docs/latex/wx/keyevent.tex

   1 \section{\class{wxKeyEvent}}\label{wxkeyevent}
   2
   3 This event class contains information about keypress (character) events.
   4
   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
  10 generated) down events but only one up so it is wrong to assume that there is
  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
  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
  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
  30 just {\tt 'A'} while the char event key code parameter will now be {\tt 'A'}
  31 as well.
  32
  33 Although in this simple case it is clear that the correct key code could be
  34 found in the key down event handler by checking the value returned by
  35 \helpref{ShiftDown()}{wxkeyeventshiftdown}, in general you should use
  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
  49 similar to but slightly different from Windows {\tt WM\_KEYDOWN} and
  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
  53 \wxheading{Derived from}
  54
  55 \helpref{wxEvent}{wxevent}
  56
  57 \wxheading{Include files}
  58
  59 <wx/event.h>
  60
  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
  68 \twocolitem{{\bf EVT\_KEY\_DOWN(func)}}{Process a wxEVT\_KEY\_DOWN event (any key has been pressed).}
  69 \twocolitem{{\bf EVT\_KEY\_UP(func)}}{Process a wxEVT\_KEY\_UP event (any key has been released).}
  70 \twocolitem{{\bf EVT\_CHAR(func)}}{Process a wxEVT\_CHAR event.}
  71 %\twocolitem{{\bf EVT\_CHAR\_HOOK(func)}}{Process a wxEVT\_CHAR\_HOOK event.}
  72 \end{twocollist}%
  73
  74
  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
  93 Virtual keycode. See \helpref{Keycodes}{keycodes} for a list of identifiers.
  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
 127 \constfunc{bool}{AltDown}{\void}
 128
 129 Returns TRUE if the Alt key was down at the time of the key event.
 130
 131 \membersection{wxKeyEvent::ControlDown}
 132
 133 \constfunc{bool}{ControlDown}{\void}
 134
 135 Returns TRUE if the control key was down at the time of the key event.
 136
 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
 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
 165 \membersection{wxKeyEvent::GetX}
 166
 167 \constfunc{long}{GetX}{\void}
 168
 169 Returns the X position of the event.
 170
 171 \membersection{wxKeyEvent::GetY}
 172
 173 \constfunc{long}{GetY}{\void}
 174
 175 Returns the Y position of the event.
 176
 177 \membersection{wxKeyEvent::MetaDown}
 178
 179 \constfunc{bool}{MetaDown}{\void}
 180
 181 Returns TRUE if the Meta key was down at the time of the key event.
 182
 183 \membersection{wxKeyEvent::GetPosition}
 184
 185 \constfunc{wxPoint}{GetPosition}{\void}
 186
 187 \constfunc{void}{GetPosition}{\param{long *}{x}, \param{long *}{y}}
 188
 189 Obtains the position at which the key was pressed.
 190
 191 \membersection{wxKeyEvent::HasModifiers}
 192
 193 \constfunc{bool}{HasModifiers}{\void}
 194
 195 Returns TRUE if either {\sc Ctrl} or {\sc Alt} keys was down
 196 at the time of the key event. Note that this function does not take into
 197 account neither {\sc Shift} nor {\sc Meta} key states (the reason for ignoring
 198 the latter is that it is common for {\sc NumLock} key to be configured as
 199 {\sc Meta} under X but the key presses even while {\sc NumLock} is on should
 200 be still processed normally).
 201
 202 \membersection{wxKeyEvent::ShiftDown}\label{wxkeyeventshiftdown}
 203
 204 \constfunc{bool}{ShiftDown}{\void}
 205
 206 Returns TRUE if the shift key was down at the time of the key event.
 207
 208