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Ch 1 -- Graphical User Interfaces for End Users
UNIX Unleashed, Internet Edition
- 1 -
Graphical User Interfaces for End Users
by Kamran Husain, edited by Chris Byers
In this chapter, you will do the following:
- Learn about major components of a graphical user interface. Along the way you
will get a brief history lesson on X Windows.
- Learn the major concepts required for using X Windows. This will introduce displays,
windows, screens, and the client server architecture in X.
- Start an X Windows session from logging in and using the X Windows Manager (XDM)
display manager.
- Get an introduction to window managers, specifically the Motif Window Manager
(MWM).
- Learn to move about in mwm windows with the keyboard and mouse.
- Use widgets and the characteristics of these widgets.
- Customize your desktop with resource files and client applications.
- Understand how to set your environment to your liking.
- Use some standard tools available in X.
- See what's in the future with COSE, CDE, X11R6, and vendor support.
What Is a GUI?
UNIX's user interface was character based when it was first developed. The curses
window package was somewhat of a relief but offered nothing in the way of displaying
complex graphics or pictures on a monitor. Something more was needed; something that
would provide a graphical interface for the user. This brought about the birth of
the term graphical user interface (GUI). A GUI is the graphical interface to an underlying
operating system.
The minimal components for a GUI are the following:
- A screen to show the data in a textual and/or graphical form.
- A keyboard interface for the user to type in information.
- A device to control the movement of a cursor or pointing device that the user
can move on the screen. The devices for this interface could be a mouse, light pen,
palette, or glove.
This list is by no means complete, but it illustrates some of the minimum requirements
for a typical GUI.
UNIX's standard character-based interface is a reminder of its age. X Windows
is UNIX's breaking into the GUI age. X Windows was developed to be a standard graphical
user interface for UNIX platforms. The development work was done at the Massachusetts
Institute of Technology (MIT). The MIT project was called Project Athena and was
funded by many corporations. The largest contribution came from Digital Equipment
Corporation (DEC).
NOTE: The X Window system is sometimes referred
to as X, X Windows, X11R5, or X11, depending on what you happen to be reading.
X Windows
The first commercial release of X Windows was X10.4 in 1986, and was the basis
for some commercial applications. The next release was X11R1 in 1987, followed by
X11R2 in 1988. Version 11 was a complete windowing package that outperformed X10
in its speed, flexibility of features, and styles for multiple screens. X11 and later
versions have become the de facto standard GUI for UNIX systems and are, therefore,
the focus of this chapter.
TIP: The way to read X11R4 is "X Version
11, Are Four".
The main features offered by X Windows are the following:
- Standard GUI for more UNIX workstations. See Chapter 2, "Graphical User
Interfaces for Programmers," which is on multiple windowing platforms and standards.
- High portability. It's written in C and is designed to be portable.
- It's highly extensible. New features can be implemented into the kernel, run
as separate applications, or can use the pre-existing applications that come with
X.
- It's very flexible. The number of features in X make it very complicated. However,
you can do a lot more with it because you can modify it to your needs and you have
access to the large collection of UNIX tools.
Displays, Screens, and Windows
X is typically run on a large screen with special graphics capabilities. X allows
you to work with multiple processes, each in its own window. Next, you'll look at
a screen dump of a typical window. Depending on your installation, you might see
a different screen. Figure 1.1 shows a typical X display running under Motif. The
same window will look different under a different Tab Window Manager (TWM). (See
Figure 1.2.) See the section "Introduction to Window Managers" for more
details.
Figure 1.1.
A typical X display with the Motif Window Manager (MWM).
Figure 1.2.
A typical X window in the Tab Window Manager (TWM).
The operations on a particular window can vary greatly. Some windows are used
only for displaying data; some are used for input and output of data. Some windows
can be resized or moved, or they can overlap or hide contents of another window.
Each window is generally independent and contains information about its contents,
including how to draw itself on the screen. The window does not have to care about
itself being hidden from view by another window because its internal operations are
not affected when it is overlapped by another window.
The display in Figure 1.1 shows a clock and an xterm. A clock simply
shows the time of day. An xterm is a terminal emulator and provides a window
into the UNIX operating system. You can have several X Windows open at one time on
a display. Each xterm is a window independent of all other xterms
on that display and contains a separate UNIX terminal session.
The fact that you can run separate processes in simultaneously displayed windows
is one of the most powerful features of X. Also, because you have the full networking
capabilities of UNIX, you can run remote sessions on several machines on separate
windows on the same display. In fact, you can even force a window to be displayed
on a remote UNIX machine running X Windows.
The background area is referred to as the root window. All application windows
are displayed on top of this window. X maintains a hierarchical tree of all the windows
on the root window. All applications that reside on the root window are its children.
Their parent is the root window. The root window's parent is the root window itself.
All components of windows also are child windows of the application window on which
they reside.
For example, button and text widgets you see in an application are all windows
on top of their controlling application's window. The depth of the tree is the number
of elements in the tree and in some cases can be a very large number.
Stacking Order
The location of the windows relative to each other on the screen itself is referred
to as their stacking order. You could compare this to stacking sheets of paper on
a large canvas. The writing or pictures on each sheet are not changed when another
sheet is stacked on top. Some parts of the lower sheet are visible while it is overlapped
by the top sheet.
When the top sheet is moved around, the writing on the lower sheets is visible
again. Changing the location and order of papers is analogous to moving windows around
on the display.
The paper on the top of the stack is always fully visible. The topmost window
is analogous to the top sheet of paper. Knowing which window is on top is very important
when working in the X Window environment. The control of the windows, their placement,
and their stacking order is handled by a special client called the window manager.
See the section "Introduction to Window Managers" later in this chapter.
Pointers in X
All X displays require some sort of pointing device. This is generally a three-button
mouse; however, you are not limited to a mouse. You can have many types of pointers,
including pens, tablets, and so on. You can get by without a pointer in some very
limited cases, but this is not the way X was designed and is, therefore, not recommended
practice.
A cursor represents the pointer position on the screen. The cursor follows your
movement of the pointer on the screen. As you slide the pointer across the screen,
you should see the cursor move with your movements. Several cursors exist in the
X Window environment for you to use in customizing. See the section "Customizing
MWM" for details.
Keep in mind that the terms "display" and "screen" are not
equivalent in X. You can actually hook two monitors and have a screen on each of
them hooked to a common display area. A display can have multiple screens. As you
move the cursor to the edge of a screen, it will appear on the other screen. Screens
are numbered from 0 up. By default, your screen 0 is hooked to display 0 for normal
operations. You can also define two screens on the same monitor. See the installation
instructions for your hardware vendor for more details.
The Client/Server Architecture
X Window was designed to be platform and kernel independent. Therefore, it is
not part of any formal operating system. X's architecture is based on a client/server
architecture. The server in the X Window system is very different from the network
servers.
Servers provide the display capabilities to user applications clients. This is
why they are referred to as display servers. The server sits between the client and
the hardware. A client makes a request for display operations to the server. The
server translates these requests into hardware directives for the underlying system.
Figure 1.3 shows the logical relationship between servers and clients.
Figure 1.3.
The logical relationship of X servers and clients.
The requests are made via message queues, using the X protocol. The X protocol
is the means of communication requests and responses between clients and servers.
The X server tracks all the user input from the keyboard and pointer. It conveys
this information via the X protocol back to the clients.
The division of work between the client and server allows each to run on completely
different platforms connected via a network. This provides several advantages: If
most of the computationally intensive work can be done on a remote site, you could
run the server on another system to spare the already overloaded system from the
overhead of graphics.
Also, only the server application has to be hardware specific. All client software
can be designed to be platform independent and easier to port.
You can run several clients on several machines from your server. Each client
can then take advantage of the machine on which it is running.
Clients can also communicate with other clients. The server can keep this information
in a common place and have it available for all other clients. This information is
referred to as properties. A property is simply a piece of information recorded by
the server for a client. Refer to the xprop program offered by the X Window
system for more information.
A lot of options exist for all the options available for customizing clients.
Look at the man page for xterm as an example. X also provides another way
of customizing appearances, using the resources file called .Xresources.
This file is usually located in the home directory.
TIP: The .Xresources file is sometimes
called .Xdefaults.
Introduction to Window Managers
How the windows are arranged is a function of a special program called the window
manager. The window manager controls the "look and feel" of all the windows
on a particular display. The window manager allows the user to move, restack, resize,
and iconify windows.
X Window comes with two window managers. These managers are called the Tab Window
Manager (TWM) and the OPEN LOOK Window Manager (OLWM). The TWM is also referred to
as Tom's Window Manager, after its author, Tom LaStrange. Earlier versions of X also
offered the Universal Window Manager (UWM); however, this is no longer offered because
it does not conform to the X Consortium's Inter-Client Communications Conventions
Manual (ICCCM) standards.
Window managers in X are different from other windowing system managers because
you are allowed to choose whichever manager you like. As long as a manager follows
the ICCCM standard, it can serve as your window manager.
The most prevalent window manager today is the Motif Window Manager (MWM) from
the OSF/Motif distribution. The Motif Window Manager is now more important than ever
before since being adopted by Common Open Software Environment (COSE) as the standard
interface for future UNIX GUIs. It's most famous for its borders around all the windows
it displays. Figure 1.4 shows the frame MWM puts around each window.
Figure 1.4.
A typical Motif frame.
Getting Started with X Window
NOTE: The first thing to remember is that X is
very flexible. You can customize almost anything in X. Therefore, be warned that
even though this chapter attempts to describe the most common features of X, they
may not work exactly as described. This is the price of flexibility. This is especially
true for all the different versions of X and window managers offered in X.
On some systems, you may have to start X from the command line after you log in.
On other systems you may have to interface through the XDM client. The case of the
XDM manager already running on your system is easy, so that's a good place to begin.
Using XDM
The XDM utility stands for X Display Manager. It manages several X displays. It
is designed to provide the same services as getty, init, and login
on character terminals. This is where the system verifies your password and performs
the login procedure. xdm runs in the background by default. It was first introduced
in X11R4 and conforms to the X Display Manager Control Protocol (XDMCP) developed
by the X Consortium.
When XDM is running on a system, a typical display would look like the one shown
in Figure 1.5.
Figure 1.5.
A typical XDM display.
The XDM session will ask for your login id and password as with any character-based
session. However, it would then bring up the X server with an xterm by default
instead of just presenting the shell prompt. This book is written with the understanding
that no customization has been done on your site or that particular machine. XDM
emulates the login and getty programs and must be run from the /etc/rc system
file. In UNIX, login verifies your password. Under XDM, the login and getty are replaced
by XDM's own functionality.
By default, the MWM window manager should be running. See if the familiar borders
exist around the xterm. If MWM is not running, type mwm & on
the xterm prompt to invoke it. Later in this section you will learn more
about how to invoke MWM.
The Hard Way to Start X
If you do not see any windows at all and you do not see a cursor, then you do
not have the X server running. In this case, you have to start X server yourself.
There are several steps to take before you start X:
- 1. If you are new to UNIX and X, contact your system administrator for
help. If you are the system administrator, this chapter will only guide you in the
right direction. Now would be a good time to read the hardware manual.
2. Confirm that xinit exists in your PATH. Use the echo $PATH
command to see if /usr/bin/X11 is in your path.
3. Look for a file called Xconfig in /usr/lib/X11 or /usr/bin/X11.
This file will contain hardware-specific information about your system. Contact your
vendor if this file does not exist.
TIP: Always make a copy of Xconfig and
save it before you modify it. Do not edit this file while you are already in X, because
X may be reading it while you are trying to edit.
- 4. Look for a file starting with the letter X with a machine
name after it. This is your X server. You will usually find X386 on PCs, Xsun on
Suns, and so on.
5. Use the which command to find out the location of the xinit
command. Use the following command on the /usr directory:
find . -name xinit -print
- 6. Type the command xinit at your prompt.
7. Wait a few seconds (or minutes, depending on your hardware). You should see
several messages whisk by, and the screen should change to that of a session without
a window manager.
8. At this point, you could run with this somewhat crippled windowing system
or you could start a window manager. For the Motif Window Manager, use the command
in the xterm:
mwm &
Note that you are running the mwm in the background. If you do not do this, you
will not be able to issue any commands to the xterm.
TIP: If you are in the Korn or C shell
at this point and you forgot the &, then type Ctrl+z to put
the job in the background. If you are not running the Korn or C shell, you can kill
MWM with Ctrl+c and then restart it with the ampersand.
So now you are running Motif and X Window on your system. Remember that a lot
of things can go wrong while you're getting to this point. Here are a few of the
most common problems:
- You cannot find the correct files. Ensure that the path includes /usr/bin/X11
or the like. On some systems, it could be /usr/bin/X11R4 or /usr/bin/X11R5,
or something similar. Use the find command to locate it.
- When working on Suns, some of your system files may reside in the /usr/openwin/bin
directories.
- You moved the cursor into the window, but now you have to click to be able to
type commands to your xterm. By itself, X Window gives the focus to a window
when a cursor is moved on to it. MWM, on the other hand, requires that you actually
click the left mouse button (Button1) for that window to get focus. Focus means that
all user input (keyboard and pointer) will now be sent to that window. MWM will change
the color of the window border to show that it has received focus.
- You do not have enough memory to run the system. This is especially true if you
are on a PC-based platform. Typically you can get away with 4 MB of dynamic RAM for
a simple X Window system, but you will almost certainly require 8 MB or more to be
able to get a reasonable response time on a PC. The memory upgrade to 8 MB is well
worth it, given the performance on a 4 MB machine. Those who are patient can live
with 4 MB.
- The configuration does not look right. You have to modify the default start-up
parameters. See the section "Customizing MWM" for more information.
- Exiting the last command in your xinit file will terminate your entire
X session. If your last command was an xterm and you logged off that xterm,
your entire session will be terminated.
Congratulations! You are now running Motif.
Figure 1.6 shows a typical xterm window in Motif.
Figure 1.6.
A typical xterm window.
The title bar is the wide horizontal band on the top of the window. This contains
the title for the application itself. In this case, this is the application itself,
xterm. You can modify it to your needs. Try this:
xterm -name "I am here" &
You can use the minimize button to iconify this xterm or the maximize
button to resize the window to occupy the entire display area. The sides and corners
can be used to resize the window by using the mouse. Note the pseudo-3D appearance
of the borders. The area of window that is used to display output and get input is
also called the window pane.
Working with Motif Windows in MWM
This section deals with some of the Motif windows you have on the screen. Typically,
you will work with a mouse for the pointer, so the text will refer to mouse devices
at times. However, you can always substitute your device name for the word "mouse"
or "pointer" and not lose any meaning of the discussion.
Using the Pointer
Pointers in the MWM environment typically use three buttons, which are called
Button1, Button2, and Button3. Button1 is the most-used button of the three and is
usually referred to as the "left button." The left button on a mouse is
the one that is pressed with your right index finger.
When you take the pointer to an item and press a button, you are clicking the
button. If you hold the pointer down with your finger and the object moves with your
pointer movements, you are dragging the object. If you click two or three times in
quick succession, you are double-clicking or triple-clicking, respectively. Drag
and drop is when you drag an object to a new location and the object stays in the
new location after you release the pointer button.
If you are left handed, you can map your mouse or pointer buttons differently.
See the section "Help for Left-Handed Users" later in this chapter.
Icons and Windows
The minimize button allows you to iconify an application. An icon is a small symbol
that represents an inactive window. The contents of that window are not visible,
although they may be updated internally by the processes running in that window.
Icons can be moved around on a window, but they cannot be resized. Icons save you
valuable screen space for applications that do not require your constant attention.
Iconifying a Window
Move the cursor to the minimize button and press the left mouse button. The window
is removed from the screen and a smaller icon appears somewhere on the left of the
screen.
To restore an icon to a screen, move the cursor to the icon and click on Button1
twice in quick succession. This is known as double-clicking the mouse. A typical
Motif icon is shown in Figure 1.7.
Figure 1.7.
A typical Motif icon.
Maximizing a Window
Move the cursor to the maximize window and press the pointer Button1. This enlarges
the window to the size of the root window. This way you can have a huge clock on
your screen. Some applications, such as older versions of calc, do not adjust
their internal graphic areas when their frame is resized. This leads to annoying
blank space on a screen.
Use the maximize button as a toggle. Clicking on an already maximized window causes
it to revert to its size and position (also known as geometry) before it was maximized.
Clicking on it again maximizes it (again).
TIP: Avoid resizing a window when running a vi
session under an xterm. This usually leads to unpredictable results and
may cause vi to behave very strangely.
Sizing a Window
The entire frame on a Motif window is a control that allows you to resize the
window. See Figure 1.8 for the size controls. You can use any of the four corners
to stretch the window. You can use the mouse to move the edges of the window by dragging
the four long bars.
Figure 1.8.
The eight sizing controls for windows.
To stretch the window using a corner, move the mouse to that corner. Press Button1
and while keeping it pressed, move the mouse. The cursor changes its shape to a double-headed
arrow. Size the window by moving the mouse while pressing Button1. Release the button
when you have achieved the desired size.
Note that some applications do not have these sizing controls enabled. An example
is the cute, but not very useful, pointer tracking program called xeyes.
(See Figure 1.9.)
Figure 1.9.
A window of the Xeyes program without resize borders.
To move the edge of the window, move the mouse to that edge. You should see your
cursor change shape to a vertical double-headed arrow if you are on a horizontal
edge (top or bottom of the window). If you are on a vertical edge, the double-headed
arrow will be horizontal. Press Button1 and while keeping it pressed move the pointer
around. This moves the edge along with your pointer. Release the button when you
have the edge where you want it.
While you are resizing this window, you will see a small box come up in the center
of the display. This box contains the size of the window in pixels if it's a graphics
image or in rows and columns (in the number of characters) if this is an xterm.
On some systems you can use the arrow keys on your keyboard to achieve precision
when resizing your windows. Remember to keep the button pressed while you use the
arrow keys on your keyboard to do the precise adjustment.
Focus and Selecting a Window
You can select which window or icon gets focus by moving the pointer to that item
and pressing the left button. This moves the window or icon to the top of the stack.
This way the window or icon will not be obscured by any other screen item.
When a window has focus, it collects all the user input from the pointer and the
keyboard. There are two types of focus for a window: click to type and explicit.
The click to type focus requires a user to click a pointer button in a window for
it to get focus. The explicit focus requires only that the cursor be in the window
for the window to get focus. Explicit focus is sometimes referred to as real estate--driven
focus.
In some cases you might want to have focus where the mouse was without having
to click the pointer button. Sometimes this is not useful for touch typists, because
a single movement of the pointer can have the keystroke sent to the wrong window.
TIP: Sometimes it's a good idea to click on the
frame to get focus to a window because clicking in the window might accidentally
press a button or other control in the window.
Once you give the focus to a client, the client window will collect all typed
or graphics information until the user clicks elsewhere. It has the focus.
Getting focus also raises the window to the top of the stack. The window frame
color also changes at this point. You can set the focus to an icon also by selecting
it with a mouse. The name of the icon expands at that point, and you see the window
menu for that icon. You can move the mouse away from the menu, but the icon will
retain the focus until you click elsewhere.
NOTE: The color change scheme will depend on
your site's default colors. In some cases, you may not see any color change at all
if the focused and out-of-focus colors are the same.
Moving a Window or an Icon
To move a window's location on the screen, do the following:
- 1. Move the cursor on top of the title bar.
2. Press and hold down pointer Button1.
3. Move the pointer to the desired location. You should see an outline of
the window border move with your pointer.
4. Move the outline to the part of the screen where you want your window to
be. This is referred to as dragging the window.
5. Release Button1. The window now appears at the new location. It also is
the window with the focus (by default).
This procedure can be duplicated for an icon. In the case of an icon, you would
click and drag with the cursor in the icon itself.
While you are moving the window, you will see a small box in the center of the
screen with two numbers in it. These are positive X and Y offsets of the top-left
corner of the window from the top-left corner of the screen. This is very useful
information when trying to precisely place a window on the screen.
On some workstations, you can achieve some fine precision by pressing the arrow
keys on the numeric keypad to move the window one step at a time. You must keep the
pointer button pressed while you use the arrow keys.
Adding a New Window
If you want to add a calculator to your screen, you can type
xcalc &
at the prompt. The calculator appears on the screen.
For an xterm, type this:
xterm &
Depending on your site, this can appear anywhere on the screen. Typically, the
new window is placed in the upper-left corner (X=0,Y=0) of the root window or in
the center of the root window.
The size and location of a window is referred to as the window's geometry.
Window Geometry
Almost all clients accept the -geometry command line option. This option
tells the window manager where to locate the window on a screen. If you do not specify
any geometry, the window manager will use its defaults.
The coordinate system for the root window is as follows:
- The origin is top left (0,0).
- The number of display units is pixels for graphics.
- The number of display units is character sizes for xterms.
A pixel is the smallest unit available on a screen. Usually screens are displayed
in 1024x768 pixels, or 2048x2048 pixels, or something similar. The size of a pixel
onscreen is very much hardware dependent. A 200x200 window appears as different sizes
on monitors with different resolutions.
The geometry parameter is of the form
heightxwidth[{+-}xoff{-+}yoff]
The height and width is usually given in pixels. In the case of xterms
it is given in lines for the height and characters per line for the width. It is
common to have a 24x80 xterm.
The xoff and yoff are offsets from the start of left and top
edges of the screen, respectively. These represent the location of the window on
the root window. The curly braces represent either the - or the +
character, but not both.
| +xoff |
A positive offset from the left edge of the screen to the left edge of the window-xoff.
A negative offset from the right edge of the screen to the right edge of the window. |
| +yoff |
A positive offset from the top edge of the screen to the top edge of the window-yoff.
A negative offset from the bottom edge of the screen to the bottom edge of the window. |
Figure 1.10 shows a visual representation of the geometry. For example,
xterm -geometry -50+50 &
places the xterm on the top-right corner, 50 pixels from the right edge
of the screen and 50 pixels from the top of the screen.
Figure 1.10.
Window geometry.
The following parameters specify the edges of the screen:
| -0-0 |
Lower-right corner |
| -0+0 |
Upper-right corner |
| +0-0 |
Lower-left corner |
| +0+0 |
Upper-left corner |
Using the Window Menu
Using the Window menu requires you to focus on a window. Let's look at a typical
Window menu. It may be different on your screen, but the basic functionality listed
here should exist for all later versions of Motif. Take the cursor to the Window
menu button and press the left button. The following menu (or something close to
it) should appear:
| Restore |
Alt+F5 |
| Move |
Alt+F7 |
| Size |
Alt+F8 |
| Minimize |
Alt+F9 |
| Maximize |
Alt+F10 |
| Lower |
Alt+F3 |
| Close |
Alt+F4 |
Using the Keyboard and the Meta Key in X
It's important to bring up this point about the keyboard and its special keys
under X. Keyboards come in different flavors, and the most important key for using
keystrokes in X can be radically different from one keyboard to another. On the PC-based
keyboards it is usually the Alt key; on Macintoshes it is the fan-shaped key; on
Suns it's Left, Right, Alternate; on other keyboards it's completely different.
In short, when this chapter refers to the Meta key, it means your special key
for your special keyboard. For a PC-based keyboard, this would be the Alt key. So
do not look for a key called Meta on your keyboard. Where the chapter says Meta,
use Alt, fan, or whatever your keyboard uses.
Now you can invoke any item on this Window menu one of two ways:
- Use the pointer. This is how you would click on the window menu and press Button1.
Now do this:
- Move the cursor to the item you want and release Button1, or
- Press the Meta key and the character that is underlined in the menu. For moving
a window, you would press Meta+M. Note that this does not work on some Motif systems.
NOTE: This may not always work. In Metro's version
of Motif 1.2, the Meta+F7 key combination enables you to move a window, but the Meta+m
key does not work at all. You may have a completely different experience with your
keyboard.
- While the window has focus, press the Meta+function key combination. Then use
the arrow keys on your keyboard to simulate the movement of the cursor, or just use
the pointer.
Note that some of these functions may not be available for a menu shown for an
icon. You will not be able to size or minimize an icon. You will, however, be allowed
to move, maximize, or close it.
Using the Root Menu
Click Button3 while the cursor is in the root window. You will see a menu pop
up on top of all the windows. This is known as the root menu. Keep in mind that this
menu is very customizable and may look radically different on your machine. You will
learn all about creating your own menu later in this chapter in the section "Customizing
MWM."
A typical root menu would list the following items:
"Root Menu"
New Window
Shuffle Up
Shuffle Down
Refresh
Utils >
Restart
Exit
While holding Button1 down, move the cursor down the list to the item you want
to select. When you get to the menu item you want, release the button. If you do
not want to select any items, move the cursor off the menu and release the button.
In the root menu list, the functionality could be as follows:
- New Window starts a new xterm and sets focus to it.
- Refresh redraws the entire screen and all windows.
- Restart kills MWM and restarts it.
- Shuffle up and down shuffles the stacking order of the windows up or down. The
window with focus is moved down to the bottom when shuffling down, and the next highest
window is given the focus. The last window in the stack is brought to the top and
given the focus when shuffling up.
- The Utils item brings up another sub menu with more choices to select from. See
the section "Customizing MWM" for details on how to set your menu items.
- Exit kills MWM and leaves you without a window manager. If this is the last command
in your start-up script, your windowing session will terminate.
TIP: On occasion, you will come across a vendor
that will not allow you to back up to the operating system. In this case, you can
try the Ctrl+Alt+Backspace key combination to get back to the prompt.
Working with Motif Clients
Most programmers find the X Windows system libraries too basic to work with, so
they use the next building block called Toolkits. The most common interface toolkit
is called the XtIntrinsics toolkit from MIT. This is called Xt. On top of Xt, you
can have other toolkits such as Motif or the OPEN LOOK Interface Toolkit (OLIT).
When you are working with Motif, you are working with a Motif toolkit. In Motif,
you are working with Motif widgets.
Widgets help users program consistent user interfaces in Motif. By using widgets,
users can quickly put together interfaces that have the same look and feel of all
Motif applications.
Some widgets display information. Some widgets collect user input (mouse or keyboard)
information. Some widgets react to user input by changing their appearance or by
performing some programmed function. Some widgets are simply containers for other
widgets. All widgets can be customized in one form or another, whether it is appearance,
font size or style, colors, or whatever other parameter is required.
All widgets of the same type have two data structures with information that describes
their attributes: instance and class. The instance data structure contains information
for a specific widget on the screen. The class information contains information required
for all widgets of the class.
Widgets are grouped into several classes. Each class depends on the type of functionality
offered by the widget. Normally the internal functions of a widget are hidden from
the applications programmer (encapsulation). A widget class shares a set of functions
and data structures for all widgets in that class. A new widget class can be derived
from an existing widget class.
The newly derived class can inherit all the parent class' data structures and
functions. A widget is created and destroyed during a Motif program execution.
NOTE: The destruction of a widget is a bit complicated
and will be discussed in detail in Chapter 2, "Graphical User Interfaces for
Programmers."
This should sound familiar to C++ programmers. True polymorphism is somewhat harder
to find in widgets. This is all done in C. For C++ programmers, the class
data structure is to the class of an object as the instance data structure
is to the instance of an object.
A widget is really a pointer to a data structure when viewed in a debugger. This
data structure is allocated on the creation of a widget and is destroyed when a widget
is destroyed.
Let's look at a typical application screen to see some widgets in action. You
will work with a demo application called xmdialogs, shown in Figure 1.11.
The widgets shown here are described later in this chapter. The xmdialogs
application can be found in the /usr/bin/X11 directory. If you do not have
this application, you can still learn about working with widgets by applying these
concepts to different applications.
Figure 1.11.
The xmdialogs demo application.
NOTE: Don't worry if you can't find this application
on your machine. You will develop the components for this application in the next
chapter. If you have the Motif 1.2 release from Metro Link, (305) 938-0283, you will
have this in your demos directory.
Figure 1.11 shows a menu bar, a file selection list with scroll bars, an option
button, some radio and toggle buttons, some push buttons, labels, and a text display
dialog.
The Actions and Help items are shown on a menu bar. By moving the pointer to either
of these items and pressing Button1, you will be presented with a menu of options
very similar in operation to the window and root menu.
Under this menu bar is a list of items in a scrollable list. This widget is of
the type XmList. The XmList lets you keep a selection of items
in a visible list. It has scroll bars to allow the user to scroll the list if the
entire list is not visible. A programmer can set the number of items that are visible
at one time. If you resize the window and if the list box sizes itself proportionately
with the window, the number of visible items in the list may change.
To select an item, move the pointer to the item of your choice and press Button1
once. The item is highlighted in a darker color. Some lists allow you to select more
than one item, some just one item. In this application you select only one type of
dialog box. Figure 1.11 shows that the bulletin board item is the selected item.
The scroll bars on the side of the list widget are of the class XmScrollbar.
A scroll bar is either a horizontal or vertical rectangle. There is a raised box
in the rectangle, called the slider box. This slider moves within the larger rectangle.
The moveable space for the slider bar is called the scroll region. The size of the
slider bar to the scroll region is proportional to the size of the work area to the
total area being viewed.
The XmScrollBar rectangle has an arrow at each end. The arrows point
out from the rectangle and in opposite directions. You can use the arrow keys to
move the slider bar within the scroll region.
- 1. Move the mouse to the slider bar arrow.
2. Click Button1.
3. The slider bar moves closer to the arrow. The slider moves as close as
possible to the arrow being clicked in the scroll area.
4. Release Button1.
You can also move the slider bar by dragging with the mouse:
- 1. Move the pointer onto the slider bar.
2. Press Button1.
3. Move the pointer up or down for a vertical scroll bar. Move the pointer
left or right for a horizontal scroll bar.
The contents of the work area as well as the slider bar should scroll with the movement
of the pointer. The viewable portion is the work area.
4. Release Button1 when list area contains the desired viewing data.
Now move your cursor to the selection item of the resize policy button. When you
click this button, you are presented with a pop-up menu containing the types of resize
policies for the dialog box you want to create. When you press the button, a menu
pops out and presents a list of options. You make the selection with your pointer
by moving the pointer to that button and releasing it. The menu disappears and your
selection is displayed in the box. In Figure 1.11 the resize policy is set to any.
This is known as an option button.
Note the diamond-shaped buttons and selections below this current menu. This is
a list of one of four possible selections for the dialog box. One of the items is
shown in a lighter gray color. This is known as being grayed out, and the option
is a not a valid option at the time. The option for the work area is disabled. You
can select one of the other three options. These items are grouped together with
a rectangular frame drawn around them. Usually buttons are grouped together in Motif
this way when their functionality falls in the same group of actions. The actions
are similar to the buttons on an old radio: Push one button and the rest in the row
of buttons all come up. This is why these are referred to as radio buttons.
Look at the two buttons called auto manage and default position. These are toggle
buttons for this application. When you select one button, the other is not influenced
at all. The functionality provided by each button is completely independent of that
of the other.
Sometimes the scroll bar is used on either side of a drawing area. This is called
a scrolled window and belongs to the XmScrolledWindow class. This widget
can hold graphics instead of a list of items. The XmScrolledWindow is used
primarily to view large graphics items in a small window, whereas XmList
is used to show a list of items from which the user can select.
Under the toggle buttons, you will see four push buttons. When a push button is
pressed, the colors on the border of the button reverse. Furthermore, the color of
the pressed rectangle changes to show the user action. Push buttons are used to invoke
some sort of action. When you select the file selection dialog from the list and
press the push button to manage it, the display shown in Figure 1.12 appears. This
is the standard File Selection dialog box under Motif, and you will see it for most
applications.
Figure 1.12.
A typical File Selection dialog box.
Other Types of Widgets
The Motif toolkit also supplies the widgets described in the following sections.
XmDialogShell
This is a subclass of TransientShell. Instances of this class are used
from modal or modeless dialog boxes. Modality refers to whether the user may interact
with other windows while the dialog box is being displayed. A modal dialog box prevents
you from moving on until you are finished with the dialog box. A modeless dialog
box lets you work with other boxes. A File Selection dialog box is a modeless dialog
box.
XmMenuShell
Instances of this class are used to create menu panes for pop-up and pull-down
menus. This is derived from the OverrideShell.
VendorShell
This is a subclass of WMShell. It provides the interface to a window
manager. These are provided by specific systems vendors, hence the name.
Other Display Widgets
These display widgets are used to provide user interaction tools via buttons,
arrows, scroll bars, and so on. This list is by no means complete because vendors
and end users can create their own versions of widgets or brand new widgets. Some
examples of commercially available widgets include spreadsheet widgets, bar chart
widgets, gauges, and so forth. These widgets provide a consistent interface and are
therefore easy to include in Motif applications. Some of the standard widgets are
listed here.
XmArrowButton
This is a directional arrow with a border around it. A programmer can modify the
direction of the arrow, as well as the thickness and color of the border, by setting
the widget's parameters. If you look at the ends of a scroll bar, you will see two
examples of such a widget.
XmDrawnButton
A DrawnButton provides a rectangular area with a border for the programmer. The
programmer can size, redraw, or reposition text or graphics within this window. This
widget provides hooks to set parameters for its border appearance, as well as to
attach functions for accepting user inputs.
XmLabel
This is a rectangular box consisting of either text or graphics. It is instantiated,
but is also used as a base class for all button widgets. A label's text can be multiline,
multifont, or even multidirectional. In the xmdialogs example, this would
be the labels Active Dialog and the Motif Dialog widgets.
Many features of labels can be modified such as fonts, foreground and background
colors, and alignment (left, center, or right justification). In fact, this can even
store a pixmap graphic image.
XmPushButton
This is a text label or pixmap with a border around it. This widget accepts keystrokes
or mouse button presses. In the xmdialogs example, these are the create,
destroy, manage, and unmanage buttons. When a button has focus, it has a heavy border.
Press the Enter key or a pointer button when the button has focus. Move the cursor
to the button. Press a key or button and hold it down. You have armed the button.
The color on the button changes and the border colors reverse. This gives the impression
that the button has been pressed inward. When you release the button, the button
reverts to its original state.
When a mouse button is pressed in this widget, the foreground and background colors
of the widget usually invert. This simulates the pressing of a button.
XmSeparator
This is used to create a line between functional sections of a screen. There is
really not much users can do with this widget except position it on the screen.
XmText
This is used to create a fully functional multiline text editor on a screen. The
user can select text by dragging the mouse from one location to another while Button1
is pressed. Users can also click anywhere on the widget to mark the insertion point.
If the text widget is enabled for user input, the user can type at the insertion
point and insert the text into the text widget.
Pull-Down Menus
These are rectangular areas in the window that allow users to select from a group
of items. The items are generally laid out in push buttons. You can select a push
button either by moving the mouse to that selection or by pressing Alt+K, where K
is the letter in the menu button that is underlined. In the xmdialogs function,
the Meta+F key selects the file item, and Meta+H selects the help item.
Pop-Up Menus
The Motif root window menu is a good example of a pop-up menu. When you press
the mouse button, a menu is displayed. You can select the items in the menu by moving
the cursor onto the item and pressing Button1.
Xmscale
The Xmscale widget is used to display the value of a data item between
two extremes. It can also be used to accept user input. A scale widget has a scroll
region very similar to the scroll bar. However, it does not have the arrow buttons
at either end.
XmScrolledWindow
This is a combination of a horizontal scroll bar, vertical scroll bar, and a drawing
area. If the size of the drawing area fits within the window, you will not see the
scroll bars. If the size of the drawing area is greater than the visible area of
the scrolled window, then you will see either the horizontal scroll bar, the vertical
scroll bar, or both. You can then use the scroll bars to move the visible portion
on top of the drawing area. This is known as panning the window.
XmFrame
This is a simple widget used to put a consistent border around one single widget.
A frame can only hold one widget at a time.
XmRowColumn
This is a general-purpose widget organizer. The widget can lay out its widget
collection in a variety of ways, including the following:
| Row major |
This is where all widgets on the row column widget are stored until one row fills
up, and a new row is created when another widget is added that will not fit on this
row. The creation of a new row is sometimes called wrap around. |
| Column major |
This is the same as a row major, but it wraps around in a columnar fashion. |
You can specify the width of each column to be that of the widest widget, the
number of fixed columns, the packing (whether all widgets should be packed as closely
as possible), or determined individually by each widget.
As mentioned earlier, there are several other widgets available in the Motif widget
set. You can see the complete listing and their options in The Programmers' Reference
Manual from the Open Software Foundation (OSF).
Gadgets
Motif widgets create a window in X Windows. A complex Motif application can create
several X Windows very quickly. Each window uses X resources in the server and having
many windows can slow your overall system performance.
Gadgets are windowless versions of widgets. Most gadgets have the same names as
widgets but have the string gadget appended to their names. So XmLabel has
an XmLabelGadget counterpart.
Gadgets do not have all the features of widgets. For example, gadgets share the
foreground and background colors of their parents. Also, some gadgets actually turn
out to be slower than the widgets they are trying to replace. Given the troubles
you can get into by using gadgets, you would be better off not using them.
Customizing with Resources
Now that you are familiar with widgets, you need to know the parameters that affect
them: resources.
What Are Resources?
As you saw in the previous sections, you can customize some aspects of an application
from the command line prompt. X allows you to modify the aspects of an existing application
every time a client runs that application. X does this by setting control variables
for that client. These control variables are called resources and have a value associated
with them.
For example, take the case of an xterm. An xterm's resources
are its font size, its pointer shape, the foreground color for all displayed text,
its background color, and so on. These are only a few of the resources for an xterm.
Most of these resources exist as predefined defaults for all the common clients in
a system.
You can specify resources on an application-specific basis or for all applications
on your system. These resources are normally stored in an ASCII file called .Xresources
in your home directory.
This file affects only those applications that you run. This file normally contains
only those options that you would customize over those in the systemwide files.
You can always override these defaults specified in the systemwide file with defaults
in your .Xresources file located in your home directory. In turn, your command
line options for a single client override those in the .Xresources file.
Keep in mind that the command line default applies only to a specific client; the
.Xresources default setting becomes the default for all your clients.
Also remember that the command line operations override any default resources
set in a file. Normally you set how you want your application to look under normal
circumstances, then override the changes via command line options.
TIP: In some systems, the .Xresources
file can also be .Xdefaults. This text will use .Xresources by
default.
To make your resource specifications available to all clients, use the X resource
database manager program, or xrdb. This stores the resources directly on
the server and makes the resource available to all clients on the system. This step
takes some care because your change will affect all your clients, regardless of what
platform they are running on.
Defining Resources
A resource definition file is basically a line-by-line list of all the resources
in the file. Each line consists of two entries: one for the resource type and the
other for the value for the resource. The two entries are separated by a colon.
The syntax for a resource definition is
client*variable: value
where client is the name of the client. The variable for that client
is set to value. Note that the colon follows the variable without any spaces.
Now look at the resource declaration for an xterm client.
XTerm*foreground: white
XTerm*background: blue
XTerm*font: 10x20
...
aixterm*foreground: white
aixterm*background: blue
aixterm*font: 10x20
On your system, you may see declarations for cterm, or in the case of
IBM's AIX machine, aixterm, instead of xterm. These are simply
names for xterm in other versions. When in doubt, search for the word XTerm,
xterm, or term in your .Xresources file. If you do not
already have an .Xresources file, you can create one yourself with an ASCII
editor.
The values can be Boolean, numeric, or string values. They can be specified for
widgets in an application, as well. For example, if you want to set the background
color for all push buttons in an application called myWorld, you would set
the following resource:
myWorld*PushButton.background: red
myWorld*background: blue
Note that the asterisk is used to represent the widgets between the actual myWorld
application and all push buttons in that application. Had we specified
myWorld.mainForm.PushButton: blue
then only the buttons on the widget, mainForm, which in turn had to exist
on myWorld, would be affected. This would be tight binding. Using the asterisk
is loose binding because it allows for multiple levels of widget hierarchy between
the objects on either side of the asterisk. If you had an application with a hierarchy
of
myWorld.mainForm.subForm.PushButton
then the first two of the following declarations would affect the push buttons
on the subForm, but the last one would not:
myWorld*PushButton.background: red
myWorld*background: blue
myWorld.mainForm.PushButton: blue
Another example would be the settings for an xterm. If you attempt to
set the scrollbars using
XTerm.scrollbar: true
it will most likely not work. There will probably be a widget hierarchy between
the top-level application and the scrollbar widgets. In this case, it will work if
you use this:
XTerm*scrollbar: true
TIP: When you use a very general setting for
a widget in your resource files, say *labelString, you will affect all such
occurrences of labelString in all files. So be careful!
After you have modified the .Xresources file, you will probably expect
to see the changes occur immediately. Not so. You now have to inform the server of
your defaults by using the xrdb command. Use the following command:
xrdb -load .Xresources
This will reflect the changes for all subsequent executions of your client. These
changes will remain in effect until they are overridden or until your session terminates.
If you saved your .Xresources file in your login directory, these changes
will be loaded whenever you start X in the future if you run this:
xrdb -load .Xresources
This command is useful when creating .Xresources for the first time in
a session. That is why in most cases this command is run when the windowing system
is first created. If you want to keep the previous settings, use the -merge
command option instead of -load, as in
xrdb -merge .myOwnResources
Also, you can use the exclamation point as the comment character at any point
in the input line before any text begins. Therefore, the following lines are comments:
! This is a comment
! another one
! commented*labelString: This resource is not used.
You can also use the cpp preprocessor's directives #if, #ifdef,
#else, and #endif. This is running through xrdb only.
cpp is not run when the .Xresources file is parsed. You can override
the run through cpp by using the -nocpp parameter on the command
line. No other parameters are required. If you want to remove a resource, use the
-remove operation:
xrdb -remove myOldResources
User and Class Resource Files
There are two types of resource files: user and class.
User files apply to each instance of all applications. These are the resources
you would set in the .Xresources file.
Class files pertain to all the instances of a particular class. These will exist
in files usually in your home directory or in your path. The name of the class file
is the name of the class. The class name is the name of the application class with
the first letter capitalized.
For example, all xterms belong to the class XTerm. Note that
the class name is the name of a type of an application, with the first letter capitalized.
XTerm is an exception in this regard because it has XT capitalized instead
of only X.
Now look at setting the resources for a particular class of an application. The
command line
*labelString: Hello World
will set the labelString resource for all widgets in every application
in your session to Hello World. This may not be exactly what you want. The command
line
Xapp*labelString: Hello World
will set the labelString resource for all widgets in every Xapp
application in your session to Hello World. This will not affect widgets within other
applications. This effect would be desirable if you were trying to set only one type
of application resource.
You can also specify your own class for setting resources. This would be via setting
the -name option on a client. For example, you could define all the resources
for an xterm with 10x20 font to be of class hugeterm. Then whenever
you run
xterm -name hugeterm &
it will use the resources in the class hugeterm. So now you can set the
foreground color to whatever you want for terminals, with a name of hugeterm.
Note that the name of a resource cannot contain the * or . characters.
These values will cause your resource setting to be ignored. MWM simply ignores bad
syntax rather than informing the user to make corrections.
Customizing MWM
Customizing MWM is very similar to customizing the X resources. However, MWM offers
a far greater set of features and allows the user to customize just about every item
on the screen. The resources here can be set to maintain a consistent set of interfaces
for all applications, without changing a line of code. For example, it's easy to
change the background color of all the forms in your applications by simply editing
the resources file rather than editing each source file individually. Here are some
more methods for setting resources:
- Use hard code resource settings.
- Set command line parameters.
- Use the environment variables to specify class files.
Hard Coding Resource Setting
You can set resources by hard coding the values in your application source code.
See Chapter 6, "The C and C++ Programming Languages."
Hard coding resource settings is justifiable in the following situations:
- When you do not want to give control to the end user for application-critical
resources. A good example is the locations of all buttons on a data entry form. An
end user is liable to shuffle them around to the point where the entry application
may become unusable.
- When you do not have to worry about locations of resource files. The application
is completely stand-alone.
- When you do not want user intervention in your program code.
- When you want to shield users from modifying their UNIX environment variables
and having to learn the customization syntax.
Using the Command Line
You saw an example of this earlier when the chapter talked about customizing X
applications and listed some of the resources that can be set from the command line.
Motif applications usually list their options in man pages.
Use the -xrm command line option to set or override a particular resource.
The syntax for this option is
xclient -xrm "resource*variable: value"
Note that you can concatenate several resource settings using the operator.
xclient -xrm "resource*variable: value"
-xrm "resource*variable: value"
-xrm "resource*variable: value"
So, how do you know which resources to set? Look in the OSF/Motif Programmers'
Reference Manual for the description of a widget's resources.
Looking at the Label widget, you will see resources grouped by the class and all
its inherited resources. Some of the resources would be declared under the class
Core, some under Manager, and so on. Now look at some of the resources
for an XmPushButton widget. You will see these listed with the letters XmN
in front of them. These letters signify that it is a Motif resource.
XmNinputCallback XcCallback XtCallBackList NULL C
XmNarmColor XmCarmColor Pixel Dynamic CSG
XmNarmPixmap XmCArmPixmap Pixmap XmUNSPECIFIED_PIXMAP
CSG
XmNdefaultButtonThickness
XmCdefaultButtonShadowThickness Dimension 0 CSG
....
Note the letters CSG for the access description. The C signifies creation. This
tells that the resource can be set upon creation. The S signifies that this value
can be set at runtime. The G signifies that it can be read (get) at runtime.
In the case of the push button widget, the XmNinputCallback class can
be set only at the time when it is created (that is, once at runtime). This is usually
done in the code section where an address to a pointer is set for this widget.
The other values can be set at runtime. For example, the XmNarmColor
can be set from a resource file because it does have the S set for it. Likewise,
when programming widgets, this resource can be read from an application because the
G value is specified for this resource.
Using Environment Variables
Motif uses several environment variables to hold its pointers to locations for
resource files.
The XENVIRONMENT environment variable can hold the complete path to a
file that holds the resource file. This must be the complete path of the application.
If this variable is not set, then the Xt toolkit will look in .Xresources-HostName
in the application's home directory.
The XUSERFILESEARCHPATH is a pointer to the locations of application
resource files. This is a colon-delimited string. Each field is expanded into meaningful
names at runtime. Some of the most common fields are these:
- %C Customize color
- %l Language part
- %L Full language instruction
- %N Application class name
- %S Suffix
The RESOURCE_MANAGER variable is set by xrd. This xrd
is executed at runtime. This usually happens at start-up.
The XFILESEARCH environment variable holds a colon-delimited list of
directories for the app-defaults file. Usually these defaults are in the
/usr/lib/X11/app-defaults directory. The files in this directory are interesting
to see. See Listing 1.1.
Listing 1.1. Typical listing of /usr/lib/x11/app-defaults.
Bitmap
Bitmap-color
Chooser
Clock-color
Doc
Editres
Editres-color
Fileview
Ghostview
Mwm
Neko
Periodic
Viewres
X3270* XCalc
XCalc-color
XClipboard
XClock
XConsole
XDbx
XFontSel
XGas
XLess
XLoad
XLock
XLogo
XLogo-color
XMdemos
XMem
XMtravel
XTerm
Xditview
Xditview-chrtr
Xedit
Xfd
Xgc
Xmag
Xman
Xmh
Xtetris
Xtetris.bw
Xtetris.c
Note that some of the classes listed here have the first two letters of their
names capitalized instead of just one (XTerm, XDbx, XMdemos).
So if your class resource settings do not work as expected, look in this directory
for some hints on what the resource class name might look like. Again, the contents
of this directory depend on your installation of Motif and X.
The search for the missing .Xresources occurs in the following order:
- Check in XUSERFILESEARCHPATH.
- If not successful or if XFILEUSERSEARCHPATH is not set, check in XAPPLRESDIR.
- If not successful or if XFILESEARCHPATH is not set, check user HOME
directory.
Keep this advice in mind: In all but the most unavoidable cases, you should not
rely on environments to set your application resources.
The methods are too complicated to learn, especially for the end user. However,
they can be a very powerful customization tool. Editing resource files is hard enough
on the programmer, but it's even worse on the user. However, in order to be a good
Motif user, you should know about the environment variables that affect applications
that come from other vendors.
Listing an Application's Resources
There are two Motif applications that can assist you in determining an application's
resources: appres and editres.
The appres program's syntax is:
appress Class application
This will list all the resources in a given class for the named application.
The second command is a menu-driven GUI program, editres, that allows
you to edit the given resources for an application. This is available for X11R5 and
later. The program displays a tree-like representation of all the widget classes
in a program and allows the user to move through the tree node by node. Search your
release for this file. If you do not have this file, do not despair. Contact your
local hardware vendor for a complete X installation.
Using the .mwmrc File
Create this file from the system.mwmrc file by copying it into your $HOME
directory as .mwmrc, and then edit it. (Look in the /usr/bin/X11
directory and search for the file system.mwmrc using the find command.)
Listing 1.2 on the CD-ROM shows a sample .mwmrc file. As stated earlier,
when working with .Xresources, you start a comment with a ! character.
Listing 1.2. A sample .mwmrc file.
!!
!! $HOME/.mwmrc
!! Modified system.mwmrc for personal changes. kh.
!!
!!
!! Root Menu Description
!!
Menu DefaultRootMenu
{
"Root Menu" f.title
"New Window" f.exec "xterm &"
"Shuffle Up" f.circle_up
"Shuffle Down" f.circle_down
"Refresh" f.refresh
"Pack Icons" f.pack_icons
! "Toggle Behavior..." f.set_behavior
no-label f.separator
"Restart..." f.restart
! "Quit..." f.quit_mwm
}
Menu RootMenu_1.1
{
"Root Menu" f.title
"New Window" f.exec "xterm &"
"Shuffle Up" f.circle_up
"Shuffle Down" f.circle_down
"Refresh" f.refresh
! "Pack Icons" f.pack_icons
! "Toggle Behavior" f.set_behavior
no-label f.separator
"Restart..." f.restart
}
!!
!! Default Window Menu Description
!!
Menu DefaultWindowMenu
{
Restore _R Alt<Key>F5 f.restore
Move _M Alt<Key>F7 f.move
Size _S Alt<Key>F8 f.resize
Minimize _n Alt<Key>F9 f.minimize
Maximize _x Alt<Key>F10 f.maximize
Lower _L Alt<Key>F3 f.lower
no-label f.separator
Close _C Alt<Key>F4 f.kill
}
!!
!! Key Binding Description
!!
Keys DefaultKeyBindings
{
Shift<Key>Escape window|icon f.post_wmenu
Alt<Key>space window|icon f.post_wmenu
Alt<Key>Tab root|icon|window f.next_key
Alt Shift<Key>Tab root|icon|window f.prev_key
Alt<Key>Escape root|icon|window f.circle_down
Alt Shift<Key>Escape root|icon|window f.circle_up
Alt Shift Ctrl<Key>exclam root|icon|window f.set_behavior
Alt<Key>F6 window f.next_key transient
Alt Shift<Key>F6 window f.prev_key transient
Shift<Key>F10 icon f.post_wmenu
! Alt Shift<Key>Delete root|icon|window f.restart
}
!!
!! Button Binding Description(s)
!!
Buttons DefaultButtonBindings
{
<Btn1Down> icon|frame f.raise
<Btn3Down> icon|frame f.post_wmenu
<Btn3Down> root f.menu DefaultRootMenu
}
Buttons ExplicitButtonBindings
{
<Btn1Down> frame|icon f.raise
<Btn3Down> frame|icon f.post_wmenu
<Btn3Down> root f.menu DefaultRootMenu
! <Btn1Up> icon f.restore
Alt<Btn1Down> window|icon f.lower
! Alt<Btn2Down> window|icon f.resize
! Alt<Btn3Down> window|icon f.move
}
Buttons PointerButtonBindings
{
<Btn1Down> frame|icon f.raise
<Btn3Down> frame|icon f.post_wmenu
<Btn3Down> root f.menu DefaultRootMenu
<Btn1Down> window f.raise
! <Btn1Up> icon f.restore
Alt<Btn1Down> window|icon f.lower
! Alt<Btn2Down> window|icon f.resize
! Alt<Btn3Down> window|icon f.move
}
!!
!! END OF mwm RESOURCE DESCRIPTION FILE
!!
There are several key features here: key bindings, button bindings, and menu items.
A binding is a mapping between a user action and a function. The key bindings
map keystrokes to actions, and the button bindings map button presses and releases
to actions. Menus display the menu items and let you organize action items into sections.
The format for the all items is
Section_type Section_Title
{
.. definitions..
.. definitions..
}
where Section_type could be Menu, Keys, or Buttons.
The Section_Title is a string defining the variable name. It's a name that
can be used to refer to this section in other portions of the file.
The functions shown in the sample file begin with an f. keyword. Some
actions are fairly obvious: f.move, f.resize, f.maximize,
f.minimize, f.title, f.lower, and so on. Some actions
are not: f.separator (displays a line on the menu item), f.circle_up
(shuffles the window stacking order up), f.circle_down (shuffles the window
stacking order down). Remember how windows are like sheets of paper stacked on a
canvas. (See the section "Stacking Order.")
See Table 1.1 for all the features available.
Table 1.1. Valid window manager functions.
| Function |
Description |
| f.menu mm |
Associates mm with a menu. |
| f.minimize |
Changes the window to an icon. |
| f.move |
Enables the interactive movement of a window. |
| f.nop |
No operation--it's a filler only. |
| f.normalize |
Restores a window to its original size. |
| f.pack_icons |
Rearranges the icons on a desktop. |
| f.pass_keys |
Toggles enabling and disabling key bindings. |
| f.quit_mwm |
Terminates mwm. |
| f.raise |
Raises a window to the top of the stack. |
| f.refresh |
Redraws all windows. |
| f.resize |
Enables the interactive sizing of a window. |
| f.restart |
Restarts MWM. |
| f.separator |
Draws a line. |
| f.title nn |
Names the menu. |
Adding Your Own Menu Items
Now you're ready to define your own menu items. Here are some examples of menu
item names:
Menu MyGames
{
"Kamran Games" f.title
no-label f.separator
"Tetris" f.exec "xtetris &"
"Mahhjong" f.exec "xmahjong &"
"Chess" f.exec "xchess &"
}
The f.title action specifies a heading for the submenu. The f.separator
action draws a line under the title. The f.exec action fires up the command
shown in double quotes.
TIP: Note the ampersand in f.exec for
starting these tasks in the background. Do not start a task that may never return
and that may therefore hang up your MWM session.
Now you can add this new menu to the root menu by adding the line
"Utils" f.menu MyGames
in your DefaultRootMenu definitions.
More on Button and Key Bindings
The key and button bindings work in the same way as menus. The first obvious difference
is the extra column with the words icon, frame, window, and root in it. These words
force the bindings on the context. The root applies to any location of the pointer
on the root window; the frame or window keywords apply binding only when the pointer
is in a window or its frame; and the icon bindings apply to icons.
In your .Xresource or .Xresources file, you will refer to these
key bindings for the class mwm as follows:
Mwm*keyBindings: DefaultKeyBindings
Here are some of the descriptions in the key bindings:
| Shift<Key>Escape |
window|icon |
f.post_wmenu |
| Alt<Key>space |
window|icon |
f.post_wmenu |
| Alt<Key>Tab |
root |
f.menu DefaultRootMenu |
The syntax for a keystroke binding is
modifier<Key>key
where modifier is Alt, Control, or Shift. The key can be a keystroke
or function key. The first two declarations describe the same action--Show the window
menu--but use different keystrokes. The third key, binding, shows a method for displaying
the root menu.
The button bindings are the bindings for your buttons. These are the three important
bindings to remember:
Buttons DefaultButtonBindings
Buttons ExplicitButtonBindings
Buttons PointerButtonBindings
In your .Xresource or .Xresources file, you will refer to one
of these button bindings for the class MWM in one of the following ways:
- Mwm*buttonBindings: DefaultButtonBindings
- Mwm*buttonBindings: ExplicitButtonBindings
- Mwm*buttonBindings: PointerButtonBindings
Customizing Your Desktop with Clients
You can customize your desktop using some of the client software that comes with
your X11R5 distribution. This chapter covers the following applications:
- xsetroot
- xset
- xdpyinfo
- xmodmap
There are several more utilities in the /usr/bin/X11 directory for you
to play with: bitmap, xmag, xcalc. Check each one out
to customize your desktop. This chapter describes the ones that are not intuitively
obvious.
xsetroot
This client customizes the root window characteristics. Some of the options available
are the following:
- -cursor cursorfile maskfile. Changes the cursor to a displayed mask
value. See the sidebar for creating your own cursor using bitmap.
- -cursor_name name. This is the name of the standard cursors in the X11
protocol.
- -bitmap filename. This creates a tiled surface on the root window with
a bitmap. Check the /usr/lib/X11/bitmaps directory for a list of the standard
bitmaps.
- -fg color foreground. The color for the bitmap on the root display.
- -bg color background. The color for the bitmap on the root display.
- -gray or -grey. Sets the background to a pleasant (for some)
gray background.
- -rv. Reverses the foreground and background colors.
- -solid color. Sets the root window to a solid color.
Look in the /usr/lib/X11 directory for the file called rgb.txt
for a list of files and look at the section called "Colors" in this chapter
for more information.
See the man pages for additional features for xsetroot.
Creating a Cursorfile
The cursorfile is an ASCII file with arrays of characters. You create a bitmap using
the bitmap utility. You then run this bitmap through bmtoa to convert a
bitmap to an array. There is a reverse utility called atobm to convert a
pre-existing array to bitmaps for use with the bitmap editor.
Using xset
The xset command sets up some of the basic options on your environment.
Some of these options may not work on your particular system. It's worth it to check
these out.
You can set the bell volume:
xset b volume frequency durationInMilliseconds.
For example, the command line
xset b 70 4000 60
sets the keyboard bell to about 70 percent of the maximum, with a frequency of
4,000 Hz, lasting 60 milliseconds.
To turn on the speaker, use xset b on. To turn it off, type xset
off. Use xset c volume to set the keyclick volume in percentages. A
volume setting of 0 turns it off. Any other number (1--100) turns it on at that percentage.
Of course, for this command to work, you have to have your speaker turned on.
To set the mouse speed, type xset m acceleration threshold at the prompt.
The acceleration is the number of times faster to travel per mouse movement that
is greater than the threshold. If your movement is below the threshold, the mouse
will not accelerate. If the movement is greater than the threshold, each pointer
movement on the screen will be greater than the physical movement by this accelerated
factor. This way you can zip across the screen with a twitch. Use care in setting
this feature unless you are very adroit.
Invoking the Screen Saver
Use xset s seconds to enable the screen saver. You can turn off the screen
saver with the off option. xset s default reverts to system default
time for blanking the screen.
For more options type in xset q.
Using Fonts
To load your own fonts, use
xset fp /user/home/myfont,/usr/lib/X11/fontsdir
xset fp rehash
The rehash command forces the server to reread its system files for your
command to take effect.
To restore to normal, use
xset fp default
xset fp rehash
See the section called "Fonts" later in this chapter.
Getting More Information About Your Display xdpyinfo
The xdpyinfo utility gives you more information about your X server.
It is used to list the capabilities of your server and all predefined parameters
for it. Some of these capabilities include the following:
- Name of display
- Version number
- Vendor name
- Extensions
The list is too exhaustive to include here and will be different for your installation.
Pipe its output to a file and review it for information about the server.
Help for Left-Handed Users xmodmap
If you are a left-handed user, it might a bit uncomfortable to use the left mouse
button with your third or second finger. The X designers kept you in mind. If you
want to swap the functionality of the pointers on your mouse, or pointer, use the
xmodmap command. First, display the current mappings with
xmodmap -pp
You will see the following display:
Physical Button
Button Code
1 1
2 2
3 3
This shows you that Button Code 1 is mapped to Physical Button 1; Button Code
2 is mapped to Physical Button 2; and Button Code 3 is mapped to Physical Button
3.
Now issue the command
xmodmap -e 'pointer = 3 2 1'
to reverse the mappings on the buttons. Now Physical Button 1 will be mapped to
Button Code 3, and so forth. To confirm this, retype the xmodmap -pp command,
and you'll see this:
Physical Button
Button Code
1 3
2 2
3 1
You can always revert to the default with xmodmap -e 'pointer = default'.
Useful Command Line Options
Some other standard input parameters that can be used from the command line to
change the behavior of a window are the following:
- -borderwidth or -bw. The border width of the frame, in pixels.
This may not be available for all clients.
- -foreground or -fg. The foreground color. For example, this
could be the text color for an xterm.
- -background or -bg. The background color. For example, this
could be the text color for an xterm.
- -display. The display on which the client will run.
- -font or -fn. The font to use for a particular text display.
- -geometry. The geometry of the window. See the section called "Geometry"
earlier in this chapter.
- -iconic. Starts the application in an iconic form.
- -rv or -reverse. Swaps the foreground and background colors.
- -title. The title for the title bar.
- -name. The name for the application.
For example, you can make one terminal name, editor, and set your resources
in the .Xresources file for the name editor. When you then invoke
a new term with the xterm -name editor command, the server will apply the
resources for editor to this xterm.
Logging In to Remote Machines
You can log in to remote machines using the xterm -display option. The
remote system must allow you to open a display on its machine. This is done with
the xhost + command on the remote machine.
-display nodename:displayname.ScreenName
This starts up a remote session on another node. displayname and ScreenName
are optional and default to zero if not entered.
When you want to open an xterm on the remote machine, alma,
you run the following command:
xterm -display alma:0.0 &
The format for the option into the display parameter is this:
[host]:[server][:screen]
If you are given permission to open a display, you will be logged in to the remote
machine. You can verify this with the uname command. Check the DISPLAY
with the echo $DISPLAY command.
When you log out with the exit command, the remote session and the xterm
are terminated.
TIP: One of the most common reasons for not being
able to open a remote terminal is that the remote host does not allow you to open
windows there. Ask the remote user to use the xhost command at the remote
machine as a part of login.
Colors
All the colors in the X Windows system are located in the /usr/lib/X11/rgb.txt
file. This file consists of four columns: the first three columns specify red, green,
and blue values, and the last entry specifies the name that you can use in your parameters.
A partial listing of the rgb.txt file is shown in Listing 1.3.
Listing 1.3. An excerpt from the rgb.txt file.
255 250 250 snow
248 248 255 ghost white
248 248 255 GhostWhite
245 245 245 white smoke
245 245 245 WhiteSmoke
220 220 220 gainsboro
255 250 240 floral white
255 250 240 FloralWhite
253 245 230 old lace
253 245 230 OldLace
250 240 230 linen
250 235 215 antique white
255 239 213 PapayaWhip
255 235 205 blanched almond
255 235 205 BlanchedAlmond
255 218 185 peach puff
255 218 185 PeachPuff
255 222 173 navajo white
255 228 181 moccasin
255 248 220 cornsilk
255 255 240 ivory
255 250 205 lemon chiffon
255 250 205 LemonChiffon
255 245 238 seashell
240 255 240 honeydew
245 255 250 mint cream
255 240 245 LavenderBlush
255 228 225 misty rose
255 228 225 MistyRose
255 255 255 white
0 0 0 black
47 79 79 dark slate grey
47 79 79 DarkSlateGrey
105 105 105 dim gray
105 105 105 DimGray
105 105 105 dim grey
105 105 105 DimGrey
112 128 144 slate gray
112 128 144 SlateGray
112 128 144 slate grey
112 128 144 SlateGrey
119 136 153 light slate gray
119 136 153 LightSlateGray
119 136 153 light slate grey
119 136 153 LightSlateGrey
190 190 190 gray
190 190 190 grey
211 211 211 light grey
Because the red, green, and blue have 256 values each, the number of possible
colors is 16,777,216. Not many workstations can display that many colors at one time.
Therefore, X uses a facility to map these colors onto the display, which is called
a colormap. A color display uses several bits for displaying entries from this map.
The xdpyinfo program gives you the number of bits for the display. This
is a frame buffer. A 1 bit frame signifies a black-and-white display. An 8 bit frame
buffer signifies 28 entries, or 256 possible colors.
Unfortunately, due to different phosphors on different screens, your color specification
on one monitor may be completely different on another monitor. Tektronix provides
a tool called xtici, an API and docs to counter such problems by using the
international CIEXYZ standard for color specifications. This is called the Color
Management System (CMS), which uses a model called HVC (Hue-Value-Chroma). In the
X11R5 (or later) release look for Xcms for more details, or contact Tektronix.
Fonts
Fonts in the X Windows system are designed for maximum flexibility. There are
two good utilities to help you sift through some of the 400 or so font types on a
basic system:
- xlsfonts. Lists the fonts in your system.
- xfontsel. Allows you to interactively see what fonts are available on
your system and to see what they look like on the screen.
Using xlsfonts
First, let's examine the font names themselves. Use the xlsfonts command
to list the fonts on your system. Type the command on an xterm, and because
the listing from xlsfonts is very long, be sure to pipe to a text file for
review. You should get a listing in which each line is of the form
-foundry-family-wt-sl-wd-p-pts-hr-vr-sp-ave-charset-style
The foundry is the company that first developed the font. The most common foundries
are misc., Adobe, Bitstream, and B&H. You may see more on your system from the
results of your xlsfonts command.
A font of the misc. foundry has a fixed width and height per character type of
font; the rest of the fonts were donated by their respective manufacturers.
The family is the general type of font: Courier, Helvetica, New Century Schoolbook,
Lucida, and so on. Some families are monospaced (that is, all their characters have
the same width). The other families are proportionally spaced (that is, each character
has a separate width). Courier and Lucida are monospaced fonts. New Century Schoolbook
is proportionally spaced.
You would use monospaced information for tabular information or running text.
This makes your text line up cleanly in running displays. Proportionally spaced fonts
are helpful for text in buttons or menu items.
The wt and sl parameters are for weights and slants, respectively.
The common weights are bold and medium. Bold text is drawn with a pen thicker than
the normal pen. The common slants are roman (r), oblique (o), and
italic (i). Roman text is upright; oblique text has characters sheared to
the right. Italic text is similar to oblique text, but the characters show a smoother
effect. You may also have a reverse oblique (ro) and reverse italic (ri)
when the text leans to the left instead of to the right.
The p stands for the point size, which has traditionally been 1/72 inch.
Most monitors traditionally support only 75 or 100 dots per inch (dpi) resolution.
Because X fonts are bitmaps, it seems logical that the most common fonts within X
are of two flavors: 75 dpi and 100 dpi. This is the number that is found in the two
fields hr and vr, which stand for the horizontal and vertical resolution,
respectively. In almost all cases, you will specify either 75 or 100 in each of these
fields.
The sp refers to the spacing between two characters on the screen. This
could be m for monospaced, p for proportional, and c for
fixed fonts where each character occupies a fixed box.
The ave is the 1/10 average width of all the characters in the set.
The character set and style is usually set to ISO8859-1. This refers to the ISO
Latin-1 character set, which includes characters found in the ASCII and other European
character sets.
Now that you have seen the large number of options just to define a font, you
can rely on using wildcards to specify most of the options for a font. The server
will match the first font name that matches your specification with a wild card.
In other words, you only have to specify the parameters you want to change and use
the asterisk for the rest.
For example, *courier-roman will get the first specification for the
roman-weighted Courier font. However, *courier will get the bold Courier
font. This is because the bold specification exists before the Roman specification
in the fonts file.
TIP: Use the xset fp=fontpath command
to set the directory (75 dpi or 100 dpi) you want searched first in the front of
the font path. This will guarantee that the correct-sized (in dpi) directory is searched
first.
The font search path is the path used by the server to search for the fonts in
your system. This path is usually set to the following value:
/usr/openwin/lib/X11/fonts/misc,/usr/openwin/lib/X11/fonts/75dpi,/usr/openwin/lib/X11/fon
ts/100dpi,
In each of these directories is a file called fonts.dir. This is a listing
of all the fonts in the directory and has two entries per line. The first entry gives
a font filename; the second entry gives the complete font description. The first
line in the file gives the number of entries in the file.
TIP: Font names are not case sensitive. New Century
Schoolbook is the same as new century schoolbook.
You can create another file in the font path to alias your own font names. This
file is called fonts.alias. The server uses only the first one it finds
in its path, so just keep one such file in the first directory in your font path.
The fonts.alias format is very similar to the fonts.dir file, except
that the first entry is not a filename, it is an alias for a font name. So if you
want to specify a special font type for all your editor xterms, you would
have a line such as this:
editterm *lucida-medium-r-*-100*
Then you can invoke your xterm with the command
xterm -fn editterm &
to get an xterm window with the desired font. This is a lot better than
typing in the full font specification. Also, by changing the alias once, you can
change it for all scripts that use this alias, rather than modifying each script
individually.
A good place to start is the /usr/lib/X11/fonts/misc directory, where
a fonts.alias exists from your initial X installation. This file has the
fixed and variable aliases defined for you to work with.
Using xfontsel
The xfontsel program helps you get a better feel for some of the parameters
of a particular font. (See Figure 1.13.)
Figure 1.13.
Using xfontsel.
You can move your pointer to any one of the parameters in the first line, and
click Button1. As you move the pointer on a field, the field will draw a box around
itself to show that it has focus.
If any font options exist for your selection, you will be presented a pop-up menu
to select from. Move the mouse to a selection and click on the selection. You will
see your selection displayed in the font specification string, as well as a sample
of what the font will look like on the fonts display screen below that.
Enhancements in X11R6
The X Consortium's latest release of X11 (X11R6) contains a good deal of new functionality,
as well as a number of bug fixes. X11R6 is backward compatible with the libraries,
protocols, and servers that were supported for X11R5, except where noted.
- X Image Extension (XIE). Involves the compression and transfer of images in compressed
form between the client and server. This compression is based on the JPEG Release
4 software from the Independent JPEG Group (IJG). This enhancement means much less
LAN traffic.
- Inter-Client Exchange (ICE). Provides a common framework to build protocols on.
ICE supplies authentication, byte order negotiation, version negotiation and error
reporting conventions. It also supports multiplexing multiple protocols over a single
transport connection. The code library, ICElib, provides a common interface to these
mechanisms so that protocol implementors need not reinvent them. This translates
into a greater development base for X11 software.
- Session Management (SM). Provides a uniform mechanism for users to save and restore
their sessions using the services of a network-based session manager. Session Management
is based on the ICE standard for standardization across platforms. It uses the SMlib
as the C interface to the protocol. XSMP is also supported in Xt.
- Included with SM is a new protocol, rstart, which greatly simplifies the task
of starting applications on remote machines. This is based on remote execution protocols
such as rsh, and it adds the ability to pass environment variables and authentication
data to the applications being started.
- Input Method Protocol. This protocol is necessary for languages which need complex
pre-editing input methods. These input methods may be implemented separately from
applications in a process called an Input Method (IM) Server. The IM Protocol standardizes
the communication between the IM Server and the IM library linked with the application.
The IM Protocol adds the following new features: Support for any of several transports
for connection with the IM library; Both the IM Server and clients can authenticate
each other for security; connection to an IM Server without restarting even if it
starts up before the IM server; initiation of string conversion to the IM Server
for reconversion of text; and specification of hot keys.
- X Logical Font Description. This has been enhanced to include general 2D linear
transformations and character set subsets for fonts, as well as support for polymorphic
fonts. This reduces rasterization time for faster screen updates, as well as support
for rotating, mirroring, and "stretching" of fonts.
- SYNC extension. Lets clients synchronize via the X servers, eliminating network
delays and differences in synchronization primitives between operating systems.
- BIG-REQUESTS extension. Allows requests greater than 2^18 bytes long. The protocol
extension, BIG-REQUESTS has been added that allows a client to extend the length
field in protocol requests to be a 32-bit value. This was added to accommodate PEX
and other extensions that transmit complex information to the server.
- XC-MISC extension. New for Release 6, this allows clients to get back ID ranges
from the server, which can be useful for long-running applications that use many
Ids over their lifetime.
- Tree Reorganization. The directories under xc/ (renamed from mit/)
have been moved in order to simplify dependencies in the build process and make things
easier to find.
- Configuration Files. The configuration files have changed, and they are located
in the their respective directories under xc/config/.
- Kerberos. This is a new authorization scheme for X Clients which implements user-to-user
authentication. This is based on MIT's Kerberos Version 5. If you have Kerberos 5
on your system, set the HasKrb5 config variable in site.def to
YES to enable Kerberos support.
- xtrans (X Transport Library). This is an attempt to combine all system and transport
specific code into a single place in the source tree for cross-platform compatibility.
- Internationalization. Also known as I18N, this is implemented as an enhancement
to the existing architecture in R5, which introduced the concept of a FontSet. This
is an attempt to cover nearly all possible languages and cultural conventions.
- Xt. Several new enhancements have been made to the Xt library for programming
and development of the X windows system. Refer to the chapter on GUI for programmers
for more details.
- PEX. This is implemented primarily as a 3D and rendering graphics engine for
X windows. However, it is distributed in a "raw" format for development
by others, because it is so costly and time consumptive to create and maintain this
type of code.
- Font Server. In this upgrade, a great deal of bug fixes have been included, as
well as renaming the font server from xfs to fs.
- X Server. A number of new funtionalities and streamlining of code was added in
this release for programmers. Refer to the section on GUI programming for more details.
- xhost. Two new families have been registered: LocalHost, for connections over
a non-network transport, and Krb5Principal, for Kerveros V5 principals. To distinguish
between the different host families, a new xhost syntax "family:name" has
been introduced. Names are as before; families are as follows: inet for Internet
host, dnet for DECnet host, nis for a Secure RPC network name, krb for Kerberos V5
principal, and local, which contains only one name, "". The old-style syntax
for names is still supported when the name does not contain a colon. This enhancement
fills a security gap that had been a problem in the past.
Works In-Progress
A number of enhancements and additional functionality is planned for the next
release of X11. The major ones are as follows:
- Enhanced support for serial lines with serial line protocol (SLIP) and low bandwidth
(LBX) features. This involves removing unused bytes from messages, compressing images,
and sending only differences across the network to the server.
- Support for Microsoft Windows NT. Most client applications will run, but not
xterm or xdm. The server also will not be supported.
- Fresco, a C++ toolkit for developing object-oriented applications. This will
support both X and Microsoft Windows.
- A session manager to record the status of all windows on a screen so that a user
can return to the state he was in when he last exited X.
- Recording of all X requests at the server for playback when debugging applications.
Contact the X Consortium for details on availability.
GUI Front Ends to UNIX
There are many GUI fronts to X Windows and UNIX. This section will briefly introduce
you to a few of the common commercially available front ends and their window managers.
Motif
Motif applications look more like a Mayan temple than a menu system. Almost every
item on the screen is rectangular. A rectangular button rests on a rectangular menu
bar, which may rest on another rectangular form, which sits on a square window.
The latest version, at the time of writing, is Motif 1.2. There are several updates
to Motif (1.2.1, 1.2.3, and so on), but Motif 1.2 is a major release from the last
major release, 1.0. The 1.2 release includes a lot of bug fixes and adds widgets
to its list of convenience functions. Get an upgrade if you are running an older
version. Some of your existing bugs may even disappear!
Sun MicroSystems OPEN LOOK and OLIT
OPEN LOOK is Sun Microsystems' windowing interface. It is perhaps the most popular
interface for end users. Its Open Desktop is a set of tools for the desktop.
The most major difference between Motif and OPEN LOOK is that OPEN LOOK uses rounded
corners, and in Motif almost everything is based on rectangles. See Figures 1.14
and 1.15 for xterm and menu, respectively.
Figure 1.14.
An xterm in OPEN LOOK.
Figure 1.15.
A menu in OPEN LOOK.
Another major difference in functionality between Motif and OPEN LOOK is the use
of mouse buttons. Motif uses the left mouse button (Button1) almost exclusively for
all operations. OPEN LOOK, on the other hand, generally uses the left mouse button
to select and the right mouse button to open menus.
Furthermore, the menu items offered by the window menus in OPEN LOOK give different
functionality than those in Motif. See Table 1.2 for a comparison of some operations.
Table 1.2. Differences between OPEN LOOK and Motif.
| Operation |
OPEN LOOK |
Motif |
| Exit application |
"Quit" |
"Close" |
| Iconify a window |
"Close" |
"Minimize" |
| De-iconify a window |
"Open" |
"Maximize" |
| Restore size |
"Restore Size" |
"Restore" |
| Push window down |
"Back" |
"Lower" |
In OPEN LOOK, the buttons have rounded edges, scroll bars are shaped like elevators,
and menu items are rectangular. It also offers pinnable menus, a feature that lets
you "pin" a menu anywhere on the screen. Notice how the pinnable main menu
is overlapped by another window, indicating that it does not have focus but is still
visible on the desktop.
Another feature carried into Motif is the ability to have a virtual backplane
for all the sessions. The display manager in the common desktop environment provides
the same functionality.
COSE and CDE
In March 1993, the Common Open Software Environment (COSE) was formed. Thus ended
the war between OPEN LOOK and Motif, supposedly. The agreement set the basis for
the common desktop environment (CDE).
CDE enables users to preserve their desktop configuration between logins. Users
return to their exact user configuration when they log back in.
Online help is available with embedded graphics, multiple fonts, and hypertext
capabilities. Applications are able to access the help system.
The CDE provides a standard text editing attachment widget. This provides functionality
similar to the composition tool in Sun's OpenWindows mail tool. Users can drag and
drop nontextual data into text, where the system will represent it as an icon. This
text widget is expected to be Multipurpose Internet Mail Extensions (MIME) capable.
The MIME feature will allow users to share nontextual data via e-mail.
The print features in CDE have been greatly enhanced. Users will be able to use
drag-and-drop features to print files and manage print queues. Beyond these capabilities,
COSE also specifies a standard method for printing X images and screen dumps. This
is very similar to the capabilities in the now all-but-abandoned NeWS system. The
standard calls for the X print server to convert the X protocol into a format acceptable
to the user's connected printer. This allows users to create screen dumps and bitmap
images from X applications much more easily.
One of the most powerful features of CDE is its scripting language. This language
allows users to create shell scripts that have pop-up windows, alerts, and dialog
boxes. Also, hooks will be included into the mail system, so users can create consistent
help menus.
Other GUI Vendors
Hewlett-Packard (HP) calls its GUI environment the Visual User Environment (VUE).
HP is perhaps the most influential corporation for the COSE user interface standard.
Unfortunately, the interface you see in Motif for a standard application may have
a different look under VUE. HP has customized its Motif libraries to conform to its
own way of doing things. For example, it overrides all attempts to set the background
colors for menu items. At the time of writing, there is no way to override this using
the xset's background commands.
VUE uses the Broadcast Message Server to dynamically change an application's colors.
You request the VUE to change the application's colors dynamically in its palette.
As a rule, all X applications must conform to the window manager's preferences on
a system. The only time this causes problems is when you are porting color-sensitive
non-COSE applications to an HP (or HP-conforming system).
There is a way around this problem. You can define your colors through the resource
files. (See the section "Using Resources" earlier in this chapter.) This
will work on HP systems with operating system Version HP9.01 or later. Contact HP
for details.
NeXT's NextStep is a completely object-oriented system that has now been released
for Intel's 486+ platforms. It is based on the multithreaded Mach kernel. NeXT initially
developed hardware for their operating systems, but now they are only a software
vendor.
One of the major problems with NeXTStep when it was first introduced was its lack
of X Windows support. Presently, NeXT is working in conjunction with Sun on a GUI
called OpenStep. This is at odds with the CDE proposed by COSE and is possibly Sun's
way of resurrecting its OPEN LOOK Interface. NeXT is also working with HP and Silicon
Graphics to port to their workstations.
NextStep's GUI is based on the Adobe Display PostScript Language. This approach
gives excellent graphics capabilities on displays you get with PostScript plotter.
Version 3.2 was the first POSIX-compliant release, but neither Motif nor OpenWindows
was available for it.
Santa Cruz Operations (SCO) is the owner of IXI corp. IXI licenses its X.desktop
product to Sun. X.desktop is the standard desktop for ODT. SCO is a founding member
of COSE and supports the CDE.
IBM's AIX Windows is very similar to OSF/Motif. The later versions of AIX Windows
have better icons and file management capabilities. If you use Motif, you will be
able to use AIX. Some quirks exist in some AIX-specific areas. A good example is
aixterm, which is used in place of xterm. Barring these minor quirks,
the transition to IBM from another Motif system is easy.
Digital Equipment Corporation (DEC) is perhaps the oldest supporter of X Windows.
Its version of DECWindows runs on Ultrix, DEC's version of UNIX. Contact (800)DIGITAL
for more information.
People do not think of Apple Computer's Macs as UNIX platforms. With its pre-existing
GUI, the Mac is a good candidate for a UNIX platform. Apple's A/UX provides a layer
for native applications to work on.
You can work in three basic environments in A/UX:
- A tty-like console
- An X11 window manager
- The Mac file finder
The first two options are almost like a UNIX and X11 session. The last option
is like a Mac Finder session. Look on the desktop for a disk with a label /.
Click on it to open subdirectories and applications underneath it. You can use the
mouse to invoke UNIX commands, such as ls, ps, and so on, from
icons in windows.
Softland system's version of Linux is PC-based UNIX for free. Linux is a UNIX
clone and comes with X11R5. You can quite painlessly and successfully port code between
Linux and other Motif platforms. Contact SLS directly at (604) 360-0188 for more
information.
Porting Non-Motif Applications to Motif
Moving from other windows front ends to CDE should give Sun users a strange feeling.
All Sun desktop tools will be available but will look different. All OPEN LOOK applications
will have to be ported over to Motif eventually. Some Sun users will have to wait
a while to get their pinnable menus back, for example. However, some relief is available
in the upcoming Motif tear-away menus, which will offer about the same functionality.
Presently, some commercial vendors are working hard to get a foothold in this
market. These are only a few applications of the development packages presently available
for porting applications--no doubt you will find more as time passes.
For those developing applications in the xview marketplace, Qualix Corporation
(San Mateo, California (800) 245-UNIX), is developing a tool called XvM. This is
an XView/Motif library that allows Xview-based applications to move to Motif by just
recompiling. This library maps the Xview API into Motif calls.
Another vendor, Integrated Computer Solutions (Cambridge, Massachusetts (617)
621-0200), provides tools to convert existing Xview applications into Motif. The
GIL to UIL conversion tool converts the existing GIL files produced by Sun's DevGuide
OPEN LOOK Interface builder into Motif UIL or directly to C or C++. You could also
use their other tool, Xview/GIL, to convert the XView API into GIL. The GIL can then
be moved into C, C++, or Motif UIL.
National Information Systems (San Jose, California (800) 441-5758), offers a package
called ACCENT consisting of four modules. The DevGuide conversion module converts
DevGuide GIL files into C/C++. The XView Conversion module converts source code,
using the Xview API into source. The OLIT converts source in the OPEN LOOK Interface
Toolkit API into C/C++ source. The fourth module, the GUI builder itself allows the
user to build Motif interfaces interactively. They have services to convert source
code to Motif for a fixed fee, as well as training facilities.
Imperial Software Technology Ltd. (Reading, England), offers a GUI builder that
has built-in OPEN LOOK to Motif conversion. Its product is called X-Designer. With
add-on options, users can convert DevGuide files into X-Designer files. With this
conversion, users can modify the converted graphics images to their taste. After
any modifications, the interface file can be saved in Motif UIL, C, or C++. The add-on
options will be a part of the new release. Their distributor is VI Corporation (North
Hampton, Massachusetts (800) 732-3200).
Where To Go from HERE
If you want more information about specific vendors, you can get a wealth of information
from the Internet about the latest releases and sources of shareware utilities. Listed
in Table 1.3 are some of the newsgroups that can provide more information about vendors.
Table 1.3. Some newsgroups with more information.
Summary
In this chapter you learned about the following:
- The major components of a graphical user interface. Along the way you got a brief
history lesson on X Windows.
- The major concepts required for using X Windows: displays, windows, screens,
and the client server architecture in X.
- Starting an X Windows session from the prompt as well as using the xdm display
manager.
- The Motif Window Manager, MWM.
- Moving about in MWM and working windows with the keyboard and mouse.
- Customizing your desktop with resource files and client applications.
- Setting your environment to your liking with resources.
- Using some standard tools available in X to further set up your desktop.
- What's new with COSE, CDE, and X11R6, and how vendors support their interfaces
for their versions of UNIX.
- Where to look next for more information.
- Using widgets and the characteristics of these widgets. This provides the basis
for learning how to program your own applications in the Motif environment.
Acknowledgments
Metro Link Software (which can be reached at (305) 938-0283) provided their version
of Motif 1.2 for developing all the routines and testing the sources in this chapter.
Their software installed cleanly with no hassles on a Linux (1.02) system running
on a 486 DX. All libraries worked great at the time and presented no compatibility
problems in porting sources to Sun and AIX.
The X Consortium's release notes for X11 version 6 were used as a reference for
upgrades in this chapter. The web site is located at http://www.x.org.
©Copyright,
Macmillan Computer Publishing. All rights reserved.
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