Athena Widget Set — C Language Interface

X Window System

X Version 11, Release 7

libXaw 1.0.7

Chris D. Peterson
formerly MIT X Consortium

X Window System is a trademark of The Open Group.

Copyright © 1985, 1986, 1987, 1988, 1989, 1991, 1994 X Consortium

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the ‘‘Software’’), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED ‘‘AS IS’’, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE X CONSORTIUM BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Except as contained in this notice, the name of the X Consortium shall not be used in advertising or otherwise to promote the sale, use or other dealings in this Software without prior written authorization from the X Consortium.

Copyright © 1985, 1986, 1987, 1988, 1989, 1991 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 Digital not be used in in advertising or publicity pertaining to distribution of the software without specific, written prior permission. 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.

Acknowledgments

Many thanks go to Ralph Swick (Project Athena / Digital) who has contributed much time and effort to this widget set. Previous versions of the widget set are largely due to his time and effort. Many of the improvements that I have been able to make are because he provided a solid foundation to build upon. While much of the effort has been Ralph’s, many other people have contributed to the code.

Mark Ackerman (formerly Project Athena)
Donna Converse (MIT X Consortium)
Jim Fulton (formerly MIT X Consortium)
Loretta Guarino-Reid (Digital WSL)
Charles Haynes (Digital WSL)
Rich Hyde (Digital WSL)
Mary Larson (Digital UEG)
Joel McCormack (Digital WSL)
Ron Newman (formerly Project Athena)
Jeanne Rich (Digital WSL)
Terry Weissman (formerly Digital WSL)

While not much remains of the X10 toolkit, many of the ideas for this widget set come from that original version. The design and implementation of the X10 toolkit were done by:

Mike Gancarz (formerly Digital UEG)
Charles Haynes (Digital WSL)
Phil Karlton (formerly Digital WSL)
Kathleen Langone (Digital UEG)
Mary Larson (Digital UEG)
Ram Rao (Digital UEG)
Smokey Wallace (formerly Digital WSL)
Terry Weissman (formerly Digital WSL)

I have used the formatting ideas, and some of the words from previous versions of this document. The X11R3 Athena widget document was written by:

Ralph R. Swick (Project Athena/ Digital)
Terry Weissman (formerly Digital WSL)
Al Mento (Digital UEG)

Putting this manual together was a major task in and of itself. I would like to thank Ralph Swick, Donna Converse, and Jim Fulton for taking the time to help convert my technical knowledge into legible text. A special thanks to Jean Diaz (O’Reilly and Associates) for spending nearly a month with me working out all the annoying little details.

Chris D. Peterson
MIT X Consortium 1989

The R5 edition of this document has been edited by the research staff of the MIT X Consortium, with significant contributions by Jim Fulton (NCD).

Donna Converse
MIT X Consortium 1991

The R6 edition of this document has been edited to reflect changes brought about by research staff of the Omron Corporation, with special recognition to Li Yuhong, Seiji Kuwari, and Hiroshi Kuribayashi for the X11R5/contrib/lib/Xaw internationalization that inspired this version.

Frank Sheeran
Omron Corporation 1994

Chapter 1

Athena Widgets and The Intrinsics

The X Toolkit is made up of two distinct pieces, the Xt Intrinsics and a widget set. The Athena widget set is a sample implementation of a widget set built upon the Intrinsics. In the X Toolkit, a widget is the combination of an X window or subwindow and its associated input and output semantics.

Because the Intrinsics provide the same basic functionality to all widget sets it may be possible to use widgets from the Athena widget set with other widget sets based upon the Intrinsics. Since widget sets may also implement private protocols, all functionality may not be available when mixing and matching widget sets. For information about the Intrinsics, see the X Toolkit Intrinsics — C Language Interface.

The Athena widget set is a library package layered on top of the Intrinsics and Xlib that provides a set of user interface tools sufficient to build a wide variety of applications. This layer extends the basic abstractions provided by X and provides the next layer of functionality primarily by supplying a cohesive set of sample widgets. Although the Intrinsics are a Consortium standard, there is no standard widget set.

To the extent possible, the Intrinsics are "policy-free". The application environment and widget set, not the Intrinsics, define, implement, and enforce:

Each individual widget implementation defines its own policy. The X Toolkit design allows for, but does not necessarily encourage, the free mixing of radically differing widget implementations.

1.1. Introduction to the X Toolkit

The X Toolkit provides tools that simplify the design of application user interfaces in the X Window System programming environment. It assists application programmers by providing a set of common underlying user-interface functions. It also lets widget programmers modify existing widgets, by subclassing, or add new widgets. By using the X Toolkit in their applications, programmers can present a similar user interface across applications to all workstation users.

The X Toolkit consists of:

While the majority of the Intrinsics functions are intended for the widget programmer, a subset of the Intrinsics functions are to be used by application programmers (see X Toolkit Intrinsics — C Language Interface). The architectural model lets the widget programmer design new widgets by using the Intrinsics and by combining other widgets. The application interface layers built on top of the X Toolkit include a coordinated set of widgets and composition policies. Some of these widgets and policies are specific to a single application domain, and others are common to a variety of applications.

The remainder of this chapter discusses the X Toolkit and Athena widget set:

1.2. Terminology

In addition to the terms already defined for X programming (see Xlib — C Language X Interface), the following terms are specific to the Intrinsics and Athena widget set and used throughout this document.

Application programmer

A programmer who uses the X Toolkit to produce an application user interface.

Child

A widget that is contained within another "parent" widget.

Class

The general group to which a specific object belongs.

Client

A function that uses a widget in an application or for composing other widgets.

FullName

The name of a widget instance appended to the full name of its parent.

Instance

A specific widget object as opposed to a general widget class.

Method

A function or procedure implemented by a widget class.

Name

The name that is specific to an instance of a widget for a given client. This name is specified at creation time and cannot be modified.

Object

A data abstraction consisting of private data and private and public functions that operate on the private data. Users of the abstraction can interact with the object only through calls to the object’s public functions. In the X Toolkit, some of the object’s public functions are called directly by the application, while others are called indirectly when the application calls the common Intrinsics functions. In general, if a function is common to all widgets, an application uses a single Intrinsics function to invoke the function for all types of widgets. If a function is unique to a single widget type, the widget exports the function.

Parent

A widget that contains at least one other ("child") widget. A parent widget is also known as a composite widget.

Resource

A named piece of data in a widget that can be set by a client, by an application, or by user defaults.

Superclass

A larger class of which a specific class is a member. All members of a class are also members of the superclass.

User

A person interacting with a workstation.

Widget

An object providing a user-interface abstraction (for example, a Scrollbar widget).

Widget class

The general group to which a specific widget belongs, otherwise known as the type of the widget.

Widget programmer

A programmer who adds new widgets to the X Toolkit.

1.3. Underlying Model

The underlying architectural model is based on the following premises:

Widgets are X windows

Every user-interface widget is associated with an X
window. The X window ID for a widget is readily avail-
able from the widget. Standard Xlib calls can be used
by widgets for many of their input and output opera-
tions.

Information hiding

The data for every widget is private to the widget and
its subclasses. That is, the data is neither directly
accessible nor visible outside of the module implement-
ing the widget. All program interaction with the wid-
get is performed by a set of operations (methods) that
are defined for the widget.

Widget semantics and widget layout geometry

Widget semantics are clearly separated from widget lay-
out geometry. Widgets are concerned with implementing
specific user-interface semantics. They have little
control over issues such as their size or placement
relative to other widget peers. Mechanisms are provid-
ed for associating geometric managers with widgets and
for widgets to make suggestions about their own geome-
try.

1.4. Conventions Used in this Manual

1.5. Format of the Widget Reference Chapters

The majority of this document is a reference guide for the Athena widget set. Chapters three through six give the programmer all information necessary to use the widgets. The layout of the chapters follows a specific pattern to allow the programmer to easily find the desired information.

The first few pages of every chapter give an overview of the widgets in that section. Widgets are grouped into chapters by functionality.

Chapter 3
Simple Widgets

Chapter 4
Menus

Chapter 5
Text Widgets

Chapter 6
Composite and Constraint Widget

Following the introduction will be a description of each widget in that chapter. When no functional grouping is obvious the widgets are listed in alphabetical order, such as in chapters three and six.

The first section of each widget’s description is a table that contains general information about this widget class. Here is the table for the Box widget, and an explanation of all the entries.

Application Header file<X11/Xaw/Box.h>

Application Header File
This file must be included when an application uses this widget. It usually contains the class definition, and some resource macros. This is often called the ‘‘public’’ header file.

After this table follows a general description of the default behavior of this widget, as seen by the user. In many cases this functionality may be overridden by the application programmer, or by the user.

The next section is a table showing the name, class, type and default value of each resource that is available to this widget. There is also a column containing notes describing special restrictions placed upon individual resources.

After the resource table is a detailed description of every resource available to that widget. Many of these are redundant, but printing them with each widget saves page flipping. The names of the resources that are inherited are printed in plain text, while the names of the resources that are new to this class are printed in bold. If you have already read the description of the superclass you need only pay attention to the resources printed in bold.

For each composite widget there is a section on layout semantics that follows the resource description. This section will describe the effect of constraint resources on the layout of the children, as well as a general description of where it prefers to place its children.

Descriptions of default translations and action routines come next, for widgets to which they apply. The last item in each widget’s documentation is the description of all convenience routines provided by the widget.

1.6. Input Focus

The Intrinsics define a resource on all Shell widgets that interact with the window manager called input. This resource requests the assistance of window manager in acquiring the input focus. The resource defaults to False in the Intrinsics, but is redefined to default to True when an application is using the Athena widget set. An application programmer may override this default and set the resource back to False if the application does not need the window manager to give it the input focus. See the X Toolkit Intrinsics — C Language Interface for details on the input resource.

Chapter 2

Using Widgets

Widgets serve as the primary tools for building a user interface or application environment. The Athena widget set consists of primitive widgets that contain no children (for example, a command button) and composite widgets which may contain one or more widget children (for example, a Box widget).

The remaining chapters explain the widgets that are provided by the Athena widget set. These user-interface components serve as an interface for application programmers who do not want to implement their own widgets. In addition, they serve as a starting point for those widget programmers who, using the Intrinsics mechanisms, want to implement alternative application programming interfaces.

This chapter is a brief introduction to widget programming. The examples provided use the Athena widgets, though most of the concepts will apply to all widget sets. Although there are several programming interfaces to the X Toolkit, only one is described here. A full description of the programming interface is provided in the document X Toolkit Intrinsics — C Language Interface.

2.1. Setting the Locale

If it is desirable that the application take advantage of internationalization (i18n), you must establish locale with XtSetLanguageProc before XtDisplayInitialize or XtAppInitialize is called. For full details, please refer to the document X Toolkit Intrinsics — C Language Interface, section 2.2. However, the following simplest-case call is sufficient in many or most applications.

Most notably, this will affect the Standard C locale, determine which resource files will be loaded, and what fonts will be required of FontSet specifications. In many cases, the addition of this line is the only source change required to internationalize Xaw programs, and will not disturb the function of programs in the default "C" locale.

2.2. Initializing the Toolkit

You must call a toolkit initialization function before invoking any other toolkit routines (besides locale setting, above). XtAppInitialize opens the X server connection, parses the command line, and creates an initial widget that will serve as the root of a tree of widgets created by this application.
Widget XtAppInitialize(app_context_return, application_class, options, num_options,

XtAppContext *app_context_return;
String application_class;
XrmOptionDescRec options[];
Cardinal num_options;
int *argc_in_out;
String *argv_in_out[];
String *fallback_resources;
ArgList args;
Cardinal num_args;

application_class
Specifies the class name of this application, which is usually the generic name for all instances of this application. A useful convention is to form the class name by capitalizing the first letter of the application name. For example, the application named ‘‘xman’’ has a class name of ‘‘Xman’’.

fallback_resources
Specifies resource values to be used if the site-wide application class defaults file cannot be opened, or NULL.

This function will remove the command line arguments that the toolkit reads from argc_in_out, and argv_in_out. It will then attempt to open the display. If the display cannot be opened, an error message is issued and XtAppInitialize terminates the application. Once the display is opened, all resources are read from the locations specified by the Intrinsics. This function returns an ApplicationShell widget to be used as the root of the application’s widget tree.

2.3. Creating a Widget

Creating a widget is a three-step process. First, the widget instance is allocated, and various instance-specific attributes are set by using XtCreateWidget. Second, the widget’s parent is informed of the new child by using XtManageChild. Finally, X windows are created for the parent and all its children by using XtRealizeWidget and specifying the top-most widget. The first two steps can be combined by using XtCreateManagedWidget. In addition, XtRealizeWidget is automatically called when the child becomes managed if the parent is already realized.

To allocate, initialize, and manage a widget, use XtCreateManagedWidget.
Widget XtCreateManagedWidget(name, widget_class, parent, args, num_args)
String name;
WidgetClass widget_class;
Widget parent;
ArgList args;
Cardinal num_args;

widget_class
Specifies the widget class pointer for the created widget.

When a widget instance is successfully created, the widget identifier is returned to the application. If an error is encountered, the XtError routine is invoked to inform the user of the error.

For further information, see X Toolkit Intrinsics — C Language Interface.

2.4. Common Resources

Although a widget can have unique arguments that it understands, all widgets have common arguments that provide some regularity of operation. The common arguments allow arbitrary widgets to be managed by higher-level components without regard for the individual widget type. Widgets will ignore any argument that they do not understand.

The following resources are retrieved from the argument list or from the resource database by all of the Athena widgets:
Name Class Type Default Value
accelerators Accelerators AcceleratorTable NULL
ancestorSensitive AncestorSensitive Boolean True
background Background Pixel XtDefaultBackground
backgroundPixmap Pixmap Pixmap XtUnspecifiedPixmap
borderColor BorderColor Pixel XtDefaultForeground
borderPixmap Pixmap Pixmap XtUnspecifiedPixmap
borderWidth BorderWidth Dimension 1
colormap Colormap Colormap Parent’s Colormap
depth Depth int Parent’s Depth
destroyCallback Callback XtCallbackList NULL
height Height Dimension widget dependent
mappedWhenManaged MappedWhenManaged Boolean True
screen Screen Screen Parent’s Screen
sensitive Sensitive Boolean True
translations Translations TranslationTable widget dependent
width Width Dimension widget dependent
x Position Position 0
y Position Position 0

The following additional resources are retrieved from the argument list or from the resource database by many of the Athena widgets:
Name Class Type Default Value
callback Callback XtCallbackList NULL
cursor Cursor Cursor widget dependent
foreground Foreground Pixel XtDefaultForeground
insensitiveBorder Insensitive Pixmap GreyPixmap

2.5. Resource Conversions

Most resources in the Athena widget set have a converter registered that will translate the string in a resource file to the correct internal representation. While some are obvious (string to integer, for example), others need specific mention of the allowable values. Three general converters are described here:

Many widgets have defined special converters that apply only to that widget. When these occur, the documentation section for that widget will describe the converter.

2.5.1. Cursor Conversion

The value for the cursorName resource is specified in the resource database as a string, and is of the following forms:

2.5.2. Pixel Conversion

The string-to-pixel converter takes any name that is acceptable to XParseColor (see Xlib — C Language X Interface). In addition this routine understands the special toolkit symbols ‘XtDefaultForeground’ and ‘XtDefaultBackground’, described in X Toolkit Intrinsics — C Language Interface. In short the acceptable pixel names are:

2.5.3. Bitmap Conversion

The string-to-bitmap converter attempts to locate a file containing bitmap data whose name is specified by the input string. If the file name is relative (i.e. does not begin with / or ./), the directories to be searched are specified in the bitmapFilePath resource--class BitmapFilePath. This resource specifies a colon (:) separated list of directories that will be searched for the named bitmap or cursor glyph (see section 2.4.1). The bitmapFilePath resource is global to the application, and may not be specified differently for each widget that wishes to convert a cursor to bitmap. In addition to the directories specified in the bitmapFilePath resource a default directory is searched. When using POSIX the default directory is /usr/include/X11/bitmaps.

2.6. Realizing a Widget

The XtRealizeWidget function performs two tasks:

void XtRealizeWidget(w)
Widget w;

For further information about this function, see the X Toolkit Intrinsics — C Language Interface.

2.7. Processing Events

Now that the application has created, managed and realized its widgets, it is ready to process the events that will be delivered by the X Server to this client. A function call that will process the events is XtAppMainLoop.
void XtAppMainLoop(app_context)
XtAppContext app_context;

app_contextSpecifies the application context of this application. The value is normally returned by XtAppInitialize.

This function never returns: it is an infinite loop that processes the X events. User input can be handled through callback procedures and application defined action routines. More details are provided in X Toolkit Intrinsics — C Language Interface.

2.8. Standard Widget Manipulation Functions

After a widget has been created, a client can interact with that widget by calling one of the standard widget manipulation routines provided by the Intrinsics, or a widget class-specific manipulation routine.

The Intrinsics provide generic routines to give the application programmer access to a set of standard widget functions. The common widget routines let an application or composite widget perform the following operations on widgets without requiring explicit knowledge of the widget type.

2.8.1. Mapping Widgets

By default, widget windows are mapped (made viewable) automatically by XtRealizeWidget. This behavior can be disabled by using XtSetMappedWhenManaged, making the client responsible for calling XtMapWidget to make the widget viewable.
void XtSetMappedWhenManaged(w, map_when_managed)
Widget w;
Boolean map_when_managed;

map_when_managed
Specifies the new value. If map_when_managed is True, the widget is mapped automatically when it is realized. If map_when_managed is False, the client must call XtMapWidget or make a second call to XtSetMappedWhenManaged to cause the child window to be mapped.

The definition for XtMapWidget is:
void XtMapWidget(w)
Widget w;

When you are creating several children in sequence for a previously realized common parent it is generally more efficient to construct a list of children as they are created (using XtCreateWidget) and then use XtManageChildren to request that their parent managed them all at once. By managing a list of children at one time, the parent can avoid wasteful duplication of geometry processing and the associated ‘‘screen flash’’.
void XtManageChildren(children, num_children)
WidgetList children;
Cardinal num_children;

num_children
Specifies the number of children to add.

If the parent is already visible on the screen, it is especially important to batch updates so that the minimum amount of visible window reconfiguration is performed.

For further information about these functions, see the X Toolkit Intrinsics — C Language Interface.

2.8.2. Destroying Widgets

To destroy a widget instance of any type, use XtDestroyWidget.
void XtDestroyWidget(w)
Widget w;

XtDestroyWidget destroys the widget and recursively destroys any children that it may have, including the windows created by its children. After calling XtDestroyWidget, no further references should be made to the widget or any children that the destroyed widget may have had.

2.8.3. Retrieving Widget Resource Values

To retrieve the current value of a resource attribute associated with a widget instance, use XtGetValues.
void XtGetValues(w, args, num_args)
Widget w;
ArgList args;
Cardinal num_args;

The arguments and values passed in the argument list are dependent on the widget. Note that the caller is responsible for providing space into which the returned resource value is copied; the ArgList contains a pointer to this storage (e.g. x and y must be allocated as Position). For further information, see the X Toolkit Intrinsics — C Language Interface.

2.8.4. Modifying Widget Resource Values

To modify the current value of a resource attribute associated with a widget instance, use XtSetValues.
void XtSetValues(w, args, num_args)
Widget w;
ArgList args;
Cardinal num_args;

The arguments and values that are passed will depend on the widget being modified. Some widgets may not allow certain resources to be modified after the widget instance has been created or realized. No notification is given if any part of a XtSetValues request is ignored.

For further information about these functions, see the X Toolkit Intrinsics — C Language Interface.

Note

The argument list entry for XtGetValues specifies the address to which the caller wants the value copied. The argument list entry for XtSetValues, however, contains the new value itself, if the size of value is less than sizeof(XtArgVal) (architecture dependent, but at least sizeof(long)); otherwise, it is a pointer to the value. String resources are always passed as pointers, regardless of the length of the string.

2.9. Using the Client Callback Interface

Widgets can communicate changes in their state to their clients by means of a callback facility. The format for a client’s callback handler is:
void CallbackProc(w, client_data, call_data)
Widget w;
XtPointer client_data;
XtPointer call_data;

client_dataSpecifies arbitrary client-supplied data that the widget should pass back to the client when the widget executes the client’s callback procedure. This is a way for the client registering the callback to also register client-specific data: a pointer to additional information about the widget, a reason for invoking the callback, and so on. If no additional information is necessary, NULL may be passed as this argument. This field is also frequently known as the closure.

Callbacks can be registered either by creating an argument containing the callback list described below or by using the special convenience routines XtAddCallback and XtAddCallbacks. When the widget is created, a pointer to a list of callback procedure and data pairs can be passed in the argument list to XtCreateWidget. The list is of type XtCallbackList:

typedef struct {

} XtCallbackRec, *XtCallbackList;

The callback list must be allocated and initialized before calling XtCreateWidget. The end of the list is identified by an entry containing NULL in callback and closure. Once the widget is created, the client can change or de-allocate this list; the widget itself makes no further reference to it. The closure field contains the client_data passed to the callback when the callback list is executed.

The second method for registering callbacks is to use XtAddCallback after the widget has been created.
void XtAddCallback(w, callback_name, callback, client_data)
Widget w;
String callback_name;
XtCallbackProc callback;
XtPointer client_data;

callback_name
Specifies the callback list within the widget to append to.

client_dataSpecifies the data to be passed to the callback when it is invoked.

XtAddCallback adds the specified callback to the list for the named widget.

All widgets provide a callback list named destroyCallback where clients can register procedures that are to be executed when the widget is destroyed. The destroy callbacks are executed when the widget or an ancestor is destroyed. The call_data argument is unused for destroy callbacks.

2.10. Programming Considerations

This section provides some guidelines on how to set up an application program that uses the X Toolkit.

2.10.1. Writing Applications

When writing an application that uses the X Toolkit, you should make sure that your application performs the following:

For further information, see Section 2.9.2.2.

XtCreateManagedWidget(name, class, parent, args, num_args);
XtRealizeWidget(shell);
XtAppMainLoop(app_context);

For information about this function, see the X Toolkit Intrinsics — C Language Interface.

cc -o application application.c −lXaw −lXmu −lXt −lSM −lICE −lXext −lX11

2.10.2. Changing Resource Values

The Intrinsics support two methods of changing the default resource values; the resource manager, and an argument list passed into XtCreateWidget. While resources values will get updated no matter which method you use, the two methods provide slightly different functionality.

Resource ManagerThis method picks up resource definitions described in Xlib — C Language X Interface from many different locations at run time. The locations most important to the application programmer are the fallback resources and the app-defaults file, (see X Toolkit Intrinsics — C Language Interface for the complete list). Since these resource are loaded at run time, they can be overridden by the user, allowing an application to be customized to fit the particular needs of each individual user. These values can also be modified without the need to rebuild the application, allowing rapid prototyping of user interfaces. Application programmers should use resources in preference to hard-coded values whenever possible.

2.10.2.1. Specifying Resources

It is important for all X Toolkit application programmers to understand how to use the X Resource Manager to specify resources for widgets in an X application. This section will describe the most common methods used to specify these resources, and how to use the X Resource manager.

Application Defaults
The application defaults (app-defaults) file (normally in /usr/lib/X11/app-defaults/classname) for an application is loaded whenever the application is started.

The resource specification has two colon-separated parts, a name, and a value. The value is a string whose format is dependent on the resource specified by name. Name is constructed by appending a resource name to a full widget name.

The full widget name is a list of the name of every ancestor of the desired widget separated by periods (.). Each widget also has a class associated with it. A class is a type of widget (e.g. Label or Scrollbar or Box). Notice that class names, by convention, begin with capital letters and instance names begin with lower case letters. The class of any widget may be used in place of its name in a resource specification. Here are a few examples:

xman.form.button1
This is a fully specified resource name, and will affect only widgets called button1 that are children of widgets called form that are children of applications named xman. (Note that while typically two widgets that are siblings will have different names, it is not prohibited.)

Xman.Form.Command
This will match any Command widget that is a child of a Form widget that is itself a child of an application of class Xman.

Xman.Form.button1
This is a mixed resource name with both widget names and classes specified.

This syntax allows an application programmer to specify any widget in the widget tree. To match more than one widget (for example a user may want to make all Command buttons blue), use an asterisk (*) instead of a period. When an asterisk is used, any number of widgets (including zero) may exist between the two widget names. For example:

The root of all application widget trees is the widget returned by XtAppInitialize. Even though this is actually an ApplicationShell widget, the toolkit replaces its widget class with the class name of the application. The name of this widget is either the name used to invoke the application (argv[0]) or the name of the application specified using the standard -name command line option supported by the Intrinsics.

The last step in constructing the resource name is to append the name of the resource with either a period or asterisk to the full or partial widget name already constructed.

xman.form.button1.label:Testing
Specifies that a particular widget in the xman application will have a label named Testing.

An exclamation point (!) in the first column of a line indicates that the rest of the line should be treated as a comment.

Final Words

The Resource manager is a powerful tool that can be used very effectively to customize X Toolkit applications at run time by either the application programmer or the user. Some final points to note:

For a complete explanation of the rules of precedence, and other specific topics see X Toolkit Intrinsics — C Language Interface and Xlib — C Language X Interface.

2.10.2.2. Creating Argument Lists

To set up an argument list for the inline specification of widget attributes, you may use any of the four approaches discussed in this section. Each resource name has a global symbol associated with it. This global symbol has the form XtNresource name. For example, the symbol for ‘‘foreground’’ is XtNforeground. For further information, see the X Toolkit Intrinsics — C Language Interface.

Argument are specified by using the following structure:

typedef struct {

} Arg, *ArgList;

The first approach is to statically initialize the argument list. For example:

static Arg arglist[] = {

};

This approach is convenient for lists that do not need to be computed at runtime and makes adding or deleting new elements easy. The XtNumber macro is used to compute the number of elements in the argument list, preventing simple programming errors:

XtCreateWidget(name, class, parent, arglist, XtNumber(arglist));

The second approach is to use the XtSetArg macro. For example:

Arg arglist[10];
XtSetArg(arglist[1], XtNwidth, 400);
XtSetArg(arglist[2], XtNheight, 300);

To make it easier to insert and delete entries, you also can use a variable index:

Arg arglist[10];
Cardinal i=0;
XtSetArg(arglist[i], XtNwidth, 400); i++;
XtSetArg(arglist[i], XtNheight, 300); i++;

The i variable can then be used as the argument list count in the widget create function. In this example, XtNumber would return 10, not 2, and therefore is not useful.

Note

You should not use auto-increment or auto-decrement within the first argument to XtSetArg. As it is currently implemented, XtSetArg is a macro that dereferences the first argument twice.

The third approach is to individually set the elements of the argument list array:

Arg arglist[10];
arglist[0].name = XtNwidth;
arglist[0].value = (XtArgVal) 400;
arglist[1].name = XtNheight;
arglist[1].value = (XtArgVal) 300;

Note that in this example, as in the previous example, XtNumber would return 10, not 2, and therefore would not be useful.

The fourth approach is to use a mixture of the first and third approaches: you can statically define the argument list but modify some entries at runtime. For example:

static Arg arglist[] = {

};
arglist[1].value = (XtArgVal) 300;

In this example, XtNumber can be used, as in the first approach, for easier code maintenance.

2.11. Example Programs

The best way to understand how to use any programming library is by trying some simple examples. A collection of example programs that introduces each of the widgets in that Athena widget set, as well as many important toolkit programming concepts, is available in the X11R6 release as distributed by the X Consortium. It can be found in the distribution directory contrib/examples/mit/Xaw, but see your site administrator for the exact location of these files on your system. See the README file from that directory for a guide to the examples.

Chapter 3

Simple Widgets

Each of these widgets performs a specific user interface function. They are simple because they cannot have widget children—they may only be used as leaves of the widget tree. These widgets display information or take user input.

StripChartA real time data graph that will automatically update and scroll.

3.1. Command Widget

Application header file<X11/Xaw/Command.h>

The Command widget is an area, often rectangular, that contains text or a graphical image. Command widgets are often referred to as ‘‘push buttons.’’ When the pointer is over a Command widget, the widget becomes highlighted by drawing a rectangle around its perimeter. This highlighting indicates that the widget is ready for selection. When mouse button 1 is pressed, the Command widget indicates that it has been selected by reversing its foreground and background colors. When the mouse button is released, the Command widget’s notify action is invoked, calling all functions on its callback list. If the pointer is moved off of the widget before the pointer button is released, the widget reverts to its normal foreground and background colors, and releasing the pointer button has no effect. This behavior allows the user to cancel an action.

3.1.1. Resources

When creating a Command widget instance, the following resources are retrieved from the argument list or from the resource database:
Name Class Type NotesDefault Value
accelerators Accelerators AcceleratorTable NULL
ancestorSensitive AncestorSensitive Boolean D True
background Background Pixel XtDefaultBackground
backgroundPixmap Pixmap Pixmap XtUnspecifiedPixmap
bitmap Bitmap Pixmap None
borderColor BorderColor Pixel XtDefaultForeground
borderPixmap Pixmap Pixmap XtUnspecifiedPixmap
borderWidth BorderWidth Dimension 1
callback Callback XtCallbackList NULL
colormap Colormap Colormap Parent’s Colormap
cornerRoundPercent CornerRoundPercentDimension 25
cursor Cursor Cursor None
cursorName Cursor String NULL
depth Depth int C Parent’s Depth
destroyCallback Callback XtCallbackList NULL
encoding Encoding UnsignedChar XawTextEncoding8bit
font Font XFontStruct XtDefaultFont
foreground Foreground Pixel XtDefaultForeground
height Height Dimension A graphic height + 2 * internalHeight
highlightThickness Thickness Dimension A 2 (0 if Shaped)
insensitiveBorder Insensitive Pixmap GreyPixmap
internalHeight Height Dimension 2
internalWidth Width Dimension 4
international International Boolean C False
justify Justify Justify XtJustifyCenter (center)
label Label String name of widget
leftBitmap LeftBitmap Bitmap None
mappedWhenManaged MappedWhenManaged Boolean True
pointerColor Foreground Pixel XtDefaultForeground
pointerColorBackgroundBackground Pixel XtDefaultBackground
resize Resize Boolean True
screen Screen Screen R Parent’s Screen
sensitive Sensitive Boolean True
shapeStyle ShapeStyle ShapeStyle Rectangle
translations Translations TranslationTable See below
width Width Dimension A graphic width + 2 * internalWidth
x Position Position 0
y Position Position 0

ancestorSensitive
The sensitivity state of the ancestors of this widget. A widget is insensitive if either it or any of its ancestors is insensitive. This resource should not be changed with XtSetValues, although it may be queried.

backgroundPixmapThe background pixmap of this widget’s window. If this resource is set to anything other than XtUnspecifiedPixmap, the pixmap specified will be used instead of the background color.

cornerRoundPercent
When a ShapeStyle of roundedRectangle is used, this resource controls the radius of the rounded corner. The radius of the rounded corners is specified as a percentage of the length of the shortest side of the widget.

destroyCallbackAll functions on this list are called when this widget is destroyed.

highlightThickness
The thickness of the rectangle that is used to highlight the internal border of this widget, alerting the user that it is ready to be selected. The default value is 2 pixels if the shapeStyle is rectangle, and 0 Pixels (no highlighting) otherwise.

insensitiveBorder
This pixmap will be tiled into the widget’s border if the widget becomes insensitive.

mappedWhenManaged
If this resource is True, then the widget’s window will automatically be mapped by the Toolkit when it is realized and managed.

pointerColorBackground
A pixel value which indexes the widget’s colormap to derive the background color of the pointer symbol specified by the cursorName resource.

3.1.2. Command Actions

The Command widget supports the following actions:

The following are the default translation bindings used by the Command widget:

The full list of actions supported by Command is:

highlight(condition)
Displays the internal highlight border in the color (foreground or background ) that contrasts with the interior color of the Command widget. The conditions WhenUnset and Always are understood by this action procedure. If no argument is passed, WhenUnset is assumed.

A very common alternative to registering callbacks is to augment a Command’s translations with an action performing the desired function. This often takes the form of:

*Myapp*save.translations: #augment <Btn1Down>,<Btn1Up>: Save()

Note

When a bitmap of depth greater that one (1) is specified the set(), unset(), and reset() actions have no effect, since there are no foreground and background colors used in a multi-plane pixmap.

3.2. Grip Widget

Application header file<X11/Xaw/Grip.h>

The Grip widget provides a small rectangular region in which user input events (such as ButtonPress or ButtonRelease) may be handled. The most common use for the Grip widget is as an attachment point for visually repositioning an object, such as the pane border in a Paned widget.

3.2.1. Resources

When creating a Grip widget instance, the following resources are retrieved from the argument list or from the resource database:
Name Class Type NotesDefault Value
accelerators Accelerators AcceleratorTable NULL
ancestorSensitive AncestorSensitiveBoolean D True
background Background Pixel XtDefaultBackground
backgroundPixmap Pixmap Pixmap XtUnspecifiedPixmap
borderColor BorderColor Pixel XtDefaultForeground
borderPixmap Pixmap Pixmap XtUnspecifiedPixmap
borderWidth BorderWidth Dimension 0
callback Callback Callback NULL
colormap Colormap Colormap Parent’s Colormap
cursor Cursor Cursor None
cursorName Cursor String NULL
depth Depth int C Parent’s Depth
destroyCallback Callback XtCallbackList NULL
foreground Foreground Pixel XtDefaultForeground
height Height Dimension 8
insensitiveBorder Insensitive Pixmap GreyPixmap
international International Boolean C False
mappedWhenManaged MappedWhenManagedBoolean True
pointerColor Foreground Pixel XtDefaultForeground
pointerColorBackgroundBackground Pixel XtDefaultBackground
screen Screen Screen R Parent’s Screen
sensitive Sensitive Boolean True
translations Translations TranslationTable NULL
width Width Dimension 8
x Position Position 0
y Position Position 0

ancestorSensitive
The sensitivity state of the ancestors of this widget. A widget is insensitive if either it or any of its ancestors is insensitive. This resource should not be changed with XtSetValues, although it may be queried.

backgroundPixmapThe background pixmap of this widget’s window. If this resource is set to anything other than XtUnspecifiedPixmap, the pixmap specified will be used instead of the background color.

destroyCallbackAll functions on this list are called when this widget is destroyed.

insensitiveBorder
This pixmap will be tiled into the widget’s border if the widget becomes insensitive.

mappedWhenManaged
If this resource is True, then the widget’s window will automatically be mapped by the Toolkit when it is realized and managed.

pointerColorBackground
A pixel value which indexes the widget’s colormap to derive the background color of the pointer symbol specified by the cursorName resource.

3.2.2. Grip Actions

The Grip widget does not declare any default event translation bindings, but it does declare a single action routine named GripAction. The client specifies an arbitrary event translation table, optionally giving parameters to the GripAction routine.

The GripAction routine executes the callbacks on the callback list, passing as call_data a pointer to a XawGripCallData structure, defined in the Grip widget’s application header file.

typedef struct _XawGripCallData {

} XawGripCallDataRec, *XawGripCallData,
GripCallDataRec, *GripCallData; /* supported for R4 compatibility */

In this structure, the event is a pointer to the input event that triggered the action. params and num_params give the string parameters specified in the translation table for the particular event binding.

The following is an example of a translation table that uses the GripAction:

For a complete description of the format of translation tables, see the X Toolkit Intrinsics — C Language Interface.

3.3. Label Widget

Application header file<X11/Xaw/Label.h>

A Label widget holds a graphic displayed within a rectangular region of the screen. The graphic may be a text string containing multiple lines of characters in an 8 bit or 16 bit character set (to be displayed with a font), or in a multi-byte encoding (for use with a fontset). The graphic may also be a bitmap or pixmap. The Label widget will allow its graphic to be left, right, or center justified. Normally, this widget can be neither selected nor directly edited by the user. It is intended for use as an output device only.

3.3.1. Resources

When creating a Label widget instance, the following resources are retrieved from the argument list or from the resource database:
Name Class Type NotesDefault Value
accelerators Accelerators AcceleratorTable NULL
ancestorSensitive AncestorSensitiveBoolean D True
background Background Pixel XtDefaultBackground
backgroundPixmap Pixmap Pixmap XtUnspecifiedPixmap
bitmap Bitmap Pixmap None
borderColor BorderColor Pixel XtDefaultForeground
borderPixmap Pixmap Pixmap XtUnspecifiedPixmap
borderWidth BorderWidth Dimension 1
colormap Colormap Colormap Parent’s Colormap
cursor Cursor Cursor None
cursorName Cursor String NULL
depth Depth int C Parent’s Depth
destroyCallback Callback XtCallbackList NULL
encoding Encoding UnsignedChar XawTextEncoding8bit
font Font XFontStruct XtDefaultFont
fontSet FontSet XFontSet XtDefaultFontSet
foreground Foreground Pixel XtDefaultForeground
height Height Dimension A graphic height + 2 * internalHeight
insensitiveBorder Insensitive Pixmap GreyPixmap
internalHeight Height Dimension 2
internalWidth Width Dimension 4
international International Boolean C False
justify Justify Justify XtJustifyCenter (center)
label Label String name of widget
leftBitmap LeftBitmap Bitmap None
mappedWhenManaged MappedWhenManagedBoolean True
pointerColor Foreground Pixel XtDefaultForeground
pointerColorBackgroundBackground Pixel XtDefaultBackground
resize Resize Boolean True
screen Screen Screen R Parent’s Screen
sensitive Sensitive Boolean True
translations Translations TranslationTable See above
width Width Dimension A graphic width + 2 * internalWidth
x Position Position 0
y Position Position 0

ancestorSensitive
The sensitivity state of the ancestors of this widget. A widget is insensitive if either it or any of its ancestors is insensitive. This resource should not be changed with XtSetValues, although it may be queried.

backgroundPixmapThe background pixmap of this widget’s window. If this resource is set to anything other than XtUnspecifiedPixmap, the pixmap specified will be used instead of the background color.

destroyCallbackAll functions on this list are called when this widget is destroyed.

insensitiveBorder
This pixmap will be tiled into the widget’s border if the widget becomes insensitive.

mappedWhenManaged
If this resource is True, then the widget’s window will automatically be mapped by the Toolkit when it is realized and managed.

pointerColorBackground
A pixel value which indexes the widget’s colormap to derive the background color of the pointer symbol specified by the cursorName resource.

3.4. List Widget

Application header file<X11/Xaw/List.h>

The List widget contains a list of strings formatted into rows and columns. When one of the strings is selected, it is highlighted, and the List widget’s Notify action is invoked, calling all routines on its callback list. Only one string may be selected at a time.

3.4.1. Resources

When creating a List widget instance, the following resources are retrieved from the argument list or from the resource database:
Name Class Type NotesDefault Value
accelerators Accelerators AcceleratorTable NULL
ancestorSensitive AncestorSensitiveBoolean D True
background Background Pixel XtDefaultBackground
backgroundPixmap Pixmap Pixmap XtUnspecifiedPixmap
borderColor BorderColor Pixel XtDefaultForeground
borderPixmap Pixmap Pixmap XtUnspecifiedPixmap
borderWidth BorderWidth Dimension 1
callback Callback Callback NULL
colormap Colormap Colormap Parent’s Colormap
columnSpacing Spacing Dimension 6
cursor Cursor Cursor XC_left_ptr
cursorName Cursor String NULL
defaultColumns Columns int 2
depth Depth int C Parent’s Depth
destroyCallback Callback XtCallbackList NULL
font Font FontStruct XtDefaultFont
fontSet FontSet XFontSet XtDefaultFontSet
forceColumns Columns Boolean False
foreground Foreground Pixel XtDefaultForeground
height Height Dimension A Enough space to contain the list
insensitiveBorder Insensitive Pixmap GreyPixmap
internalHeight Height Dimension 2
internalWidth Width Dimension 4
international International Boolean C False
list List Pointer name of widget
longest Longest int A 0
mappedWhenManaged MappedWhenManagedBoolean True
numberStrings NumberStrings int A computed for NULL terminated list
pasteBuffer Boolean Boolean False
pointerColor Foreground Pixel XtDefaultForeground
pointerColorBackgroundBackground Pixel XtDefaultBackground
rowSpacing Spacing Dimension 2
screen Screen Screen R Parent’s Screen
sensitive Sensitive Boolean True
translations Translations TranslationTable See below
verticalList Boolean Boolean False
width Width Dimension A Enough space to contain the list
x Position Position 0
y Position Position 0

ancestorSensitive
The sensitivity state of the ancestors of this widget. A widget is insensitive if either it or any of its ancestors is insensitive. This resource should not be changed with XtSetValues, although it may be queried.

backgroundPixmapThe background pixmap of this widget’s window. If this resource is set to anything other than XtUnspecifiedPixmap, the pixmap specified will be used instead of the background color.

destroyCallbackAll functions on this list are called when this widget is destroyed.

insensitiveBorder
This pixmap will be tiled into the widget’s border if the widget becomes insensitive.

mappedWhenManaged
If this resource is True, then the widget’s window will automatically be mapped by the Toolkit when it is realized and managed.

pointerColorBackground
A pixel value which indexes the widget’s colormap to derive the background color of the pointer symbol specified by the cursorName resource.

3.4.2. List Actions

The List widget supports the following actions:

The following is the default translation table used by the List Widget:

The full list of actions supported by List widget is:

3.4.3. List Callbacks

All procedures on the List widget’s callback list will have a XawListReturnStruct passed to them as call_data. The structure is defined in the List widget’s application header file.

typedef struct _XawListReturnStruct {

} XawListReturnStruct;

Note

The list_index item used to be called simply index.
Unfortunately, this name collided with a global name defined on some
operating systems, and had to be changed.

3.4.4. Changing the List

To change the list that is displayed, use XawListChange.
void XawListChange(w, list, nitems, longest, resize)
Widget w;
String * list;
int nitems, longest;
Boolean resize;

XawListChange will unset all list elements that are currently set before the list is actually changed. The list is used in place, and must remain usable for the lifetime of the List widget, or until list has been changed again with this function or with XtSetValues.

3.4.5. Highlighting an Item

To highlight an item in the list, use XawListHighlight.
void XawListHighlight(w, item)
Widget w;
int item;

Only one item can be highlighted at a time. If an item is already highlighted when XawListHighlight is called, the highlighted item is unhighlighted before the new item is highlighted.

3.4.6. Unhighlighting an Item

To unhighlight the currently highlighted item in the list, use XawListUnhighlight.
void XawListUnhighlight(w)
Widget w;

3.4.7. Retrieving the Currently Selected Item

To retrieve the list element that is currently set, use XawListShowCurrent.
XawListReturnStruct *XawListShowCurrent(w)
Widget w;

XawListShowCurrent returns a pointer to an XawListReturnStruct structure, containing the currently highlighted item. If the value of the index member is XAW_LIST_NONE, the string member is undefined, and no item is currently selected.

3.4.8. Restrictions

Many programmers create a ‘‘scrolled list’’ by putting a List widget with many entries as a child of a Viewport widget. The List continues to create a window as big as its contents, but that big window is only visible where it intersects the parent Viewport’s window. (I.e., it is ‘‘clipped.’’)

While this is a useful technique, there is a serious drawback. X does not support windows above 32,767 pixels in width or height, but this height limit will be exceeded by a List’s window when the List has many entries (i.e., with a 12 point font, about 3000 entries would be too many.)

3.5. Panner Widget

Application header file<X11/Xaw/Panner.h>

A Panner widget is a rectangle, called the ‘‘canvas,’’ on which another rectangle, the ‘‘slider,’’ moves in two dimensions. It is often used with a Porthole widget to move, or ‘‘scroll,’’ a third widget in two dimensions, in which case the slider’s size and position gives feedback as to what portion of the third widget is visible.

The slider may be scrolled around the canvas by pressing, dragging, and releasing Button1; the default translation also enables scrolling via arrow keys and some other keys. While scrolling is in progress, the application receives notification through callback procedures. Notification may be done either continuously whenever the slider moves or discretely whenever the slider has been given a new location.

3.5.1. Resources

When creating a Panner widget instance, the following resources are retrieved from the argument list or from the resource database:
Name Class Type NotesDefault Value
accelerators Accelerators AcceleratorTable NULL
allowOff AllowOff Boolean False
ancestorSensitive AncestorSensitiveBoolean D True
background Background Pixel XtDefaultBackground
backgroundPixmap Pixmap Pixmap XtUnspecifiedPixmap
backgroundStipple BackgroundStippleString NULL
borderColor BorderColor Pixel XtDefaultForeground
borderPixmap Pixmap Pixmap XtUnspecifiedPixmap
borderWidth BorderWidth Dimension 1
canvasHeight CanvasHeight Dimension 0
canvasWidth CanvasWidth Dimension 0
colormap Colormap Colormap Parent’s Colormap
cursor Cursor Cursor None
cursorName Cursor String NULL
defaultScale DefaultScale Dimension 8
depth Depth int C Parent’s Depth
destroyCallback Callback XtCallbackList NULL
foreground Foreground Pixel XtDefaultForeground
height Height Dimension A depends on orientation
internalSpace InternalSpace Dimension 4
international International Boolean C False
lineWidth LineWidth Dimension 0
mappedWhenManaged MappedWhenManagedBoolean True
pointerColor Foreground Pixel XtDefaultForeground
pointerColorBackgroundBackground Pixel XtDefaultBackground
reportCallback ReportCallback Callback NULL
resize Resize Boolean True
rubberBand RubberBand Boolean False
screen Screen Screen R Parent’s Screen
sensitive Sensitive Boolean True
shadowColor ShadowColor Pixel XtDefaultForeground
shadowThickness ShadowThickness Dimension 2
sliderX SliderX Position 0
sliderY SliderY Position 0
sliderHeight SliderHeight Dimension 0
sliderWidth SliderWidth Dimension 0
translations Translations TranslationTable See below
width Width Dimension A depends on orientation
x Position Position 0
y Position Position 0

ancestorSensitive
The sensitivity state of the ancestors of this widget. A widget is insensitive if either it or any of its ancestors is insensitive. This resource should not be changed with XtSetValues, although it may be queried.

backgroundPixmapThe background pixmap of this widget’s window. If this resource is set to anything other than XtUnspecifiedPixmap, the pixmap specified will be used instead of the background color.

backgroundStipple
The name of a bitmap pattern to be used as the background for the area representing the canvas.

destroyCallbackAll functions on this list are called when this widget is destroyed.

mappedWhenManaged
If this resource is True, then the widget’s window will automatically be mapped by the Toolkit when it is realized and managed.

pointerColorBackground
A pixel value which indexes the widget’s colormap to derive the background color of the pointer symbol specified by the cursorName resource.

shadowThicknessThe width of the shadow underneath the slider.

3.5.2. Panner Actions

The actions supported by the Panner widget are:

page(xamount,yamount)
This action moves the slider by the specified amounts. The format for the amounts is a signed or unsigned floating-point number (e.g., +1.0 or −.5) followed by either p indicating pages (slider sizes), or c indicating canvas sizes. Thus, page(+0,+.5p) represents vertical movement down one-half the height of the slider and page(0,0) represents moving to the upper left corner of the canvas.

set(what,value)This action changes the behavior of the Panner. The what argument must currently be the string rubberband and controls the value of the rubberBand resource. The value argument may have one of the values on, off, or toggle.

The default bindings for Panner are:

3.5.3. Panner Callbacks

The functions registered on the reportCallback list are invoked by the notify action as follows:
void ReportProc(panner, client_data, report)

client_dataSpecifies the client data.

3.6. Repeater Widget

Application header file<X11/Xaw/Repeater.h>

The Repeater widget is a subclass of the Command widget; see the Command documentation for details. The difference is that the Repeater can call its registered callbacks repeatedly, at an increasing rate. The default translation does so for the duration the user holds down pointer button 1 while the pointer is on the Repeater.

3.6.1. Resources

When creating a Repeater widget instance, the following resources are retrieved from the argument list or from the resource database:
Name Class Type NotesDefault Value
accelerators Accelerators AcceleratorTable NULL
ancestorSensitive AncestorSensitive Boolean D True
background Background Pixel XtDefaultBackground
backgroundPixmap Pixmap Pixmap XtUnspecifiedPixmap
bitmap Bitmap Pixmap None
borderColor BorderColor Pixel XtDefaultForeground
borderPixmap Pixmap Pixmap XtUnspecifiedPixmap
borderWidth BorderWidth Dimension 1
callback Callback XtCallbackList NULL
colormap Colormap Colormap Parent’s Colormap
cornerRoundPercent CornerRoundPercentDimension 25
cursor Cursor Cursor None
cursorName Cursor String NULL
decay Decay Int 5
depth Depth int C Parent’s Depth
destroyCallback Callback XtCallbackList NULL
encoding Encoding UnsignedChar XawTextEncoding8bit
flash Boolean Boolean False
font Font XFontStruct XtDefaultFont
fontSet FontSet XFontSet XtDefaultFontSet
foreground Foreground Pixel XtDefaultForeground
height Height Dimension A graphic height + 2 * internalHeight
highlightThickness Thickness Dimension A 2 (0 if Shaped)
initialDelay Delay Int 200
insensitiveBorder Insensitive Pixmap GreyPixmap
internalHeight Height Dimension 2
internalWidth Width Dimension 4
international International Boolean C False
justify Justify Justify XtJustifyCenter (center)
label Label String name of widget
leftBitmap LeftBitmap Bitmap None
mappedWhenManaged MappedWhenManaged Boolean True
minimumDelay MinimumDelay Int 10
pointerColor Foreground Pixel XtDefaultForeground
pointerColorBackgroundBackground Pixel XtDefaultBackground
repeatDelay Delay Int 50
resize Resize Boolean True
screen Screen Pointer R Parent’s Screen
sensitive Sensitive Boolean True
shapeStyle ShapeStyle ShapeStyle Rectangle
startCallback StartCallback Callback NULL
stopCallback StopCallback Callback NULL
translations Translations TranslationTable See below
width Width Dimension A graphic width + 2 * internalWidth
x Position Position 0
y Position Position 0

ancestorSensitive
The sensitivity state of the ancestors of this widget. A widget is insensitive if either it or any of its ancestors is insensitive. This resource should not be changed with XtSetValues, although it may be queried.

backgroundPixmapThe background pixmap of this widget’s window. If this resource is set to anything other than XtUnspecifiedPixmap, the pixmap specified will be used instead of the background color.

cornerRoundPercent
When a ShapeStyle of roundedRectangle is used, this resource controls the radius of the rounded corner. The radius of the rounded corners is specified as a percentage of the length of the shortest side of the widget.

destroyCallbackAll functions on this list are called when this widget is destroyed.

highlightThickness
The thickness of the rectangle that is used to highlight the internal border of this widget, alerting the user that it is ready to be selected. The default value is 2 pixels if the shapeStyle is rectangle, and 0 Pixels (no highlighting) otherwise.

insensitiveBorder
This pixmap will be tiled into the widget’s border if the widget becomes insensitive.

mappedWhenManaged
If this resource is True, then the widget’s window will automatically be mapped by the Toolkit when it is realized and managed.

pointerColorBackground
A pixel value which indexes the widget’s colormap to derive the background color of the pointer symbol specified by the cursorName resource.

3.6.2. Repeater Actions

The Repeater widget supports the following actions beyond those of the Command button:

The following are the default translation bindings used by the Repeater widget:

3.7. Scrollbar Widget

Application header file<X11/Xaw/Scrollbar.h>

A Scrollbar widget is a rectangle, called the ‘‘canvas,’’ on which another rectangle, the ‘‘thumb,’’ moves in one dimension, either vertically or horizontally. A Scrollbar can be used alone, as a value generator, or it can be used within a composite widget (for example, a Viewport). When a Scrollbar is used to move, or ‘‘scroll,’’ the contents of another widget, the size and the position of the thumb usually give feedback as to what portion of the other widget’s contents are visible.

Each pointer button invokes a specific action. Pointer buttons 1 and 3 do not move the thumb automatically. Instead, they return the pixel position of the cursor on the scroll region. When pointer button 2 is clicked, the thumb moves to the current pointer position. When pointer button 2 is held down and the pointer is moved, the thumb follows the pointer.

The pointer cursor in the scroll region changes depending on the current action. When no pointer button is pressed, the cursor appears as a double-headed arrow that points in the direction that scrolling can occur. When pointer button 1 or 3 is pressed, the cursor appears as a single-headed arrow that points in the logical direction that the thumb will move. When pointer button 2 is pressed, the cursor appears as an arrow that points to the top or the left of the thumb.

When the user scrolls, the application receives notification through callback procedures. For both discrete scrolling actions, the callback returns the Scrollbar widget, the client_data, and the pixel position of the pointer when the button was released. For continuous scrolling, the callback routine returns the scroll bar widget, the client data, and the current relative position of the thumb. When the thumb is moved using pointer button 2, the callback procedure is invoked continuously. When either button 1 or 3 is pressed, the callback procedure is invoked only when the button is released and the client callback procedure is responsible for moving the thumb.

3.7.1. Resources

When creating a Scrollbar widget instance, the following resources are retrieved from the argument list or from the resource database:
Name Class Type NotesDefault Value
accelerators Accelerators AcceleratorTable NULL
ancestorSensitive AncestorSensitiveBoolean D True
background Background Pixel XtDefaultBackground
backgroundPixmap Pixmap Pixmap XtUnspecifiedPixmap
borderColor BorderColor Pixel XtDefaultForeground
borderPixmap Pixmap Pixmap XtUnspecifiedPixmap
borderWidth BorderWidth Dimension 1
colormap Colormap Colormap parent’s Colormap
cursor Cursor Cursor None
cursorName Cursor String NULL
depth Depth int C parent’s Depth
destroyCallback Callback XtCallbackList NULL
foreground Foreground Pixel XtDefaultForeground
height Height Dimension A depends on orientation
insensitiveBorder Insensitive Pixmap GreyPixmap
international International Boolean C False
jumpProc Callback XtCallbackList NULL
length Length Dimension 1
mappedWhenManaged MappedWhenManagedBoolean True
minimumThumb MinimumThumb Dimension 7
orientation Orientation Orientation XtorientVertical (vertical)
pointerColor Foreground Pixel XtDefaultForeground
pointerColorBackgroundBackground Pixel XtDefaultBackground
screen Screen Screen R parent’s Screen
scrollDCursor Cursor Cursor XC_sb_down_arrow
scrollHCursor Cursor Cursor XC_sb_h_double_arrow
scrollLCursor Cursor Cursor XC_sb_left_arrow
scrollProc Callback XtCallbackList NULL
scrollRCursor Cursor Cursor XC_sb_right_arrow
scrollUCursor Cursor Cursor XC_sb_up_arrow
scrollVCursor Cursor Cursor XC_sb_v_arrow
sensitive Sensitive Boolean True
shown Shown Float 0.0
thickness Thickness Dimension 14
thumb Thumb Bitmap GreyPixmap
thumbProc Callback XtCallbackList NULL
topOfThumb TopOfThumb Float 0.0
translations Translations TranslationTable See below
width Width Dimension A depends on orientation
x Position Position 0
y Position Position 0

ancestorSensitive
The sensitivity state of the ancestors of this widget. A widget is insensitive if either it or any of its ancestors is insensitive. This resource should not be changed with XtSetValues, although it may be queried.

backgroundPixmapThe background pixmap of this widget’s window. If this resource is set to anything other than XtUnspecifiedPixmap, the pixmap specified will be used instead of the background color.

destroyCallbackAll functions on this list are called when this widget is destroyed.

insensitiveBorder
This pixmap will be tiled into the widget’s border if the widget becomes insensitive.

mappedWhenManaged
If this resource is True, then the widget’s window will automatically be mapped by the Toolkit when it is realized and managed.

pointerColorBackground
A pixel value which indexes the widget’s colormap to derive the background color of the pointer symbol specified by the cursorName resource.

3.7.2. Scrollbar Actions

The actions supported by the Scrollbar widget are:

StartScroll(value)
The possible values are Forward, Backward, or Continuous. This must be the first action to begin a new movement.

NotifyScroll(value)
The possible values are Proportional or FullLength. If the argument to StartScroll was Forward or Backward, NotifyScroll executes the scrollProc callbacks and passes either; the position of the pointer, if value is Proportional, or the full length of the scroll bar, if value is FullLength. If the argument to StartScroll was Continuous, NotifyScroll returns without executing any callbacks.

NotifyThumb()   Calls the jumpProc callbacks and passes the relative position of the pointer as a percentage of the scroll bar length.

The default bindings for Scrollbar are:

Examples of additional bindings a user might wish to specify in a resource file are:

*Scrollbar.Translations: \

3.7.3. Scrollbar Callbacks

There are two callback lists provided by the Scrollbar widget. The procedural interface for these functions is described here.

The calling interface to the scrollProc callback procedure is:
void ScrollProc(scrollbar, client_data, position)
Widget scrollbar;
XtPointer client_data;
XtPointer position; /* int */

client_dataSpecifies the client data.

The scrollProc callback is used for incremental scrolling and is called by the NotifyScroll action. The position argument is a signed quantity and should be cast to an int when used. Using the default button bindings, button 1 returns a positive value, and button 3 returns a negative value. In both cases, the magnitude of the value is the distance of the pointer in pixels from the top (or left) of the Scrollbar. The value will never be greater than the length of the Scrollbar.

The calling interface to the jumpProc callback procedure is:
void JumpProc(scrollbar, client_data, percent)
Widget scrollbar;
XtPointer client_data;
XtPointer percent_ptr; /* float* */

client_dataSpecifies the client data.

percent_ptrSpecifies the floating point position of the thumb (0.0 − 1.0).

The jumpProc callback is used to implement smooth scrolling and is called by the NotifyThumb action. Percent_ptr must be cast to a pointer to float before use; i.e.

With the default button bindings, button 2 moves the thumb interactively, and the jumpProc is called on each new position of the pointer, while the pointer button remains down. The value specified by percent_ptr is the current location of the thumb (from the top or left of the Scrollbar) expressed as a percentage of the length of the Scrollbar.

3.7.4. Convenience Routines

To set the position and length of a Scrollbar thumb, use XawScrollbarSetThumb.
void XawScrollbarSetThumb(w, top, shown)
Widget w;
float top;
float shown;

XawScrollbarThumb moves the visible thumb to a new position (0.0 − 1.0) and length (0.0 − 1.0). Either the top or shown arguments can be specified as −1.0, in which case the current value is left unchanged. Values greater than 1.0 are truncated to 1.0.

If called from jumpProc, XawScrollbarSetThumb has no effect.

3.7.5. Setting Float Resources

The shown and topOfThumb resources are of type float. These resources can be difficult to get into an argument list. The reason is that C performs an automatic cast of the float value to an integer value, usually truncating the important information. The following code fragment is one portable method of getting a float into an argument list.

3.8. Simple Widget

Application Header file<Xaw/Simple.h>

The Simple widget is not very useful by itself, as it has no semantics of its own. It main purpose is to be used as a common superclass for the other simple Athena widgets. This widget adds six resources to the resource list provided by the Core widget and its superclasses.

3.8.1. Resources

When creating a Simple widget instance, the following resources are retrieved from the argument list or from the resource database:
Name Class Type NotesDefault Value
accelerators Accelerators AcceleratorTable NULL
ancestorSensitive AncestorSensitiveBoolean D True
background Background Pixel XtDefaultBackground
backgroundPixmap Pixmap Pixmap XtUnspecifiedPixmap
borderColor BorderColor Pixel XtDefaultForeground
borderPixmap Pixmap Pixmap XtUnspecifiedPixmap
borderWidth BorderWidth Dimension 1
colormap Colormap Colormap Parent’s Colormap
cursor Cursor Cursor None
cursorName Cursor String NULL
depth Depth int C Parent’s Depth
destroyCallback Callback XtCallbackList NULL
height Height Dimension 0
insensitiveBorder Insensitive Pixmap GreyPixmap
international International Boolean C False
mappedWhenManaged MappedWhenManagedBoolean True
pointerColor Foreground Pixel XtDefaultForeground
pointerColorBackgroundBackground Pixel XtDefaultBackground
screen Screen Screen R Parent’s Screen
sensitive Sensitive Boolean True
translations Translations TranslationTable NULL
width Width Dimension 0
x Position Position 0
y Position Position 0

ancestorSensitive
The sensitivity state of the ancestors of this widget. A widget is insensitive if either it or any of its ancestors is insensitive. This resource should not be changed with XtSetValues, although it may be queried.

backgroundPixmapThe background pixmap of this widget’s window. If this resource is set to anything other than XtUnspecifiedPixmap, the pixmap specified will be used instead of the background color.

destroyCallbackAll functions on this list are called when this widget is destroyed.

insensitiveBorder
This pixmap will be tiled into the widget’s border if the widget becomes insensitive.

mappedWhenManaged
If this resource is True, then the widget’s window will automatically be mapped by the Toolkit when it is realized and managed.

pointerColorBackground
A pixel value which indexes the widget’s colormap to derive the background color of the pointer symbol specified by the cursorName resource.

3.9. StripChart Widget

Application Header file<Xaw/StripChart.h>

The StripChart widget is used to provide a roughly real time graphical chart of a single value. For example, it is used by the common client program xload to provide a graph of processor load. The StripChart reads data from an application, and updates the chart at the update interval specified.

3.9.1. Resources

When creating a StripChart widget instance, the following resources are retrieved from the argument list or from the resource database:
Name Class Type NotesDefault Value
accelerators Accelerators AcceleratorTable NULL
ancestorSensitive AncestorSensitiveBoolean D True
background Background Pixel XtDefaultBackground
backgroundPixmap Pixmap Pixmap XtUnspecifiedPixmap
borderColor BorderColor Pixel XtDefaultForeground
borderPixmap Pixmap Pixmap XtUnspecifiedPixmap
borderWidth BorderWidth Dimension 1
colormap Colormap Colormap Parent’s Colormap
cursor Cursor Cursor None
cursorName Cursor String NULL
depth Depth int C Parent’s Depth
destroyCallback Callback XtCallbackList NULL
foreground Foreground Pixel XtDefaultForeground
getValue Callback XtCallbackList NULL
height Height Dimension 120
highlight Foreground Pixel XtDefaultForeground
insensitiveBorder Insensitive Pixmap GreyPixmap
international International Boolean C False
jumpScroll JumpScroll int A half the width of the widget
mappedWhenManaged MappedWhenManagedBoolean True
minScale Scale int 1
pointerColor Foreground Pixel XtDefaultForeground
pointerColorBackgroundBackground Pixel XtDefaultBackground
screen Screen Pointer R Parent’s Screen
sensitive Sensitive Boolean True
translations Translations TranslationTable NULL
update Interval int 10
width Width Dimension 120
x Position Position 0
y Position Position 0

ancestorSensitive
The sensitivity state of the ancestors of this widget. A widget is insensitive if either it or any of its ancestors is insensitive. This resource should not be changed with XtSetValues, although it may be queried.

backgroundPixmapThe background pixmap of this widget’s window. If this resource is set to anything other than XtUnspecifiedPixmap, the pixmap specified will be used instead of the background color.

destroyCallbackAll functions on this list are called when this widget is destroyed.

insensitiveBorder
This pixmap will be tiled into the widget’s border if the widget becomes insensitive.

mappedWhenManaged
If this resource is True, then the widget’s window will automatically be mapped by the Toolkit when it is realized and managed.

pointerColorBackground
A pixel value which indexes the widget’s colormap to derive the background color of the pointer symbol specified by the cursorName resource.

3.9.2. Getting the StripChart Value

The StripChart widget will call the application routine passed to it as the getValue callback function every update seconds to obtain another point for the StripChart graph.

The calling interface for the getValue callback is:
void (*getValueProc)(w, client_data, value)
Widget w;
XtPointer client_data;
XtPointer value; /* double * */

client_dataSpecifies the client data.

This function is used by the StripChart to call an application routine. The routine will pass the value to be graphed back to the the StripChart in the value field of this routine.

3.10. Toggle Widget

Application Header file<Xaw/Toggle.h>

The Toggle widget is an area, often rectangular, that displays a graphic. The graphic may be a text string containing multiple lines of characters in an 8 bit or 16 bit character set (to be displayed with a font), or in a multi-byte encoding (for use with a fontset). The graphic may also be a bitmap or pixmap.

This widget maintains a Boolean state (e.g. True/False or On/Off) and changes state whenever it is selected. When the pointer is on the Toggle widget, the Toggle widget may become highlighted by drawing a rectangle around its perimeter. This highlighting indicates that the Toggle widget is ready for selection. When pointer button 1 is pressed and released, the Toggle widget indicates that it has changed state by reversing its foreground and background colors, and its notify action is invoked, calling all functions on its callback list. If the pointer is moved off of the widget before the pointer button is released, the Toggle widget reverts to its previous foreground and background colors, and releasing the pointer button has no effect. This behavior allows the user to cancel the operation.

Toggle widgets may also be part of a ‘‘radio group.’’ A radio group is a list of at least two Toggle widgets in which no more than one Toggle may be set at any time. A radio group is identified by the widget ID of any one of its members. The convenience routine XawToggleGetCurrent will return information about the Toggle widget in the radio group.

Toggle widget state is preserved across changes in sensitivity.

3.10.1. Resources

When creating a Toggle widget instance, the following resources are retrieved from the argument list or from the resource database:
Name Class Type NotesDefault Value
accelerators Accelerators AcceleratorTable NULL
ancestorSensitive AncestorSensitive Boolean D True
background Background Pixel XtDefaultBackground
backgroundPixmap Pixmap Pixmap XtUnspecifiedPixmap
bitmap Bitmap Pixmap None
borderColor BorderColor Pixel XtDefaultForeground
borderPixmap Pixmap Pixmap XtUnspecifiedPixmap
borderWidth BorderWidth Dimension 1
callback Callback XtCallbackList NULL
colormap Colormap Colormap Parent’s Colormap
cornerRoundPercent CornerRoundPercentDimension 25
cursor Cursor Cursor None
cursorName Cursor String NULL
depth Depth int C Parent’s Depth
destroyCallback Callback XtCallbackList NULL
encoding Encoding UnsignedChar XawTextEncoding8bit
font Font XFontStruct XtDefaultFont
fontSet FontSet XFontSet XtDefaultFontSet
foreground Foreground Pixel XtDefaultForeground
height Height Dimension A graphic height + 2 * internalHeight
highlightThickness Thickness Dimension A 2 (0 if Shaped)
insensitiveBorder Insensitive Pixmap GreyPixmap
internalHeight Height Dimension 2
internalWidth Width Dimension 4
international International Boolean C False
justify Justify Justify XtJustifyCenter (center)
label Label String name of widget
leftBitmap LeftBitmap Bitmap None
mappedWhenManaged MappedWhenManaged Boolean True
pointerColor Foreground Pixel XtDefaultForeground
pointerColorBackgroundBackground Pixel XtDefaultBackground
radioData RadioData Pointer Name of widget
radioGroup Widget Widget No radio group
resize Resize Boolean True
screen Screen Screen R Parent’s Screen
sensitive Sensitive Boolean True
shapeStype ShapeStyle ShapeStyle Rectangle
state State Boolean Off
translations Translations TranslationTable See below
width Width Dimension A graphic width + 2 * internalWidth
x Position Position 0
y Position Position 0

ancestorSensitive
The sensitivity state of the ancestors of this widget. A widget is insensitive if either it or any of its ancestors is insensitive. This resource should not be changed with XtSetValues, although it may be queried.

backgroundPixmapThe background pixmap of this widget’s window. If this resource is set to anything other than XtUnspecifiedPixmap, the pixmap specified will be used instead of the background color.

cornerRoundPercent
When a ShapeStyle of roundedRectangle is used, this resource controls the radius of the rounded corner. The radius of the rounded corners is specified as a percentage of the length of the shortest side of the widget.

destroyCallbackAll functions on this list are called when this widget is destroyed.

highlightThickness
The thickness of the rectangle that is used to highlight the internal border of this widget, alerting the user that it is ready to be selected. The default value is 2 pixels if the shapeStyle is rectangle, and 0 Pixels (no highlighting) otherwise.

insensitiveBorder
This pixmap will be tiled into the widget’s border if the widget becomes insensitive.

mappedWhenManaged
If this resource is True, then the widget’s window will automatically be mapped by the Toolkit when it is realized and managed.

pointerColorBackground
A pixel value which indexes the widget’s colormap to derive the background color of the pointer symbol specified by the cursorName resource.

3.10.2. Toggle Actions

The Toggle widget supports the following actions:

The following are the default translation bindings used by the Toggle widget:

3.10.3. Toggle Actions

The full list of actions supported by Toggle is:

highlight(condition)
Displays the internal highlight border in the color (foreground or background ) that contrasts with the interior color of the Toggle widget. The conditions WhenUnset and Always are understood by this action procedure. If no argument is passed then WhenUnset is assumed.

Note

When a bitmap of depth greater that one (1) is specified the set(), unset(), and reset() actions have no effect, since there are no foreground and background colors used in a multi-plane pixmap.

3.10.4. Radio Groups

There are typically two types of radio groups desired by applications. The default translations for the Toggle widget implement a "zero or one of many" radio group. This means that there may be no more than one Toggle widget active, but there need not be any Toggle widgets active.

The other type of radio group is "one of many" and has the more strict policy that there will always be exactly one radio button active. Toggle widgets can be used to provide this interface with a slight modification to the translation table of each Toggle in the group.

This translation table will not allow any Toggle to be unset except as a result of another Toggle becoming set. It is the application programmer’s responsibility to choose an initial state for the radio group by setting the state resource of one of its member widgets to True.

3.10.5. Convenience Routines

The following functions allow easy access to the Toggle widget’s radio group functionality.

3.10.5.1. Changing the Toggle’s Radio Group.

To enable an application to change the Toggle’s radio group, add the Toggle to a radio group, or remove the Toggle from a radio group, use XawToggleChangeRadioGroup.
void XawToggleChangeRadioGroup(w, radio_group)
Widget w, radio_group;

radio_groupSpecifies any Toggle in the new radio group. If NULL then the Toggle will be removed from any radio group of which it is a member.

If a Toggle is already set in the new radio group, and the Toggle to be added is also set then the previously set Toggle in the radio group is unset and its callback procedures are invoked.

Finding the Currently selected Toggle in a radio group of Toggles

To find the currently selected Toggle in a radio group of Toggle widgets use XawToggleGetCurrent.
XtPointer XawToggleGetCurrent(radio_group);
Widget radio_group;

radio_groupSpecifies any Toggle widget in the radio group.

The value returned by this function is the radioData of the Toggle in this radio group that is currently set. The default value for radioData is the name of that Toggle widget. If no Toggle is set in the radio group specified then NULL is returned.

Changing the Toggle that is set in a radio group.

To change the Toggle that is currently set in a radio group use XawToggleSetCurrent.
void XawToggleSetCurrent(radio_group, radio_data);
Widget radio_group;
XtPointer radio_data;

radio_groupSpecifies any Toggle widget in the radio group.

radio_dataSpecifies the radioData identifying the Toggle that should be set in the radio group specified by the radio_group argument.

XawToggleSetCurrent locates the Toggle widget to be set by matching radio_data against the radioData for each Toggle in the radio group. If none match, XawToggleSetCurrent returns without making any changes. If more than one Toggle matches, XawToggleSetCurrent will choose a Toggle to set arbitrarily. If this causes any Toggle widgets to change state, all routines in their callback lists will be invoked. The callback routines for a Toggle that is to be unset will be called before the one that is to be set.

Unsetting all Toggles in a radio group.

To unset all Toggle widgets in a radio group use XawToggleUnsetCurrent.
void XawToggleUnsetCurrent(radio_group);
Widget radio_group;

radio_groupSpecifies any Toggle widget in the radio group.

If this causes a Toggle widget to change state, all routines on its callback list will be invoked.

Chapter 4

Menus

The Athena widget set provides support for single paned non-hierarchical popup and pulldown menus. Since menus are such a common user interface tool, support for them must be provided in even the most basic widget sets. In menuing as in other areas, the Athena Widget Set provides only basic functionality.

Menus in the Athena widget set are implemented as a menu container (the SimpleMenu widget) and a collection of objects that comprise the menu entries. The SimpleMenu widget is itself a direct subclass of the OverrideShell widget class, so no other shell is necessary when creating a menu. The managed children of a SimpleMenu must be subclasses of the Sme (Simple Menu Entry) object.

The Athena widget set provides three classes of Sme objects that may be used to build menus.

The SimpleMenu widget informs the window manager that it should ignore its window by setting the Override Redirect flag. This is the correct behavior for the press-drag-release style of menu operation. If click-move-click or ‘‘pinable’’’ menus are desired it is the responsibility of the application programmer, using the SimpleMenu resources, to inform the window manager of the menu.

To allow easy creation of pulldown menus, a MenuButton widget is also provided as part of the Athena widget set.

4.1. Using the Menus

The default configuration for the menus is press-drag-release. The menus will typically be activated by clicking a pointer button while the pointer is over a MenuButton, causing the menu to appear in a fixed location relative to that button; this is a pulldown menu. Menus may also be activated when a specific pointer and/or key sequence is used anywhere in the application; this is a popup menu (e.g. clicking Ctrl-<pointer button 1> in the common application xterm). In this case the menu should be positioned under the cursor. Typically menus will be placed so the pointer cursor is on the first menu entry, or the last entry selected by the user.

The menu remains on the screen as long as the pointer button is held down. Moving the pointer will highlight different menu items. If the pointer leaves the menu, or moves over an entry that cannot be selected then no menu entry will highlighted. When the desired menu entry has been highlighted, releasing the pointer button removes the menu, and causes any mechanism associated with this entry to be invoked.

4.2. SimpleMenu Widget

Application Header file<X11/Xaw/SimpleMenu.h>

The SimpleMenu widget is a container for the menu entries. It is a direct subclass of shell, and is should be created with XtCreatePopupShell, not XtCreateManagedWidget. This is the only part of the menu that actually is associated with a window. The SimpleMenu serves as the glue to bind the individual menu entries together into a menu.

4.2.1. Resources

The resources associated with the SimpleMenu widget control aspects that will affect the entire menu.
Name Class Type Notes Default Value
accelerators Accelerators AcceleratorTable NULL
ancestorSensitive AncestorSensitive Boolean D True
allowShellResize AllowShellResize Boolean True
background Background Pixel XtDefaultBackground
backgroundPixmap Pixmap Pixmap XtUnspecifiedPixmap
backingStore BackingStore BackingStore see below
borderColor BorderColor Pixel XtDefaultForeground
borderPixmap Pixmap Pixmap XtUnspecifiedPixmap
borderWidth BorderWidth Dimension 1
bottomMargin VerticalMargins Dimension 0
children ReadOnly WidgetList R NULL
createPopupChildProc CreatePopupChildProc Function NULL
colormap Colormap Colormap Parent’s Colormap
cursor Cursor Cursor None
depth Depth int C Parent’s Depth
destroyCallback Callback XtCallbackList NULL
geometry Geometry String NULL
height Height Dimension Enough space to contain all entries
label Label String NULL
labelClass LabelClass Pointer SmeBSBObjectClass
mappedWhenManaged MappedWhenManaged Boolean True
menuOnScreen MenuOnScreen Boolean True
numChildren ReadOnly Cardinal R 0
overrideRedirect OverrideRedirect Boolean True
popdownCallback Callback XtCallbackList NULL
popupCallback Callback XtCallbackList NULL
popupOnEntry PopupOnEntry Widget A Label or first entry
rowHeight RowHeight Dimension 0
saveUnder SaveUnder Boolean False
screen Screen Screen R Parent’s Screen
sensitive Sensitive Boolean True
topMargin VerticalMargins Dimension 0
translations Translations TranslationTable See below
visual Visual Visual CopyFromParent
width Width Dimension Width of widest entry
x Position Position 0
y Position Position 0

ancestorSensitive
The sensitivity state of the ancestors of this widget. A widget is insensitive if either it or any of its ancestors is insensitive. This resource should not be changed with XtSetValues, although it may be queried.

backgroundPixmapThe background pixmap of this widget’s window. If this resource is set to anything other than XtUnspecifiedPixmap, the pixmap specified will be used instead of the background color.