Gtkdialog User's Manual

This manual documents version {No value for `VERSION'} of the Gtkdialog utility.

Copyright © 2003 Laszlo Pere.

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.1 or any later version published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover Texts, and with no Back-Cover Texts.

Menu:

• Getting Gtkdialog: How to find, download and install the program.
• Introduction: A brief description of the package.
• Invoking the Program: How to call the program from various languages.
• Widgets: The elements of dialog boxes.
• Containers: Dialog elements grouping widgets together.
• Actions: What is happening when something happening.

The source of Gtkdialog can be downloaded from Anonymous FTP at URL ftp://linux.pte.hu/pub/gtkdialog/.

The program can be installed using the standard `./configure', `make' and `make install' command sequence. Further details can be found in the `INSTALL' file included.

Copyright © 2003 Laszlo Pere.

The gtkdialog is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2.0 of the License, or (at your option) any later version.

The program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this software; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.

Gtkdialog is a small utility program based on the GTK+ library. The program mainly made for GUI development for shell scripts but can be used with many other programming languages. The programmer can easily create GUI not just for any shell script or UNIX command but for any interpreted or compiled program capable to start child process and use pipes.

Our first example program shows how to call the `gtkdialog' from a BASH script.

example-3.1.1.sh

#! /bin/bash
 
export MAIN_DIALOG='
<vbox>
  <text>
    <label>This is a label...</label>
  </text>
  <hbox>
    <button ok></button>
    <button cancel></button>
  </hbox>
</vbox>'
 
gtkdialog --program MAIN_DIALOG

This example uses a very plain way to open a dialog box. We store the description of the dialog box in the `MAIN_DIALOG' environment variable which is exported to the child processes with the BASH `export' built-in. Then we call the `gtkdialog' program with the `--program' option which is followed by the name of the variable holding the dialog box description. It is simple and easy to write BASH scripts in this manner.

A similar calling method can be used when user input is needed. The `gtkdialog' send the state of the widgets to the standard output when exiting and this is how we can get user input for the BASH program. The next example code show the reading process.

example-3.1.2.sh

#! /bin/bash
 
export DIALOG='
<vbox>
  <entry>
    <variable>ENTRY</variable>
  </entry>
  <hbox>
    <button ok></button>
    <button cancel></button>
  </hbox>
</vbox>'
 
I=$IFS; IFS=""
for STATEMENTS in  $(gtkdialog --program DIALOG); do
  eval $STATEMENTS
done
IFS=$I
 
if [ "$EXIT" = "OK" ]; then
  echo "You entered: $ENTRY."
else
  echo "You pressed the Cancel button."
fi

In the example script we use the `for' built-in to go through the list `gtkdialog' produced. Changing the field separator (IFS) is a little bit disturbing but necessary since this is the only way to protect the space characters in user input.

In larger software projects it may be a good idea to break the code to separate files. Since `gtkdialog' can read the description program from file it is easy to write self executable programs with it. This is how the next example constructed.

example-3.1.3.sh

#! /usr/local/bin/gtkdialog -f
<vbox>
  <checkbox>
    <label>This is a checkbox</label>
    <variable>CHECK1</variable>
  </checkbox>
  <checkbox>
    <label>Another one</label>
    <variable>CHECK2</variable>
  </checkbox>
  <button>
    <label>OK</label>
  </button>
</vbox>

When used in this fashion the state of the widgets can get from the standard output of the script as usually.

The dialog description language is a simple XML like language capable to denote any complex dialog box containing widgets and boxes.

Widgets are simple GUI elements such as buttons, entry fields, lists, etc. Widget can have attributes, states and actions (*note Actions::).

The widgets are grouped together with containers (*note Containers::), horizontal and vertical boxes or frames. Every widget should placed in one of the containers, no widgets can be alone for it is dangerous outside.

Menu:

• Static label: Labels containing static text
• Pushbutton: Pushbutton widgets
• Pre-defined pushbuttons: Pushbuttons with pixmap and text label
• Entry: One line text entry widgets
• Checkbox: Checkbox widgets
• Pixmap: Static pixmap widgets
• Menus: Making menubars, menus and menuitems
• Trees: Complex widget for trees

Label is a static text widget created with `<text></text>' tag.

The text in a static label, can be set with the `<label>STRING</label>' or the `<input file>FILENAME</input>' expression.

The pushbutton is a clickable widget defined with the `<button></button>' tags.

The `<label>STRING</label>' directive sets the text label of the pushbutton. If no label and pixmap is given for the button, gtkdialog will use OK as default.

When creating buttons, the `<input file>FILENAME</input>' tag can be used to insert a pixmap into the button. The FILENAME must be a pixmap file. Gtkdialog will find this file with the `locate' utility if necessary.

The pushbuttons can contain a label and a pixmap simultaneously. For this you have to use the `<label></label>' and the `<input file></input>' as the next example shows:

<button>
  <input file>/usr/share/GUIcompletion/button_save.xpm</input>
  <label>The label</label>
</button>

The `<action>COMMAND</action>' directive tells the gtkdialog what to do, when the button is pressed. If the action is not given explicitly the gtkdialog uses the default action, which is to exit the program. In this case the printed variable list will contain a variable named EXIT, with the label of the activated button as value.

The buttons can handle more than one actions simultaneously. If there are more `<action></action>' directive for the given button, they will be executed one by one, in the right order.

The `<visible>STATE</visible>' specify the initial visibility of the button. The STATE can be either `enabled' or `disabled'. When a button is disabled, it is shaded and can not be activated by mouse or keyboard.

Gtkdialog supports a few pre-defined pushbuttons for simplify the creation of dialog boxes. The pre-defined buttons can be used the same manner the normal pushbuttons, but they have a default text, pixmap and output variable. Here is the list of available pre-defined pushbuttons:

• `<button ok></button>'
• `<button cancel></button>'
• `<button help></button>'
• `<button yes></button>'
• `<button no></button>'

The entry widget is a simple text input field, which can be used to get a string from the user.

The `<default>STRING</default>' directive sets the default content of the entry.

The `<visible>VISIBILITY</visible>' sets the initial state of the entry widget. The VISIBILITY can be `enabled', which means the entry can be used, `disabled', which means the content of the entry can not be altered or `password'.

The entry widgets with the visibility set to `password' are editable, but unreadable as it is common with entries holding password style information.

The entry widgets are activating actions after their contents are changed.

The checkbox is a simple widget with a label and a check mark which can be turned on and off by the user. Checkboxes are made with the `<checkbox></checkbox>' directive.

The label is the text shown beside the check mark. Every checkbox should have a label.

The initial state of the checkbox can be set by the `<default>STATE</default>' directive, where the STATE can be either `yes' or `no'.

The `<action></action>' directive tells the gtkdialog what to do, when the state of the checkbox is changed. As every widgets, the checkbox can hold multiply actions which are executed serially in the order they are written.

Actions of checkboxes can be written as conditional instructions with `if true' and `if false' prefixes as in the next example:

<checkbox>
  <label>This is a checkbox...</label>
  <variable>CHECKBOX</variable>
  <action>echo Checkbox is $CHECKBOX now.</action>
  <action>if true enable:ENTRY</action>
  <action>if false disable:ENTRY</action>
</checkbox>

The `<visible>STATE</visible>' specify the initial visibility of the checkbox. The STATE can be either `enabled' or `disabled'. When a checkbox is disabled, it is shaded and its state can not be altered anyway.

The value of a checkbox can be `true' or `false' and depends only on its state.

The `<pixmap></pixmap>' defines a static pixmap widget.

The widget must have an input file defined with the `<input file>FILENAME</input>' tags. The FILENAME is the graphic image file for the pixmap. Gtkdialog will load this file if it can be opened for read, or will try to find a file with similar name (using the `locate' utility program) if the file is unreadable.

The next example defines a static pixmap:

<pixmap>
  <input file>help.png</input>
</pixmap>

The `<menubar></menubar>' defines menu bar which can be placed as any other screen elements. In the menubar widget you have to create menus with the `<menu></menu>' tag, and inside the menu must be at least one menu item created by the `<menuitem></menuitem>' tag.

The next example shows how to create a simple menubar with only one menu:

<menubar>
  <menu>
    <menuitem>
      <label>gtk-open</label>
    </menuitem>
    <menuitem>
      <label>gtk-save</label>
    </menuitem>
    <menuitem>
      <label>gtk-quit</label>
      <action>EXIT="quit"</action>
    </menuitem>
    <label>File</label>
  </menu>
</menubar>

OK, it is not complete, but the next example seems to be just fine.

<vbox>
  <tree>
    <label>Device    |Directory        |File         </label>
    <item>Hard drive |/usr/            |letter.tex    </item>
    <item>Hard drive |/etc/            |inittab       </item>
    <item>Hard drive |/etc/            |fstab         </item>
    <item>Network    |alpha:/home      |quota.user    </item>
    <item>Network    |alpha:/home      |quota.group   </item>
    <item>Network    |beta:/home/pipas |tmp           </item>
    <item>Network    |beta:/home/pipas |latexfiles    </item>
    <item>Network    |beta:/home/pipas |book          </item>
    <item>Network    |beta:/home/pipas |bin           </item>
    <item>Network    |beta:/home/pipas |documentation </item>
  </tree>
  <button ok></button>
</vbox>

When the user changes the state of a widget, gtkdialog checks if there is something to do with it. If the tampered widget have one or more actions, the program will execute them for the new situation to be handled.

Every widget can have multiply actions, a list of commands must be executed when the widget changed. Gtkdialog executes the axtions in the order they found in the dialog description program, so one can write a complet program as a series of instructions.

Menu:

• Start and exit: Actions that starts programs and exits dialogs
• Widget manipulation: Actions affect widgets

If the action of a widget is created with the simple `<action>COMMAND</action>' directive, gtkdialog will execute it in a subshell. That means it will start up `/bin/sh' to handle the operation. Here is how the subshell operation works:

1. First gtkdialog updates the environment variables holds the state and value of the widgets. This is how the child process will know what is happening in the GUI called it.
2. Next the include file is checked. If the gtkdialog started with the `-i FILE' option gtkdialog will ask the subshell to include the FILE before the execution of command.
   
   This strange method is needed for the action driven programs, where the subshell have to load the shell functions from the calling script.
3. At the third step gtkdialog starts the command and waits for it to complete. (Commands usually can be run in the background by writing a `&' as last character, so the subshell will not wait the program to complete.)

The `Exit:VALUE' command exits `gtkdialog' immediately. The VALUE will be printed to standard output as the value of the variable named EXIT.

The command closes the named window opened by the `Launch:' command. The program remain active if there are more windows active.

The command opens a new window using the environment variable `Widget'.

The command disables the given widget if it is enabled. If the widget is disabled when the command is activated, nothing happens.

The disabled widgets are insensitive to user actions, their shapes are indicating they are temporary unavailable.

The command enables the given widget if it is diabled. If the widget is enabled nothing happens.

The command refresh the named widget. If the widget have one or more input actions, they will be called by `gtkdialog'.

Some widgets can hold much data. (Currently only the edit widget capable to perform this action.)

The `Save:' action will save the data found in the named widget to the filename found in `<output file>' attribute.

: This function is not working now, need to be fixed.