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1.1 root 1: .NH 2
2: Keyboard Operations
3: .PP
4: X does not predefine the keyboard to be ascii characters.
5: It is often useful to know that the ``a'' key just went down,
6: or possibly that it just went back up.
7: Client programs are sent keyboard events,
8: which contain a ``keycode''
9: which assigns a number to each physical key on the
10: keyboard.
11: (For historical reasons, the keycodes are a superset of the DEC LK201 keyboard
12: keycodes.)
13: Client programs which want to deal with
14: ascii text will then have to convert the keycode into ascii
15: explicitly.
16: The transformation of keycode to ascii is arbitrary,
17: and facilities are provided to aid people in customizing the keyboard
18: layout to whatever they want.
19: Remember that keyboards often differ dramatically,
20: so writing code that presumes the existance of a particular key
21: not on the main part of the keyboard is fraught with portability
22: problems.
23: It may also be difficult to get key up events on certain X implementations
24: due to hardware or software restrictions.
25: .PP
26: Keyboard events are normally sent to the smallest enclosing window
27: which is interested in that type of event underneath the
28: mouse's position.
29: It is also possible to assign the keyboard `input focus' to a specific
30: window.
31: When the input focus is attached to a window,
32: keyboard events will go to the client which has selected
33: input on that window rather than the window under the mouse.
34: .PP
35: WARNING:
36: Some implementations cannot support up events.
37: You should think seriously before designing software that takes
38: advantage of up events if you are concerned about wide portability,
39: though there are some applications that can exploit up events
40: to provide superior user interfaces.
41: You should also be VERY careful when selecting which keys may be used
42: in such applications.
43: It may be impossible
44: to guarantee the existance of a set of keys on all keyboard with the probable
45: exception of a-z, spacebar, and carriage return.
46: .FD
47: .IN "XFocusKeyboard"
48: .IN "Definitions" "XFocusKeyboard"
49: XFocusKeyboard (w)
50: Window w;
51: .FN
52: .IN "Input Focus"
53: \fIXFocusKeyboard\fP designates a window as the `input focus' window. If
54: the window that would normally receive a \fIKeyPressed\fP or \fIKeyReleased\fP
55: event is not the focus window or one of its descendents, the event will
56: be sent to the focus window instead.
57: The events will go to whatever
58: client has selected input on the focus window; in general, this may be
59: .IN "XFocusKeyboard"
60: a client other than the one which has called \fIXFocusKeyboard\fP. For
61: instance, a window manager may allow the user to designate an arbitrary
62: window as the keyboard focus.
63: .LP
64: The root window is the default focus window.
65: If the focus window is
66: closed, the closest existing ancestor inherits the input focus.
67: .FD
68: .IN "Definitions" "XLookupMapping"
69: .IN "XLookupMapping"
70: .IN "Keycode to Ascii Conversion"
71: .IN "Keyboard" "Customization"
72: char *XLookupMapping(event, nbytes)
73: XKeyPressedEvent *event;
74: int *nbytes;
75: .FN
76: .PP
77: This function is very useful for mapping down events to counted
78: character strings (an array of characters and the length; the null
79: character is legitimate in this use.)
80: It returns a pointer to a static counted character string which must not be
81: touched by a client, and the number of bytes in the string.
82: .PP
83: This mapping is normally stored in the user's home directory in the
84: .IN "File" "$HOME/.Xkeymap"
85: .IN "File" "/usr/lib/Xkeymap.txt"
86: file ".Xkeymap".
87: If this file is not present, \fIXLookupMapping\fP
88: falls back to a built in table.
89: If no text is defined for that key, \fInbytes\fP will be zero.
90: The \fI~/.Xkeymap\fP file is produced by the \fIkeycomp(1)\fP program,
91: which reads
92: a text file of keyboard mappings. The file \fI/usr/lib/Xkeymap.txt\fP contains
93: a set of standard keyboard mappings.
94: The function performs normal interpretation of `shift' bits (meta, shift,
95: shift lock, control).
96: The user should strncpy the result if needed to his own storage if the
97: data must be modified.
98: .FD
99: .IN "Definitions" "XRebindCode"
100: .IN "XRebindCode"
101: .IN "Keyboard" "Customization"
102: XRebindCode(keycode, shiftbits, str, nbytes)
103: unsigned int keycode;
104: unsigned int shiftbits;
105: char *str;
106: int nbytes;
107: .FN
108: .PP
109: If you wish to rebind the keyboard, you can use this routine to change
110: (on a non-permanent basis) the binding of the keyboard.
111: Given a keycode,
112: the meta bits (or the \fIX*Masks\fP together to specify the bits
113: you wish to set), a string and the number of bytes in the string,
114: .IN "XLookupMapping"
115: subsequent calls to \fIXLookupMapping\fP will return the supplied string.
116: The string should be stored in static storage;
117: an automatic string may have been deallocated by the time it is needed.
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