require one icon—in this case document-save, by the icon naming spec­i­fi­ca­tion. Before each appli­ca­tion would ship their own icons, which can cause redun­dancy and also forbids the user from chang­ing the style of their desktop through dif­fer­ent icon sets. Many appli­ca­tions still ship their own icons. Appli­ca­tions that ship their own hard-​coded icons do so because there isn’t an icon theme-​ing feature that would find the appro­pri­ate icon for the given feature for that desktop envi­ron­ment (or at least not without third-​party theme-​ing pro­grams), because the devel­oper does not know a theme and icon spec­i­fi­ca­tion exists or because there is no entry for that func­tion in the icon spec­i­fi­ca­tion.

Licensing issues

The Tango icon theme was licensed under the Cre­ative Commons Attribution-​ShareAlike 2.5 License, which pro­moted the usage and editing of the icons, pro­vided all use cases and deriv­a­tives were doc­u­mented with an orig­i­nal author note and gen­er­ally a link-​back to the Tango Desktop Project home­page. In addi­tion, deriv­a­tives had to be licensed under the same license as the orig­i­nal work i.e. deriv­a­tive works of the Tango icons would also have to be licensed under the CC Attribution-​ShareAlike 2.5 license.

Every­thing was dandy. The project received a good share of media atten­tion and promotion—it even was on Slash­dot a few times. After a while though some issues started to arise:

• The Free Soft­ware Foun­da­tion indi­cated that the CC Attribution-​ShareAlike 2.5 license and their GNU General Public License (GPL) was not compatible—developers could not ship Tango icons with their GPL-licensed code. Fur­ther­more the Debian Free Soft­ware Guide­lines (DFSG) noted the same thing, and would shift free soft­ware ship­ping with Tango icons or deriv­a­tives of Tango icons (such as custom icons created for fea­tures that weren’t covered by the icon spec­i­fi­ca­tion) from the general repos­i­tory to the non-​free repos­i­tory.
• Artists could not mix Tango icons with icons from the GNOME icon theme that was being redone to follow the Tango style guide, as the GNOME icon theme is licensed under the GPL. I expe­ri­enced some of the licens­ing issues myself as I created icons for Bazaar’s graph­i­cal front-​end appli­ca­tion, Olive (bzr-​gtk) last year. (Bazaar is a dis­trib­uted version control system.)
• Through the media atten­tion Tango received, numer­ous web­sites includ­ing pro­fes­sional busi­ness web­sites and/or their soft­ware began using the Tango icons without attri­bu­tion, in some cases fully claim­ing the icons as their work.

Tango and the public domain

Once the Tango icon theme was complete—i.e. there were icons at all required sizes for each entry in the icon specification—it was essen­tially dep­re­cated. We rec­om­mended artists and devel­op­ers alike to use and build on the GNOME icon theme, as it was licensed under the GPL; we cared less about third parties that wanted to use the icons on their website and in their products—after all the Tango icon theme was still there for them and all they were required to do was provide attri­bu­tion and share-​alike (as before).

Until now we have just been pro­mot­ing Tango as an example icon set that com­plies to the icon naming spec­i­fi­ca­tion and is based on the Tango style guide. However, this might now change! With the licens­ing issues we have for a while dis­cussed the pos­si­bil­ity of re-​licensing the Tango icon theme to deal with the above men­tioned prob­lems. This was until now con­sid­ered an arduous and unlikely task as numer­ous artists had con­tributed to the theme and each would have to agree to re-​license their respec­tive con­tri­bu­tions (an issue that many larger free soft­ware projects face when re-​licensing) and in par­tic­u­larly because some of the artists were working for Novell at the time of their con­tri­bu­tions (who sub­se­quently owned the rights to the work). Jakub Steiner had a long debate with the Novell legal and open source review board who have just agreed to re-​license its share of the theme into the public domain (much of which was per­formed by Jakub himself, as he worked for Novell; kudos).

Implications

This fixes all of the licens­ing issues, but raised the ques­tion of usage. Ideally it would be nice to be attrib­uted in some respect however legally anyone can claim author­ship over the icons in deriv­a­tives and even simple use cases. I don’t think this is much of an issue as a large number of use cases lacked attri­bu­tion in the first place and this was almost impos­si­ble to combat—we don’t want to hunt down unat­trib­uted use cases or deriv­a­tivesy, and ulti­mately a library of free icons could still give Tango and free soft­ware a lot of public atten­tion.

I dis­cussed the re-​licensing briefly with Andy Fitzsi­mon at GUADEC and he noted this would be great as there would be a large pool of public domain shapes and ele­ments to draw from for future icons. Rodney Dawes made a similar obser­va­tion and rec­om­mended we shouldn’t release the icon set as-​is into the public domain, instead:

“…create a new repos­i­tory which houses the Public Domain ele­ments which make up the icons we offer in tango-​icon-​theme. This new module could be tango-​icon-​assets or some­thing similar, and would contain just the assets in SVG form (in the one-​canvas work­flow style), such as ‘paper sheet’ and ‘error emblem’. Every­thing in this module would be Public Domain, and there would be no need for any build system work at all, as it is purely a repos­i­tory of build­ing blocks for cre­at­ing full icons.

From there, we can make tango-​icon-​theme into an LGPL icon theme, made up of the public domain assets. This module would provide a clearer licens­ing scheme, for devel­op­ers to be con­fi­dent about using our icons. This would also provide a nice method of allow­ing con­trib­u­tors to submit icons based off the tango assets for inclu­sion, but who do not wish to relin­quish copy­right in doing so. There icons could be LGPL, yet the parts that com­prise them, could be Public Domain, save for minor dif­fer­ences.

We could also pull over some of the Public Domain assets into other icons and themes, such as OpenOf​fice.org and gnome-​icon-​theme, without issue. The paper sheet for example would be a great place to start doing that.”

Tango’s future

Jakub has emailed all the other con­trib­u­tors of the Tango icon theme request­ing their response regard­ing the re-​license, and thus far every­one seems in agree­ment with Jakub’s and Rodney’s pro­posal. So, look forward to a public domain Tango assets library and TangoNG—a “next generation” Tango icon theme, better than the first!