rdesktop/doc/keymapping.txt

Keyboard mapping
================
This release of rdesktop uses a new, portable keyboard mapping
implementation. It should hopefully work on all X11 systems. This new
implementation only looks at X11 keysyms: Not on (nonportable)
keycodes or modifier status. This means that rdesktop will obey your
local keyboard configuration. For example, if you have swapped
CapsLock and Control, rdesktop will use this mapping. 

XKB is currently not used. It seems like a good idea to me, but since
some X servers (like Xvnc) does not support XKB, we still need to use
the plain old interface as well, at least. 

There are still some small problems.

* NumLock handling: NumLock is switched off when typing a non-numlock
  key. rdesktop does not know which keys are NumLock-dependent and
  not. When you type a numlock-dependent key again, NumLock is
  switched on on the server again. The only problem really is that the
  NumLock indicator in Wordpad etc switches on and off when you type. 

* CapsLock: CapsLock changes are never sent to the RDP server. This is
  a problem of the same type as NumLock: rdesktop does not know which
  keys that are modified by CapsLock and which are not. So, the
  CapsLock indicator in Wordpad etc will always be off. 

Composing/Multi_key is supported. For more information, see:

  MIT:              $SRC/xc/nls/X11/locale/Compose/iso8859-1
  XFree86:          /usr/X11R6/lib/X11/locale/*/Compose
  Solaris' Openwin: /usr/openwin/include/X11/Suncompose.h
                    /usr/openwin/lib/locale/*/Compose
  Irix6:            compose(5)


Keymap files
=============
The keymap-files have two-letter names. These follows ISO 639
(2-letter codes). ISO639 can be found at
http://www.w3.org/WAI/ER/IG/ert/iso639.htm

(You can find a translation from Windows keyboard layout numbers to
keymap names by looking at
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\MIME\Database\RFC1766 in the
registry.)


Contents of keymap files
========================
The keymaps are line based. There are four different types of lines:

1) include-lines
Syntax:
include <another-map-file>


2) map-lines
Syntax:
map <hex-number>

Map-lines specifies how the remote RDP server should interpret the
sent scancodes. 


3) Translation-lines
Syntax:
<keysym-name> <scancode> [flags..]

The scancode can be found in scancodes.h. Note: The scancode value for
extended keys can be calculated by OR:ing with 0x80. Example: The
Delete key have the scancode sequence 0xe0, 0x52. You can get the
scancode value to put into the map file by running:

python -c "print hex(0x80 | 0x52)"

If flags are "altgr", "shift", "numlock", the scancode sent for this
keysym will be prefix with AltGr, Shift or Numlock. 

If flags include "addupper", an translation for this keysyms uppercase
name will as well, in addition to the non-uppercase name. Example:

x 2d addupper

...will add an translation for "X" automatically, just like if you
would specify:

X 2d shift

If flags include "localstate", the modifier to send will be determined
by the local modifier state. 

If flags is "inhibit", nothing will be sent to the server. 


4) enable_compose

If any line starts with the keyword "enable_compose", rdesktop will
enable local Compose/Multi_key handling. Enabling this will often make
it impossible to compose characters with dead keys (on the remote
side). This is because when local compose support is enabled, dead
keys will not be sent to the remote side. 


Suggested X11 keysym mapping on PCs
===================================
Unfortunately, there is no standard for which keysyms a given key
should generate. If you have a PC-keyboard with Windows keys, I suggest this mapping:

Keyboard keys:
CtrlLeft WinLeft AltLeft Space AltGr WinRight Menu CtrlRight

...should generate keysyms:
Control_L Hyper_L Alt_L space Mode_switch Hyper_R Menu Control_R

Additionally:
Shift-Alt should produce Meta_L
Shift-AltGr should produce Multi_Key. 

Use a modifier-map like this:

shift       Shift_L (0x32),  Shift_R (0x3e)
lock        Caps_Lock (0x25)
control     Control_L (0x42),  Control_R (0x6d)
mod1        Alt_L (0x40)
mod2        Num_Lock (0x4d)
mod3        Mode_switch (0x71)
mod4        Hyper_L (0x73),  Hyper_R (0x74)
mod5        Scroll_Lock (0x4e)