]> git.saurik.com Git - wxWidgets.git/blob - docs/latex/wx/body.tex
I think I found out how GTK+ want popup windows
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1 \chapter{Introduction}\label{introduction}
2 \pagenumbering{arabic}%
3 \setheader{{\it CHAPTER \thechapter}}{}{}{}{}{{\it CHAPTER \thechapter}}%
4 \setfooter{\thepage}{}{}{}{}{\thepage}%
5
6 \section{What is wxWidgets?}\label{whatis}
7
8 wxWidgets is a C++ framework providing GUI (Graphical User
9 Interface) and other facilities on more than one platform. Version 2 currently
10 supports all desktop versions of MS Windows, Unix with GTK+, Unix with Motif,
11 and MacOS. An OS/2 port is in progress.
12
13 wxWidgets was originally developed at the Artificial Intelligence
14 Applications Institute, University of Edinburgh, for internal use,
15 and was first made publicly available in 1992.
16 Version 2 is a vastly improved version written and maintained by
17 Julian Smart, Robert Roebling, Vadim Zeitlin, Vaclav Slavik and many others.
18
19 This manual contains a class reference and topic overviews.
20 For a selection of wxWidgets tutorials, please see the documentation page on the \urlref{wxWidgets web site}{http://www.wxwidgets.org}.
21
22 Please note that in the following, ``MS Windows" often refers to all
23 platforms related to Microsoft Windows, including 16-bit and 32-bit
24 variants, unless otherwise stated. All trademarks are acknowledged.
25
26 \section{Why another cross-platform development tool?}\label{why}
27
28 wxWidgets was developed to provide a cheap and flexible way to maximize
29 investment in GUI application development. While a number of commercial
30 class libraries already existed for cross-platform development,
31 none met all of the following criteria:
32
33 \begin{enumerate}\itemsep=0pt
34 \item low price;
35 \item source availability;
36 \item simplicity of programming;
37 \item support for a wide range of compilers.
38 \end{enumerate}
39
40 Since wxWidgets was started, several other free or almost-free
41 GUI frameworks have emerged. However, none has the range of
42 features, flexibility, documentation and the well-established
43 development team that wxWidgets has.
44
45 As open source software, wxWidgets has benefited from comments,
46 ideas, bug fixes, enhancements and the sheer enthusiasm of
47 users. This gives wxWidgets a certain advantage over its
48 commercial competitors (and over free libraries without an
49 independent development team), plus a robustness against the
50 transience of one individual or company. This openness and
51 availability of source code is especially important when the
52 future of thousands of lines of application code may depend upon
53 the longevity of the underlying class library.
54
55 Version 2 goes much further than previous versions in terms of
56 generality and features, allowing applications to be produced
57 that are often indistinguishable from those produced using
58 single-platform toolkits such as Motif, GTK+ and MFC.
59
60 The importance of using a platform-independent class library
61 cannot be overstated, since GUI application development is very
62 time-consuming, and sustained popularity of particular GUIs
63 cannot be guaranteed. Code can very quickly become obsolete if
64 it addresses the wrong platform or audience. wxWidgets helps to
65 insulate the programmer from these winds of change. Although
66 wxWidgets may not be suitable for every application (such as an
67 OLE-intensive program), it provides access to most of the
68 functionality a GUI program normally requires, plus many extras
69 such as network programming, PostScript output, and HTML
70 rendering; and it can of course be extended as needs dictate.
71 As a bonus, it provides a far cleaner and easier programming
72 interface than the native APIs. Programmers may find it
73 worthwhile to use wxWidgets even if they are developing on only
74 one platform.
75
76 It is impossible to sum up the functionality of wxWidgets in a few paragraphs, but
77 here are some of the benefits:
78
79 \begin{itemize}\itemsep=0pt
80 \item Low cost (free, in fact!)
81 \item You get the source.
82 \item Available on a variety of popular platforms.
83 \item Works with almost all popular C++ compilers and Python.
84 \item Over 50 example programs.
85 \item Over 1000 pages of printable and on-line documentation.
86 \item Includes Tex2RTF, to allow you to produce your own documentation
87 in Windows Help, HTML and Word RTF formats.
88 \item Simple-to-use, object-oriented API.
89 \item Flexible event system.
90 \item Graphics calls include lines, rounded rectangles, splines, polylines, etc.
91 \item Constraint-based and sizer-based layouts.
92 \item Print/preview and document/view architectures.
93 \item Toolbar, notebook, tree control, advanced list control classes.
94 \item PostScript generation under Unix, normal MS Windows printing on the PC.
95 \item MDI (Multiple Document Interface) support.
96 \item Can be used to create DLLs under Windows, dynamic libraries on Unix.
97 \item Common dialogs for file browsing, printing, colour selection, etc.
98 \item Under MS Windows, support for creating metafiles and copying
99 them to the clipboard.
100 \item An API for invoking help from applications.
101 \item Ready-to-use HTML window (supporting a subset of HTML).
102 \item Network support via a family of socket and protocol classes.
103 \item Support for platform independent image processing.
104 \item Built-in support for many file formats (BMP, PNG, JPEG, GIF, XPM, PNM, PCX).
105 \end{itemize}
106
107 \begin{comment}
108 \section{Changes from version 2.0}\label{versionchanges20}
109
110 These are a few of the differences between versions 2.0 and 2.2.
111
112 Removals:
113
114 \begin{itemize}\itemsep=0pt
115 \item GTK 1.0 no longer supported.
116 \end{itemize}
117
118 Additions and changes:
119
120 \begin{itemize}\itemsep=0pt
121 \item Corrected many classes to conform better to documented behaviour.
122 \item Added handlers for more image formats (Now GIF, JPEG, PCX, BMP, XPM, PNG, PNM).
123 \item Improved support for socket and network functions.
124 \item Support for different national font encodings.
125 \item Sizer based layout system.
126 \item HTML widget and help system.
127 \item Added some controls (e.g. wxSpinCtrl) and supplemented many.
128 \item Many optical improvements to GTK port.
129 \item Support for menu accelerators in GTK port.
130 \item Enhanced and improved support for scrolling, including child windows.
131 \item Complete rewrite of clipboard and drag and drop classes.
132 \item Improved support for ODBC databases.
133 \item Improved tab traversal in dialogs.
134 \end{itemize}
135 \end{comment}
136
137 \section{wxWidgets requirements}\label{requirements}
138
139 To make use of wxWidgets, you currently need one of the following setups.
140
141 (a) MS-Windows:
142
143 \begin{enumerate}\itemsep=0pt
144 \item A 32-bit or 64-bit PC running MS Windows.
145 \item A Windows compiler: MS Visual C++ (embedded Visual C++ for wxWinCE
146 port), Borland C++, Watcom C++, Cygwin, MinGW, Metrowerks CodeWarrior,
147 Digital Mars C++. See {\tt install.txt} for details about compiler
148 version supported.
149 \item At least 100 MB of disk space for source tree and additional space for
150 libraries and application building (depends on compiler and build settings).
151 \end{enumerate}
152
153 (b) Unix:
154
155 \begin{enumerate}\itemsep=0pt
156 \item Almost any C++ compiler, including GNU C++ (EGCS 1.1.1 or above).
157 \item Almost any Unix workstation, and one of: GTK+ 1.2, GTK+ 2.0, Motif 1.2 or higher, Lesstif.
158 If using the wxX11 port, no such widget set is required.
159 \item At least 100 MB of disk space for source tree and additional space for
160 libraries and application building (depends on compiler and build settings).
161 \end{enumerate}
162
163 (c) Mac OS/Mac OS X:
164
165 \begin{enumerate}\itemsep=0pt
166 \item A PowerPC Mac running Mac OS 8.6/9.x (eg. Classic) or Mac OS X 10.x.
167 \item CodeWarrior 5.3, 6 or 7 for Classic Mac OS.
168 \item The Apple Developer Tools (eg. GNU C++), CodeWarrior 7 or above for Mac OS X.
169 \item At least 100 MB of disk space for source tree and additional space for
170 libraries and application building (depends on compiler and build settings).
171 \end{enumerate}
172
173 \section{Availability and location of wxWidgets}\label{where}
174
175 \winhelponly{wxWidgets is available by anonymous FTP and World Wide Web
176 from ftp://biolpc22.york.ac.uk/pub and/or http://www.wxwidgets.org.}
177 \winhelpignore{wxWidgets is available by anonymous FTP and World Wide Web
178 from \urlref{ftp://biolpc22.york.ac.uk/pub}{ftp://biolpc22.york.ac.uk/pub}
179 and/or \urlref{http://www.wxwidgets.org}{http://www.wxwidgets.org}.}
180
181 You can also buy a CD-ROM using the form on the Web site.
182
183 \section{Acknowledgements}\label{acknowledgements}
184
185 Thanks are due to AIAI for being willing to release the original version of
186 wxWidgets into the public domain, and to our patient partners.
187
188 We would particularly like to thank the following for their contributions to wxWidgets, and the many others who have been involved in
189 the project over the years. Apologies for any unintentional omissions from this list.
190
191 Yiorgos Adamopoulos, Jamshid Afshar, Alejandro Aguilar-Sierra, AIAI,
192 Patrick Albert, Karsten Ballueder, Mattia Barbon, Michael Bedward,
193 Kai Bendorf, Yura Bidus, Keith Gary Boyce, Chris Breeze, Pete Britton,
194 Ian Brown, C. Buckley, Marco Cavallini, Dmitri Chubraev, Robin Corbet, Cecil Coupe,
195 Stefan Csomor, Andrew Davison, Gilles Depeyrot, Neil Dudman, Robin Dunn,
196 Hermann Dunkel, Jos van Eijndhoven, Chris Elliott, David Elliott, Tom Felici,
197 Thomas Fettig, Matthew Flatt, Pasquale Foggia, Josep Fortiana, Todd Fries,
198 Dominic Gallagher, Guillermo Rodriguez Garcia, Wolfram Gloger, Norbert Grotz,
199 Stefan Gunter, Bill Hale, Patrick Halke, Stefan Hammes, Guillaume Helle,
200 Harco de Hilster, Cord Hockemeyer, Markus Holzem, Olaf Klein, Leif Jensen,
201 Bart Jourquin, Guilhem Lavaux, Ron Lee, Jan Lessner, Nicholas Liebmann,
202 Torsten Liermann, Per Lindqvist, Thomas Runge, Tatu M\"{a}nnist\"{o},
203 Scott Maxwell, Thomas Myers, Oliver Niedung, Stefan Neis, Hernan Otero,
204 Ian Perrigo, Timothy Peters, Giordano Pezzoli, Harri Pasanen, Thomaso Paoletti,
205 Garrett Potts, Marcel Rasche, Robert Roebling, Dino Scaringella,
206 Jobst Schmalenbach, Arthur Seaton, Paul Shirley, Wlodzimierz `ABX' Skiba,
207 Vaclav Slavik, Julian Smart, Stein Somers, Petr Smilauer, Neil Smith,
208 Kari Syst\"{a}, George Tasker, Arthur Tetzlaff-Deas, Jonathan Tonberg,
209 Jyrki Tuomi, Janos Vegh, Andrea Venturoli, David Webster, Otto Wyss,
210 Vadim Zeitlin, Xiaokun Zhu, Edward Zimmermann.
211
212 `Graphplace', the basis for the wxGraphLayout library, is copyright Dr. Jos
213 T.J. van Eijndhoven of Eindhoven University of Technology. The code has
214 been used in wxGraphLayout with his permission.
215
216 We also acknowledge the author of XFIG, the excellent Unix drawing tool,
217 from the source of which we have borrowed some spline drawing code.
218 His copyright is included below.
219
220 {\it XFig2.1 is copyright (c) 1985 by Supoj Sutanthavibul. Permission to
221 use, copy, modify, distribute, and sell this software and its
222 documentation for any purpose is hereby granted without fee, provided
223 that the above copyright notice appear in all copies and that both that
224 copyright notice and this permission notice appear in supporting
225 documentation, and that the name of M.I.T. not be used in advertising or
226 publicity pertaining to distribution of the software without specific,
227 written prior permission. M.I.T. makes no representations about the
228 suitability of this software for any purpose. It is provided ``as is''
229 without express or implied warranty.}
230
231 \chapter{Multi-platform development with wxWidgets}\label{multiplat}
232 \setheader{{\it CHAPTER \thechapter}}{}{}{}{}{{\it CHAPTER \thechapter}}%
233 \setfooter{\thepage}{}{}{}{}{\thepage}%
234
235 This chapter describes the practical details of using wxWidgets. Please
236 see the file install.txt for up-to-date installation instructions, and
237 changes.txt for differences between versions.
238
239 \section{Include files}\label{includefiles}
240
241 The main include file is {\tt "wx/wx.h"}; this includes the most commonly
242 used modules of wxWidgets.
243
244 To save on compilation time, include only those header files relevant to the
245 source file. If you are using precompiled headers, you should include
246 the following section before any other includes:
247
248 \begin{verbatim}
249 // For compilers that support precompilation, includes "wx.h".
250 #include <wx/wxprec.h>
251
252 #ifdef __BORLANDC__
253 #pragma hdrstop
254 #endif
255
256 #ifndef WX_PRECOMP
257 // Include your minimal set of headers here, or wx.h
258 #include <wx/wx.h>
259 #endif
260
261 ... now your other include files ...
262 \end{verbatim}
263
264 The file {\tt "wx/wxprec.h"} includes {\tt "wx/wx.h"}. Although this incantation
265 may seem quirky, it is in fact the end result of a lot of experimentation,
266 and several Windows compilers to use precompilation which is largely automatic for
267 compilers with necessary support. Currently it is used for Visual C++ (including
268 embedded Visual C++), Borland C++, Open Watcom C++ and newer versions of GCC.
269
270 \section{Libraries}\label{libraries}
271
272 Most ports of wxWidgets can create either a static library or a shared
273 library. wxWidgets can also be built in multilib and monolithic variants.
274 See the \helpref{libraries list}{librarieslist} for more
275 information on these.
276
277 \section{Configuration}\label{configuration}
278
279 When using project files and makefiles directly to build wxWidgets,
280 options are configurable in the file
281 \rtfsp{\tt "wx/XXX/setup.h"} where XXX is the required platform (such as msw, motif, gtk, mac). Some
282 settings are a matter of taste, some help with platform-specific problems, and
283 others can be set to minimize the size of the library. Please see the setup.h file
284 and {\tt install.txt} files for details on configuration.
285
286 When using the 'configure' script to configure wxWidgets (on Unix and other platforms where
287 configure is available), the corresponding setup.h files are generated automatically
288 along with suitable makefiles. When using the RPM packages
289 for installing wxWidgets on Linux, a correct setup.h is shipped in the package and
290 this must not be changed.
291
292 \section{Makefiles}\label{makefiles}
293
294 On Microsoft Windows, wxWidgets has a different set of makefiles for each
295 compiler, because each compiler's 'make' tool is slightly different.
296 Popular Windows compilers that we cater for, and the corresponding makefile
297 extensions, include: Microsoft Visual C++ (.vc), Borland C++ (.bcc),
298 OpenWatcom C++ (.wat) and MinGW/Cygwin (.gcc). Makefiles are provided
299 for the wxWidgets library itself, samples, demos, and utilities.
300
301 On Linux, Mac and OS/2, you use the 'configure' command to
302 generate the necessary makefiles. You should also use this method when
303 building with MinGW/Cygwin on Windows.
304
305 We also provide project files for some compilers, such as
306 Microsoft VC++. However, we recommend using makefiles
307 to build the wxWidgets library itself, because makefiles
308 can be more powerful and less manual intervention is required.
309
310 On Windows using a compiler other than MinGW/Cygwin, you would
311 build the wxWidgets library from the build/msw directory
312 which contains the relevant makefiles.
313
314 On Windows using MinGW/Cygwin, and on Unix, MacOS X and OS/2, you invoke
315 'configure' (found in the top-level of the wxWidgets source hierarchy),
316 from within a suitable empty directory for containing makefiles, object files and
317 libraries.
318
319 For details on using makefiles, configure, and project files,
320 please see docs/xxx/install.txt in your distribution, where
321 xxx is the platform of interest, such as msw, gtk, x11, mac.
322
323 \section{Windows-specific files}\label{windowsfiles}
324
325 wxWidgets application compilation under MS Windows requires at least two
326 extra files, resource and module definition files.
327
328 \subsection{Resource file}\label{resources}
329
330 The least that must be defined in the Windows resource file (extension RC)
331 is the following statement:
332
333 \begin{verbatim}
334 #include "wx/msw/wx.rc"
335 \end{verbatim}
336
337 which includes essential internal wxWidgets definitions. The resource script
338 may also contain references to icons, cursors, etc., for example:
339
340 \begin{verbatim}
341 wxicon icon wx.ico
342 \end{verbatim}
343
344 The icon can then be referenced by name when creating a frame icon. See
345 the MS Windows SDK documentation.
346
347 \normalbox{Note: include wx.rc {\it after} any ICON statements
348 so programs that search your executable for icons (such
349 as the Program Manager) find your application icon first.}
350
351 \section{Allocating and deleting wxWidgets objects}\label{allocatingobjects}
352
353 In general, classes derived from wxWindow must dynamically allocated
354 with {\it new} and deleted with {\it delete}. If you delete a window,
355 all of its children and descendants will be automatically deleted,
356 so you don't need to delete these descendants explicitly.
357
358 When deleting a frame or dialog, use {\bf Destroy} rather than {\bf delete} so
359 that the wxWidgets delayed deletion can take effect. This waits until idle time
360 (when all messages have been processed) to actually delete the window, to avoid
361 problems associated with the GUI sending events to deleted windows.
362
363 Don't create a window on the stack, because this will interfere
364 with delayed deletion.
365
366 If you decide to allocate a C++ array of objects (such as wxBitmap) that may
367 be cleaned up by wxWidgets, make sure you delete the array explicitly
368 before wxWidgets has a chance to do so on exit, since calling {\it delete} on
369 array members will cause memory problems.
370
371 wxColour can be created statically: it is not automatically cleaned
372 up and is unlikely to be shared between other objects; it is lightweight
373 enough for copies to be made.
374
375 Beware of deleting objects such as a wxPen or wxBitmap if they are still in use.
376 Windows is particularly sensitive to this: so make sure you
377 make calls like wxDC::SetPen(wxNullPen) or wxDC::SelectObject(wxNullBitmap) before deleting
378 a drawing object that may be in use. Code that doesn't do this will probably work
379 fine on some platforms, and then fail under Windows.
380
381 \section{Architecture dependency}\label{architecturedependency}
382
383 A problem which sometimes arises from writing multi-platform programs is that
384 the basic C types are not defined the same on all platforms. This holds true
385 for both the length in bits of the standard types (such as int and long) as
386 well as their byte order, which might be little endian (typically
387 on Intel computers) or big endian (typically on some Unix workstations). wxWidgets
388 defines types and macros that make it easy to write architecture independent
389 code. The types are:
390
391 wxInt32, wxInt16, wxInt8, wxUint32, wxUint16 = wxWord, wxUint8 = wxByte
392
393 where wxInt32 stands for a 32-bit signed integer type etc. You can also check
394 which architecture the program is compiled on using the wxBYTE\_ORDER define
395 which is either wxBIG\_ENDIAN or wxLITTLE\_ENDIAN (in the future maybe wxPDP\_ENDIAN
396 as well).
397
398 The macros handling bit-swapping with respect to the applications endianness
399 are described in the \helpref{Byte order macros}{byteordermacros} section.
400
401 \section{Conditional compilation}\label{conditionalcompilation}
402
403 One of the purposes of wxWidgets is to reduce the need for conditional
404 compilation in source code, which can be messy and confusing to follow.
405 However, sometimes it is necessary to incorporate platform-specific
406 features (such as metafile use under MS Windows). The symbols
407 listed in the file {\tt symbols.txt} may be used for this purpose,
408 along with any user-supplied ones.
409
410 \section{C++ issues}\label{cpp}
411
412 The following documents some miscellaneous C++ issues.
413
414 \subsection{Templates}\label{templates}
415
416 wxWidgets does not use templates (except for some advanced features that
417 are switched off by default) since it is a notoriously unportable feature.
418
419 \subsection{RTTI}\label{rtti}
420
421 wxWidgets does not use C++ run-time type information since wxWidgets provides
422 its own run-time type information system, implemented using macros.
423
424 \subsection{Type of NULL}\label{null}
425
426 Some compilers (e.g. the native IRIX cc) define NULL to be 0L so that
427 no conversion to pointers is allowed. Because of that, all these
428 occurrences of NULL in the GTK+ port use an explicit conversion such
429 as
430
431 {\small
432 \begin{verbatim}
433 wxWindow *my_window = (wxWindow*) NULL;
434 \end{verbatim}
435 }%
436
437 It is recommended to adhere to this in all code using wxWidgets as
438 this make the code (a bit) more portable.
439
440 \subsection{Precompiled headers}\label{precompiledheaders}
441
442 Some compilers, such as Borland C++ and Microsoft C++, support
443 precompiled headers. This can save a great deal of compiling time. The
444 recommended approach is to precompile {\tt "wx.h"}, using this
445 precompiled header for compiling both wxWidgets itself and any
446 wxWidgets applications. For Windows compilers, two dummy source files
447 are provided (one for normal applications and one for creating DLLs)
448 to allow initial creation of the precompiled header.
449
450 However, there are several downsides to using precompiled headers. One
451 is that to take advantage of the facility, you often need to include
452 more header files than would normally be the case. This means that
453 changing a header file will cause more recompilations (in the case of
454 wxWidgets, everything needs to be recompiled since everything includes {\tt "wx.h"}!)
455
456 A related problem is that for compilers that don't have precompiled
457 headers, including a lot of header files slows down compilation
458 considerably. For this reason, you will find (in the common
459 X and Windows parts of the library) conditional
460 compilation that under Unix, includes a minimal set of headers;
461 and when using Visual C++, includes {\tt wx.h}. This should help provide
462 the optimal compilation for each compiler, although it is
463 biased towards the precompiled headers facility available
464 in Microsoft C++.
465
466 \section{File handling}\label{filehandling}
467
468 When building an application which may be used under different
469 environments, one difficulty is coping with documents which may be
470 moved to different directories on other machines. Saving a file which
471 has pointers to full pathnames is going to be inherently unportable. One
472 approach is to store filenames on their own, with no directory
473 information. The application searches through a number of locally
474 defined directories to find the file. To support this, the class {\bf
475 wxPathList} makes adding directories and searching for files easy, and
476 the global function {\bf wxFileNameFromPath} allows the application to
477 strip off the filename from the path if the filename must be stored.
478 This has undesirable ramifications for people who have documents of the
479 same name in different directories.
480
481 As regards the limitations of DOS 8+3 single-case filenames versus
482 unrestricted Unix filenames, the best solution is to use DOS filenames
483 for your application, and also for document filenames {\it if} the user
484 is likely to be switching platforms regularly. Obviously this latter
485 choice is up to the application user to decide. Some programs (such as
486 YACC and LEX) generate filenames incompatible with DOS; the best
487 solution here is to have your Unix makefile rename the generated files
488 to something more compatible before transferring the source to DOS.
489 Transferring DOS files to Unix is no problem, of course, apart from EOL
490 conversion for which there should be a utility available (such as
491 dos2unix).
492
493 See also the File Functions section of the reference manual for
494 descriptions of miscellaneous file handling functions.
495
496 \chapter{Utilities and libraries supplied with wxWidgets}\label{utilities}
497 \setheader{{\it CHAPTER \thechapter}}{}{}{}{}{{\it CHAPTER \thechapter}}%
498 \setfooter{\thepage}{}{}{}{}{\thepage}%
499
500 In addition to the core wxWidgets library, a number of further
501 libraries and utilities are supplied with each distribution.
502
503 Some are under the 'contrib' hierarchy which mirrors the
504 structure of the main wxWidgets hierarchy. See also the 'utils'
505 hierarchy. The first place to look for documentation about
506 these tools and libraries is under the wxWidgets 'docs' hierarchy,
507 for example {\tt docs/htmlhelp/fl.chm}.
508
509 For other user-contributed packages, please see the Contributions page
510 on the \urlref{wxWidgets Web site}{http://www.wxwidgets.org}.
511
512 \begin{description}\itemsep=0pt
513 \item[{\bf Helpview}]
514 Helpview is a program for displaying wxWidgets HTML
515 Help files. In many cases, you may wish to use the wxWidgets HTML
516 Help classes from within your application, but this provides a
517 handy stand-alone viewer. See \helpref{wxHTML Notes}{wxhtml} for more details.
518 You can find it in {\tt samples/html/helpview}.
519 \item[{\bf Tex2RTF}]
520 Supplied with wxWidgets is a utility called Tex2RTF for converting\rtfsp
521 \LaTeX\ manuals HTML, MS HTML Help, wxHTML Help, RTF, and Windows
522 Help RTF formats. Tex2RTF is used for the wxWidgets manuals and can be used independently
523 by authors wishing to create on-line and printed manuals from the same\rtfsp
524 \LaTeX\ source. Please see the separate documentation for Tex2RTF.
525 You can find it under {\tt utils/tex2rtf}.
526 \item[{\bf Helpgen}]
527 Helpgen takes C++ header files and generates a Tex2RTF-compatible
528 documentation file for each class it finds, using comments as appropriate.
529 This is a good way to start a reference for a set of classes.
530 Helpgen can be found in {\tt utils/HelpGen}.
531 \item[{\bf Emulator}]
532 Xnest-based display emulator for X11-based PDA applications. On some
533 systems, the Xnest window does not synchronise with the
534 'skin' window. This program can be found in {\tt utils/emulator}.
535 \item[{\bf Configuration Tool}]
536 The wxWidgets Configuration Tool is a work in progress
537 intended to make it easier to configure wxWidgets
538 features in detail. It exports setup.h configurations and will
539 eventually generate makefile config files. Invoking compilers is
540 also on the cards. Since configurations are
541 handled one at a time, the tool is of limited used until further
542 development can be done. The program can be found in {\tt utils/configtool}.
543 \item[{\bf XRC resource system}]
544 This is the sizer-aware resource system, and uses
545 XML-based resource specifications that can be generated by tools
546 such as \urlref{wxDesigner}{http://www.roebling.de} and XRC's own wxrcedit.
547 You can find this in {\tt src/xrc}, {\tt include/wx/xrc}, {\tt samples/xrc}, and {\tt utils/wxrcedit}.
548 For more information, see the \helpref{XML-based resource system overview}{xrcoverview}.
549 \item[{\bf Object Graphics Library}]
550 OGL defines an API for applications that need to display objects connected by lines.
551 The objects can be moved around and interacted with.
552 You can find this in {\tt contrib/src/ogl}, {\tt contrib/include/wx/ogl}, and {\tt contrib/samples/ogl}.
553 \item[{\bf Frame Layout library}]
554 FL provides sophisticated pane dragging and docking facilities.
555 You can find this in {\tt contrib/src/fl}, {\tt contrib/include/wx/fl}, and {\tt contrib/samples/fl}.
556 \item[{\bf Gizmos library}]
557 Gizmos is a collection of useful widgets and other classes. Classes include wxLEDNumberCtrl,
558 wxEditableListBox, wxMultiCellCanvas.
559 You can find this in {\tt contrib/src/gizmos}, {\tt contrib/include/wx/gizmos}, and {\tt contrib/samples/gizmos}.
560 \item[{\bf Net library}]
561 Net is a collection of very simple mail and web related classes. Currently
562 there is only wxEmail, which makes it easy to send email messages via MAPI on Windows or sendmail on Unix.
563 You can find this in {\tt contrib/src/net} and {\tt contrib/include/wx/net}.
564 \item[{\bf Animate library}]
565 Animate allows you to load animated GIFs and play them on a window. The library can be extended
566 to use other animation formats.
567 You can find this in {\tt contrib/src/animate}, {\tt contrib/include/wx/animate}, and {\tt contrib/samples/animate}.
568 \item[{\bf MMedia library}]
569 Mmedia supports a variety of multimedia functionality. The status of this library is currently unclear.
570 You can find this in {\tt contrib/src/mmedia}, {\tt contrib/include/wx/mmedia}, and {\tt contrib/samples/mmedia}.
571 \item[{\bf Styled Text Control library}]
572 STC is a wrapper around Scintilla, a syntax-highlighting text editor.
573 You can find this in {\tt contrib/src/stc}, {\tt contrib/include/wx/stc}, and {\tt contrib/samples/stc}.
574 \item[{\bf Plot}]
575 Plot is a simple curve plotting library.
576 You can find this in {\tt contrib/src/plot}, {\tt contrib/include/wx/plot}, and {\tt contrib/samples/plot}.
577 \end{description}
578
579 \chapter{Programming strategies}\label{strategies}
580 \setheader{{\it CHAPTER \thechapter}}{}{}{}{}{{\it CHAPTER \thechapter}}%
581 \setfooter{\thepage}{}{}{}{}{\thepage}%
582
583 This chapter is intended to list strategies that may be useful when
584 writing and debugging wxWidgets programs. If you have any good tips,
585 please submit them for inclusion here.
586
587 \section{Strategies for reducing programming errors}\label{reducingerrors}
588
589 \subsection{Use ASSERT}\label{useassert}
590
591 Although I haven't done this myself within wxWidgets, it is good
592 practice to use ASSERT statements liberally, that check for conditions that
593 should or should not hold, and print out appropriate error messages.
594 These can be compiled out of a non-debugging version of wxWidgets
595 and your application. Using ASSERT is an example of `defensive programming':
596 it can alert you to problems later on.
597
598 \subsection{Use wxString in preference to character arrays}\label{usewxstring}
599
600 Using wxString can be much safer and more convenient than using char *.
601 Again, I haven't practiced what I'm preaching, but I'm now trying to use
602 wxString wherever possible. You can reduce the possibility of memory
603 leaks substantially, and it is much more convenient to use the overloaded
604 operators than functions such as strcmp. wxString won't add a significant
605 overhead to your program; the overhead is compensated for by easier
606 manipulation (which means less code).
607
608 The same goes for other data types: use classes wherever possible.
609
610 \section{Strategies for portability}\label{portability}
611
612 \subsection{Use relative positioning or constraints}\label{userelativepositioning}
613
614 Don't use absolute panel item positioning if you can avoid it. Different GUIs have
615 very differently sized panel items. Consider using the constraint system, although this
616 can be complex to program.
617
618 Alternatively, you could use alternative .wrc (wxWidgets resource files) on different
619 platforms, with slightly different dimensions in each. Or space your panel items out
620 to avoid problems.
621
622 \subsection{Use wxWidgets resource files}\label{useresources}
623
624 Use .xrc (wxWidgets resource files) where possible, because they can be easily changed
625 independently of source code.
626
627 \section{Strategies for debugging}\label{debugstrategies}
628
629 \subsection{Positive thinking}\label{positivethinking}
630
631 It is common to blow up the problem in one's imagination, so that it seems to threaten
632 weeks, months or even years of work. The problem you face may seem insurmountable:
633 but almost never is. Once you have been programming for some time, you will be able
634 to remember similar incidents that threw you into the depths of despair. But
635 remember, you always solved the problem, somehow!
636
637 Perseverance is often the key, even though a seemingly trivial problem
638 can take an apparently inordinate amount of time to solve. In the end,
639 you will probably wonder why you worried so much. That's not to say it
640 isn't painful at the time. Try not to worry -- there are many more important
641 things in life.
642
643 \subsection{Simplify the problem}\label{simplifyproblem}
644
645 Reduce the code exhibiting the problem to the smallest program possible
646 that exhibits the problem. If it is not possible to reduce a large and
647 complex program to a very small program, then try to ensure your code
648 doesn't hide the problem (you may have attempted to minimize the problem
649 in some way: but now you want to expose it).
650
651 With luck, you can add a small amount of code that causes the program
652 to go from functioning to non-functioning state. This should give a clue
653 to the problem. In some cases though, such as memory leaks or wrong
654 deallocation, this can still give totally spurious results!
655
656 \subsection{Use a debugger}\label{usedebugger}
657
658 This sounds like facetious advice, but it is surprising how often people
659 don't use a debugger. Often it is an overhead to install or learn how to
660 use a debugger, but it really is essential for anything but the most
661 trivial programs.
662
663 \subsection{Use logging functions}\label{uselogging}
664
665 There is a variety of logging functions that you can use in your program:
666 see \helpref{Logging functions}{logfunctions}.
667
668 Using tracing statements may be more convenient than using the debugger
669 in some circumstances (such as when your debugger doesn't support a lot
670 of debugging code, or you wish to print a bunch of variables).
671
672 \subsection{Use the wxWidgets debugging facilities}\label{usedebuggingfacilities}
673
674 You can use wxDebugContext to check for
675 memory leaks and corrupt memory: in fact in debugging mode, wxWidgets will
676 automatically check for memory leaks at the end of the program if wxWidgets is suitably
677 configured. Depending on the operating system and compiler, more or less
678 specific information about the problem will be logged.
679
680 You should also use \helpref{debug macros}{debugmacros} as part of a `defensive programming' strategy,
681 scattering wxASSERTs liberally to test for problems in your code as early as possible. Forward thinking
682 will save a surprising amount of time in the long run.
683
684 See the \helpref{debugging overview}{debuggingoverview} for further information.
685