File: FAQ.html

package info (click to toggle)
tix 8.4.3-4
  • links: PTS
  • area: main
  • in suites: squeeze, wheezy
  • size: 8,448 kB
  • ctags: 6,844
  • sloc: ansic: 28,077; tcl: 22,774; python: 7,577; makefile: 332; cs: 253; sh: 185; perl: 128
file content (399 lines) | stat: -rw-r--r-- 11,656 bytes parent folder | download | duplicates (6)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
<HTML>

<!--	$Id: FAQ.html,v 1.5 2004/12/24 01:27:22 hobbs Exp $	-->
<HEAD>
<TITLE>Tix Frequently Asked Questions</TITLE>
</HEAD>
<BODY BGCOLOR="#ffffff" TEXT="#000000" LINK="#0000ff" VLINK="#800000" ALINK="#800080">
<FONT FACE="Tahoma, Arial, Helvetica">
<center><h1>Tix Frequently Asked Questions</h1></center>


<hr>

<h3>
    Legal Issues
</h3>
<DL>
<DT> <b><a name=legal.1> [L.1] </a> 
    Is Tix free software?
</b><p>
<DD>
<b> ANSWER: </b> 

    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. <p>

<p>
</DL>
<hr>
<h3>
    General Questions About Using The Tix Library
</h3>
<DL>
<DT> <b><a name=general.1> [G.1] </a> 
    What does the "<code>-disablecallback</code>"
    option do?
</b><p>
<DD>
<b> ANSWER: </b> 

    Many Tix widgets have both a <code>-value</code> option and a
    <code>-command</code> option. Any modification of the
    <code>-value</code> will cause the <code>-command</code> callback
    to be executed. Sometimes this is undesirable. For example,
    calling "<code>config -value</code>" inside the callback procedure
    will cause the callback to be re-entered and thus an infinite
    recursion. <p>

    The <code>-disablecallback</code> can be used to advoid this
    problem. When this option is set, the <code>-command</code>
    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:

    <blockquote><pre>
    proc my_callback {w} {
	$w config -disablecallback true
	$w config value blah
	$w config -disablecallback false
    }
    </pre></blockquote>

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

    <blockquote><pre>
    proc my_callback {w} {
	tixSetSilent $w blah
    }
    </pre></blockquote>

<p>
<DT> <b><a name=general.2> [G.2] </a> 
    How do I set the width of the entry subwidget inside the tixControl widget?
</b><p>
<DD>
<b> ANSWER: </b> 

    You can use the option database or the -options flag to set the
    configuration options of the subwidgets. E.g: <pre>

option add *TixControl*entry.width 10
</pre>

  OR

<pre>
tixControl .c -options {
   entry.width  10
}
</pre>

<p>
<DT> <b><a name=general.6> [G.6] </a> 

    I am not using the tixForm geometry manager, but it is giving me
errors about TixForm. What happened?
</b><p>
<DD>
<b> ANSWER: </b> 

    When you get error messages like this:

<pre> (TixForm) Error:Trying to use more than one geometry
           manager for the same master window.
           Giving up after 50 iterations.</pre>

    Most likely, the problem is when using tixLabelFrame widgets, you
    packed to the wrong frame: <p>

    This is WRONG:

<pre>   tixLabelFrame .d
        button .d.b
        pack .d.b </pre>

This is the correct way:

<pre>   tixLabelFrame .d
        set f [.d subwidget frame]
        button $f.b
        pack $f.b
        pack .d </pre>

    Remember you don't pack directly into a TixLabelFrame
    widget. Instead, you should pack into its <code>frame</code>
    subwidget.

<p>
<DT> <b><a name=general.7> [G.7] </a> 
    How do I generate the <code>tclIndex</code> file for Tix?
</b><p>
<DD>
<b> ANSWER: </b> 

    Tix <code>tclIndex</code> files cannot be generated using the
    standard auto_mkindex procedure. You must use the tixindex program
    in the <code>tools/</code> subdirectory in the Tix
    distribution. The syntax is 
    <pre> tixindex *.tcl
    </pre>

<p>
<DT> <b><a name=general.8> [G.8] </a> 
    Can I ignore the default arguments passed by the various
    <code>-command</code> and <code>-browsecmd</code> options?
</b><p>
<DD>
<b> ANSWER: </b> 
    You can use the <code>tixBreak</code> command. For example:
<pre> tixFileSelectDialog .c -command "puts foo; tixBreak" </pre>

<p>
<DT> <b><a name=general.9> [G.9] </a> 
    What does <code>tixWidgetDoWhenIdle</code> do?
</b><p>
<DD>
<b> ANSWER: </b> 

    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.: 


<pre>  tixWidgetDoWhenIdle tixComboBox::Update $w blah blah ..</pre>

    will execute tixComboBox::Update only if $w exists. $w may be
    destroyed after tixWidgetDoWhenIdle is called but before an idle
    event happens.

<p>
<DT> <b><a name=general.feature_req> [G.10] </a> 
    Why isn't such a feature in Tix? Will it be implemented?
</b><p>
<DD>
<b> ANSWER: </b> 

    Generally requests for new features are welcomed. You can submit
    your requests to <a href=http://tix.sourceforge.net> http://tix.sourceforge.net </a> and
    we'll be happy to hear from you. <p>

    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:

    <ul>
    <li> they do not add new capability to the widgets
    <li> they are not universally liked
    <li> they confuse the user.
    </ul>

    <p>
    Some examples are:

    <ul>

    <li> <b>Different foreground and background colors for the
    NoteBook tabs</b>: 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.

    <li> <b>Ring-binder metaphore for the NoteBook widget</b>: a waste
    of screen real estate.

    <li> <b>Rows of tabs for the NoteBook widget</b>: 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.

    </ul>


<p>
<DT> <b><a name=general.softwares> [G.11] </a> 
    Who are using Tix in their software?
</b><p>
<DD>
<b> ANSWER: </b> 

See <A HREF=http://tix.sourceforge.net>http://tix.sourceforge.net</A>


<p>
<DT> <b><a name=general.twice> [G.12] </a> 

    I am using a DirList widget. When the user clicks on an item, the
    procedure of my <code>-browsecmd</code> gets called
    twice. However, I just want it to be called once.
</b><p>
<DD>
<b> ANSWER: </b> 

    The <code>-browsecmd</code> procedure is triggered by three types
    of events: <code>&lt;1&gt;</code>,
    <code>&lt;ButtonRelease-1&gt;</code>, and
    <code>&lt;B1-Motion&gt;</code>. When the user clicks on an entry,
    a <code>&lt;1&gt;</code> and a
    <code>&lt;ButtonRelease-1&gt;</code> event will happen in rapid
    session, which causes your <code>-browsecmd</code> procedure to be
    called twice. <p>

    A crude fix for this problem is to ignore all the
    <code>&lt;ButtonRelease-1&gt;</code> events. You can find out the
    event that triggers the <code>-browsecmd</code> procedure by the
    <code>tixEvent</code> command. Here is an example:

    <blockquote><pre>
    tixDirList .c -browsecmd Browse

    proc Browse {args} {
	if {[tixEvent type] == "<code>&lt;ButtonRelease-1&gt;</code>"} {
	    return
	}
	# ....
    }
    </pre></blockquote>

    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: <p>

    <ol>
        <li> <code>&lt;1&gt;</code> on entry one.
        <li> <code>&lt;B1-Motion&gt;</code> on entry two.
        <li> <code>&lt;ButtonRelease-1&gt;</code> on entry three.
    </ol> <p>

    Therefore, if you use the above method, the browse event on entry
    three will be lost! <p>

    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
    "<b>detailed view</b>" 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. <p>

    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). <p>

    To implement this policy, the Browse procedure should be modified
    as the following:

    <blockquote><pre>
    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
	}
    }
    </pre></blockquote> <p>

<p>
<DT> <b><a name=general.destroy> [G.13] </a> 

    I get an error <i>"can't read data(-value): no such element in
    array</i>" when I use the tixExFileSelectDialog.
</b><p>
<DD>
<b> ANSWER: </b> 

    If you use tixExFileSelectDialog like this:

<pre>
	tixExFileSelectDialog .f -command foo

	foo {filename} {
	    destroy .f
	    do some other stuff ...
	}
</pre>

 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:

<pre>
	can't read "data(-value)": no such element in array
	    while executing
	"set data(-selection) $data(-value)..."
	    (procedure "tixComboBox::SetValue" line 30)
</pre>


  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:

<pre>
	foo {filename} {
	    wm withdraw .f
	    do some other stuff ...

	    after idle {if [winfo exists .f] {destroy .f}}
	}
</pre>

  Execute the "after" command at the very end of the
  -command. Otherwise the idle handler may be activated by some
  "update" calls.

<p>
</DL>
<hr>
<h3>
    Question About Porting to Specific Platforms/Software
</h3>
<DL>
<DT> <b><a name=port.1> [P.1] </a> 
    The configure script gave me strange errors.
</b><p>
<DD>
<b> ANSWER: </b> 
    The problem may be you have several operating systems sharing the
    same file system. Some people encounter error messages like this:

<blockquote><pre>
# ./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
</pre></blockquote>

    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

<blockquote><pre>
make distclean
./configure
make all
</pre></blockquote>