
General FAQ
See also top-level FAQ page.
List of questions in this category
What is wxWidgets?
wxWidgets is a class library that allows you to compile graphical C++
programs on a range of different platforms. wxWidgets defines a common API
across platforms, but uses the native graphical user interface (GUI) on each
platform, so your program will take on the native 'look and feel' that
users are familiar with.
Although GUI applications are mostly built programmatically, there are
several dialog editors to help build attractive dialogs and panels. wxDesigner Software's
wxDesigner and Anthemion
Software's DialogBlocks
are two commercial examples, but there are others, see the wiki
tools page for some of them.
You don't have to use C++ to use wxWidgets: there is a
Python interface for wxWidgets, and also a
Perl interface.
Can I use wxWidgets for both proprietary (commercial) projects, and GPL'ed projects?
Yes. Please see the licence for
details, but basically you can distribute proprietary binaries without
distributing any source code, and neither will wxWidgets conflict with GPL
code you may be using or developing with it.
The conditions for using wxWidgets are the same whether you are a
personal, academic or commercial developer.
Is there support?
No official support, but the mailing list is very helpful and some people
say that wxWidgets support is better than for much commercial software. The
developers are keen to fix bugs as soon as possible, though obviously there
are no guarantees.
Who uses wxWidgets?
Many organisations - commercial, government, and academic - across the
world. It's impossible to estimate the true number of users, since wxWidgets
is obtained by many different means, and we cannot monitor distribution.
See the Users page for a list of some
users and their applications, and also the
Feedback page for comments.
Our highest-profile user yet is industry veteran and Lotus Corp. founder
Mitch Kapor and his Open Source Applications Foundation.
What platforms are supported by wxWidgets?
- Windows 95/98/ME, NT, 2000, XP, and Vista.
- Linux and other Unix platforms with GTK+.
- Unix with Motif or the free Motif clone Lesstif.
- Mac OS X 10.3 and above (10.2 with the older 2.6 versions).
- Embedded platforms are being investigated, see the
wxUniversal project.
- An OS/2 port is in progress, and you can also compile wxWidgets for
GTK+ or Motif on OS/2.
How does wxWidgets support platform-specific features?
This is a hotly-debated topic amongst the developers. My own philosophy is
to make wxWidgets as platform-independent as possible, but allow in a few
classes (functions, window styles) that are platform-specific. For example,
Windows metafiles and Windows 95 taskbar icons have their own classes on
Windows, but nowhere else. Because these classes are provided and are
wxWidgets-compatible, it doesn't take much coding effort for an application
programmer to add support for some functionality that the user on a particular
platform might otherwise miss. Also, some classes that started off as
platform-specific, such as the MDI classes, have been emulated on other
platforms. I can imagine that even wxTaskBarIcon may be implemented for Unix
desktops one day.
In other words, wxWidgets is not a 'lowest common denominator' approach,
but it will still be possible to write portable programs using the core API.
Forbidding some platform-specific classes would be a stupid approach that
would alienate many potential users, and encourage the perception that
toolkits such as wxWidgets are not up to the demands of today's sophisticated
applications.
Currently resources such as bitmaps and icons are handled in a
platform-specific way, but it is hoped to reduce this dependence in due
course.
Another reason why wxWidgets is not a 'lowest common denominator' toolkit
is that some functionality missing on some platform has been provided using
generic, platform-independent code, such as the wxTreeCtrl and wxListCtrl
classes.
Does wxWidgets use STL, or the standard string class?
No. This is a much-discussed topic that has (many times) ended with the
conclusion that it is in wxWidgets' best interests to avoid use of templates.
Not all compilers can handle templates adequately so it would dramatically
reduce the number of compilers and platforms that could be supported. It would
also be undesirable to make wxWidgets dependent on another large library that
may have to be downloaded and installed. In addition, use of templates can
lead to executable bloat, which is something wxWidgets is strenuously trying
to avoid.
The standard C++ string class is not used, again because it is not
available to all compilers, and it is not necessarily a very efficient
implementation. Also, we retain more flexibility by being able to modify our
own string class. Some compatibility with the string class has been built into
wxString.
There is nothing to stop an application using templates or the string class
for its own purposes. With wxWidgets debugging options on, you may find you
get errors when including STL headers. You can work around it either by
switching off memory checking, or by adding this to a header before you
include any STL files:
#ifdef new
#undef new
#endif
Is there a rich edit/markup widget for wxWidgets?
These are the possibilities so far:
- See www.scintilla.org
for a very nice syntax-highlighting editor widget. Robin Dunn has
written a wxWidgets wrapper for this widget, available in the wxWidgets
distribution under contrib/src/stc.
- If you only need to display marked-up information, rather than edit it,
then wxHTML will suit your needs. wxHTML is built into wxWidgets - please
see the reference manual for details, and samples/html.
- There are rich edit widgets in both WIN32 and GTK+, but there is
currently no wxWidgets wrapper for these (but text attribute functions
are being added in the wxWidgets 2.3.x series).
How to use C++ exceptions with wxWidgets?
wxWidgets library itself is unfortunately not exception-safe (as its
initial version predates, by far, the addition of the exceptions to the C++
language). However you can still use the exceptions in your own code and use
the other libraries using the exceptions for the error reporting together with
wxWidgets.
There are a few issues to keep in mind, though:
- You shouldn't let the exceptions propagate through wxWidgets code, in
particular you should always catch the exceptions thrown by the
functions called from an event handler in the handler itself and not let
them propagate upwards to wxWidgets.
- You may need to ensure that the compiler support for the exceptions is
enabled as, considering that wxWidgets itself doesn't use the exceptions
and turning their support on results in the library size augmentation of
10% to 20%, it is turned off by default for a few compilers. Moreover,
for gcc (or at least its mingw version) you must also turn on the RTTI
support to be able to use the exceptions, so you should use
--disable-no_rtti --disable-no_exceptions options when
configuring the library (attention to the double negation).
How is wxWidgets being developed?
We are using the SVN system to develop and
maintain wxWidgets. This allows us to make alterations and upload them
instantly to the server, from which others can update their source.
To build source from SVN, see the BuildSVN.txt file in the top-level
wxWidgets distribution directory.
How is wxWidgets distributed?
You can download wxWidgets from our downloads
page. If you are feeling adventurous, you may also check out the sources
directly from SVN.
What is wxBase?
wxBase is a subset of wxWidgets comprised by the non-GUI classes. It
includes wxWidgets container and primitive data type classes (including
wxString, wxDateTime and so on) and also useful wrappers for the operating
system objects such as files, processes, threads, sockets and so on. With very
minor exceptions wxBase may be used in exactly the same way as wxWidgets but
it doesn't require a GUI to run and so is ideal for creating console mode
utilities or server programs. It is also possible to create a program which
can be compiled either as a console application (using wxBase) or a GUI one
(using a full featured wxWidgets port).
What is wxUniversal?
The main difference between wxUniversal-based ports (such as wxX11, wxMGL)
and other ports (such as wxMSW, wxGTK+, wxMac) is that wxUniversal implements
all controls (or widgets) in wxWidgets itself thus allowing to have much more
flexibility (for example, support for themes even under MS Windows). It also
means that it is now much easier to port wxWidgets to a new platform as only
the low-level classes must be ported which make for a small part of the
library.
You may find more about wxUniversal
here.
What about Java?
The Java honeymoon period is over :-) and people are realising that it
cannot meet all their cross-platform development needs. We don't anticipate a
major threat from Java, and the level of interest in wxWidgets is as high as
ever.
What about .NET/Mono?
Microsoft is spending a lot on promoting the .NET initiative, which is a
set of languages, APIs and web service components for Windows. Ximian has
started an open source version of .NET, mostly for Linux. C# is Microsoft's
alternative to Java, supporting 'managed code', garbage collection and
various other Java-like language features.
Although this may be attractive to some developers, there is a variety of
reasons why the .NET/Mono combination is unlikely to make wxWidgets redundant.
Please note that the following comments are Julian Smart's opinions.
- Not everyone wants or needs net services.
- C++ will be used for a long time to come; compared with C++, C# is a
recent development and its future is not certain.
- Mono Forms may only target Winelib (at least to begin with), so the end
result is not as native as wxWidgets (I'm aware there is GTK# for use
with the C# language).
- C# is usually byte-compiled and therefore slower. Plus, .NET adds a
layer of overhead to the client computer that wxWidgets does not
require.
- Mono hasn't proven its long-term viability yet (it's a complex system of
components); wxWidgets is ready now.
- You may not wish to buy into Microsoft marketing spin and APIs.
- Microsoft may at some point sue developers of non-Microsoft .NET
implementations. After all, platform-independence is not in Microsoft's
interest.
- .NET might never be implemented on some platforms, especially Mac and
embedded variants of Linux.
- wxPython and other language variants provide further reasons for
wxWidgets to continue.
- The same issue exists for Qt: if Qt sales remain strong, it's a good
indication that the market for a C++ based approach is still there.
(Either that, or everyone's turning to wxWidgets!)
There is nothing to stop folk from developing a C# version of the wxWidgets
API. We already have bindings to Python, Perl, JavaScript, Lua, Basic, and
Eiffel. Update: A wx.NET
project is now in progress.
How can I help the project?
Please check out the Community pages, in
particular the suggested projects,
and mail the developers' mailing list with your own suggestions.
How do I start a new port?
Please subscribe to the developers' mailing list
(wx-dev) and ask if anyone else is interested in helping with the port, or has
specific suggestions. Also please read the
coding standards.
Each port consists of a platform-specific part (e.g. src/msw,
include/wx/msw), a generic set of widgets and dialogs for when the port
doesn't support them natively (src/generic, include/wx/generic) and the common
code that all ports use (src/common, include/wx). By browsing the source you
should get a good idea of the general pattern.
To kick start a new port development one possible strategy is to take a port
that most closely matches your port, and strip out the implementation so you
have a skeleton port that compiles, and then start implementing the classes
using your target platform native API.
You will need to define a symbol for the new port, e.g. __WXXBOX__. Look at
files such as wx/defs.h, wx/wxchar.h for areas where you'll need to add to
existing conditionals to set up wide character support and other issues. If
the GUI runs on a Unix variant, define the __UNIX__ variable in your
makefile.
Then you can start implementing the port, starting with wxWindow,
wxTopLevelWindow, wxFrame, wxDialog so you can get the minimal sample running
as soon as possible.
If GDI objects (wxPen, wxBrush, etc.) are not concepts in your native GUI,
you may wish to use very generic versions of some of these - see the wxX11
port.
Consider using the wxUniversal widget set as a quick way to implement
wxWidgets on your platform. You only need to define some basic classes such as
device contexts, wxWindow, wxTopLevelWindow, GDI objects etc. and the actual
widgets will be drawn for you. See wxX11, wxMGL, and wxMSW/Univ for sample
wxUniversal ports.
To begin with, you can use whatever makefiles or project files work for
you. Look at existing makefiles to see what generic/common/Unix files need to
be included. Later, you'll want to integrate support for your port into
configure (Unix-like systems and gcc under Windows), and bakefile (for other
makefiles on Windows).
Submit your port as patches via SourceForge; you might wish to separate it
into one patch that touches common headers and source files, and another
containing the port-specific code, to make it much easier for us to review and
apply the patches.
Good luck!