keymapping.txt

Linux环境下的远程登陆客户端软件,其采用RDP协议

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.

* CapsLock: CapsLock changes are never sent to the RDP
  server. 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 names of the keymaps follows RFC1766. 

(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", the scancode sent for this
keysym will be prefix with AltGr, or Shift. 

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 Super_L Alt_L space Mode_switch Super_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        Super_L (0x73),  Super_R (0x74)
mod5        Scroll_Lock (0x4e)


Updating / writing keymap files
===============================
When writing new or updating keymap files, please use comments and
blanks, to increase readability. The "sv" keymap is a good template. 

When you need to add a translation to a keymap file, do:

    1. Get the "key number" for this key, by looking at keynums.png. 

    2. Take a look at scancodes.h, and look for
    SCANCODE_KEY_<my-key-number>. The scancode value is at the end of
    the line. If the line contains (SCANCODE_EXTENDED | 0xsomething),
    then you should OR 0x80 to this value. For example, you can do:
    
    python -c "print hex(0x80 | 0xsomething)"

    3. Put the scancode (from step 2) and keysym name (found in the
    error message) into the keymap file. 


Special keys
============

* The combination Ctrl-Alt-Enter toggles between fullscreen and
  non-fullscreen mode. 

* Meta, Hyper and Super are treated as windows keys. RDP4 does not
  support the windows keys though, so if you are running RDP4, these
  keys will translate to Ctrl-Esc. 


Links
=====
http://www.win.tue.nl/~aeb/linux/kbd/scancodes.html