This page describes customizing the ViewStation's
keyboard. It includes references to keyboard diagnostic tools. Changing
the keyboard's mapping (with xmodmap) is discussed as well as event
translation resources for application programs.
Key
Handling in a Client/Server Environment
One objective of Client/Server architecture is to handle
configurations such as keyboard layouts or keypress assignments
separately, either on the server or on the client, so communication
between the two is independent of the actual configuration of either.
What this means for keyboards and keymaps is that the X terminal server
handles everything about the keyboard configuration (hardware
connections, keyboard layout, etc.) and produces a resulting key
function called a "keysym". This keysym is a neutral function, such as
"A" or "Backspace" or "F4". The client application receives this keysym
and interprets it according to its own configuration (F4 may mean "Save
and Exit" or "Next Page" or something else).
In this way a keysym, such as "F24", may be generated by any
keyboard configuration (such as different keyboard layouts,
multinational languages, use of Shift or other modifier keys, etc.) on
the X terminal. This keyboard configuration is handled by a server file
called xmodmap.
At the same time, the "F24" keysym may be interpreted by
clients in any way they wish (such as "Home the cursor" in one
application, "Insert marker text" in another, and "<string = your
email address>" in another). This keysym interpretation is handled by a
client resource called an event translation. This design lets any user
produce an "F24" keysym, with whatever keyboard configuration, and have
F24 produce the expected behavior on any application. For the user
wanting to modify the keymapping, there are two avenues of approach:
1. Change xmodmap (the keyboard configuration file to produce the
keysym on the X terminal), or
2. Change the event translation file (to interpret the keysym in
the client application )
There are some considerations that will influence your choice.
Changing xmodmap (the Keyboard Mapping on the ViewStation)
You can change the ViewStation's keymapping (both keyboard and mouse),
but these changes will apply to everything you do. This may be desired
in the case of switching mouse buttons for a left-handed user, or using
a multinational keyboard. However, for most cases, this change is too
broad and may introduce unexpected behavior and problems for your
application programs.
Changing the event translation (the Keysym
Interpretation on the Client) In most cases, this is the desired action
since it applies to a specific application and key behavior. This
change requires modifying the event translation resource for the client
in your .Xdefaults file. Both of these methods are described on
separate pages, with examples.
X
Keymapping Tools
This section describes some X clients that are
convenient tools for analyzing keymaps.
Using Xmodmap to Customize a Keyboard
This page discusses
Xmodmap and redefining keyboard keys.
Using
Event Translation Resources
This page describes event
translation resources to change keymaps for your application programs.
HDSterm Event Translation Resources and
Examples
This page describes event translation resources for the
ViewStation's HDSterm client; examples are included.
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