InfoMagic Source Code 1993 July/THE_SOURCE_CODE_CD_ROM.iso/X/mit/doc/Xt/CH10

Text File | 1991-08-27 | 43.9 KB | 1,420 lines

.\" $XConsortium: CH10,v 1.8 91/08/26 13:38:16 swick Exp $
.\"
.\" Copyright 1985, 1986, 1987, 1988, 1991
.\" Massachusetts Institute of Technology, Cambridge, Massachusetts,
.\" and Digital Equipment Corporation, Maynard, Massachusetts.
.\"
.\" Permission to use, copy, modify and distribute this documentation for any
.\" purpose and without fee is hereby granted, provided that the above copyright
.\" notice appears in all copies and that both that copyright notice and this
.\" permission notice appear in supporting documentation, and that the name of
.\" M.I.T. or Digital not be used in in advertising or publicity pertaining
.\" to distribution of the software without specific, written prior permission.
.\" M.I.T and Digital makes no representations about the suitability of the
.\" software described herein for any purpose.
.\" It is provided ``as is'' without express or implied warranty.
\&
.sp 1
.ce 3
\s+1\fBChapter 10\fP\s-1

\s+1\fBTranslation Management\s-1
.sp 2
.nr H1 10
.nr H2 0
.nr H3 0
.nr H4 0
.nr H5 0
.LP
.XS
Chapter 10 \- Translation Management
.XE
Except under unusual circumstances,
widgets do not hardwire the mapping of user events into widget behavior
by using the event manager.
Instead, they provide a default mapping of events into behavior
that you can override.
.LP
The translation manager provides an interface to specify and manage the
mapping of X event sequences into widget-supplied functionality,
for example, calling procedure \fIAbc\fP when the \fIy\fP key
is pressed.
.LP
The translation manager uses two kinds of tables to perform translations:
.IP \(bu 5
The action tables, which are in the widget class structure,
specify the mapping of externally available procedure name strings
to the corresponding procedure implemented by the widget class.
.IP \(bu 5
A translation table, which is in the widget class structure,
specifies the mapping of event sequences to procedure name strings.
.LP
You can override the translation table in the class structure
for a specific widget instance by supplying a different translation table
for the widget instance.  The resources
XtNtranslations and XtNbaseTranslations are used to modify the class
default translation table; see Section 10.3.

.NH 2
Action Tables
.XS
\fB\*(SN Action Tables\fP
.XE
.LP
All widget class records contain an action table,
an array of
.PN XtActionsRec
entries.
In addition,
an application can register its own action tables with the translation manager
so that the translation tables it provides to widget instances can access
application functionality directly.
The translation action procedure pointer is of type
.PN XtActionProc .
.IN "action_proc procedure" "" "@DEF@"
.IN "XtActionProc" "" "@DEF@"
.FD 0
typedef void (*XtActionProc)(Widget, XEvent*, String*, Cardinal*);
.br
      Widget \fIw\fP;
.br
      XEvent *\fIevent\fP;
.br
      String *\fIparams\fP;
.br
      Cardinal *\fInum_params\fP;
.FN
.IP \fIw\fP 1i
Specifies the widget that caused the action to be called.
.IP \fIevent\fP 1i
Specifies the event that caused the action to be called.
If the action is called after a sequence of events,
then the last event in the sequence is used.
.IP \fIparams\fP 1i
Specifies a pointer to the list of strings that were specified
in the translation table as arguments to the action, or NULL.
.IP \fInum_params\fP 1i
Specifies the number of entries in \fIparams\fP.
.IN "XtActionsRec"
.IN "XtActionList"
.LP
.Ds 0
.TA .5i 3i
.ta .5i 3i
typedef struct _XtActionsRec {
    String string;
    XtActionProc proc;
} XtActionsRec, *XtActionList;
.De
The \fIstring\fP field is the name used in translation tables to access
the procedure.
The \fIproc\fP field is a pointer to a procedure that implements
the functionality.

When the action list is specified as the
.PN CoreClassPart
\fIactions\fP field the string pointed to by \fIstring\fP must be
permanently allocated prior to or during the execution of the class
initialization procedure and must not be subsequently deallocated.

.LP
Action procedures should not assume that the widget in which they
are invoked is realized; an accelerator specification can cause
an action procedure to be called for a widget that does not yet
have a window.  Widget writers should also note which of a widget's
callback lists are invoked from action procedures and warn clients
not to assume the widget is realized in those callbacks.
.LP
For example, a Pushbutton widget has procedures to take the following actions:
.IP \(bu 5
Set the button to indicate it is activated.
.IP \(bu 5
Unset the button back to its normal mode.
.IP \(bu 5
Highlight the button borders.
.IP \(bu 5
Unhighlight the button borders.
.IP \(bu 5
Notify any callbacks that the button has been activated.
.LP
The action table for the Pushbutton widget class makes these functions
available to translation tables written for Pushbutton or any subclass.
The string entry is the name used in translation tables.
The procedure entry (usually spelled identically to the string)
is the name of the C procedure that implements that function:
.LP
.IN "Action Table"
.Ds
.TA .5i 1.5i
.ta .5i 1.5i
XtActionsRec actionTable[] = {
    {"Set",    Set},
    {"Unset",    Unset},
    {"Highlight",    Highlight},
    {"Unhighlight",    Unhighlight}
    {"Notify",    Notify},
};
.De
.LP
The \*(xI reserve all action names and parameters starting with
the characters ``Xt'' for future standard enhancements.  Users,
applications, and widgets should not declare action names or pass
parameters starting with these characters except to invoke specified
built-in \*(xI functions.

.NH 3
Action Table Registration
.XS
\fB\*(SN Action Table Registration\fP
.XE
.LP
.IN "actions"
The \fIactions\fP and \fInum_actions\fP fields of
.PN CoreClassPart
specify the actions implemented by a widget class.  These are
automatically registered with the \*(xI when the class is initialized
and must be allocated in writable storage prior to Core class_part
initialization, and never deallocated.  To save memory and optimize
access, the \*(xI may overwrite the storage in order to compile the
list into an internal representation.
.sp

.LP
To declare an action table within an application
and register it with the translation manager, use
.PN XtAppAddActions .
.IN "XtAppAddActions" "" "@DEF@"
.FD 0
void XtAppAddActions(\fIapp_context\fP, \fIactions\fP, \fInum_actions\fP)
.br
      XtAppContext \fIapp_context\fP;
.br
      XtActionList \fIactions\fP;
.br
      Cardinal \fInum_actions\fP;
.FN
.IP \fIapp_context\fP 1i
Specifies the application context.
.IP \fIactions\fP 1i
Specifies the action table to register.
.IP \fInum_actions\fP 1i
Specifies the number of entries in this action table.
.LP
If more than one action is registered with the same name,
the most recently registered action is used.
If duplicate actions exist in an action table,
the first is used.
The \*(xI register an action table containing
.PN XtMenuPopup
and
.PN XtMenuPopdown
as part of
.PN XtCreateApplicationContext .

.NH 3
Action Names to Procedure Translations
.XS
\fB\*(SN Action Names to Procedure Translations\fP
.XE
.LP
The translation manager uses a simple algorithm to resolve the name of
a procedure specified in a translation table into the
actual procedure specified
in an action table.
When the widget
is realized, the translation manager
performs a search for the name in the following tables, in order:
.IP \(bu 5
The widget's class and all superclass action tables, in subclass-to-superclass
order.
.IP \(bu 5
The parent's class and all superclass action tables, in subclass-to-superclass
order, then on up the ancestor tree.
.IP \(bu 5
The action tables registered with
.PN XtAppAddActions
and
.PN XtAddActions
from the most recently added table to the oldest table.
.LP
As soon as it finds a name,
the translation manager stops the search.
If it cannot find a name,
the translation manager generates a warning message.

.NH 3
Action Hook Registration
.XS
\fB\*(SN Action Hook Registration\fP
.XE
.LP
An application can specify a procedure that will be called just before
every action routine is dispatched by the translation manager.  To do
so, the application supplies a procedure pointer of type
.PN XtActionHookProc .
.IN "XtActionHookProc" "" "@DEF@"
.FD 0
typedef void (*XtActionHookProc)(Widget, XtPointer, String, XEvent*, \
String*, Cardinal*);
.br
      Widget \fIw\fP;
.br
      XtPointer \fIclient_data\fP;
.br
      String \fIaction_name\fP;
.br
      XEvent* \fIevent\fP;
.br
      String* \fIparams\fP;
.br
      Cardinal* \fInum_params\fP;
.FN
.IP \fIw\fP 1i
Specifies the widget whose action is about to be dispatched.
.IP \fIclient_data\fP 1i
Specifies the application-specific closure that was passed to
.PN XtAppAddActionHook.
.IP \fIaction_name\fP 1i
Specifies the name of the action to be dispatched.
.IP \fIevent\fP 1i
Specifies the event argument that will be passed to the action routine.
.IP \fIparams\fP 1i
Specifies the action parameters that will be passed to the action routine.
.IP \fInum_params\fP 1i
Specifies the number of entries in \fIparams\fP.
.LP
Action hooks should not modify any of the data pointed to by the
arguments other than the \fIclient_data\fP argument.
.sp
.LP
To add an action hook, use
.PN XtAppAddActionHook .
.IN "XtAppAddActionHook" "" "@DEF@"
.FD 0
XtActionHookId XtAppAddActionHook(\fIapp\fP, \fIproc\fP, \fIclient_data\fP)
.br
      XtAppContext \fIapp\fP;
.br
      XtActionHookProc \fIproc\fP;
.br
      XtPointer \fIclient_data\fP;
.FN
.IP \fIapp\fP 1i
Specifies the application context.
.IP \fIproc\fP 1i
Specifies the action hook procedure.
.IP \fIclient_data\fP 1i
Specifies application-specific data to be passed to the action hook.
.LP
.PN XtAppAddActionHook
adds the specified procedure to the front of a list
maintained in the application context.  In the future, when an action
routine is about to be invoked for any widget in this application
context, either through the translation manager or via
.PN XtCallActionProc ,
the action hook procedures will be called in reverse
order of registration just prior to invoking the action routine.
.LP
Action hook procedures are removed automatically and the
.PN XtActionHookId s
destroyed when the application context in which
they were added is destroyed.
.sp
.LP
To remove an action hook procedure without destroying the application
context, use
.PN XtRemoveActionHook .
.IN "XtRemoveActionHook" "" "@DEF@"
.FD 0
void XtRemoveActionHook(\fIid\fP)
.br
      XtActionHookId \fIid\fP;
.FN
.IP \fIid\fP 1i
Specifies the action hook id returned by
.PN XtAppAddActionHook .
.LP
.PN XtRemoveActionHook
removes the specified action hook procedure from
the list in which it was registered.

.NH 2
Translation Tables
.XS
\fB\*(SN Translation Tables\fP
.XE
.LP
All widget instance records contain a translation table,
which is a resource with a default value specified elsewhere in the
class record.
A translation table specifies what action procedures are invoked for
an event or a sequence of events.
A translation table
is a string containing a list of translations from an event sequence
into one or more action procedure calls.
The translations are separated from one another by newline characters
(ASCII LF).
The complete syntax of translation tables is specified in Appendix B.
.LP
As an example, the default behavior of Pushbutton is
.IP \(bu 5
Highlight on enter window.
.IP \(bu 5
Unhighlight on exit window.
.IP \(bu 5
Invert on left button down.
.IP \(bu 5
Call callbacks and reinvert on left button up.
.LP
The following illustrates Pushbutton's default translation table:
.LP
.IN "Translation tables"
.Ds
.TA .5i 1.5i
.ta .5i 1.5i
static String defaultTranslations =
    "<EnterWindow>:    Highlight()\\n\\
    <LeaveWindow>:    Unhighlight()\\n\\
    <Btn1Down>:    Set()\\n\\
    <Btn1Up>:    Notify() Unset()";
.De
.LP
The \fItm_table\fP field of the
.PN CoreClassPart
should be filled in at class initialization time with
the string containing the class's default translations.
If a class wants to inherit its superclass's translations,
it can store the special value
.PN XtInheritTranslations
into \fItm_table\fP.
In Core's class part initialization procedure,
the \*(xI compile this translation table into an efficient internal form.
Then, at widget creation time,
this default translation table is
combined with the XtNtranslations
and XtNbaseTranslations resources; see Section 10.3.
.LP
The resource conversion mechanism automatically compiles
string translation tables that are specified in the resource database.
If a client uses translation tables that are not retrieved via a
resource conversion,
it must compile them itself using
.PN XtParseTranslationTable .
.LP
The \*(xI use the compiled form of the translation table to register the
necessary events with the event manager.
Widgets need do nothing other than specify the action and translation tables
for events to be processed by the translation manager.

.NH 3
Event Sequences
.XS
\fB\*(SN Event Sequences\fP
.XE
.LP
An event sequence is a comma-separated list of X event descriptions
that describes a specific sequence of X events to map to a set of
program actions.
Each X event description consists of three parts:
The X event type, a prefix consisting of the X modifier bits, and
an event-specific suffix.
.LP
Various abbreviations are supported to make translation tables easier
to read.  The events must match incoming events in left-to-right order
to trigger the action sequence.

.NH 3
Action Sequences
.XS
\fB\*(SN Action Sequences\fP
.XE
.LP
Action sequences specify what program or widget actions to take in response to
incoming X events. An action sequence consists of space-separated
action procedure call specifications.
Each action procedure call consists of the name of an action procedure and a
parenthesized list of zero or more comma-separated
string parameters to pass to that procedure.
The actions are invoked in left-to-right order as specified in the
action sequence.

.NH 3
Multi-click Time
.XS
\fB\*(SN Multi-click Time\fP
.XE
.LP
Translation table entries may specify actions that are taken when two
or more identical events occur consecutively within a short time
interval, called the multi-click time.  The multi-click time value may
be specified as an application resource with name ``multiClickTime'' and
.IN "multiClickTime" "" "@DEF@"
.IN "Resources" "multiClickTime"
class ``MultiClickTime'' and may also be modified dynamically by the
application.  The multi-click time is unique for each Display value and
is retrieved from the resource database by
.PN XtDisplayInitialize .
If no value is specified, the initial value is 200 milliseconds.
.sp
.LP
To set the multi-click time dynamically, use
.PN XtSetMultiClickTime .
.IN "XtSetMultiClickTime" "" "@DEF@"
.FD 0
void XtSetMultiClickTime(\fIdisplay\fP, \fItime\fP)
.br
      Display *\fIdisplay\fP;
.br
      int \fItime\fP;
.FN
.IP \fIdisplay\fP 1i
Specifies the display connection.
.IP \fItime\fP 1i
Specifies the multi-click time in milliseconds.
.LP
.PN XtSetMultiClickTime
sets the time interval used by the translation
manager to determine when multiple events are interpreted as a
repeated event.  When a repeat count is specified in a translation
entry, the interval between the timestamps in each pair of repeated
events (e.g., between two
.PN ButtonPress
events) must be less than the
multi-click time in order for the translation actions to be taken.
.sp
.LP
To read the multi-click time, use
.PN XtGetMultiClickTime .
.IN "XtGetMultiClickTime" "" "@DEF@"
.FD 0
int XtGetMultiClickTime(\fIdisplay\fP)
.br
      Display *\fIdisplay\fP;
.FN
.IP \fIdisplay\fP 1i
Specifies the display connection.
.LP
.PN XtGetMultiClickTime
returns the time in milliseconds that the
translation manager uses to determine if multiple events are to be
interpreted as a repeated event for purposes of matching a translation
entry containing a repeat count.

.NH 2
Translation Table Management
.XS
\fB\*(SN Translation Table Management\fP
.XE
.LP
Sometimes an application needs to merge
its own translations with a widget's translations.
For example, a window manager provides functions to move a window.
The window manager wishes to bind this operation to a specific
pointer button in the title bar without the possibility of user
override and bind it to other buttons that may be overridden by the user.
.LP
To accomplish this,
the window manager should first create the title bar
and then should merge the two translation tables into
the title bar's translations.
One translation table contains the translations that the window manager
wants only if the user has not specified a translation for a particular event
or event sequence (i.e., those that may be overridden).
The other translation table contains the translations that the
window manager wants regardless of what the user has specified.
.LP
Three \*(xI functions support this merging:
.TS
lw(2i) lw(3.75i).
T{
.PN XtParseTranslationTable
T}    T{
Compiles a translation table.
T}
.sp
T{
.PN XtAugmentTranslations
T}    T{
Merges a compiled translation table into a widget's
compiled translation table, ignoring any new translations that
conflict with existing translations.
T}
.sp
T{
.PN XtOverrideTranslations
T}    T{
Merges a compiled translation table into a widget's
compiled translation table, replacing any existing translations that
conflict with new translations.
T}
.TE
.sp
.LP
To compile a translation table, use
.PN XtParseTranslationTable .
.IN "XtParseTranslationTable" "" "@DEF@"
.FD 0
XtTranslations XtParseTranslationTable(\fItable\fP)
.br
      String \fItable\fP;
.FN
.IP \fItable\fP 1i
Specifies the translation table to compile.
.LP
The
.PN XtParseTranslationTable
function compiles the translation table, provided in the format given
in Appendix B, into an opaque internal representation
of type
.PN XtTranslations .
Note that if an empty translation table is required for any purpose,
one can be obtained by calling
.PN XtParseTranslationTable
and passing an empty string.
.sp
.LP
To merge additional translations into an existing translation table, use
.PN XtAugmentTranslations .
.IN "XtAugmentTranslations" "" "@DEF@"
.FD 0
void XtAugmentTranslations(\fIw\fP, \fItranslations\fP)
.br
      Widget \fIw\fP;
.br
      XtTranslations \fItranslations\fP;
.FN
.IP \fIw\fP 1i
Specifies the widget into which the new translations are to be merged.  \*(cI
.IP \fItranslations\fP 1i
Specifies the compiled translation table to merge in.
.LP
The
.PN XtAugmentTranslations
function merges the new translations into the existing widget
translations, ignoring any
.PN #replace ,
.PN #augment ,
or
.PN #override
directive that may have been specified
in the translation string.  The translation table specified by
\fItranslations\fP is not altered by this process.
.PN XtAugmentTranslations
logically appends the string representation of the new translations to
the string representation of the widget's current translations and reparses
the result with no warning messages about duplicate left-hand sides, then
stores the result back into the widget instance; i.e.,
if the new translations contain an event or event sequence that
already exists in the widget's translations,
the new translation is ignored.
.sp
.LP
To overwrite existing translations with new translations, use
.PN XtOverrideTranslations .
.IN "XtOverrideTranslations" "" "@DEF@"
.FD 0
void XtOverrideTranslations(\fIw\fP, \fItranslations\fP)
.br
      Widget \fIw\fP;
.br
      XtTranslations \fItranslations\fP;
.FN
.IP \fIw\fP 1i
Specifies the widget into which the new translations are to be merged. \*(cI
.IP \fItranslations\fP 1i
Specifies the compiled translation table to merge in.
.LP
The
.PN XtOverrideTranslations
function merges the new translations into the existing widget
translations, ignoring any
.PN #replace ,
.PN #augment ,
or
.PN #override
directive that may have been
specified in the translation string.  The translation table
specified by \fItranslations\fP is not altered by this process.
.PN XtOverrideTranslations
logically appends the string representation of the widget's current
translations to the string representation of the new translations and
reparses the result with no warning messages about duplicate left-hand
sides, then stores the result back into the widget instance; i.e.,
if the new translations contain an event or event sequence that
already exists in the widget's translations,
the new translation overrides the widget's translation.
.LP
To replace a widget's translations completely, use
.PN XtSetValues
on the XtNtranslations resource and specify a compiled translation table
as the value.
.sp
.LP
To make it possible for users to easily modify translation tables in their
resource files,
the string-to-translation-table resource type converter
allows the string to specify whether the table should replace,
augment, or override any
existing translation table in the widget.
To specify this,
a sharp sign (#) is given as the first character of the table
followed by one of the keywords ``replace'', ``augment'', or
``override'' to indicate
whether to replace, augment, or override the existing table.
The replace or merge
operation is performed during the
Core
instance initialization and
during the
Core
set_values invocation.
Each merge operation produces a new
translation resource value; if the original tables were shared by
other widgets, they are unaffected.  If no directive is
specified, ``#replace'' is assumed.

At instance initialization
the XtNtranslations resource is first fetched.  Then, if it was
not specified or did not contain ``#replace'', the
resource database is searched for the resource XtNbaseTranslations.
If XtNbaseTranslations is found it is merged into the widget class
translation table.  Then the widget \fItranslations\fP field is
merged into the result, or into the class translation table if
XtNbaseTranslations was not found.  This final table is then
stored into the widget \fItranslations\fP field.  If the XtNtranslations
resource specified ``#replace'' no merge is done.
If neither XtNbaseTranslations or XtNtranslations are specified,
the class translation table is copied into the widget instance.

.sp
.LP
To completely remove existing translations, use
.PN XtUninstallTranslations .
.IN "XtUninstallTranslations" "" "@DEF@"
.FD 0
void XtUninstallTranslations(\fIw\fP)
.br
      Widget \fIw\fP;
.FN
.IP \fIw\fP 1i
Specifies the widget from which the translations are to be removed.   \*(cI
.LP
The
.PN XtUninstallTranslations
function causes the entire translation table for the widget to be removed.

.NH 2
Using Accelerators
.XS
\fB\*(SN Using Accelerators\fP
.XE
.LP
It is often desirable to be able to bind events in one widget to actions in
another.
In particular,
it is often useful to be able to invoke menu actions from the keyboard.
The \*(xI provide a facility, called accelerators, that lets you
accomplish this.
.IN "Accelerator" "" "@DEF@"
An accelerator table is a translation table that is bound with its
actions in the context of a particular widget, the \fIsource\fP widget.
The accelerator table can then be installed on one or more \fIdestination\fP widgets.
When an event sequence in the destination widget would cause an
accelerator action to be taken, and if the source widget is sensitive,
the actions are executed as though triggered by the same event sequence
in the accelerator source
widget.  The event is
passed to the action procedure without modification.  The action
procedures used within accelerators must not assume that the source
widget is realized nor that any fields of the event are in reference
to the source widget's window if the widget is realized.
.LP
Each widget instance contains that widget's exported accelerator table
as a resource.
Each class of widget exports a method that takes a
displayable string representation of the accelerators
so that widgets can display their current accelerators.
The representation is the accelerator table in canonical
translation table form (see Appendix B).
The display_accelerator procedure pointer is of type
.PN XtStringProc .
.IN "display_accelerator procedure" "" "@DEF@"
.IN "XtStringProc" "" "@DEF@"
.FD 0
typedef void (*XtStringProc)(Widget, String);
.br
      Widget \fIw\fP;
.br
      String \fIstring\fP;
.FN
.IP \fIw\fP 1i
Specifies the source widget that supplied the accelerators.
.IP \fIstring\fP 1i
Specifies the string representation of the accelerators for this widget.
.LP
Accelerators can be specified in resource files,
and the string representation is the same as for a translation table.
However,
the interpretation of the
.PN #augment
and
.PN #override
directives applies to
what will happen when the accelerator is installed;
that is, whether or not the accelerator translations will override the
translations in the destination widget.
The default is
.PN #augment ,
which means that the accelerator translations have lower priority
than the destination translations.
The
.PN #replace
directive is ignored for accelerator tables.
.sp
.LP
To parse an accelerator table, use
.PN XtParseAcceleratorTable .
.IN "XtParseAcceleratorTable" "" "@DEF@"
.FD 0
XtAccelerators XtParseAcceleratorTable(\fIsource\fP)
.br
      String \fIsource\fP;
.FN
.IP \fIsource\fP 1i
Specifies the accelerator table to compile.
.LP
The
.PN XtParseAcceleratorTable
function compiles the accelerator table into an opaque internal representation.
The client
should set the XtNaccelerators resource of
each widget that is to be activated by these translations
to the returned value.
.sp
.LP
To install accelerators from a widget on another widget, use
.PN XtInstallAccelerators .
.IN "XtInstallAccelerators" "" "@DEF@"
.FD 0
void XtInstallAccelerators(\fIdestination\fP, \fIsource\fP)
.br
      Widget \fIdestination\fP;
.br
      Widget \fIsource\fP;
.FN
.IP \fIdestination\fP 1i
Specifies the widget on which the accelerators are to be installed.  \*(cI
.IP \fIsource\fP 1i
Specifies the widget from which the accelerators are to come.  \*(cI
.LP
The
.PN XtInstallAccelerators
function installs the \fIaccelerators\fP resource value from
\fIsource\fP onto \fIdestination\fP
by merging the the source accelerators into the destination translations.
If the source \fIdisplay_accelerator\fP field is non-NULL,
.PN XtInstallAccelerators
calls it with the source widget and a string representation
of the accelerator table,
which indicates that its accelerators have been installed
and that it should display them appropriately.
The string representation of the accelerator table is its
canonical translation table representation.
.sp
.LP
As a convenience for installing all accelerators from a widget and all its
descendants onto one destination, use
.PN XtInstallAllAccelerators .
.IN "XtInstallAllAccelerators" "" "@DEF@"
.FD 0
void XtInstallAllAccelerators(\fIdestination\fP, \fIsource\fP)
.br
      Widget \fIdestination\fP;
.br
      Widget \fIsource\fP;
.FN
.IP \fIdestination\fP 1i
Specifies the widget on which the accelerators are to be installed.  \*(cI
.IP \fIsource\fP 1i
Specifies the root widget of the widget tree
from which the accelerators are to come.  \*(cI
.LP
The
.PN XtInstallAllAccelerators
function recursively descends the widget tree rooted at \fIsource\fP
and installs the accelerators resource value
of each widget encountered onto \fIdestination\fP.
A common use is to call
.PN XtInstallAllAccelerators
and pass the application main window as the source.

.NH 2
KeyCode-to-KeySym Conversions
.XS
\*(SN KeyCode-to-KeySym Conversions
.XE
.LP
The translation manager provides support for automatically translating
KeyCodes in incoming key events into KeySyms.
KeyCode-to-KeySym translator procedure pointers are of type
.PN XtKeyProc .
.IN "XtKeyProc" "" "@DEF@"
.FD 0
typedef void (*XtKeyProc)(Display*, KeyCode, Modifiers, Modifiers*, \
KeySym*);
.br
      Display *\fIdisplay\fP;
.br
      KeyCode \fIkeycode\fP;
.br
      Modifiers \fImodifiers\fP;
.br
      Modifiers *\fImodifiers_return\fP;
.br
      KeySym *\fIkeysym_return\fP;
.FN
.IP \fIdisplay\fP 1.1i
Specifies the display that the KeyCode is from.
.IP \fIkeycode\fP 1.1i
Specifies the KeyCode to translate.
.IP \fImodifiers\fP 1.1i
Specifies the modifiers to the KeyCode.
.IP \fImodifiers_return\fP 1.1i
Specifies a location in which to store
a mask that indicates the subset of all
modifiers that are examined by the key translator.
.IP \fIkeysym_return\fP 1.1i
Specifies a location in which to store the resulting KeySym.
.LP
This procedure takes a KeyCode and modifiers and produces a KeySym.
For any given key translator function,
\fImodifiers_return\fP will be a constant that indicates the subset of all
modifiers that are examined by the key translator.
.LP
The KeyCode-to-KeySym translator procedure
must be implemented such that multiple calls with the same
\fIdisplay\fP, \fIkeycode\fP, and \fImodifiers\fP return the same
result until either a new case converter (
.PN XtCaseProc )
is installed or a
.PN MappingNotify
event is received.

.sp
.LP
The \*(xI maintain tables internally to map KeyCodes to KeySyms
for each open display.  Translator procedures and other clients may
share a single copy of this table to perform the same mapping.
.LP
To return a pointer to the KeySym-to-KeyCode mapping table for a
particular display, use
.PN XtGetKeysymTable .
.IN "XtGetKeysymTable" "" "@DEF@"
.FD 0
KeySym *XtGetKeysymTable(\fIdisplay\fP, \fImin_keycode_return\fP, \
\fIkeysyms_per_keycode_return\fP)
.br
      Display *\fIdisplay\fP;
.br
      KeyCode *\fImin_keycode_return\fP;
.br
      int *\fIkeysyms_per_keycode_return\fP;
.FN
.IP \fIdisplay\fP 1i
Specifies the display whose table is required.
.IP \fImin_keycode_return\fP 1i
Returns the minimum KeyCode valid for the display.
.IP \fIkeysyms_per_keycode_return\fP 1i
Returns the number of KeySyms stored for each KeyCode.
.LP
.PN XtGetKeysymTable
returns a pointer to the \*(xI' copy of the
server's KeyCode-to-KeySym table.  This table must not be modified.
There are \fIkeysyms_per_keycode_return\fP KeySyms associated with each
KeyCode, located in the table with indices starting at index
.IP
    (test_keycode - min_keycode_return) * keysyms_per_keycode_return
.LP
for KeyCode \fItest_keycode\fP.  Any entries that have no KeySyms associated
with them contain the value
.PN NoSymbol .
Clients should not cache the KeySym table but should call
.PN XtGetKeysymTable
each time the value is
needed, as the table may change prior to dispatching each event.
.LP
For more information on this table, see Section 12.7 in \fI\*(xL\fP.
.sp
.LP
To register a key translator, use
.PN XtSetKeyTranslator .
.IN "XtSetKeyTranslator" "" "@DEF@"
.FD 0
void XtSetKeyTranslator(\fIdisplay\fP, \fIproc\fP)
.br
      Display *\fIdisplay\fP;
.br
      XtKeyProc \fIproc\fP;
.FN
.IP \fIdisplay\fP 1i
Specifies the display from which to translate the events.
.IP \fIproc\fP 1i
Specifies the procedure to perform key translations.
.LP
The
.PN XtSetKeyTranslator
function sets the specified procedure as the current key translator.
The default translator is
.PN XtTranslateKey ,
an
.PN XtKeyProc
that uses the Shift, Lock, and group modifiers with the interpretations
defined in \fI\*(xP\fP, Section 5.
It is provided so that new translators can call it to get default
KeyCode-to-KeySym translations and so that the default translator
can be reinstalled.
.sp
.LP
To invoke the currently registered KeyCode-to-KeySym translator,
use
.PN XtTranslateKeycode .
.IN "XtTranslateKeycode" "" "@DEF@"
.FD 0
void XtTranslateKeycode(\fIdisplay\fP, \fIkeycode\fP, \fImodifiers\fP, \
\fImodifiers_return\fP, \fIkeysym_return\fP)
.br
      Display *\fIdisplay\fP;
.br
      KeyCode \fIkeycode\fP;
.br
      Modifiers \fImodifiers\fP;
.br
      Modifiers *\fImodifiers_return\fP;
.br
      KeySym *\fIkeysym_return\fP;
.FN
.IP \fIdisplay\fP 1.1i
Specifies the display that the KeyCode is from.
.IP \fIkeycode\fP 1.1i
Specifies the KeyCode to translate.
.IP \fImodifiers\fP 1.1i
Specifies the modifiers to the KeyCode.
.IP \fImodifiers_return\fP 1.1i
Returns a mask that indicates the modifiers actually used
to generate the KeySym.
.IP \fIkeysym_return\fP 1.1i
Returns the resulting KeySym.
.LP
The
.PN XtTranslateKeycode
function passes the specified arguments
directly to the currently registered KeyCode-to-KeySym translator.
.sp
.LP
To handle capitalization of nonstandard KeySyms, the \*(xI allow
clients to register case conversion routines.
Case converter procedure pointers are of type
.PN XtCaseProc .
.IN "XtCaseProc" "" "@DEF@"
.FD 0
typedef void (*XtCaseProc)(Display*, KeySym, KeySym*, KeySym*);
.br
      Display *\fIdisplay\fP;
.br
      KeySym \fIkeysym\fP;
.br
      KeySym *\fIlower_return\fP;
.br
      KeySym *\fIupper_return\fP;
.FN
.IP \fIdisplay\fP 1i
Specifies the display connection for which the conversion is required.
.IP \fIkeysym\fP 1i
Specifies the KeySym to convert.
.IP \fIlower_return\fP 1i
Specifies a location into which to store the lower-case equivalent for
the KeySym.
.IP \fIupper_return\fP 1i
Specifies a location into which to store the upper-case equivalent for
the KeySym.
.LP
If there is no case distinction,
this procedure should store the KeySym into both return values.
.sp
.LP
To register a case converter, use
.PN XtRegisterCaseConverter .
.IN "XtRegisterCaseConverter" "" "@DEF@"
.FD 0
void XtRegisterCaseConverter(\fIdisplay\fP, \fIproc\fP, \fIstart\fP, \fIstop\fP)
.br
    Display *\fIdisplay\fP;
.br
    XtCaseProc \fIproc\fP;
.br
    KeySym \fIstart\fP;
.br
    KeySym \fIstop\fP;
.FN
.IP \fIdisplay\fP 1i
Specifies the display from which the key events are to come.
.IP \fIproc\fP 1i
Specifies the
.PN XtCaseProc
to do the conversions.
.IP \fIstart\fP 1i
Specifies the first KeySym for which this converter is valid.
.IP \fIstop\fP 1i
Specifies the last KeySym for which this converter is valid.
.LP
The
.PN XtRegisterCaseConverter
registers the specified case converter.
The \fIstart\fP and \fIstop\fP arguments provide the inclusive range of KeySyms
for which this converter is to be called.
The new converter overrides any previous converters for KeySyms in that range.
No interface exists to remove converters;
you need to register an identity converter.
When a new converter is registered,
the \*(xI  refresh the keyboard state if necessary.
The default converter understands case conversion for all
Latin KeySyms defined in \fI\*(xP\fP, Appendix A.
.sp
.LP
To determine upper- and lower-case equivalents for a KeySym, use
.PN XtConvertCase .
.IN "XtConvertCase" "" "@DEF@"
.FD 0
void XtConvertCase(\fIdisplay\fP, \fIkeysym\fP, \fIlower_return\fP, \
\fIupper_return\fP)
.br
    Display *\fIdisplay\fP;
.br
    KeySym \fIkeysym\fP;
.br
    KeySym *\fIlower_return\fP;
.br
    KeySym *\fIupper_return\fP;
.FN
.IP \fIdisplay\fP 1i
Specifies the display that the KeySym came from.
.IP \fIkeysym\fP 1i
Specifies the KeySym to convert.
.IP \fIlower_return\fP 1i
Returns the lower-case equivalent of the KeySym.
.IP \fIupper_return\fP 1i
Returns the upper-case equivalent of the KeySym.
.LP
The
.PN XtConvertCase
function calls the appropriate converter and returns the results.
A user-supplied
.PN XtKeyProc
may need to use this function.

.NH 2
Obtaining a KeySym in an Action Procedure
.XS
\fB\*(SN Obtaining a KeySym in an Action Procedure\fP
.XE
.LP
When an action procedure is invoked on a
.PN KeyPress
or
.PN KeyRelease
event, it often has a need to retrieve the KeySym and modifiers
corresponding to the event that caused it to be invoked.  In order to
avoid repeating the processing that was just performed by the
\*(xI to match the translation entry, the KeySym and modifiers
are stored for the duration of the action procedure and are made
available to the client.
.LP
To retrieve the KeySym and modifiers that matched the final event
specification in the translation table entry, use
.PN XtGetActionKeysym .
.IN "XtGetActionKeysym" "" "@DEF@"
.FD 0
KeySym XtGetActionKeysym(\fIevent\fP, \fImodifiers_return\fP)
.br
      XEvent *\fIevent\fP;
.br
      Modifiers *\fImodifiers_return\fP;
.FN
.IP \fIevent\fP 1.25i
Specifies the event pointer passed to the action procedure by the \*(xI.
.IP \fImodifiers_return\fP 1.25i
Returns the modifiers that caused the match, if non-NULL.
.LP
If
.PN XtGetActionKeysym
is called after an action procedure has been
invoked by the \*(xI and before that action procedure returns, and
if the event pointer has the same value as the event pointer passed to
that action routine, and if the event is a
.PN KeyPress
or
.PN KeyRelease
event, then
.PN XtGetActionKeysym
returns the KeySym that matched the final
event specification in the translation table and, if \fImodifiers_return\fP
is non-NULL, the modifier state actually used to generate this KeySym;
otherwise, if the event is a
.PN KeyPress
or
.PN KeyRelease
event, then
.PN XtGetActionKeysym
calls
.PN XtTranslateKeycode
and returns the results;
else it returns
.PN NoSymbol
and does not examine \fImodifiers_return\fP.
.LP
Note that if an action procedure invoked by the \*(xI
invokes a subsequent action procedure (and so on) via
.PN XtCallActionProc ,
the nested action procedure may also call
.PN XtGetActionKeysym
to retrieve the \*(xI' KeySym and modifiers.

.NH 2
KeySym-to-KeyCode Conversions
.XS
\*(SN KeySym-to-KeyCode Conversions
.XE
.LP
To return the list of KeyCodes that map to a particular KeySym in
the keyboard mapping table maintained by the \*(xI, use
.PN XtKeysymToKeycodeList .
.IN "XtKeysymToKeycodeList" "" "@DEF@"
.FD 0
void XtKeysymToKeycodeList(\fIdisplay\fP, \fIkeysym\fP, \fIkeycodes_return\fP, \
\fIkeycount_return\fP)
.br
      Display *\fIdisplay\fP;
.br
      KeySym \fIkeysym\fP;
.br
      KeyCode **\fIkeycodes_return\fP;
.br
      Cardinal *\fIkeycount_return\fP;
.FN
.IP \fIdisplay\fP 1.25i
Specifies the display whose table is required.
.IP \fIkeysym\fP 1.25i
Specifies the KeySym for which to search.
.IP \fIkeycodes_return\fP 1.25i
Returns a list of KeyCodes that have \fIkeysym\fP
associated with them, or NULL if \fIkeycount_return\fP is 0.
.IP \fIkeycount_return\fP 1.25i
Returns the number of KeyCodes in the keycode list.
.LP
The
.PN XtKeysymToKeycodeList
procedure returns all the KeyCodes that have \fIkeysym\fP
in their entry for the keyboard mapping table associated with \fIdisplay\fP.
For each entry in the
table, the first four KeySyms (groups 1 and 2) are interpreted as
specified by \fI\*(xP\fP, Section 5.  If no KeyCodes map to the
specified KeySym, \fIkeycount_return\fP is zero and *\fIkeycodes_return\fP is NULL.
.LP
The caller should free the storage pointed to by \fIkeycodes_return\fP using
.PN XtFree
when it is no longer useful.  If the caller needs to examine
the KeyCode-to-KeySym table for a particular KeyCode, it should call
.PN XtGetKeysymTable .

.NH 2
Registering Button and Key Grabs For Actions
.XS
\fB\*(SN Registering Button and Key Grabs For Actions\fP
.XE
.LP
To register button and key grabs for a widget's window according to the
event bindings in the widget's translation table, use
.PN XtRegisterGrabAction .
.IN "XtRegisterGrabAction" "" "@DEF@"
.FD 0
void XtRegisterGrabAction(\fIaction_proc\fP, \fIowner_events\fP, \
\fIevent_mask\fP, \fIpointer_mode\fP, \fIkeyboard_mode\fP)
.br
      XtActionProc \fIaction_proc\fP;
.br
      Boolean \fIowner_events\fP;
.br
      unsigned int \fIevent_mask\fP;
.br
      int \fIpointer_mode\fP, \fIkeyboard_mode\fP;
.FN
.IP \fIaction_proc\fP 1i
Specifies the action procedure to search for in translation tables.
.sp
.IP \fIowner_events\fP
.br
.ns
.IP \fIevent_mask\fP
.br
.ns
.IP \fIpointer_mode\fP
.br
.ns
.IP \fIkeyboard_mode\fP 1i
Specify arguments to
.PN XtGrabButton
or
.PN XtGrabKey .
.LP
.PN XtRegisterGrabAction
adds the specified \fIaction_proc\fP to a list known to
the translation manager.  When a widget is realized, or when the
translations of a realized widget or the accelerators installed on a
realized widget are modified, its translation table and any installed
accelerators are scanned for action procedures on this list.
If any are invoked on
.PN ButtonPress
or
.PN KeyPress
events as the only or final event
in a sequence, the \*(xI will call
.PN XtGrabButton
or
.PN XtGrabKey
for the widget with every button or KeyCode which maps to the
event detail field, passing the specified \fIowner_events\fP, \fIevent_mask\fP,
\fIpointer_mode\fP, and \fIkeyboard_mode\fP.  For
.PN ButtonPress
events, the modifiers
specified in the grab are determined directly from the translation
specification and \fIconfine_to\fP and \fIcursor\fP are specified as
.PN None .
For
.PN KeyPress
events, if the translation table entry specifies colon (:) in
the modifier list, the modifiers are determined by calling the key
translator procedure registered for the display and calling
.PN XtGrabKey
for every combination of standard modifiers which map the KeyCode to
the specified event detail KeySym, and ORing any modifiers specified in
the translation table entry, and \fIevent_mask\fP is ignored.  If the
translation table entry does not specify colon in the modifier list,
the modifiers specified in the grab are those specified in the
translation table entry only.  For both
.PN ButtonPress
and
.PN KeyPress
events, don't-care modifiers are ignored unless the translation entry
explicitly specifies ``Any'' in the \fImodifiers\fP field.
.LP
If the specified \fIaction_proc\fP is already registered for the calling
process, the new values will replace the previously specified values
for any widgets that become realized following the call, but existing
grabs are not altered on currently-realized widgets.
.LP
When translations or installed accelerators are modified for a
realized widget, any previous key or button grabs registered
as a result of the old bindings are released if they do not appear in
the new bindings and are not explicitly grabbed by the client with
.PN XtGrabKey
or
.PN XtGrabButton .

.NH 2
Invoking Actions Directly
.XS
\fB\*(SN Invoking Actions Directly\fP
.XE
.LP
Normally action procedures are invoked by the \*(xI when an
event or event sequence arrives for a widget. To
invoke an action procedure directly, without generating
(or synthesizing) events, use
.PN XtCallActionProc .
.IN "XtCallActionProc" "" "@DEF@"
.FD 0
void XtCallActionProc(\fIwidget\fP, \fIaction\fP, \fIevent\fP, \fIparams\fP, \
\fInum_params\fP)
.br
      Widget \fIwidget\fP;
.br
      String \fIaction\fP;
.br
      XEvent *\fIevent\fP;
.br
      String *\fIparams\fP;
.br
      Cardinal \fInum_params\fP;
.FN
.IP \fIwidget\fP 1i
Specifies the widget in which the action is to be invoked.  \*(cI
.IP \fIaction\fP 1i
Specifies the name of the action routine.
.IP \fIevent\fP 1i
Specifies the contents of the \fIevent\fP passed to the action routine.
.IP \fIparams\fP 1i
Specifies the contents of the \fIparams\fP passed to the action routine.
.IP \fInum_params\fP 1i
Specifies the number of entries in \fIparams\fP.
.LP
.PN XtCallActionProc
searches for the named action routine in the same
manner and order as translation tables are bound, as described in
Section 10.1.2, except that application action tables are searched, if
necessary, as of the time of the call to
.PN XtCallActionProc .
If found,
the action routine is invoked with the specified widget, event pointer,
and parameters.  It is the responsibility of the caller to ensure that
the contents of the \fIevent\fP, \fIparams\fP, and \fInum_params\fP arguments are
appropriate for the specified action routine and, if necessary, that
the specified widget is realized or sensitive.  If the named action
routine cannot be found,
.PN XtCallActionProc
generates a warning message and returns.

.NH 2
Obtaining a Widget's Action List
.XS
\*(SN Obtaining a Widget's Action List
.XE
.LP
Occasionally a subclass will require the pointers to one or more of
its superclass's action procedures.  This would be needed, for
example, in order to envelope the superclass's action.  To retrieve
the list of action procedures registered in the superclass's
\fIactions\fP field, use
.PN XtGetActionList .
.IN "XtGetActionList" "" "@DEF@"
.FD 0
void XtGetActionList(\fIwidget_class\fP, \fIactions_return\fP, \
\fInum_actions_return\fP)
.br
      WidgetClass \fIwidget_class\fP;
.br
      XtActionList *\fIactions_return\fP;
.br
      Cardinal *\fInum_actions_return\fP;
.FN
.IP \fIwidget_class\fP 1i
Specifies the widget class whose actions are to be returned.
.IP \fIactions_return\fP 1i
Returns the action list.
.IP \fInum_actions_return\fP 1i
Returns the number of action procedures declared by the class.
.LP
.PN XtGetActionList
returns the action table defined by the specified
widget class.  This table does not include actions defined by the
superclasses.  If \fIwidget_class\fP is not initialized, or is not
.PN coreWidgetClass
or a subclass thereof, or if the class does not define any actions,
*\fIactions_return\fP will be NULL and *\fInum_actions_return\fP
will be zero.
If *\fIactions_return\fP is non-NULL the client is responsible for freeing
the table using
.PN XtFree
when it is no longer needed.

.bp