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

\section{\class{wxKeyEvent}}\label{wxkeyevent}

This event class contains information about keypress (character) events.

Notice that there are three different kinds of keyboard events in wxWindows:
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.

If the key up event is caught and the event handler does not call
event.Skip() then the coresponding char event will not happen.  This
is by design and enables the programs that handle both types of events
to be a bit simpler.

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} wxWindows sample and pressing some keys
in any of the text controls shown in it.

{\bf Note for Windows programmers:} The key and char events in wxWindows 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 wxWindows (unless it is used as an acclerator).

\wxheading{Derived from}

\helpref{wxEvent}{wxevent}

\wxheading{Include files}

<wx/event.h>

\wxheading{Event table macros}

To process a key event, use these event handler macros to direct input to member
functions that take a wxKeyEvent argument.

\twocolwidtha{7cm}
\begin{twocollist}\itemsep=0pt
\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.}
\end{twocollist}%


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

\membersection{wxKeyEvent::m\_altDown}

\member{bool}{m\_altDown}

TRUE if the Alt key is pressed down.

\membersection{wxKeyEvent::m\_controlDown}

\member{bool}{m\_controlDown}

TRUE if control is pressed down.

\membersection{wxKeyEvent::m\_keyCode}

\member{long}{m\_keyCode}

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

\membersection{wxKeyEvent::m\_metaDown}

\member{bool}{m\_metaDown}

TRUE if the Meta key is pressed down.

\membersection{wxKeyEvent::m\_shiftDown}

\member{bool}{m\_shiftDown}

TRUE if shift is pressed down.

\membersection{wxKeyEvent::m\_x}

\member{int}{m\_x}

X position of the event.

\membersection{wxKeyEvent::m\_y}

\member{int}{m\_y}

Y position of the event.

\membersection{wxKeyEvent::wxKeyEvent}

\func{}{wxKeyEvent}{\param{WXTYPE}{ keyEventType}}

Constructor. Currently, the only valid event types are wxEVT\_CHAR and wxEVT\_CHAR\_HOOK.

\membersection{wxKeyEvent::AltDown}

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

Returns TRUE if the Alt key was down at the time of the key event.

\membersection{wxKeyEvent::ControlDown}

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

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

\membersection{wxKeyEvent::GetKeyCode}

\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.

\membersection{wxKeyEvent::GetRawKeyCode}

\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}

\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::GetX}

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

Returns the X position of the event.

\membersection{wxKeyEvent::GetY}

\constfunc{long}{GetY}{\void}

Returns the Y position of the event.

\membersection{wxKeyEvent::MetaDown}

\constfunc{bool}{MetaDown}{\void}

Returns TRUE if the Meta key was down at the time of the key event.

\membersection{wxKeyEvent::GetPosition}

\constfunc{wxPoint}{GetPosition}{\void}

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

Obtains the position at which the key was pressed.

\membersection{wxKeyEvent::HasModifiers}

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

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
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::ShiftDown}\label{wxkeyeventshiftdown}

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

Returns TRUE if the shift key was down at the time of the key event.
Commit	Line	Data
a660d684 KB	1	\section{\class{wxKeyEvent}}\label{wxkeyevent}
a660d684 KB	2
4ce81a75	3	This event class contains information about keypress (character) events.
a660d684	4
f17393f1 VZ	5	Notice that there are three different kinds of keyboard events in wxWindows:
	6	key down and up events and char events. The difference between the first two
	7	is clear - the first corresponds to a key press and the second to a key
	8	release - otherwise they are identical. Just note that if the key is
	9	maintained in a pressed state you will typically get a lot of (automatically
68304caf	10	generated) down events but only one up so it is wrong to assume that there is
f17393f1 VZ	11	one up event corresponding to each down one.
	12
	13	Both key events provide untranslated key codes while the char event carries
	14	the translated one. The untranslated code for alphanumeric keys is always
	15	an upper case value. For the other keys it is one of {\tt WXK\_XXX} values
	16	from the \helpref{keycodes table}{keycodes}. The translated key is, in
	17	general, the character the user expects to appear as the result of the key
	18	combination when typing the text into a text entry zone, for example.
	19
68304caf RD	20	If the key up event is caught and the event handler does not call
	21	event.Skip() then the coresponding char event will not happen. This
	22	is by design and enables the programs that handle both types of events
	23	to be a bit simpler.
	24
f17393f1 VZ	25	A few examples to clarify this (all assume that {\sc Caps Lock} is unpressed
	26	and the standard US keyboard): when the {\tt 'A'} key is pressed, the key down
	27	event key code is equal to {\tt ASCII A} $== 65$. But the char event key code
	28	is {\tt ASCII a} $== 97$. On the other hand, if you press both {\sc Shift} and
	29	{\tt 'A'} keys simultaneously , the key code in key down event will still be
68304caf	30	just {\tt 'A'} while the char event key code parameter will now be {\tt 'A'}
f17393f1 VZ	31	as well.
	32
	33	Although in this simple case it is clear that the correct key code could be
68304caf RD	34	found in the key down event handler by checking the value returned by
68304caf RD	35	\helpref{ShiftDown()}{wxkeyeventshiftdown}, in general you should use
f17393f1 VZ	36	{\tt EVT\_CHAR} for this as for non alphanumeric keys the translation is
	37	keyboard-layout dependent and can only be done properly by the system itself.
	38
	39	Another kind of translation is done when the control key is pressed: for
	40	example, for {\sc Ctrl-A} key press the key down event still carries the
	41	same key code {\tt 'a'} as usual but the char event will have key code of
	42	$1$, the ASCII value of this key combination.
	43
	44	You may discover how the other keys on your system behave interactively by
	45	running the \helpref{text}{sampletext} wxWindows sample and pressing some keys
	46	in any of the text controls shown in it.
	47
	48	{\bf Note for Windows programmers:} The key and char events in wxWindows are
68304caf	49	similar to but slightly different from Windows {\tt WM\_KEYDOWN} and
f17393f1 VZ	50	{\tt WM\_CHAR} events. In particular, Alt-x combination will generate a char
	51	event in wxWindows (unless it is used as an acclerator).
	52
a660d684 KB	53	\wxheading{Derived from}
	54
	55	\helpref{wxEvent}{wxevent}
	56
954b8ae6 JS	57	\wxheading{Include files}
	58
	59	<wx/event.h>
	60
a660d684 KB	61	\wxheading{Event table macros}
	62
	63	To process a key event, use these event handler macros to direct input to member
	64	functions that take a wxKeyEvent argument.
	65
	66	\twocolwidtha{7cm}
	67	\begin{twocollist}\itemsep=0pt
4ce81a75 JS	68	\twocolitem{{\bf EVT\_KEY\_DOWN(func)}}{Process a wxEVT\_KEY\_DOWN event (any key has been pressed).}
4ce81a75 JS	69	\twocolitem{{\bf EVT\_KEY\_UP(func)}}{Process a wxEVT\_KEY\_UP event (any key has been released).}
a660d684	70	\twocolitem{{\bf EVT\_CHAR(func)}}{Process a wxEVT\_CHAR event.}
f17393f1	71	%\twocolitem{{\bf EVT\_CHAR\_HOOK(func)}}{Process a wxEVT\_CHAR\_HOOK event.}
a660d684 KB	72	\end{twocollist}%
a660d684 KB	73
4ce81a75	74
a660d684 KB	75	\latexignore{\rtfignore{\wxheading{Members}}}
	76
	77	\membersection{wxKeyEvent::m\_altDown}
	78
	79	\member{bool}{m\_altDown}
	80
	81	TRUE if the Alt key is pressed down.
	82
	83	\membersection{wxKeyEvent::m\_controlDown}
	84
	85	\member{bool}{m\_controlDown}
	86
	87	TRUE if control is pressed down.
	88
	89	\membersection{wxKeyEvent::m\_keyCode}
	90
	91	\member{long}{m\_keyCode}
	92
3972fb49	93	Virtual keycode. See \helpref{Keycodes}{keycodes} for a list of identifiers.
a660d684 KB	94
	95	\membersection{wxKeyEvent::m\_metaDown}
	96
	97	\member{bool}{m\_metaDown}
	98
	99	TRUE if the Meta key is pressed down.
	100
	101	\membersection{wxKeyEvent::m\_shiftDown}
	102
	103	\member{bool}{m\_shiftDown}
	104
	105	TRUE if shift is pressed down.
	106
	107	\membersection{wxKeyEvent::m\_x}
	108
	109	\member{int}{m\_x}
	110
	111	X position of the event.
	112
	113	\membersection{wxKeyEvent::m\_y}
	114
	115	\member{int}{m\_y}
	116
	117	Y position of the event.
	118
	119	\membersection{wxKeyEvent::wxKeyEvent}
	120
	121	\func{}{wxKeyEvent}{\param{WXTYPE}{ keyEventType}}
	122
	123	Constructor. Currently, the only valid event types are wxEVT\_CHAR and wxEVT\_CHAR\_HOOK.
	124
	125	\membersection{wxKeyEvent::AltDown}
	126
803ef874	127	\constfunc{bool}{AltDown}{\void}
a660d684 KB	128
	129	Returns TRUE if the Alt key was down at the time of the key event.
	130
	131	\membersection{wxKeyEvent::ControlDown}
	132
803ef874	133	\constfunc{bool}{ControlDown}{\void}
a660d684 KB	134
	135	Returns TRUE if the control key was down at the time of the key event.
	136
f6bcfd97 BP	137	\membersection{wxKeyEvent::GetKeyCode}
	138
	139	\constfunc{int}{GetKeyCode}{\void}
	140
	141	Returns the virtual key code. ASCII events return normal ASCII values,
	142	while non-ASCII events return values such as {\bf WXK\_LEFT} for the
	143	left cursor key. See \helpref{Keycodes}{keycodes} for a full list of the virtual key codes.
	144
a160a325 VZ	145	\membersection{wxKeyEvent::GetRawKeyCode}
	146
	147	\constfunc{wxUint32}{GetRawKeyCode}{\void}
	148
	149	Returns the raw key code for this event. This is a platform-dependent scan code
	150	which should only be used in advanced applications.
	151
	152	{\bf NB:} Currently the raw key codes are not supported by all ports, use
	153	{\tt #ifdef wxHAS\_RAW\_KEY\_CODES} to determine if this feature is available.
	154
	155	\membersection{wxKeyEvent::GetRawKeyFlags}
	156
	157	\constfunc{wxUint32}{GetRawKeyFlags}{\void}
	158
	159	Returns the low level key flags for this event. The flags are
	160	platform-dependent and should only be used in advanced applications.
	161
	162	{\bf NB:} Currently the raw key flags are not supported by all ports, use
	163	{\tt #ifdef wxHAS\_RAW\_KEY\_CODES} to determine if this feature is available.
	164
a660d684 KB	165	\membersection{wxKeyEvent::GetX}
a660d684 KB	166
803ef874	167	\constfunc{long}{GetX}{\void}
a660d684 KB	168
	169	Returns the X position of the event.
	170
	171	\membersection{wxKeyEvent::GetY}
	172
803ef874	173	\constfunc{long}{GetY}{\void}
a660d684 KB	174
	175	Returns the Y position of the event.
	176
a660d684 KB	177	\membersection{wxKeyEvent::MetaDown}
a660d684 KB	178
803ef874	179	\constfunc{bool}{MetaDown}{\void}
a660d684 KB	180
	181	Returns TRUE if the Meta key was down at the time of the key event.
	182
803ef874	183	\membersection{wxKeyEvent::GetPosition}
a660d684	184
803ef874 JS	185	\constfunc{wxPoint}{GetPosition}{\void}
	186
	187	\constfunc{void}{GetPosition}{\param{long }{x}, \param{long }{y}}
a660d684 KB	188
	189	Obtains the position at which the key was pressed.
	190
f6bcfd97 BP	191	\membersection{wxKeyEvent::HasModifiers}
	192
	193	\constfunc{bool}{HasModifiers}{\void}
	194
d11710cb	195	Returns TRUE if either {\sc Ctrl} or {\sc Alt} keys was down
f6bcfd97	196	at the time of the key event. Note that this function does not take into
d11710cb	197	account neither {\sc Shift} nor {\sc Meta} key states (the reason for ignoring
68304caf	198	the latter is that it is common for {\sc NumLock} key to be configured as
d11710cb VZ	199	{\sc Meta} under X but the key presses even while {\sc NumLock} is on should
d11710cb VZ	200	be still processed normally).
f6bcfd97	201
f17393f1	202	\membersection{wxKeyEvent::ShiftDown}\label{wxkeyeventshiftdown}
a660d684	203
803ef874	204	\constfunc{bool}{ShiftDown}{\void}
a660d684 KB	205
	206	Returns TRUE if the shift key was down at the time of the key event.
	207
	208