Canonical may switch its Linux device stack from GNOME Mobile and the Hildon framework to Qt, says an industry report. The potential switch follows Nokia-owned Qt Software's announcement of a more flexible LGPL licensing option for its forthcoming Qt 4.5 release.

(Click for larger view of this Qt 4.4 media player demo)

At this week's linux.conf.au conference in Hobart, Tasmania, Australia, Canonical's David Mandala made reference to the possible switch while describing how much Ubuntu Mobile has changed over the last year, says a ComputerWorld article. Mandala was quoted in the article as saying that Canonical is considering a switch to Qt due in large part to the change to LGPL licensing.

According to the ComputerWorld article, the dilemma between choosing GNOME Mobile and Qt is linked closely to the the “radical change” of Ubuntu's port to the ARMv7 architecture, which it announced in November. Mandala was quoted as saying that a major challenge with the ARM port is to remind developers to write applications for the lower screen resolutions typical of embedded devices. This concern led Canonical to select GNOME Mobile (Hildon framework), which is optimized for smaller screen sizes, instead of incorporating the full GNOME desktop, says the story. However, Mandala was quoted as saying that Qt might be “a better framework than Hildon for screen input.”

Ubuntu's move to Qt is far from a done deal, however. Mandala was also said to have added, “Intel and Nokia are creating a huge amount of change, so hang tight for a couple of months.”

According to the ComputerWorld story, Ubuntu Mobile for Netbooks will get in line with the release of the next desktop Ubuntu release, Jaunty Jackalope, in April. “Jaunty will have a full image for netbook devices,” Mandala was quoted as saying in the article. “Jaunty netbook edition will have a cut-down set of applications compared with the Ubuntu desktop, but apt-get works and you can install what you like.”

The recent news that Qt Software was expanding its Qt licensing to support GNU LGPL (“Lesser” or “Library” General Public License) came last week. The news was widely hailed by the open source development community. For example, Ubuntu's founder, Mark Shuttleworth, supplied an upbeat quote for the press release.

The device graphics framework “wars”

Qt Software's CTO, Benoit Schillings, likes to downplay the ongoing competition between Qt and GTK. He sees it as a choice between languages, saying, “GTK is the dominant C framework, and Qt is the dominant C++ framework.” Yet, with Qt's loosened licensing, there does seem to be a healthy competition shaping up between the two, in the best open source tradition.

GNOME and its underlying GTK graphics framework have been pressed into service in quite a few Linux devices over the last couple of years. The trend was started by Nokia, which funds the watershed Maemo project. Maemo proved that full “desktop” software could not only work in devices, but might actually work better, by virtue of being better tested in the real world. Today, Intel has arguably picked up the GNOME mantle, investing hugely in its Moblin stack (for example recently hiring Alan Cox away from Red Hat to help out with it), while Nokia has gravitated toward Qt.

Qtopia and its underlying Qt graphics framework have a much longer Linux device track record, stretching back to the earliest days of the technology. Qt Software's Qt Extended stack (formerly Qtopia) powered the Sharp Zaurus back when it used extremely weak StrongARM chips, and extremely small QVGA (240 x 320) displays. (Today, the stack also powers a few modern Linux PDAs such as the recent Imovio iKit). The underlying Qt framework, meanwhile, runs in Motorola's Linux phones, and literally countless other devices covered on the pages of this site over the last ten years.

Nokia purchased Qt Software (then Trolltech) and announced plans in April to port Qt to Maemo. Meanwhile, other ports of Qt to Windows CE, Symbian S60, and other mobile platforms make it clear that Nokia sees value in broadening Qt's user and development base.

Qt's new LGPL license places copyleft restrictions on the licensed program itself, but does not extend these restrictions to software that links to it. That makes it less restrictive than the GNU GPL, previously offered for Qt, which demands that any “derivatives” — including linked applications — be made available under the same terms.

Canonical moves toward devices

In early 2007, Canonical launched the Ubuntu Mobile and Embedded project, and in June of last year, Canonical released an Ubuntu Mobile-based version of Ubuntu 8.04 called Ubuntu MID Edition, in cooperation with the Intel sponsored Moblin project. The initial developer release is available for both the Intel Atom and Intel's A100/110 platform, targeting the Samsung Q1U ultra-mobile PC.

While several desktop Linux distributions have spun off netbook versions over the the last year, Canonical has been especially rigorous in expanding Ubuntu into netbooks and other mobile devices. Last year Canonical and Ubuntu Founder Mark Shuttleworth predicted Linux dominance in devices. The next month, Ampro began distributing a Ubuntu Linux derivative with its x86-compatible single-board computers (SBCs) called “Ampro Embedded Linux” (AEL). Canonical has also launched an Ubuntu Netbook remix version of its distribution. In September, the Foresight group adopted Ubuntu Netbook remix for a new version of its Foresight Linux desktop distribution called Foresight Mobile Edition 1.0.

GNOME Mobile-based devices, left to right:
Nokia N810, Bug Labs BugBase, OpenMoko Neo Freerunner

The GNOME project formally released the GNOME Mobile version of its Linux desktop environment in September, but by then the environment was already widely used in mobile devices (see images above). GNOME Mobile is based on the GNOME 2.24 desktop that was also released in September, and is targeted at mobile phones, handhelds, and other devices with constrained display, input, and system resources. GNOME Mobile's core infrastructure is based on GLib and D-Bus. GLib offers core application building blocks for portable C libraries and applications, and supplies the core object system, main loop implementation, and utility functions for strings and common data structures.

Availability

The ComputerWorld article by Rodney Gedda, “Ubuntu Mobile looks at Qt development environment,” should be here.

 
This article was originally published on LinuxDevices.com and has been donated to the open source community by QuinStreet Inc. Please visit LinuxToday.com for up-to-date news and articles about Linux and open source.