docs/latex/wx/tsamples.tex

   1 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   2 %% Name:        tsamples.tex
   3 %% Purpose:     Samples description
   4 %% Author:      Vadim Zeitlin
   5 %% Modified by:
   6 %% Created:     02.11.99
   7 %% RCS-ID:      $Id$
   8 %% Copyright:   (c) wxWindows team
   9 %% Licence:     wxWindows licence
  10 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  11
  12 \section{wxWindows samples}\label{samples}
  13
  14 Probably the best way to learn wxWindows is by reading the source of some 50+
  15 samples provided with it. Many aspects of wxWindows programming can be learnt
  16 from them, but sometimes it is not simple to just choose the right sample to
  17 look at. This overview aims at describing what each sample does/demonstrates to
  18 make it easier to find the relevant one if a simple grep through all sources
  19 didn't help. They also provide some notes about using the samples and what
  20 features of wxWindows are they supposed to test.
  21
  22 There are currently more than 50 different samples as part of wxWindows and
  23 this list is not complete.
  24
  25 \subsection{Minimal sample}\label{sampleminimal}
  26
  27 The minimal sample is what most people will know under the term Hello World,
  28 i.e. a minimal program that doesn't demonstrate anything apart from what is
  29 needed to write a program that will display a "hello" dialog. This is usually
  30 a good starting point for learning how to use wxWindows.
  31
  32 \subsection{Calendar sample}\label{samplecalendar}
  33
  34 This font shows the \helpref{calendar control}{wxcalendarctrl} in action. It
  35 shows how to configure the control (see the different options in the calendar
  36 menu) and also how to process the notifications from it.
  37
  38 \subsection{Checklist sample}\label{samplechecklist}
  39
  40 This sample demonstrates the use of the \helpref{wxCheckListBox}{wxchecklistbox}
  41 class intercepting check, select and double click events. It also tests the
  42 use of various methods modifiying the control, such as by deleting items
  43 from it or inserting new once (these fucntions are actually implememted in
  44 the parent class \helpref{wxListBox}{wxlistbox} so the sample tests that class
  45 as well). The layout of the dialog is created using a \helpref{wxBoxSizer}{wxboxsizer}
  46 demonstrating a simple dynamic layout.
  47
  48 \subsection{Config sample}\label{sampleconfig}
  49
  50 This sample demonstrates the \helpref{wxConfig}{wxconfigbase} classes in a platform
  51 indepedent way, i.e. it uses text based files to store a given configuration under
  52 Unix and uses the Registry under Windows.
  53
  54 See \helpref{wxConfig overview}{wxconfigoverview} for the descriptions of all
  55 features of this class.
  56
  57 \subsection{Dialogs sample}\label{sampledialogs}
  58
  59 This sample shows how to use the common dialogs available from wxWindows. These
  60 dialogs are desrcibed in details in the \helpref{Common dialogs overview}{commondialogsoverview}.
  61
  62 \subsection{Dynamic sample}\label{sampledynamic}
  63
  64 This sample is a very small sample that demonstrates the use of the
  65 \helpref{wxEvtHandler::Connect}{wxevthandlerconnect} method. This method
  66 should be used whenever it is not known at compile time, which control
  67 will receive which event or which controls are actually going to be in
  68 a dialog or frame. This is most typically the case for any scripting
  69 languge that would work as a wrapper for wxWindows or programs where
  70 forms or similar datagrams can be created by the uses.
  71
  72 \subsection{Scroll subwindow sample}\label{samplescrollsub}
  73
  74 This sample demonstrates the use of the \helpref{wxScrolledWindow}{wxscrolledwindow}
  75 class including placing subwindows into it and drawing simple graphics. It uses the
  76 \helpref{SetTargetWindow}{wxscrolledwindowsettargetwindow} method and thus the effect
  77 of scrolling does not show in the scrolled window itself, but in one of its subwindows.
  78
  79 Additionally, this samples demonstrates how to optimize drawing operations in wxWindows,
  80 in particular using the \helpref{wxWindow::IsExposed}{wxwindowisexposed} method with
  81 the aim to prevent unnecessary drawing in the window and thus reducing or removing
  82 flicker on screen.
  83
  84 \subsection{Font sample}\label{samplefont}
  85
  86 The font sample demonstrates \helpref{wxFont}{wxfont},
  87 \helpref{wxFontEnumerator}{wxfontenumerator} and
  88 \helpref{wxFontMapper}{wxfontmapper} classes. It allows you to see the fonts
  89 available (to wxWindows) on the computer and shows all characters of the
  90 chosen font as well.
  91
  92 \subsection{DnD sample}\label{samplednd}
  93
  94 This sample shows both clipboard and drag and drop in action. It is quite non
  95 trivial and may be safely used as a basis for implementing the clipboard and
  96 drag and drop operations in a real-life program.
  97
  98 When you run the sample, its screen is split in several parts. On the top,
  99 there are two listboxes which show the standard derivations of
 100 \helpref{wxDropTarget}{wxdroptarget}:
 101 \helpref{wxTextDropTarget}{wxtextdroptarget} and
 102 \helpref{wxFileDropTarget}{wxfiledroptarget}.
 103
 104 The middle of the sample window is taken by the log window which shows what is
 105 going on (of course, this only works in debug builds) and may be helpful to see
 106 the sequence of steps of data transfer.
 107
 108 Finally, the last part is used for two things: you can drag text from it to
 109 either one of the listboxes (only one will accept it) or another application
 110 and, also, bitmap pasted from clipboard will be shown there.
 111
 112 So far, everything we mentioned was implemented with minimal amount of code
 113 using standard wxWindows classes. The more advanced features are demonstrated
 114 if you create a shape frame from the main frame menu. A shape is a geometric
 115 object which has a position, size and color. It models some
 116 application-specific data in this sample. A shape object supports its own
 117 private \helpref{wxDataFormat}{wxdataformat} which means that you may cut and
 118 paste it or drag and drop (between one and the same or different shapes) from
 119 one sample instance to another (or the same). However, chances are that no
 120 other program supports this format and so shapes can also be rendered as
 121 bitmaps which allows them to be pasted/dropped in many other applications.
 122
 123 Take a look at DnDShapeDataObject class to see how you may use
 124 \helpref{wxDataObject}{wxdataobject} to achieve this.
 125
 126
 127 \subsection{HTML samples}\label{samplehtml}
 128
 129 Eight HTML samples (you can find them in directory {\tt samples/html})
 130 cover all features of HTML sub-library.
 131
 132 {\bf Test} demonstrates how to create \helpref{wxHtmlWindow}{wxhtmlwindow}
 133 and also shows most of supported HTML tags.
 134
 135 {\bf Widget} shows how you can embed ordinary controls or windows within
 136 HTML page. It also nicely explains how to write new tag handlers and extend
 137 the library to work with unsupported tags.
 138
 139 {\bf About} may give you an idea how to write good-looking about boxes.
 140
 141 {\bf Zip} demonstrates use of virtual file systems in wxHTML. The zip archives
 142 handler (ships with wxWindows) allows you to access HTML pages stored
 143 in compressed archive as if they were ordinary files.
 144
 145 {\bf Virtual} is yet another VFS demo. This one generates pages at run-time.
 146 You may find it useful if you need to display some reports in your application.
 147
 148 {\bf Printing} explains use of \helpref{wxHtmlEasyPrinting}{wxhtmleasyprinting}
 149 class which serves as as-simple-as-possible interface for printing HTML
 150 documents without much work. In fact, only few function calls are sufficient.
 151
 152 {\bf Help} and {\bf Helpview} are variations on displaying HTML help
 153 (compatible with MS HTML Help Workshop). {\it Help} shows how to embed
 154 \helpref{wxHtmlHelpController}{wxhtmlhelpcontroller} in your application
 155 while {\it Helpview} is simple tool that only pops up help window and
 156 displays help books given at command line.
 157
 158 \subsection{Layout sample}\label{samplelayout}
 159
 160 The layout sample demonstrates the two different layout systems offered
 161 by wxWindows. When starting the program, you will see a frame with some
 162 controls and some graphics. The controls will change their size whenever
 163 you resize the entire frame and the exact behaviour of the size changes
 164 is determined using the \helpref{wxLayoutConstraints}{wxlayoutconstraints}
 165 class. See also the \helpref{overview}{constraintsoverview} and the
 166 \helpref{wxIndividualLayoutConstraint}{wxindividuallayoutconstraint}
 167 class for further information.
 168
 169 The menu in this sample offers two more tests, one showing how to use
 170 a \helpref{wxBoxSizer}{wxboxsizer} in a simple dialog and the other one
 171 showing how to use sizers in connection with a \helpref{wxNotebook}{wxnotebook}
 172 class. See also \helpref{wxNotebookSizer}{wxnotebooksizer} and
 173 \helpref{wxSizer}{wxsizer}.
 174
 175 \subsection{Text sample}\label{sampletext}
 176
 177 This sample demonstrates four features: firstly the use and many variants of
 178 the \helpref{wxTextCtrl}{wxtextctrl} class (single line, multi line, read only,
 179 password, ignoring TAB, ignoring ENTER).
 180
 181 Secondly it shows how to intercept a \helpref{wxKeyEvent}{wxkeyevent} in both
 182 the raw form using the {\tt EVT_KEY_UP} and {\tt EVT_KEY_DOWN} macros and the
 183 higherlevel from using the {\tt EVT_CHAR} macro. All characters will be logged
 184 in a log window at the bottom of the main window. By pressing some of the function
 185 keys, you can test some actions in the text ctrl as well as get statitics on the
 186 text ctrls, which is useful for testing if these statitics actually are correct.
 187
 188 Thirdly, on platforms which support it, the sample will offer to copy text to the
 189 \helpref{wxClipboard}{wxclipboard} and to paste text from it. The GTK version will
 190 use the so called PRIMARY SELECTION, which is the pseudo clipboard under X and
 191 best known from pasting text to the XTerm program.
 192
 193 Last not least: some of the text controls have tooltips and the sample also shows
 194 how tooltips can be centrally disabled and their latency controlled.
 195
 196 \subsection{Thread sample}\label{samplethread}
 197
 198 This sample demonstrates the use of threads in connection with GUI programs.
 199 There are two fundamentally different ways to use threads in GUI programs and
 200 either way has to take care of the fact that the GUI library itself usually
 201 is not multi-threading safe, i.e. that it might crash if two threads try to
 202 access the GUI class simultaneously. One way to prevent that is have a normal
 203 GUI program in the main thread and some worker threads which work in the
 204 background. In order to make communication between the main thread and the
 205 worker threads possible, wxWindows offers the \helpref{wxPostEvent}{wxpostevent}
 206 function and this sample makes use of this function.
 207
 208 The other way to use a so called Mutex (such as those offered in the \helpref{wxMutex}{wxmutex}
 209 class) that prevent threads from accessing the GUI classes as long as any other
 210 thread accesses them. For this, wxWindows has the \helpref{wxMutexGuiEnter}{wxmutexguienter}
 211 and \helpref{wxMutexGuiLeave}{wxmutexguileave} functions, both of which are
 212 used and tested in the sample as well.
 213
 214 See also \helpref{Multithreading overview}{wxthreadoverview} and \helpref{wxThread}{wxthread}.
 215
 216 \subsection{Toolbar sample}\label{sampletoolbar}
 217
 218 The toolbar sample shows the \helpref{wxToolBar}{wxtoolbar} class in action.
 219
 220 The following things are demonstrated:
 221
 222 \begin{itemize}
 223
 224 \item Creating the toolbar using \helpref{wxToolBar::AddTool}{wxtoolbaraddtool}
 225 and \helpref{wxToolBar::AddControl}{wxtoolbaraddcontrol}: see
 226 MyApp::InitToolbar in the sample.
 227
 228 \item Using {\tt EVT\_UPDATE\_UI} handler for automatically enabling/disabling
 229 toolbar buttons without having to explicitly call EnableTool. This is is done
 230 in MyFrame::OnUpdateCopyAndCut.
 231
 232 \item Using \helpref{wxToolBar::DeleteTool}{wxtoolbardeletetool} and
 233 \helpref{wxToolBar::InsertTool}{wxtoolbarinserttool} to dynamically update the
 234 toolbar.
 235
 236 \end{itemize}