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                        TIX FREQUENTLY ASKED QUESTIONS

  TABLE OF CONTENTS

   Legal Issues

          + [L.1] Is Tix free software?

   General Questions About Using The Tix Library

          + [G.1] What does the "-disablecallback" option do?

          + [G.2] How do I set the width of the entry subwidget inside

            the tixControl widget?

          + [G.3] What is the "setslient" method?

          + [G.4] Is there a Tix interface builder in the works?

          + [G.5] Can you tell me about the syntax of tixForm

          + [G.6] I am not using the tixForm geometry manager, but it is

            giving me errors about TixForm. What happened?

          + [G.7] How do I generate the tclIndex file for Tix?

          + [G.8] Can I ignore the default arguments passed by the

            various -command and -broeswcmd options?

          + [G.9] What does tixWidgetDoWhenIdle do?

          + [G.10] Why isn't such a feature in Tix? Will it be

            implemented?

          + [G.11] Who are using Tix in their software?

          + [G.12] I am using a DirList widget. When the user clicks on

            an item, the procedure of my -browsecmd gets called twice.

            However, I just want it to be called once.

          + [G.13] I get an error "can't read data(-value): no such

            element in array" when I use the tixExFileSelectDialog.

   Question About Porting to Specific Platforms/Software

          + [P.1] The configure script gave me strange errors.

          + [P.2] Does Tix 4.1 work with Tk 4.1

          + [P.3] Does Tix work with Incr Tcl 2.0?

          + [P.4] How do I get Tix to work with Expect?

          + [P.5] Solaris 2.4: Filenames in FileSelectBox are chopped

            off.

          + [P.6] Do I still need libXpm?

          + [P.7] I get a coredump as soon as tixwish starts up.

   Porting from Tix 3.6 to Tix 4.x

          + [X.1] What happened to the tixInit command?

          + [X.2] How do I set the schemes and fontsets in Tix 4.x?

          + [X.3] How do I choose the default TK color schemes and

            fontsets? Tix is messing up the colors of my existing

            programs.

          + [X.4] I want the old bisque look of Tk 3.6. tk_bisque doesn't

            work.

     _________________________________________________________________

  LEGAL ISSUES

   [L.1] Is Tix free software?

          ANSWER: Tix is distributed under the same license as Tcl/Tk

          (a.k.a. BSD style license). Application developers can freely

          redistribute Tix along with their products.

          We will continue to provide free technical support and

          maintainence for Tix. However, to recover the development

          costs, we would appreciate financial supports for the Tix user

          community. If you like Tix and would like to make a donation to

          the Tix Project, please send mail to xpi@xpi.com.

     _________________________________________________________________

  GENERAL QUESTIONS ABOUT USING THE TIX LIBRARY

   [G.1] What does the "-disablecallback" option do?

          ANSWER: Many Tix widgets have both a -value option and a

          -command option. Any modification of the -value will cause the

          -command callback to be executed. Sometimes this is

          undesirable. For example, calling "config -value" inside the

          callback procedure will cause the callback to be re-entered and

          thus an infinite recursion.

          The -disablecallback can be used to advoid this problem. When

          this option is set, the -command callback will not be executed

          even if the -value of a widget is changed. Therefore, if you

          need to modify the -value of a widget inside its callback, do

          this:

    proc my_callback {w} {

        $w config -disablecallback true

        $w config value blah

        $w config -disablecallback false

    }

   If you find this too troublesome, you can call the command

          tixSetSilent:

    proc my_callback {w} {

        tixSetSilent $w blah

    }

   [G.2] How do I set the width of the entry subwidget inside the

          tixControl widget?

          ANSWER: You can use the option database or the -options flag to

          set the configuration options of the subwidgets. E.g:

option add *TixControl*entry.width 10

   OR

tixControl .c -options {

   entry.width  10

}

   [G.3] What is the "setslient" method?

          ANSWER: This is an obsolete method. You could use it to achieve

          the same effect as the -disablecallback option. selsilent used

          to be a widget command for the ComboBox, Control, etc. It has

          been removed since Tix 4.0a4 and replaced by the tixSetSilent

          command. Please note that tixSetSilent is not a widget command

          but an external procedure.

   [G.4] Is there a Tix interface builder in the works?

          ANSWER: Yes. But I don't know when it will be finished.

          (probably in 96).

   [G.5] Can you tell me about the syntax of tixForm

          ANSWER: Please see the file man/Form.html or man/Form.n.

   [G.6] I am not using the tixForm geometry manager, but it is giving me

          errors about TixForm. What happened?

          ANSWER: When you get error messages like this:

 (TixForm) Error:Trying to use more than one geometry

           manager for the same master window.

           Giving up after 50 iterations.

   Most likely, the problem is when using tixLabelFrame widgets, you

          packed to the wrong frame:

          This is WRONG:

   tixLabelFrame .d

        button .d.b

        pack .d.b

   This is the correct way:

   tixLabelFrame .d

        set f [.d subwidget frame]

        button $f.b

        pack $f.b

        pack .d

   Remember you don't pack directly into a TixLabelFrame widget. Instead,

          you should pack into its frame subwidget.

   [G.7] How do I generate the tclIndex file for Tix?

          ANSWER: Tix tclIndex files cannot be generated using the

          standard auto_mkindex procedure. You must use the tixindex

          program in the tools/ subdirectory in the Tix distribution. The

          syntax is

 tixindex *.tcl

   [G.8] Can I ignore the default arguments passed by the various

          -command and -broeswcmd options?

          ANSWER: You can use the tixBreak command. For example:

 tixFileSelectDialog .c -command "puts foo; tixBreak"

   [G.9] What does tixWidgetDoWhenIdle do?

          ANSWER: It does the same thing as tixDoWhileIdle (and "after

          -idle"). The difference is it takes its second argument as the

          name of a widget and executes this command only if the widget

          exists: i.e.:

  tixWidgetDoWhenIdle tixComboBox::Update $w blah blah ..

   will execute tixComboBox::Update only if $w exists. $w may be

          destroyed after tixWidgetDoWhenIdle is called but before an

          idle event happens.

   [G.10] Why isn't such a feature in Tix? Will it be implemented?

          ANSWER: Generally requests for new features are welcomed. You

          can send your requests to tix@xpi.com and we'll be happy to

          hear from you.

          We can't guarantee to implement the requested features

          immediately. Usually it depends on how important the features.

          If the feature is requested by more people, it will usually get

          done faster. However, some frequently requested features

          probably won't be imlemented. Usually these features are

          cosmetic changes and:

          + they do not add new capability to the widgets

          + they are not universally liked

          + they confuse the user.

          Some examples are:

          + Different foreground and background colors for the NoteBook

            tabs: having a lot of colors may antagonize the users that

            are "color haters"; also, the different colors don't make it

            easier for the user to locate the desired tab.

          + Ring-binder metaphore for the NoteBook widget: a waste of

            screen real estate.

          + Rows of tabs for the NoteBook widget: the user may be

            confused when the rows of tabs are switched. If you need to

            have a lot of tabs for the notebook, use the ListNoteBook

            widget instead.

   [G.11] Who are using Tix in their software?

          ANSWER: I have compiled a list of softwares that use Tix. See

          http://www.xpi.com/tix/software.html. (These are only the

          ones that I have heard of, either from the authors themselves

          or from the TCL FAQ. There should be more of them).

   [G.12] I am using a DirList widget. When the user clicks on an item,

          the procedure of my -browsecmd gets called twice. However, I

          just want it to be called once.

          ANSWER: The -browsecmd procedure is triggered by three types of

          events: <1>, , and . When the user

          clicks on an entry, a <1> and a  event will

          happen in rapid session, which causes your -browsecmd procedure

          to be called twice.

          A crude fix for this problem is to ignore all the

           events. You can find out the event that

          triggers the -browsecmd procedure by the tixEvent command. Here

          is an example:

    tixDirList .c -browsecmd Browse

    proc Browse {args} {

        if {[tixEvent type] == ""} {

            return

        }

        # ....

    }

   However, the above solution is not perfect. For example, if the user

          clicks down the button at entry one, drags it over entries two

          and three and release it on top of entry three, the following

          events may be caused:

         1. <1> on entry one.

         2.  on entry two.

         3.  on entry three.

          Therefore, if you use the above method, the browse event on

          entry three will be lost!

          To devise a better solution, it's better to understand the

          basic design conventions of a Tix-based GUI. Suppose we have a

          list of entries displayed in a listbox (or DirList, or HList).

          When the user clicks on an entry, the GUI usually responds by

          displaying a "detailed view" of the entry. For example, if we

          put a list of file names in a listbox, when the user clicks on

          a file name, we display the contents of the file in a text

          window. If the user then clicks on another file name, the text

          window will load in the contents of the new file.

          Now what happens if the user clicks on the same entry twice? Do

          we reload the contents of the file into the text window? This

          is usually unnecessary, inefficient and probably not what the

          user wants to do. The Tix convention is, when the user clicks

          on the same entry again, the detail view is not updated. If the

          user wants to force an update (e.g, the user knows the file's

          contents has been changed and wants to see the new version), he

          or she can double-click on the entry and the application will

          respond by redisplaying the detail view (reloading the file).

          To implement this policy, the Browse procedure should be

          modified as the following:

    proc Browse {args} {

        global currentView

        set ent [tixEvent value]

        if {$ent == $currentView} {

            # We have already displayed the detailed view of $ent.

            #

            return

        } else {

            set currentView $ent

            DisplayDetail $ent

        }

    }

   [G.13] I get an error "can't read data(-value): no such element in

          array" when I use the tixExFileSelectDialog.

          ANSWER: If you use tixExFileSelectDialog like this:

        tixExFileSelectDialog .f -command foo

        foo {filename} {

            destroy .f

            do some other stuff ...

        }

   it will cause a Tcl error because the dialog assumes that it still

          exists after calling your command. This usually result in

          errors like this:

        can't read "data(-value)": no such element in array

            while executing

        "set data(-selection) $data(-value)..."

            (procedure "tixComboBox::SetValue" line 30)

   This "feature" is built into many Tix widgets and can't be fixed

          easily. To work around the problem, never destroy widgets

          inside -command calls. Usually you should unmap toplevel

          windows instead. If you must destroy widgets, do it with an

          "after" command. For example, the foo procedure should be

          rewritten as:

        foo {filename} {

            wm withdraw .f

            do some other stuff ...

            after idle {if [winfo exists .f] {destroy .f}}

        }

   Execute the "after" command at the very end of the -command. Otherwise

          the idle handler may be activated by some "update" calls.

     _________________________________________________________________

  QUESTION ABOUT PORTING TO SPECIFIC PLATFORMS/SOFTWARE

   [P.1] The configure script gave me strange errors.

          ANSWER: The problem may be you have several operating systems

          sharing the same file system. Some people encounter error

          messages like this:

# ./configure --prefix=/usr/vendor/tcl

loading cache ./config.cache

checking for a BSD compatible install... /usr/bin/installbsd -c

checking for ranlib... ranlib

checking how to run the C preprocessor... cc -E

checking for unistd.h... ./configure[603]: "${ac_cv_header_$ac_safe+set}": bad

substitution

   The problem is at line 2, configure loaded in ./config.cache, which

          may have been created by a different operating system, with

          settings only usuable for that operating system. To get around

          this, you should type

make distclean

./configure

make all

   [P.2] Does Tix 4.1 work with Tk 4.1

          ANSWER: Yes, just enable the "Tk 4.1 ..." option in the setup

          program. It will also compile Tix in a dynamic lobrary.

   [P.3] Does Tix work with Incr Tcl 2.0?

          ANSWER: Yes just enable the "Itcl 2.0 ..." option in the setup

          program. Make sure you have ITcl 2.0 installed. Beta versions

          will *NOT* work. Also make sure you have installed the source

          tree of ITcl 2.0 in the same directory where you install the

          Tix source tree.

   [P.4] How do I get Tix to work with Expect?

          ANSWER: From Paul Schmidt (kuato@netcom.com):

     I have integrated Tcl7.4, Tk4.0, Expect-5.19 and Tix4.0 on Linux

     1.2.13 (ELF) and Solaris 2.4. It isn't too hard. For an expectk+Tix

     binary you need to add a call to Tix_Init in exp_main_tk.c. If you

     can find the call to Tk_Init then just cut&paste and replace it with

     Tix_Init. Do the same if you want a Tk+Tix window shell in

     TkAppInit.c. Worked like a charm. If you have any problems just

     holler.

   [P.5] Solaris 2.4: Filenames in FileSelectBox are chopped off.

          ANSWER: Problem:

     With Tix4.0a7 (and also with Tix4.0a6) on Solaris 2.4, when running

     the widget demo, in tixFileSelectBox, in the two scolling lists (for

     Files an Directories), some of the file and directory names have

     their first 2 letters chopped off. And some files are repeated.

   Solution: tixwish has some conflicts with /usr/ucblib/libucb.so.1 and

          you should not linke it tixwish (you don't need it). Here is a

          solution provided by Charles L Ditzel

          (charles@hanami.cyberspace.com):

     To fix the problem I was having, all I did was:

   unsetenv LD_LIBRARY_PATH

   set my PATH to something basic like:

     /usr/bin:/usr/ccs/bin:/bin:/usr/openwin/bin:/opt/SUNWspro/bin

   removed config.cache

   ./configure

   make clean

   make

     and now it works!! Must have been something in my old PATH or

     LD_LIBRARY_PATH that was causing it to pick up

     /usr/ucblib/libucb.so.

   [P.6] Do I still need libXpm?

          ANSWER: No, now Tix has its own XPM file reader. You no longer

          need libXpm.

   [P.7] I get a coredump as soon as tixwish starts up.

          ANSWER: Try to get a backtrace of the stack when the core dump

          happens (with a debugger, for example). If the core dump

          happens right inside the call to Tk_ConfigureWidget() inside

          the file tixInit.c, then the problem is because you compiled

          libtk.a and libtix.a with different versions of the Th header

          file tk.h. Delete all the .o files from the src directory of

          Tix, fix the Makefile so that now you can compile libtix.a with

          the same tk.h that you used to compile libtk.a.

     _________________________________________________________________

  PORTING FROM TIX 3.6 TO TIX 4.X

   [X.1] What happened to the tixInit command?

          ANSWER: You don't need to use it anymore. It is provided in Tix

          4.x only for backward compatibility.

   [X.2] How do I set the schemes and fontsets in Tix 4.x?

          ANSWER: You can set the color schemes and fontsets using the

          standard X resource database (.Xdefaults file). You can add

          these two lines in the user's .Xdefaults file:

        *TixScheme:   Gray

        *TixFontSet:  14Point

   If you want to switch color schemes and fontsets during run time, you

          can issue the following commands:

        tix config -scheme Gray -fontset 14Point

   Please read the tix manual page for more details

   [X.3] How do I choose the default TK color schemes and fontsets? Tix

          is messing up the colors of my existing programs.

          ANSWER: Add these two lines in your .Xdefaults:

        *TixScheme:   TK

        *TixFontSet:  TK

   [X.4] I want the old bisque look of Tk 3.6. tk_bisque doesn't work.

          ANSWER: The Tix widgets are not compatible with tk_bisque. If

          you want a bisque-ish look you can add to your .Xdefaults file

          the following line:

        *TixScheme:   Bisque