Version: $Revision: 1.35 $
Date: $Date: 2015/08/31 02:17:17 $
Copyright: (C) 2005 Free Software Foundation, Inc.
This document describes how to change the mouse and keyboard mappings so that GNUstep can be used properly. This document applies only to the X-Windows based backend.
The OpenStep specification requires 3 main different keyboard modifiers: CONTROL, COMMAND and ALTERNATE.
By default, GNUstep uses
Control_L (left Ctrl)
Control_R (right Ctrl)
Alt_L (left alt)
as COMMAND, and
Alt_R (right alt,
sometimes called AltGr) as ALTERNATE. As a
special exception, if
Alt_R is not bound to any
key on your keyboard, GNUstep will try to use
Mode_switch for ALTERNATE instead.
Some X server map AltGr onto
To allow for this the second code ALTERNATE may be
bound to this key.
If this layout does not work for you, because your keyboard misses some of these keys, or they have different X names or they conflict heavily with your window manager shortcuts (or for any other reason), read on.
Under GNUstep, you may change the default as you wish: you may choose which keys of your keyboard you want to use for CONTROL, COMMAND and ALTERNATE (You may even use different keys for different GNUstep applications, without conflict). These settings are internal to GNUstep, and will not influence the behaviour of other X apps.
You may choose up to 2 keys per modifier.
Note that, if your keyboard is properly set up for X, you should not need to remap your X keyboard to use GNUstep. By changing the defaults, you should be able to use GNUstep whatever the X keyboard mapping might be.
What you have to do, is simply to instruct GNUstep to use different keys for CONTROL, COMMAND and ALTERNATE.
The keys to use are determined at the application startup, by reading the user defaults database.
To set the keys which will act as CONTROL you have to set
similarly for the other keys:
Valid values are all the standard strings for X keys.
To disable completely a key, use
NoSymbol as preference.
Each value which you do not explicity set is substituted with its default value. The default values are:
Mode_switchif there is no
What could go wrong is for example that you don't have an
key. With the default settings, you will not be able to enter the
COMMAND key (which is quite an important key). What you can do in
this case is to use
Control_R as COMMAND, giving the
following commands (from the command line):
defaults write NSGlobalDomain GSFirstCommandKey Control_R defaults write NSGlobalDomain GSSecondControlKey NoSymbol
These commands write in the GNUstep user database; the information will be used every time you start a GNUstep application.
The first line sets
Control_R to be read as COMMAND.
The second line disables the second control key, which would otherwise
be bound to
Control_R by default. If you omit it,
Control_R will be used at the same time as COMMAND and as
CONTROL, which is not very useful.
To delete these preferences and restore the defaults, use
defaults delete NSGlobalDomain GSFirstCommandKey defaults delete NSGlobalDomain GSSecondControlKey
To get a list of currently set defaults, you may use
The list might be very long; you may want to extract only
setting for the
GSFirstCommandKey, for example:
defaults read | grep GSFirstCommandKey
A thing which could go wrong if you are trying to use a
setting different from the default, and you do not know
much about X, is that you can't find out the name of one
of your key. In this case, you may try having a look at
the output of programs like
xkeycaps; even if you do not understand it
completely, the output can inspire the right guessing.
A problem you are likely to encounter is that of conflicts with the window manager keyboard shortcuts. Good window managers let you change the keyboard shortcuts, so you may move the wm shortcuts that you do not use to keys which do not conflict (at least not too much) with GNUstep.
A final potential worry on X11 has to do with keyboards where hitting
'shift' or another key can affect the interpretation of a modifier
key. For example, on some Apple USB keyboards one key to the left
of the space bar maps to "Option" without shift pressed, and "Alt"
when it IS pressed. Such keyboard mappings are often useful in
non-English contexts to access accents or non-Roman characters.
However if such a key is used as a modifier in GNUstep problems can
occur when trying to use the modifier in conjunction with a shifted
character. In particular, you will need to hit and release the
modifier and the shift key in a particular order, or else things
will not work as expected, and the modifier may become "stuck". If
you experience such a problem, set the GNUstep back default