-|
+ |
-wxWindows 2 FAQ: General
+wxWidgets 2 FAQ: General
|
@@ -22,131 +23,97 @@ 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.
+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 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 wxWidgets: there is a Python interface for wxWidgets 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
+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 wxWindows 2 are the same whether you are a personal, academic
+The conditions for using wxWidgets 2 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
-wxWindows support is better than for much commercial software. The developers are
+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.
-
+
Many organisations - commercial, government, and academic - across the
-world. It's impossible to estimate the true number of users, since
-wxWindows is obtained by many different means, and we cannot monitor
+world. It's impossible to estimate the true number of users, since
+wxWidgets 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 wxWidgets 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
+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 wxWindows-compatible, it doesn't take much
+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
@@ -154,29 +121,29 @@ 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, 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 wxWindows are not up to the demands
-of today's sophisticated applications.
+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 wxWindows 2 is not a 'lowest common denominator' toolkit is that
+Another reason why wxWidgets 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
+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 undersirable to make
-wxWindows dependent on another large library that may have to be downloaded and installed.
+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
-wxWindows 2 is strenously trying to avoid.
+wxWidgets 2 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
@@ -184,46 +151,222 @@ 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 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
+
+
+
-
How is wxWindows 2 being developed?
-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
+
+
+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).
+
+
+
+
+
+
+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).
+
+
+
+
+
+
+We are using the CVS 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.
-
How is wxWindows 2 distributed?
+To build source from CVS, see the file BuildCVS.txt in the top-level wxWidgets distribution
+directory.
+
+
-By ftp, and via the wxWindows CD-ROM.
+By ftp, and via the wxWidgets CD-ROM.
+
+If you are feeling adventurous, you may also check out the sources directly
+from cvs.
+
-
What are the plans for the future?
+
-Currently we're working too hard on getting wxWindows 2 finished (are GUI toolkits ever
-finished?) to think very far ahead. However, we know we want to make wxWindows as robust
+Currently we're working too hard on getting wxWidgets finished (are GUI toolkits ever
+finished?) to think very far ahead. However, we know we want to make wxWidgets 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 wxWidgets 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
+We will investigate the possibility of compiler or operating system vendors bundling wxWidgets with
their product.
-The high-level goal of wxWindows is to be thought of as the number one C++ framework,
+The high-level goal of wxWidgets 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 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).
+
+
+
+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.
+
+
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 wxWindows is as high as ever.
+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.
+
+
+
+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.
-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 subscribe to the wx-dev developers' mailing list 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.
+
+Take a port that most closely matches your port, and strip out
+the implementation so you have a skeleton port that compiles. Ask on wx-dev
+first for the wxStubs port - however, any such predefined skeleton
+port may be out of date, so make a judgement on whether to use it.
+Perhaps it will still save you time to clean up wxStubs, and
+others may benefit from this too.
+
+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!