@c $Id: custom.texi,v 4.1 2000/12/11 09:54:19 cibrario Rel $

@node Customizing saturn, The sutil Library, Command Line Options, Top
@chapter Customizing saturn
@cindex Customizing saturn

The @code{saturn} program uses OSF/Motif widgets to make up its
user interface, and supports the standard X application
resource mechanism for customization; in addition, it is fully
internationalized and uses a message catalog to retrieve almost
all error and informational messages the user will ever see.

Therefore, you can modify the ``look and feel'' of @code{saturn}
to fit your preferences to a great extent, without touching
the source code and/or rebuilding the executable.

This chapter deals with advanced customization, that is, X resources,
message catalog, and so on, and does not discuss the command-line
options of @code{saturn}; see @ref{Command Line Options}, for more
information about command-line options.

@menu
* Widget Tree::                 
* Custom Resources::            
* Application Actions::         
* Message Catalog::             
* Environment Variables::       
* Customizing the Translation Table::  
* Customizing the Font Size::   
* Configuration Options::       
@end menu


@node Widget Tree, Custom Resources, Customizing saturn, Customizing saturn
@section Widget Tree
@cindex Widget Tree

This is @code{saturn}'s widget tree; all widgets are standard Motif
widgets.  See the Motif documentation for more information about
standard widget's resources.

@table @code
@item main (XmMainWindow)
This is the emulator's main window, and is a child of the main
application shell.
@item *fsb (XmFileSelectionBox)
This is the file selection box that pops up when a fast load/save
operation is started.  Notice the star; it is there because this
widget is wrapped in a dialog.
@item *error (XmMessageBox)
This is the message box that pops up when @code{saturn} wants to tell
something to the user, usually when an error occurs. Notice the star; it
is there because this widget is wrapped in a dialog.
@item main.@var{faceplate} (XmRowColumn)
This container contains all widgets of the calculator's faceplate.
The name of this widget, @var{faceplate}, depends on the value
of the custom resource @code{.face}; this way you can define
a different set of resources for each faceplate.
@item main.@var{faceplate}.kbd (XmForm)
This form contains all calculator's keys.
@item main.@var{faceplate}.kbd.@var{n} (XmForm)
Another @code{XmForm}, containing all widgets pertaining to calculator's
key number @var{n}.
@item main.@var{faceplate}.kbd.@var{n}.ul (XmLabel)
@itemx main.@var{faceplate}.kbd.@var{n}.ur (XmLabel)
@itemx main.@var{faceplate}.kbd.@var{n}.ll (XmLabel)
@itemx main.@var{faceplate}.kbd.@var{n}.lr (XmLabel)
These widgets contain, respectively, the upper-left, upper-right,
lower-left, and lower-right label of calculator's key number @var{n}.
@item main.@var{faceplate}.kbd.@var{n}.btn (XmToggleButton)
This widget represents calculator's key number @var{n}.
@item main.@var{faceplate}.frame (XmFrame)
This widget encloses the LCD display area.
@item main.@var{faceplate}.frame.lcd (XmDrawingArea)
This widget is the LCD display area of the emulated calculator.
@item main.@var{faceplate}.msg (XmTextField)
This text field is used by the emulator to display its most important
messages; for example, it is used to display the name of the
emulator's pseudo-terminal.
@end table

In the list above:

@table @var
@item faceplate
is the name of the active calculator's faceplate selected by the
@code{.face} custom resource.
@item n
is the ASCII decimal representation of a non-negative integer number,
that identifies a calculator's key uniquely; its value goes from
@code{0} to the value of the @var{faceplate}.@code{nKeys} resource minus
one, inclusive.
@end table

@node Custom Resources, Application Actions, Widget Tree, Customizing saturn
@section Custom Resources
@cindex Custom Resources

In addition to standard Motif resources, @code{saturn} has the
following custom resources:

@table @code
@item main.@var{faceplate}.nKeys
This resource must translate into an integer, representing the number of
keys that faceplate @var{faceplate} has.
@item main.@var{faceplate}.kbd.@var{n}.btn.inOut
This resource associates calculator's key number @var{n} with a
combination of IN/OUT codes seen by the emulated CPU.  It is a
string, and can be either:

@table @code
@item @var{o}/@var{i}
When pressed, the key activates the bit(s) of the IN register specified
by the @var{i} bit @strong{mask}, when bit @strong{number} @var{o} is
set in the OUT register.  Both @var{i} and @var{o} are hexadecimal
constants.  For example, on the HP49 the calculator's function key
@code{F1} sets the IN bit mask @code{01} when OUT bit number @code{5} is set;
accordingly, the IN/OUT mapping of this key is @code{5/01}.
@item *
This special value uniquely identifies the ON/Cancel key.
@end table
@item *compoundString
This custom resource can be set for @code{XmLabel} and
@code{XmToggleButton} widgets only and, when set, overrides the standard
resource @code{labelString}.  Its value is a string with the
following syntax:

@example
   @var{compoundString}: ([# @var{fontlist_tag}] @var{string})*
@end example

Here, @var{string} is a sequence of ordinary characters,
excluding @code{#}, and @var{fontlist_tag} can be:
@table @code
@item #
Put a single @code{#} character in current compound string segment.
@item @var{space}
Create a new compound string segment using @code{XmFONTLIST_DEFAULT_TAG}
as tag.
@item @var{tag}
Create a new segment using @var{tag} as tag; @var{tag} can be
any single character, except @code{#} and @var{space}.
@end table

Each segment is limited to @code{MAX_CS_SEGMENT_LEN} characters; longer
segments are silently truncated.

The resource is scanned from left to right according to the syntax
described above.  The result is a compound string (@code{XmString})
that becomes the @code{labelString} resource of the target widget.
The original value of the @code{labelString} resource is discarded
when @code{compoundString} is defined.  This resource allows you
to have more than one font in button labels.
@end table

In the list above:

@table @var
@item faceplate
is the name of the calculator's faceplate selected by the
@code{.face} custom resource.
@item n
is the ASCII decimal representation of a non-negative integer number
that uniquely identifies a calculator's key; its value goes from
@code{0} to the value of the @var{faceplate}.@code{nKeys} resource minus
one, inclusive.
@end table

Notice also that all command-line options are mapped into custom
top-level application resources, too; in this case, the name of the
resource is the same as the name of the option.  For example,
the @code{-face} command-line option is mapped to the custom
resource @code{.face}.

@node Application Actions, Message Catalog, Custom Resources, Customizing saturn
@section Application Actions
@cindex Application Actions

The emulator installs the application actions listed below:

@table @code
@item kbdKeyPress
@itemx kbdKeyRelease
Both actions accept one string as argument; the string represents an
IN/OUT mapping with the same syntax already described for the
@code{inOut} custom resource.  These functions command the emulation of
a key press and key release event, respectively.
@end table

These actions are useful to define keyboard shortcuts.  For example, on
the HP49 the calculator's function key @code{F1} sets the IN bit mask
@code{01} when OUT bit number @code{5} is set; accordingly, the IN/OUT
mapping of this key is @code{5/01}.

If you want to define the X keysym @code{F1} to act as a shortcut for
this calculator's key, simply add the following two lines to the
@code{translations} resource of your faceplate:

@example
...
<KeyDown>F1: kbdKeyPress(5/01) \n\
<KeyUp>F1: kbdKeyRelease(5/01) \n\
...
@end example


@node Message Catalog, Environment Variables, Application Actions, Customizing saturn
@section Message Catalog
@cindex Message Catalog

The @code{saturn} emulator opens the message catalog @code{saturn.cat}
during startup, and retrieves all its messages from there.  Internally,
@code{saturn} uses a pair of integers to uniquely identify a message.

By default, that is, when the @code{NLSPATH} environment variable is not
set, @code{saturn} first attempts to locate the message catalog in the
system's default location of such files; if this first attempt fails,
@code{saturn} prints a warning and generates an alternate catalog name
using the directory name found in @code{argv[0]}; if even this second
attempt fails, @code{saturn} tries again using the @code{C} locale
instead of the current one.  If all attempts fail, @code{saturn}
terminated.

The @code{.msf} files found in the source distribution of @code{saturn}
list all message codes and translate them into human-readable english
messages; they can be used as a starting point to prepare message
catalogs for additional languages.  See the documentation of
@code{gencat}, for more information about how to process them to
generate a @code{.cat} file.


@node Environment Variables, Customizing the Translation Table, Message Catalog, Customizing saturn
@section Environment Variables
@cindex Environment Variables

The @code{saturn} emulator looks at the following environment variables:

@table @code
@item NLSPATH
@itemx LC_ALL
@itemx LC_MESSAGES
@itemx LANG
These environment variables are used to locate the @code{saturn}'s
message catalog, and to specialize the load paths of application
resources; see the documentation of @code{catopen()} and
@code{XtResolvePathname()}, for more information.

@item DISPLAY
This variable contains the default X display name used by @code{saturn}.

@item XENVIRONMENT
This variable is used to locate the per-host user environment
resources; see the documentation of @code{XtDisplayInitialize()}, for
more information.

@item XUSERFILESEARCHPATH
@itemx XAPPLRESDIR
These variables control the loading process of the user's application
resource file; see the documentation of @code{XtDisplayInitialize()}, for
more information.

@item XFILESEARCHPATH
This variable controls the loading process of the application class
resource file; see the documentation of @code{XtDisplayInitialize()}, for
more information.
@end table


@node Customizing the Translation Table, Customizing the Font Size, Environment Variables, Customizing saturn
@section Customizing the Translation Table
@cindex Customizing the Translation Table

As said before, all widgets in a given faceplate have their own
translation table; this table is useful to define keyboard
shortcuts.  The default application resource file distributed
with the emulator, @file{Saturn.ad}, already contains a
predefined set of shortcuts; to customize it, proceed
as follows:

@itemize @bullet
@item
Locate the translation table of the faceplate you are interested in.
For example, the predefined HP49's faceplate name is @code{hp49}; the X
resource specifier of its base translation table is:

@example
*hp49*baseTranslations
@end example

@item
This resource has two lines of text for each key on the real keyboard
you want to map on the emulated keyboard; for example, these lines map
the @code{0} keypad key to the @code{0} key of the calculator:

@example
<KeyDown>KP_0: kbdKeyPress(3/01) \n\
<KeyUp>KP_0: kbdKeyRelease(3/01) \n\
@end example

@item
Here, @code{KP_0} is the name of the X keysym (representing a keyboard
key or a combination of keys) that is currently mapped to the @code{0}
key (@code{3/01} are the OUT/IN bit masks of the @code{0} key on the
calculator, reflecting its wiring on the calculator's keyboard).  To
change the mapping to another key, simply replace the old X keysym name
with the new one.  For example, if you want to remap the @code{F8} key
to the @code{0} key, update the lines above as follows:

@example
<KeyDown>F8: kbdKeyPress(3/01) \n\
<KeyUp>F8: kbdKeyRelease(3/01) \n\
@end example

If you want to keep the existing mapping, too, duplicate the existing
lines and change the X keysym on the duplicate only.

@item
To get the keysym name of a given key you can use, for example, the
@code{xev} utility: when you start it, it opens a small window on your
screen and starts dumping on stdout all X events that window receives.
Give the focus to the @code{xev} window, press the key you are
interested in and look at its output; you should see something like:

@example
KeyPress event, serial 22, synthetic NO, window 0x4800001,
    root 0x26, subw 0x0, time 18446744071995733347, (77,-9),
        root:(123,37),
    state 0x1, keycode 34 (keysym 0x7b, braceleft), same_screen YES,
    XLookupString gives 1 characters:  "@{"
@end example

Here, I pressed the @code{@{} key, and @code{xev} is telling me that its
keysym name is @code{braceleft}.  Use that name if you want to put the
@code{@{} key in translations.

@item
Be careful with continuation characters: each line of the translation
table resource except the last one must end with @code{\n\}

@item
Keep in mind that this is a simple example; actually, since
@code{saturn} leverages the standard X Toolkit translation table parser
and translator, it accepts the @strong{full} translation table syntax
described in MIT documents, that is much more complex and powerful than
this.

@end itemize


@node Customizing the Font Size, Configuration Options, Customizing the Translation Table, Customizing saturn
@section Customizing the Font Size
@cindex Customizing the Font Size

The simplest way to change the size of the @code{saturn}'s main window
is to change the size of the fonts it uses.  To do this, locate the
@code{fontList} resources of the faceplate you want to modify in your
application resource file.  For example, the default application
resource file sets the following resources for the @code{hp49}
faceplate:

@example
*hp49.kbd*fontList: *helvetica-*-r-*-*-12-*,*symbol-*-*-*-*-12-*=S
*hp49.kbd*btn.fontList: *helvetica-*-r-*-*-14-*,*symbol-*-*-*-*-14-*=S
@end example

Fonts are selected with their standard XLFD font designators;
in the above lines, @code{12} and @code{14} are the @code{pxlsz} specifiers.
Make them smaller to reduce the font size; make them bigger to
enlarge the font size.  For example:

@example
*hp49.kbd*fontList: *helvetica-*-r-*-*-8-*,*symbol-*-*-*-*-8-*=S
*hp49.kbd*btn.fontList: *helvetica-*-r-*-*-10-*,*symbol-*-*-*-*-10-*=S
@end example

reduces the window size to about 400x700 pixels on my system.

If this is not enough, you can define a brand new keyboard layout;
again, no need to touch the source code, only resources must be
updated. Hint: for each key, its @code{topPosition},
@code{bottomPosition}, @code{leftPosition} and @code{rightPosition}
resources determine where the key is located on the keyboard faceplate.


@node Configuration Options,  , Customizing the Font Size, Customizing saturn
@section Configuration Options
@cindex Configuration Options

In addition to the run-time customization methods mentioned above,
@code{saturn} has build-time configuration options, too.  See the
documentation embedded in the source file @code{config.h}, for more
information.  Of course, you can change these options only if you build
@code{saturn} yourself from the source distribution.