-|
+ |
-wxWindows 2 FAQ: General
+wxWindows 2 FAQ: General
|
@@ -22,21 +23,44 @@ wxWindows 2 FAQ: General
See also top-level FAQ page.
+List of questions in this category
+
+
wxWindows is a class library that allows you to compile graphical C++ programs on a range of
different platforms. wxWindows 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.
+so your program will take on the native 'look and feel' that users are familiar with.
-Although GUI applications are mostly built programmatically, there is a dialog editor to help
-build attractive dialogs and panels.
+Although GUI applications are mostly built programmatically, there are several dialog editors to help
+build attractive dialogs and panels. Robert Roebling's wxDesigner
+and Anthemion Software's DialogBlocks
+are two commercial examples, but there are others: see the Useful Tools page.
-You don't have to use C++ to use wxWindows: wxWindows 1 has been interfaced to several interpreted languages,
-such as CLIPS, Python, Scheme, XLisp and Perl, and there is a Python interface for wxWindows 2.
+You don't have to use C++ to use wxWindows: there is a Python interface for wxWindows 2,
+and also a Perl interface.
-
Can I use wxWindows 2 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 wxWindows
@@ -46,7 +70,7 @@ The conditions for using wxWindows 2 are the same whether you are a personal, ac
or commercial developer.
-
Is there support?
+
No official support, but the mailing list is very helpful and some people say that
wxWindows support is better than for much commercial software. The developers are
@@ -56,97 +80,39 @@ keen to fix bugs as soon as possible, though obviously there are no guarantees.
Many organisations - commercial, government, and academic - across the
-world. It's impossible to estimate the true number of users, since
+world. It's impossible to estimate the true number of users, since
wxWindows is obtained by many different means, and we cannot monitor
distribution. The mailing list contains around 300-400 entries which is
quite large for a list of this type.
-
I am about to start a wxWindows 1.xx project. Should I use 2 instead?
-
-wxWindows 2 is still in beta but it's actually pretty useable (Windows, GTK, Motif).
-
-Porting to wxWindows 2 from 1.xx will not be too painful; see the next question
-for ways in which you can make it easier.
-
-
Why would I want to use wxWindows 2 in preference to wxWindows 1.xx?
-
-Some reasons:
-
-
-- In 2 there is far more flexibility, for example in the way windows can be
-nested, and the way events are intercepted.
-
- There is more functionality for producing sophisticated applications,
-for example using the wxTreeCtrl and wxListCtrl classes.
-
- There is better C++-conformance (such as usage of wxString and const) which
-will make your applications more reliable and easier to maintain.
-
- wxWindows 2 will be better supported than 1.xx.
-
- The GTK version is attractive for people interested in writing Linux and GNOME
-applications.
-
- The Mac version will be one of the best frameworks available on that platform.
-
-
-How can I prepare for wxWindows 2?
-
-To make porting to wxWindows 2 easier in the future, take a look at some
-tips for writing existing code in a 2-compatible way.
-
-
How much has the API changed since 1.xx?
-
-It's difficult to summarize, but some aspects haven't changed very much. For example, if you have some
-complex drawing code, you will mostly need to make sure it's parameterised with a device
-context (instead of obtaining one from a window or storing it). You won't have
-to completely rewrite the drawing code.
-
-The way that events are handled has changed, so for example, where you overrode
-OnSize before, you now have a non-virtual OnSize with a single event class argument.
-To make this function known to wxWindows, you add an entry in an 'event table' using macros. Addition of these macros
-will eventually be made easier by a tool which will allow selection from a list
-and copy-and-paste into your editor. This is extended to button presses, listbox selection
-etc. so callbacks have gone (they may be added back for limited backward compatibility).
-
-The class hierarchy has changed to allow greater flexibility but it probably won't affect your
-existing application. One exception to this is MDI applications which now use separate MDI classes instead of style
-flags. As a result, it won't be possible to switch between MDI and SDI operation at run-time
-without further coding, but a benefit is less interdependence between areas of code,
-and therefore smaller executable size.
-
-Panel items (now called controls) no longer have labels associated with most of them,
-and default panel layout has been removed. The idea is that you make greater use
-of dialog resources, for better-looking dialogs.
-
-
What classes have disappeared?
-
-wxForm, wxTextWindow (subsumed into wxTextCtrl).
-
-Does wxWindows 2 mean that wxWindows 1.xx is dead?
-
-While wxWindows 2 is being developed, there will be further patches to wxWindows 1.xx.
-Obviously we are investing most of our energy into the new code, but we're also trying
-to fix bugs in the current version.
+See Users for a list of some users and their applications, and
+also Feedback for comments.
+Our highest-profile user yet is industry veteran and Lotus Corp. founder Mitch Kapor
+and his Open Source Applications Foundation.
+
-
What platforms will be supported by wxWindows 2?
+
-- Windows 3.1, Windows 95/98, Windows NT;
-
- Linux and other Unix platforms with GTK+;
-
- Unix with Motif or the free Motif clone Lesstif;
-
- Mac (coming later in 1999);
-
- A BeOS port is being investigated.
-
- A Windows CE port is being investigated.
-
- There are no plans to support OS/2 or XView. However,
-you may be able to compile the GTK and Motif versions under OS/2 with X and GTK
-installed, or the Windows version with IBM's Open32 extensions.
+
- Windows 3.1, Windows 95/98, Windows NT, Windows 2000, Windows ME.
+
- Linux and other Unix platforms with GTK+.
+
- Unix with Motif or the free Motif clone Lesstif.
+
- Mac OS.
+
- Embedded platforms are being investigated. See the wxUniversal project.
+
- An OS/2 port is in progress, and you can also compile wxWindows for GTK+ or Motif
+on OS/2.
-
How does wxWindows 2 support platform-specific features?
+
This is a hotly-debated topic amongst the developers. My own philosophy
is to make wxWindows 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 wxWindows-compatible, it doesn't take much
+are provided and are wxWindows-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
@@ -154,24 +120,24 @@ 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, wxWindows is not a 'lowest common denominator' approach,
+In other words, wxWindows 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 wxWindows are not up to the demands
-of today's sophisticated applications.
+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 wxWindows 2 is not a 'lowest common denominator' toolkit is that
+Another reason why wxWindows 2 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 wxWindows 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
-wxWindows' best interests to avoid use of templates. Not all compilers can handle
+wxWindows' 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 undersirable to make
wxWindows dependent on another large library that may have to be downloaded and installed.
@@ -184,28 +150,91 @@ by being able to modify our own string class. Some compatibility with the string
has been built into wxString.
There is nothing to stop an application using templates or the string class for its own
-purposes.
+purposes. With wxWindows 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
+
-How is wxWindows 2 being developed?
+
+
+
+
+
+These are the possibilities so far:
+
+
+- See www.scintilla.org for
+a very nice syntax-highlighting editor widget. Robin Dunn has written a wxWindows wrapper
+for this widget, available in the wxWindows 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 wxWindows - 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 wxWindows wrapper for these (but text attribute functions are being added in the wxWindows 2.3.x series).
+
+
+
+
+
+
+wxWindows 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
+wxWindows.
+
+
+There are a few issues to keep in mind, though:
+
+ - You shouldn't let the exceptions propagate through wxWindows 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 wxWindows.
+
+
- You may need to ensure that the compiler support for the exceptions is
+ enabled as, considering that wxWindows 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).
+
+
+
+
+
We are using the CVS system to develop and maintain wxWindows. This allows
-us to make alterations and upload them instantly to the server in Edinburgh, from
+us to make alterations and upload them instantly to the server, from
which others can update their source.
-
How is wxWindows 2 distributed?
+To build source from CVS, see the file BuildCVS.txt in the top-level wxWindows distribution
+directory.
-By ftp, and via the wxWindows CD-ROM.
+
-What are the plans for the future?
+By ftp, and via the wxWindows CD-ROM.
+
+If you are feeling adventurous, you may also check out the sources directly
+from cvs.
+
+
+
-Currently we're working too hard on getting wxWindows 2 finished (are GUI toolkits ever
+Currently we're working too hard on getting wxWindows finished (are GUI toolkits ever
finished?) to think very far ahead. However, we know we want to make wxWindows as robust
and well-publicised as possible. We also want to aim for better platform-independence of
-resources such as icons and bitmaps, standardising on the PNG for all platforms.
+resources such as icons and bitmaps, standardising on PNG and XPM for all platforms.
-Other possibilities include: DCOM/CORBA compatibility; a wxWindows book; an
-IDE;
-other platforms; other interface abilities such as speech output.
+Other possibilities include: DCOM/CORBA compatibility; a wxWindows book;
+wxWorkshop, an IDE;
+other platforms, especially embedded systems; other interface abilities such as speech output.
We will investigate the possibility of compiler or operating system vendors bundling wxWindows with
their product.
@@ -213,17 +242,76 @@ their product.
The high-level goal of wxWindows is to be thought of as the number one C++ framework,
for virtually any platform. Move over, MFC!
-
What about Java?
+
+
+wxBase is a subset of wxWindows comprised by the non-GUI classes. It includes
+wxWindows 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 wxWindows 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 wxWindows port).
+
+
+
+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
+wxWindows 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 wxWindows 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.
+
+
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
+meet all their cross-platform development needs. We don't anticipate a major threat
from Java, and the level of interest in wxWindows is as high as ever.
-
How can I help the project?
+
+
+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 wxWindows 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
+wxWindows (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 wxWindows does not require.
+
- Mono hasn't proven its long-term viability yet (it's a complex system of components); wxWindows 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 wxWindows 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 wxWindows!)
+
+
+There is nothing to stop folk from developing a C# version of the wxWindows API;
+we already have bindings to Python, Perl, JavaScript, Lua, Basic, and Eiffel.
+Update: a wx.NET project is now in progress.
+
+
+
+
-Please check out the Backroom pages,
-in particular the suggested projects, and
-mail Julian Smart or the developers' mailing list with your own suggestions.
+Please check out the Community pages,
+in particular the suggested projects, and
+mail the developers' mailing list with your own suggestions.