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+<H1 ALIGN=CENTER>Whitepaper: wxWidgets on the GNOME desktop</H1>
+<P STYLE="margin-top: 0.42cm; page-break-after: avoid"><FONT FACE="Albany, sans-serif"><FONT SIZE=4>Introduction</FONT></FONT></P>
+<P>wxWidgets<A HREF="http://www.wxwidgets.org/"><SUP>[1]</SUP></A>
+(formely known as wxWindows) is a C++ cross-platform GUI library,
+whose distintive feature is the use of native calls and native
+widgets on the respective platform, i.e. an application compiled for
+the Linux platform will use the GTK+<A HREF="http://www.gtk.org/"><SUP>[2]</SUP></A>
+library for displaying the various widgets. There is also a version
+(„port“) of wxWidgets which uses the Motif toolkit for
+displaying its widgets (this port is commonly referred to as wxMotif)
+and another one, which only uses X11 calls and which draws its
+widgets entirely itself, without using any outside library. This port
+is called wxX11 or sometimes more generally wxUniv (short for
+wxUniversal), since this widget set (implemented entirely within
+wxWidgets) is available whereever wxWidgets is available. Since this
+short overview is mainly about how to write wxWidgets applications
+for the GNOME<A HREF="http://www.gnome.org/"><SUP>[3]</SUP></A>
+desktop, I will focus on the GTK+ port, which is generally referred
+to as wxGTK.
+</P>
+<P>wxGTK still supports the old version GTK+ 1.2, but it now defaults
+to the uptodate version GTK+ 2.X, which is the basis for the current
+GNOME desktop. By way of using GTK+ 2.X and its underlying text
+rendering library Pango<A HREF="http://www.pango.org/"><SUP>[4]</SUP></A>,
+wxGTK fully supports the Unicode character set and it can render text
+in any language and script, that is supported by Pango.</P>
+<P STYLE="margin-top: 0.42cm; page-break-after: avoid"><FONT FACE="Albany, sans-serif"><FONT SIZE=4>wxWidgets'
+design principles sofar</FONT></FONT></P>
+<P>The three main design goals of the wxWidgets library are
+portability across the supported platforms, complete integration with
+the supported platforms and a broad range of functionality covering
+most aspects of GUI and non-GUI application programming. Sometimes,
+various aspects of these design goals contradict each other and this
+holds true especially for the Linux platform which – from the
+point of view of the desktop environment integration – is
+lagging behind the other two major desktops (Windows and MacOS X)
+mostly because of the schism between the GTK+ based GNOME desktop and
+the Qt<A HREF="http://www.trolltech.com/"><SUP>[5]</SUP></A> based
+KDE<A HREF="http://www.kde.org/"><SUP>[6]</SUP></A> desktop. So far,
+the typical wxWidgets user targeted Windows, maybe MacOS X and Linux
+<I>in general</I>, so the aim was to make wxGTK applications run as
+well as possible on as many versions of Linux as possible, including
+those using the KDE environment. Luckily, most of these distributions
+included the GTK+ library (for running applications like the GIMP,
+GAIM, Evolution or Mozilla) whereas the GNOME libraries were not
+always installed by default. Also, the GNOME libraries didn't really
+offer substantial value so that the hassle of installing them was
+hardly justified. Therefore, much effort was spent on making wxGTK
+fully functional without relying on the GNOME libraries, mostly by
+reimplementing as much as sensible of the missing functionality. This
+included a usable file selection dialog, a printing system for
+PostScript output, code for querying MIME-types and file-icon
+associations, classes for storing application preferences and
+configurations, the possibility to display mini-apps in the taskbar,
+a full-featured HTML based help system etc. With all that in place
+you can write a pretty fully featured wxWidgets application on an
+old Linux system with little more installed than X11 and GTK+.</P>
+<P STYLE="margin-top: 0.42cm; page-break-after: avoid"><FONT FACE="Albany, sans-serif"><FONT SIZE=4>Recent
+developments</FONT></FONT></P>
+<P>Recently, several key issues have been addressed by the GNOME
+project. Sometimes integrated into the newest GTK+ releases (such as
+the file selecter), sometimes as part of the GNOME libraries (such as
+the new printing system with Pango integration or the mime-types
+handling in gnome-vfs), sometimes as outside projects (such as the
+media/video backend based on the Gstreamer<A HREF="http://gstreamer.freedesktop.org/"><SUP>[7]</SUP></A>
+project). Also, care has been taken to unify the look and feel of
+GNOME applications by writing down a number of rules (modestly called
+„Human Interface Guidelines“<A HREF="http://developer.gnome.org/projects/gup/hig"><SUP>[8]</SUP></A>)
+and more and more decisions are taken in a desktop neutral way (for
+both GNOME and KDE), mostly as part of the FreeDesktop<A HREF="http://www.freedesktop.org/"><SUP>[9]</SUP></A>
+initiative. This development together with the rising number of
+OpenSource projects using wxWidgets mainly for the Linux and more
+specifically GNOME desktop has led to a change of direction within
+the wxWidgets project, now working on making more use of GNOME
+features when present. The general idea is to call the various GNOME
+libraries if they are present and to offer a reasonable fallback if
+not. I'll detail on the various methods chosen below:</P>
+<P STYLE="margin-top: 0.42cm; page-break-after: avoid"><FONT FACE="Albany, sans-serif"><FONT SIZE=4>Printing
+system</FONT></FONT></P>
+<P>The old printing system ....</P>
+<P STYLE="margin-top: 0.42cm; page-break-after: avoid"><FONT FACE="Albany, sans-serif"><FONT SIZE=4>MIME-type
+handling</FONT></FONT></P>
+<P>The old mime-type system used to simply query some files stored in
+„typical“ locations for the respective desktop
+environment. Since both the format and the location of these files
+changed rather frequently, this system was never fully working as
+desired for reading the MIME-types and it never worked at all for
+writing MIME-types or icon/file associations. ...</P>
+<P STYLE="margin-top: 0.42cm; page-break-after: avoid"><FONT FACE="Albany, sans-serif"><FONT SIZE=4>The
+new file dialog</FONT></FONT></P>
+<P>Previously, wxGTK application made use of a file dialog written in
+wxWidgets itself, since the default GTK+ file dialog was simplistic
+to say the least. This has changed with version GTK+ 2.4, where a
+nice and powerful dialog has been added. We now query the GTK+
+library, if the new file dialog functions are available and wxGTK
+applications will show and use them if that is the case, otherwise,
+they will fall back to the old generic one.</P>
+<P STYLE="margin-top: 0.42cm; page-break-after: avoid"><FONT FACE="Albany, sans-serif"><FONT SIZE=4>File
+configuration and preferences</FONT></FONT></P>
+<P>The usual Unix way of saving file configuration and preferences is
+to write and read a so called „dot-file“, basically a
+text file in a user's home directory starting with a dot. This was
+deemed insufficient by the GNOME desktop project and therefore they
+introduced the so called GConf system, for storing and retrieving
+application and sessions information....</P>
+<P STYLE="margin-top: 0.42cm; page-break-after: avoid"><FONT FACE="Albany, sans-serif"><FONT SIZE=4>Results
+and discussion</FONT></FONT></P>
+<P>One of wxWidgets' greatest merits is the ability to write an
+application that not only runs on different operating systems but
+especially under Linux even on rather old systems with only a minimal
+set of libraries installed – using a single application binary.
+This was possible since most of the relevant functionality was either
+located in the only required library (GTK+) or was implemented within
+wxWidgets. Recent development outside the actual GTK+ project has
+made it necessary to rethink this design and make use of other
+projects' features in order to stay uptodate with current
+techological trends. Therefore, a system was implemented within
+wxWidgets that queries the system at runtime about various libraries
+and makes use of their features whenever possible, but falls back to
+a reasonable solution if not. The result is that you can create and
+distribute application binaries that run on old Linux systems and
+integrate fully with modern desktops, if they are available. This is
+not currently possible with any other software.</P>
+<P>Copyright 2004 © Robert Roebling, MD. No reprint permitted
+without written prior authorisation.<BR>Last modified 14/11/04</P>
+<P STYLE="margin-top: 0.42cm; page-break-after: avoid"><FONT FACE="Albany, sans-serif"><FONT SIZE=4>About
+the author</FONT></FONT></P>
+<P>Robert Roebling works as a medical doctor in the Department of
+Neurology at the University clinic of Ulm in Germany. He has studied
+Computer Sciences for a few semesters and is involved in the
+wxWidgets projects since about 1996. He has started and written most
+of wxGTK port (beginning with GTK+ around 0.9) and has contributed to
+quite a number projects within wxWidgets, ranging from the image
+classes to Unicode support to making both the Windows and the GTK+
+ports work on embedded platform (mostly PDAs). He is happily married,
+has two children and never has time.</P>
+<P STYLE="margin-top: 0.42cm; page-break-after: avoid"><FONT FACE="Albany, sans-serif"><FONT SIZE=4>Links
+and citations</FONT></FONT></P>
+<P>[1] See the wxWidgets homepage at <A HREF="http://www.wxwidgets.org/">www.wxwidgets.org</A>.<BR>[2]
+See the GTK+ homepage at <A HREF="http://www.gtk.org/">www.gtk.org</A>.<BR>[3]
+See more about GNOME at <A HREF="http://www.gnome.org/">www.gnome.org</A>,
+<A HREF="http://www.gnomedesktop.org/">www.gnomedesktop.org</A>,
+<A HREF="http://www.gnomejournal.org/">www.gnomejournal.org</A>,
+<A HREF="http://www.gnomefiles.org/">www.gnomefiles.org</A>.<BR>[4]
+See the Pango homepage at <A HREF="http://www.pango.org/">www.pango.org</A>.<BR>[5]
+See the Qt homepage at <A HREF="http://www.trolltech.com/">www.trolltech.com</A>.<BR>[6]
+See the KDE homepage at <A HREF="http://www.kde.org/">www.kde.org</A>.<BR>[7]
+See Gstreamer homepage at <A HREF="http://gstreamer.freedesktop.org/">gstreamer.freedesktop.org</A>.<BR>[8]
+See GNOME's Human Interface Guidelines at
+<A HREF="http://developer.gnome.org/projects/gup/hig">developer.gnome.org/projects/gup/hig</A>.<BR>[9]
+See FreeDesktop's homepage at <A HREF="http://www.freedesktop.org/">www.freedesktop.org</A>.<BR><BR><BR>
+</P>
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