Fix wxBufferedDC so that it adheres to its documented behavior (which is in use in...

[wxWidgets.git] / docs / latex / wx / keyevent.tex

diff --git a/docs/latex/wx/keyevent.tex b/docs/latex/wx/keyevent.tex
index 34dfc6afd3e0b69e6dcc4bd0d305760c67d159ab..eff2b8c547f81767d843a939b3c235170e7ed5c2 100644 (file)
--- a/docs/latex/wx/keyevent.tex
+++ b/docs/latex/wx/keyevent.tex
@@ -2,6 +2,58 @@
 
 This event class contains information about keypress (character) events.
 
 
 This event class contains information about keypress (character) events.
 

+Notice that there are three different kinds of keyboard events in wxWidgets:
+key down and up events and char events. The difference between the first two
+is clear - the first corresponds to a key press and the second to a key
+release - otherwise they are identical. Just note that if the key is
+maintained in a pressed state you will typically get a lot of (automatically
+generated) down events but only one up so it is wrong to assume that there is
+one up event corresponding to each down one.
+
+Both key events provide untranslated key codes while the char event carries
+the translated one. The untranslated code for alphanumeric keys is always
+an upper case value. For the other keys it is one of {\tt WXK\_XXX} values
+from the \helpref{keycodes table}{keycodes}. The translated key is, in
+general, the character the user expects to appear as the result of the key
+combination when typing the text into a text entry zone, for example.
+
+A few examples to clarify this (all assume that {\sc Caps Lock} is unpressed
+and the standard US keyboard): when the {\tt 'A'} key is pressed, the key down
+event key code is equal to {\tt ASCII A} $== 65$. But the char event key code
+is {\tt ASCII a} $== 97$. On the other hand, if you press both {\sc Shift} and
+{\tt 'A'} keys simultaneously , the key code in key down event will still be
+just {\tt 'A'} while the char event key code parameter will now be {\tt 'A'}
+as well.
+
+Although in this simple case it is clear that the correct key code could be
+found in the key down event handler by checking the value returned by
+\helpref{ShiftDown()}{wxkeyeventshiftdown}, in general you should use
+{\tt EVT\_CHAR} for this as for non-alphanumeric keys the translation is
+keyboard-layout dependent and can only be done properly by the system itself.
+
+Another kind of translation is done when the control key is pressed: for
+example, for {\sc Ctrl-A} key press the key down event still carries the
+same key code {\tt 'a'} as usual but the char event will have key code of
+$1$, the ASCII value of this key combination.
+
+You may discover how the other keys on your system behave interactively by
+running the \helpref{text}{sampletext} wxWidgets sample and pressing some keys
+in any of the text controls shown in it.
+
+{\bf Note:} If a key down ({\tt EVT\_KEY\_DOWN}) event is caught and
+the event handler does not call {\tt event.Skip()} then the corresponding
+char event ({\tt EVT\_CHAR}) will not happen.  This is by design and
+enables the programs that handle both types of events to be a bit
+simpler.
+
+{\bf Note for Windows programmers:} The key and char events in wxWidgets are
+similar to but slightly different from Windows {\tt WM\_KEYDOWN} and
+{\tt WM\_CHAR} events. In particular, Alt-x combination will generate a char
+event in wxWidgets (unless it is used as an accelerator).
+
+{\bf Tip:} be sure to call {\tt event.Skip()} for events that you don't process in
+key event function, otherwise menu shortcuts may cease to work under Windows.
+

 \wxheading{Derived from}
 
 \helpref{wxEvent}{wxevent}
 \wxheading{Derived from}
 
 \helpref{wxEvent}{wxevent}


@@ -17,128 +69,252 @@ functions that take a wxKeyEvent argument.
 
 \twocolwidtha{7cm}
 \begin{twocollist}\itemsep=0pt
 
 \twocolwidtha{7cm}
 \begin{twocollist}\itemsep=0pt

-\twocolitem{{\bf EVT\_CHAR(func)}}{Process a wxEVT\_CHAR event (a non-modifier key has been pressed).}

 \twocolitem{{\bf EVT\_KEY\_DOWN(func)}}{Process a wxEVT\_KEY\_DOWN event (any key has been pressed).}
 \twocolitem{{\bf EVT\_KEY\_UP(func)}}{Process a wxEVT\_KEY\_UP event (any key has been released).}
 \twocolitem{{\bf EVT\_CHAR(func)}}{Process a wxEVT\_CHAR event.}
 \twocolitem{{\bf EVT\_KEY\_DOWN(func)}}{Process a wxEVT\_KEY\_DOWN event (any key has been pressed).}
 \twocolitem{{\bf EVT\_KEY\_UP(func)}}{Process a wxEVT\_KEY\_UP event (any key has been released).}
 \twocolitem{{\bf EVT\_CHAR(func)}}{Process a wxEVT\_CHAR event.}

-\twocolitem{{\bf EVT\_CHAR\_HOOK(func)}}{Process a wxEVT\_CHAR\_HOOK event.}
+%\twocolitem{{\bf EVT\_CHAR\_HOOK(func)}}{Process a wxEVT\_CHAR\_HOOK event.}

 \end{twocollist}%
 
 \end{twocollist}%
 

-\wxheading{See also}
-
-\helpref{wxWindow::OnChar}{wxwindowonchar}, 
-\helpref{wxWindow::OnCharHook}{wxwindowoncharhook}, 
-\helpref{wxWindow::OnKeyDown}{wxwindowonkeydown}, 
-\helpref{wxWindow::OnKeyUp}{wxwindowonkeyup}

 
 \latexignore{\rtfignore{\wxheading{Members}}}
 
 
 \latexignore{\rtfignore{\wxheading{Members}}}
 

-\membersection{wxKeyEvent::m\_altDown}
+
+\membersection{wxKeyEvent::m\_altDown}\label{wxkeyeventmaltdown}

 
 \member{bool}{m\_altDown}
 
 
 \member{bool}{m\_altDown}
 

-TRUE if the Alt key is pressed down.
+\textbf{Deprecated: } Please use \helpref{GetModifiers}{wxkeyeventgetmodifiers}
+instead!
+
+true if the Alt key is pressed down.

 
 

-\membersection{wxKeyEvent::m\_controlDown}
+
+\membersection{wxKeyEvent::m\_controlDown}\label{wxkeyeventmcontroldown}

 
 \member{bool}{m\_controlDown}
 
 
 \member{bool}{m\_controlDown}
 

-TRUE if control is pressed down.
+\textbf{Deprecated: } Please use \helpref{GetModifiers}{wxkeyeventgetmodifiers}
+instead!
+
+true if control is pressed down.

 
 

-\membersection{wxKeyEvent::m\_keyCode}
+
+\membersection{wxKeyEvent::m\_keyCode}\label{wxkeyeventmkeycode}

 
 \member{long}{m\_keyCode}
 
 
 \member{long}{m\_keyCode}
 

+\textbf{Deprecated: } Please use \helpref{GetKeyCode}{wxkeyeventgetkeycode}
+instead!
+

 Virtual keycode. See \helpref{Keycodes}{keycodes} for a list of identifiers.
 
 Virtual keycode. See \helpref{Keycodes}{keycodes} for a list of identifiers.
 

-\membersection{wxKeyEvent::m\_metaDown}
+
+\membersection{wxKeyEvent::m\_metaDown}\label{wxkeyeventmmetadown}

 
 \member{bool}{m\_metaDown}
 
 
 \member{bool}{m\_metaDown}
 

-TRUE if the Meta key is pressed down.
+\textbf{Deprecated: } Please use \helpref{GetModifiers}{wxkeyeventgetmodifiers}
+instead!
+
+true if the Meta key is pressed down.

 
 

-\membersection{wxKeyEvent::m\_shiftDown}
+
+\membersection{wxKeyEvent::m\_shiftDown}\label{wxkeyeventmshiftdown}

 
 \member{bool}{m\_shiftDown}
 
 
 \member{bool}{m\_shiftDown}
 

-TRUE if shift is pressed down.
+\textbf{Deprecated: } Please use \helpref{GetModifiers}{wxkeyeventgetmodifiers}
+instead!
+
+true if shift is pressed down.

 
 

-\membersection{wxKeyEvent::m\_x}
+
+\membersection{wxKeyEvent::m\_x}\label{wxkeyeventmx}

 
 \member{int}{m\_x}
 
 
 \member{int}{m\_x}
 

+\textbf{Deprecated: } Please use \helpref{GetX}{wxkeyeventgetx} instead!
+

 X position of the event.
 
 X position of the event.
 

-\membersection{wxKeyEvent::m\_y}
+
+\membersection{wxKeyEvent::m\_y}\label{wxkeyeventmy}

 
 \member{int}{m\_y}
 
 
 \member{int}{m\_y}
 

+\textbf{Deprecated: } Please use \helpref{GetY}{wxkeyeventgety} instead!
+

 Y position of the event.
 
 Y position of the event.
 

-\membersection{wxKeyEvent::wxKeyEvent}
+
+\membersection{wxKeyEvent::wxKeyEvent}\label{wxkeyeventctor}

 
 \func{}{wxKeyEvent}{\param{WXTYPE}{ keyEventType}}
 
 Constructor. Currently, the only valid event types are wxEVT\_CHAR and wxEVT\_CHAR\_HOOK.
 
 
 \func{}{wxKeyEvent}{\param{WXTYPE}{ keyEventType}}
 
 Constructor. Currently, the only valid event types are wxEVT\_CHAR and wxEVT\_CHAR\_HOOK.
 

-\membersection{wxKeyEvent::AltDown}
+
+\membersection{wxKeyEvent::AltDown}\label{wxkeyeventaltdown}

 
 \constfunc{bool}{AltDown}{\void}
 
 
 \constfunc{bool}{AltDown}{\void}
 

-Returns TRUE if the Alt key was down at the time of the key event.
+Returns true if the Alt key was down at the time of the key event.
+
+Notice that \helpref{GetModifiers}{wxkeyeventgetmodifiers} is easier to use
+correctly than this function so you should consider using it in new code.
+
+
+\membersection{wxKeyEvent::CmdDown}\label{wxkeyeventcmddown}
+
+\constfunc{bool}{CmdDown}{\void}
+
+\textsc{Cmd} is a pseudo key which is the same as Control for PC and Unix
+platforms but the special \textsc{Apple} (a.k.a as \textsc{Command}) key under
+Macs: it makes often sense to use it instead of, say, ControlDown() because Cmd
+key is used for the same thing under Mac as Ctrl elsewhere (but Ctrl still
+exists, just not used for this purpose under Mac). So for non-Mac platforms
+this is the same as \helpref{ControlDown()}{wxkeyeventcontroldown} and under
+Mac this is the same as \helpref{MetaDown()}{wxkeyeventmetadown}.
+

 
 

-\membersection{wxKeyEvent::ControlDown}
+\membersection{wxKeyEvent::ControlDown}\label{wxkeyeventcontroldown}

 
 \constfunc{bool}{ControlDown}{\void}
 
 
 \constfunc{bool}{ControlDown}{\void}
 

-Returns TRUE if the control key was down at the time of the key event.
+Returns true if the control key was down at the time of the key event.

 
 

-\membersection{wxKeyEvent::GetKeyCode}
+Notice that \helpref{GetModifiers}{wxkeyeventgetmodifiers} is easier to use
+correctly than this function so you should consider using it in new code.
+
+
+\membersection{wxKeyEvent::GetKeyCode}\label{wxkeyeventgetkeycode}

 
 \constfunc{int}{GetKeyCode}{\void}
 
 Returns the virtual key code. ASCII events return normal ASCII values,
 while non-ASCII events return values such as {\bf WXK\_LEFT} for the
 
 \constfunc{int}{GetKeyCode}{\void}
 
 Returns the virtual key code. ASCII events return normal ASCII values,
 while non-ASCII events return values such as {\bf WXK\_LEFT} for the

-left cursor key. See \helpref{Keycodes}{keycodes} for a full list of the virtual key codes.
+left cursor key. See \helpref{Keycodes}{keycodes} for a full list of
+the virtual key codes.

 
 

-\membersection{wxKeyEvent::GetX}
+Note that in Unicode build, the returned value is meaningful only if the
+user entered a character that can be represented in current locale's default
+charset. You can obtain the corresponding Unicode character using
+\helpref{GetUnicodeKey}{wxkeyeventgetunicodekey}.

 
 

-\constfunc{long}{GetX}{\void}

 
 

-Returns the X position of the event.
+\membersection{wxKeyEvent::GetModifiers}\label{wxkeyeventgetmodifiers}

 
 

-\membersection{wxKeyEvent::GetY}
+\constfunc{int}{GetModifiers}{\void}

 
 

-\constfunc{long}{GetY}{\void}
+Return the bitmask of modifier keys which were pressed when this event
+happened. See \helpref{key modifier constants}{keymodifiers} for the full list
+of modifiers.

 
 

-Returns the Y position of the event.
+Notice that this function is easier to use correctly than, for example, 
+\helpref{ControlDown}{wxkeyeventcontroldown} because when using the latter you
+also have to remember to test that none of the other modifiers is pressed:

 
 

-\membersection{wxKeyEvent::MetaDown}
+\begin{verbatim}
+    if ( ControlDown() && !AltDown() && !ShiftDown() && !MetaDown() )
+        ... handle Ctrl-XXX ...
+\end{verbatim}

 
 

-\constfunc{bool}{MetaDown}{\void}
+and forgetting to do it can result in serious program bugs (e.g. program not
+working with European keyboard layout where \textsc{AltGr} key which is seen by
+the program as combination of \textsc{Ctrl} and \textsc{Alt} is used). On the
+other hand, you can simply write
+
+\begin{verbatim}
+    if ( GetModifiers() == wxMOD_CONTROL )
+        ... handle Ctrl-XXX ...
+\end{verbatim}

 
 

-Returns TRUE if the Meta key was down at the time of the key event.
+with this function.

 
 

-\membersection{wxKeyEvent::GetPosition}
+
+\membersection{wxKeyEvent::GetPosition}\label{wxkeyeventgetposition}

 
 \constfunc{wxPoint}{GetPosition}{\void}
 
 \constfunc{void}{GetPosition}{\param{long *}{x}, \param{long *}{y}}
 
 
 \constfunc{wxPoint}{GetPosition}{\void}
 
 \constfunc{void}{GetPosition}{\param{long *}{x}, \param{long *}{y}}
 

-Obtains the position at which the key was pressed.
+Obtains the position (in client coordinates) at which the key was pressed.
+

 
 

-\membersection{wxKeyEvent::HasModifiers}
+\membersection{wxKeyEvent::GetRawKeyCode}\label{wxkeyeventgetrawkeycode}
+
+\constfunc{wxUint32}{GetRawKeyCode}{\void}
+
+Returns the raw key code for this event. This is a platform-dependent scan code
+which should only be used in advanced applications.
+
+{\bf NB:} Currently the raw key codes are not supported by all ports, use
+{\tt\#ifdef wxHAS\_RAW\_KEY\_CODES} to determine if this feature is available.
+
+
+\membersection{wxKeyEvent::GetRawKeyFlags}\label{wxkeyeventgetrawkeyflags}
+
+\constfunc{wxUint32}{GetRawKeyFlags}{\void}
+
+Returns the low level key flags for this event. The flags are
+platform-dependent and should only be used in advanced applications.
+
+{\bf NB:} Currently the raw key flags are not supported by all ports, use
+{\tt \#ifdef wxHAS\_RAW\_KEY\_CODES} to determine if this feature is available.
+
+
+\membersection{wxKeyEvent::GetUnicodeKey}\label{wxkeyeventgetunicodekey}
+
+\constfunc{wxChar}{GetUnicodeKey}{\void}
+
+Returns the Unicode character corresponding to this key event.
+
+This function is only available in Unicode build, i.e. when
+\texttt{wxUSE\_UNICODE} is $1$.
+
+
+\membersection{wxKeyEvent::GetX}\label{wxkeyeventgetx}
+
+\constfunc{long}{GetX}{\void}
+
+Returns the X position (in client coordinates) of the event.
+
+
+\membersection{wxKeyEvent::GetY}\label{wxkeyeventgety}
+
+\constfunc{long}{GetY}{\void}
+
+Returns the Y (in client coordinates) position of the event.
+
+
+\membersection{wxKeyEvent::HasModifiers}\label{wxkeyeventhasmodifiers}

 
 \constfunc{bool}{HasModifiers}{\void}
 
 
 \constfunc{bool}{HasModifiers}{\void}
 

-Returns TRUE if either of {\sc Ctrl}, {\sc Alt} or {\sc Meta} keys was down
+Returns true if either {\sc Ctrl} or {\sc Alt} keys was down

 at the time of the key event. Note that this function does not take into
 at the time of the key event. Note that this function does not take into

-account the {\sc Shift} key state.
+account neither {\sc Shift} nor {\sc Meta} key states (the reason for ignoring
+the latter is that it is common for {\sc NumLock} key to be configured as
+{\sc Meta} under X but the key presses even while {\sc NumLock} is on should
+be still processed normally).
+
+
+\membersection{wxKeyEvent::MetaDown}\label{wxkeyeventmetadown}
+
+\constfunc{bool}{MetaDown}{\void}
+
+Returns true if the Meta key was down at the time of the key event.
+
+Notice that \helpref{GetModifiers}{wxkeyeventgetmodifiers} is easier to use
+correctly than this function so you should consider using it in new code.
+

 
 

-\membersection{wxKeyEvent::ShiftDown}
+\membersection{wxKeyEvent::ShiftDown}\label{wxkeyeventshiftdown}

 
 \constfunc{bool}{ShiftDown}{\void}
 
 
 \constfunc{bool}{ShiftDown}{\void}
 

-Returns TRUE if the shift key was down at the time of the key event.
+Returns true if the shift key was down at the time of the key event.

 
 

+Notice that \helpref{GetModifiers}{wxkeyeventgetmodifiers} is easier to use
+correctly than this function so you should consider using it in new code.