See the file man.macros.
TixIntro - Introduction to the Tix library
Tix, which stands for Tk Interface Extension, is an extension
    library for Tcl/Tk. Tix adds many new widgets, image types and other
    commands that allows you to create compelling Tcl/Tk-based GUI
  applications.
One advantage of Tix over other Tk widget libraries is many of the
    Tix standard widgets are implemented in native code. This enhances
    performance and provides native look-and-feel for your applications.
This version of Tix works with Tcl/Tk version 8.0 or above. If Tix
    has been installed properly on your system, you can load the package into
    any Tk script by invoking the command package require Tix After this command
    has successfully returned, you can start using the functionalities of the
    Tix library. See the EXAMPLES section below for example scripts that
    use Tix.
If the "package require Tix" command fails, you probably
    need to install a new copy of Tix on your system. You can download the
    latest version of Tix from the web site http://tix.sourceforge.net/.
Tix includes the following standard widgets which, like their
    counterparts in Tk, are implemented in native code to achieve high
    performance and native look-and-feel.
  - tixGrid
- The tixGrid widget displays items in a spread-sheet format.
- tixHList
- Hierarchical listbox widget. This widget display entries in a tree-like
      format.
- tixInputOnly
- A transparent window that can be used to cover another widget so as to
      disable mouse input.
- tixNBFrame
- The tixNBFrame widget is used internally by the tixNoteBook
      widget to display choices among a set of overlapping pages.
- tixTList
- Tabular listbox widget. This widget is similar to the built-in Tk
      listbox widget but provides more flexibility in displaying the list
      entries.
Tix provides many new types of mega widgets: these are
    widgets that are composed of built-in Tk widgets and the Tix standard
    widgets mentioned above.
  - tixBalloon
- The tixBalloon widget provides context-sensitive on-screen
    help.
- tixButtonBox
- A convenience class for creating a box of button widgets.
- tixCheckList
- A subclass of tixTree that presents single- or multiple choices to
      the user in a tree-like format.
- tixComboBox
- A combination of the listbox and entry widgets that allows
      the user to input an item by typing or by selecting from a list of
    items.
- tixControl
- The tixControl widget allows the user to adjust a value using arrow
      buttons.
- tixDirList
- A directory selection widget that displays the file system as a cascading
      list.
- tixDirSelectDialog
- A dialog for selecting a directory. This widget is
      deprecated. Use tk_chooseDirectory instead.
- tixDirTree
- A directory selection widget that displays the file system in a tree
      format.
- tixExFileSelectBox
- A widget for selecting a file. This widget is deprecated.
      Use tk_getOpenFile instead.
- tixExFileSelectDialog
- A dialog for selecting a file. This widget is deprecated.
      Use tk_getOpenFile instead.
- tixFileEntry
- A special entry widget that allows the user to choose a file by typing in
      its name or by selecting from a file dialog.
- tixFileSelectBox
- A widget for selecting a file. This widget is deprecated.
      Use tk_getOpenFile instead.
- tixFileSelectDialog
- A dialog for selecting a file. This widget is deprecated.
      Use tk_getOpenFile instead.
- tixLabelEntry
- A convenience class for creating an entry with an associated
      label widget.
- tixLabelFrame
- A labelled frame widget for grouping together a set of related
      widgets.
- tixListNoteBook
- The tixListNoteBook widget allows the user to choose from a set of
      over-lapping pages by selecting from a list box.
- tixMeter
- The tixMeter widget displays a bar graph to indicate progress.
- tixNoteBook
- The tixNoteBook widget allows the user to choose from a set of
      over-lapping pages with a tabbed notebook metaphore.
- The tixOptionMenu widget allows the user to choose a value from a
      pop-up menu.
- tixPanedWindow
- The tixPanedWindow widgets allows the user to adjust the visible
      size of several frame widgets with handle bars.
- The tixPopupMenu widget can be used to implement context-sensitive
      pop-up menu.
- tixScrolledHList
- A tixHList widget with smart scrollbars. Like other Tix scrolled
      widgets, the scroll bars can be displayed on an as-needed basis.
- tixScrolledListBox
- A Tk listbox widget with smart scrollbars.
- tixScrolledText
- A Tk text widget with smart scrollbars.
- tixScrolledWindow
- A Tk frame widget with smart scrollbars.
- tixSelect
- The tixSelect widget uses a set of buttons to present single- or
      multiple selection options to the user.
- tixStdButtonBox
- A subclass of tixButtonBox that provides four standard buttons (OK,
      Apply, Cancel Help) for Motif(TM)-like dialog boxes.
- tixTree
- A subclass of tixScrolledHList that supports expanding and
      collapsing of entries in a hierarchical list.
Three Tix standard widgets tixGrid, tixHList and
    tixTList support the Display Items mechanism. Display items
    are created by the widget command of these standard widgets. You can
    customize the items using styles objects.
  - tixDisplayStyle
- Create style objects to customize display items.
Tix provides two additional image types to the Tk image
    framework.
  - compound
- The compound image type allows you to combine images, widgets, and
      text strings into a single Tk image object.
- pixmap
- The pixmap image type supports the XPM format.
The following Tcl command are also included in the Tix library to
    perform various functions.
  - tixDestroy
- Destroy Tix objects instances of classes defined by tixClass
      construct.
- tixForm
- A geometry manager based on attachment rules. This geometry manager
      is deprecated. Use the Tk grid geometry manager
    instead.
- tixMwm
- A command to communicate with the Mwm, the Motif(TM) Window Manager. Works
      on Unix only.
- tix
- The tix command controls the Tix application context.
- tixGetBoolean
- The tixGetBoolean command converts a string to a boolean
    value.
- tixGetInt
- The tixGetInt command converts a string to a integer value.
- tixUtils
- The tixUtils manual page describes some utility Tix commands.
  - tixwish
- The tixwish program can be used to execute Tix-based applications.
      tixwish is deprecated. You shuld use the standard wish
      program from Tk and access Tix via the "package require Tix"
      command.
The following is an example script that uses a tixTree
    widget.
set tree [tixTree .t] pack $tree -expand yes -fill both for {set i
    0} {$i < 2} {incr i} {
  
   $tree subwidget hlist add $i -itemtype imagetext \
  
   -text "Folder $i" -image [tix getimage folder]
  
   for {set j 0} {$j < 5} {incr j} {
  
   $tree subwidget hlist add $i.$j -itemtype imagetext \
  
   -text "File $i.$j" -image [tix getimage textfile]
  
   } } $tree autosetmode