Regarding Text Widget in Perl/Tk

[Vinesh Varghese]

Hi Friends,

I am presently working on an Automation project where I am using Active
state perl as the programming language on windows platform. For the
above mentioned project I am using Perl/Tk for the GUI. I created a Text
Widget and wanted to show the output from my perl code on the text box.
I tried tieing the STDOUT to the text box , but the output is shown only
after the program is terminated. What ever I am printing to STDOUT is
accumulated and shown at once after the program is terminated. I wanted
to show them as and when the program is running. I don't know where I am
mistaken. Please help me in this regard.

Thanks is Advance,

Vinesh


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[R. Joseph Newton]

[email]vinesh.varghese@wipro.com[/email] wrote:

> Hi Friends,
>
> I am presently working on an Automation project where I am using Active
> state perl as the programming language on windows platform. For the
> above mentioned project I am using Perl/Tk for the GUI. I created a Text
> Widget and wanted to show the output from my perl code on the text box.
> I tried tieing the STDOUT to the text box , but the output is shown only
> after the program is terminated. What ever I am printing to STDOUT is
> accumulated and shown at once after the program is terminated. I wanted
> to show them as and when the program is running. I don't know where I am
> mistaken. Please help me in this regard.
>
> Thanks is Advance,
>
> Vinesh

The text appearing in a Tk [or any other GUI library] widget
is an attribute, generally '-text', of the
widget. It has nothing to do with standard input/output
communications. In order to properly manage the
behavior of Tk widgets, you must understand the widget
itself.

perldoc Tk::Text
perldoc Tk::WidgetName

Joseph

Hmmm--this didn't go through to the group because something
hashed the list address. Just as well. The Tk docs are
very poor in samples, so here is a small working example of
loading some text to a Text widget. They are complicated
little buggers, and if you do the lead work of reading the
docs, I am happy to help clarify some of the questions the
docs raise. I'm sure others will be also, but you do have
to start by reading the docs for any Tk widget you are
trying to use.

my $text = '';
open IN, "txt/txt$padded_path.txt" or die "Could not open
$!";
my $line;
$text .= $line while $line = <IN>;
close IN or die "Could not close $!";
my $text_area = $message_area->{'SubWidget'}->{'text'};
$text_area->delete('0.1', 'end');
$text_area->insert('end', $text);

The snippet above clears a text widget entirely, and loads
it from the start--in this case, also the end, with the new
text held in $text.


Joseph

[Gary Stainburn]

Hi folks,

I'm looking to write an app that I want both Linux and Windows users to be
able to use. This app will be interactive (my train simulator/controller app
for those who followed my previous threads) so I will need some form of user
interface.

As I've never looked at Tk before I would appreciate people's opinions on it.
Specifically, how easy is it to develop, and how portable is it between the
two platforms?

Any comments about deploying on a Windows platform would also be appreciated
(I want to provide it as a download, so simple install would be good).
--
Gary Stainburn

This email does not contain private or confidential material as it
may be snooped on by interested government parties for unknown
and undisclosed purposes - Regulation of Investigatory Powers Act, 2000

[Wolf Blaum]

For Quality purpouses, Gary Stainburn 's mail on Friday 30 January 2004 16:26
may have been monitored or recorded as:

> Hi folks,
>

Hi Gary,

> As I've never looked at Tk before I would appreciate people's opinions on
> it. Specifically, how easy is it to develop, and how portable is it between
> the two platforms?

I havent read your privious thred, so I dont really know if this is helpful
for you:

most of the scripts I ever wrote that I wanted to have a GUI for were scripts
that needed (sometimes complicated) config files.
So what I did was writing qw/simle/ GUIs using Tk to produce these config
files, that way keeping program logic and User Interface seperate (and easily
exchangable). In that approach it is possible to do a little interactivity
even when the "real" programm is running, but if you need to promt users for
something ever second at runtime, thats probably to not a good idea.
However, the GUIs are pretty reusable and for these simple tasks pretty easy
to write.

> Any comments about deploying on a Windows platform would also be
> appreciated (I want to provide it as a download, so simple install would be
> good). --

The pairs of script/gui I wrote so far worked fine on SuSe Linux 8.0 up and
Win32 (didnt try other OS).
I once did a Win package for download using the tarma installer TI
([url]www.tarma.com[/url]) which installed activestateperl if required and my script/GUI
pair - TI is freeware that produces a Win Installer for you. Worked fine.

If you only need to do a Win GUI, look at the GUI Loft, too. ([url]www.banhof.se/[/url]
~johanl/perl/Loft/)
Thats a WYSIWYG GUI design tool, pretty delphi like, except that it doesent
produce code but a design file which you can work with in you app, so you can
click your GUI together and focus on the logic. Neat thing.

As Joseph was pointing out, examples in the Tk docu are an endangerd species:
Mastering Perl/Tk by Steve Lidie and Nacy Walsh is an extended zoo of these.

Enjoy clicking around, Wolf

[Wolf Blaum]

For Quality purpouses, zentara 's mail on Friday 30 January 2004 16:22 may
have been monitored or recorded as:

Hi,

neat trick! Great.
However, I have a, well, couriosity?

My script looks pretty much the same, except the print in &dosomething
(since it is acctually your script:-))

> Here is a set of programs, that do what you want.
> ################################################## ####
> #!/usr/bin/perl -w
> use strict;
> use Tk;
> my $mw = new MainWindow;
>
> my $listbox = $mw->Scrolled("Listbox", -scrollbars => "osoe",
> -height => 5,
> -selectmode => "multiple")
> ->pack(-side => "left");
>
> my $start = $mw->Button( -text => 'Start', -command => \&start )->pack;
> $mw->Button( -text => 'Exit', -command => \&exit )->pack;
>
>
> #start external command to pipe
> sub start {
> $start->configure(-state => 'disabled');
> open(C, "./read-own-stdout-piper 2>&1 |") or warn $!;
> $mw->fileevent( \*C, 'readable', \&doSomething );
>
> }
>
> sub doSomething {
> if ( eof(C) ) { # Child closed pipe
> close(C); # Close parent's part of pipe,
> # filevent is cancelled as well
> wait; # Avoid zombies
> return;
> }
> my $text = <C>; # Get text from child and put it into listbox
> print $text; #only diffeerence.

chomp($text);

> $listbox->insert( 'end', 'Got: ' . $text );
> $listbox->see('end');
> }
>
> MainLoop;
>
> __END__
> ##############################################

and the called script looks different (but prints to STDOUT and has a $|++ for
flush.

When I call the GUI from a command prompt opend under X I should see two
parallel outputs, one in the terminal and one in the listbox, right.

I do see these outputs on both, but the one in the listbox is way slower than
the one to the console. However, the relation seams to be random (ie there is
no, say constant 5 line adtvantage).
I also tried the
tie @array, "Tk::Listbox", $listbox in &start and only call
$listbox->see('end') in &dosomething with the result, that I get to see the
whole output in the listbox at once and only when the callled script is
finished.

Any Idea?

Thanks a lot,
Wolf

[R. Joseph Newton]

zentara wrote:

> Try putting a "TK::after in the event loop to set the timing.

Yee-haw!! Just what I was looking for! Thanks. Serendipity is a wonderful thing.

Joseph

[Wolf Blaum]

For Quality purpouses, zentara 's mail on Saturday 31 January 2004 17:23 may
have been monitored or recorded as:

>
> It's hard to say without showing us your script.

well, the called script (not the gui) is bout 500 lines...

> Try putting a "TK::after in the event loop to set the timing.

That works: no clue why, bu a great tip. Thanks.

Wolf

[Mike Flannigan]

I tried to send off-list, but the e-mail address did not
work, so I'm posting to the list:



Hey, I was very impressed when this script you provided
ran for me. All I did is run the first script and it
creates the box nicely.

I don't know much about spawning child processes. I'm
on vacation and much of my Perl documentation is at
home.

I was wondering if you could help me get this script
tied to one of my Perl programs on my Win2000 box.
After much experimentation, I've changed the line
open(C, "./read-own-stdout-piper 2>&1 |") or warn $!;
to
open(C, "round2.bat 2>&1 |") or warn $!;

round2.bat is a DOS batch file with a single line:
perl round2.pl # (that is the way I run perl programs)

round2.pl has:

use strict;
use warnings;
my $number = 5.6278;
my $rounded = sprintf '%.2f', $number;
print "$rounded\n";
$|++; # << SHOULD THIS LINE BE HERE?

AND IT ALL WORKS!


I can't just do
open(C, "round2.pl 2>&1 |") or warn $!;
because then it just opens round2.pl in my text editor,
since that is the association I have ".pl" set to. I tried
open(C, "'perl round2.pl' 2>&1 |") or warn $!;
but that didn't work either.

That "Got:" prompt isn't too cool, but I'm sure I'll
learn how to turn that off later.

Also, it's unfortunate that copy and paste don't work
in that TK box.

Anyway, thanks a bunch. If there are other posts
on the NG related to this, I'll see them when I get
home.


Mike Flannigan
Houston, TX


_______________________________________


Subject: Re: Regarding Text Widget in Perl/Tk
Date: Fri, 30 Jan 2004 10:22:24 -0500
From: zentara <zentara@highstream.net>
To: [email]beginners@perl.org[/email]


On Thu, 29 Jan 2004 20:01:10 +0530, [email]vinesh.varghese@wipro.com[/email] (Vinesh
Varghese) wrote:

>I am presently working on an Automation project where I am using Active

>state perl as the programming language on windows platform. For the
>above mentioned project I am using Perl/Tk for the GUI. I created a

Text

>Widget and wanted to show the output from my perl code on the text

box.

>I tried tieing the STDOUT to the text box , but the output is shown

only

>after the program is terminated. What ever I am printing to STDOUT is
>accumulated and shown at once after the program is terminated. I wanted

>to show them as and when the program is running. I don't know where I

am

>mistaken. Please help me in this regard.

Since you don't show your code, it's hard to say what your problem is.

Here is a set of programs, that do what you want.
################################################## ####
#!/usr/bin/perl -w
use strict;
use Tk;
my $mw = new MainWindow;

my $listbox = $mw->Scrolled("Listbox", -scrollbars => "osoe",
-height => 5,
-selectmode => "multiple")
->pack(-side => "left");

my $start = $mw->Button( -text => 'Start', -command => \&start )->pack;
$mw->Button( -text => 'Exit', -command => \&exit )->pack;


#start external command to pipe
sub start {
$start->configure(-state => 'disabled');
open(C, "./read-own-stdout-piper 2>&1 |") or warn $!;
$mw->fileevent( \*C, 'readable', \&doSomething );

}

sub doSomething {
if ( eof(C) ) { # Child closed pipe
close(C); # Close parent's part of pipe,
# filevent is cancelled as well
wait; # Avoid zombies
return;
}
my $text = <C>; # Get text from child and put it into listbox
chomp($text);
$listbox->insert( 'end', 'Got: ' . $text );
$listbox->see('end');
}

MainLoop;

__END__
##############################################
#and here is read-own-stdout-piper

#!/usr/bin/perl
$|++;
for my $i ( 0 .. 10) {
print $i, "\n";
sleep 1;
}
__END__
############################################

[R. Joseph Newton]

Mike Flannigan wrote:

> I was wondering if you could help me get this script
> tied to one of my Perl programs on my Win2000 box.
> After much experimentation, I've changed the line
> open(C, "./read-own-stdout-piper 2>&1 |") or warn $!;
> to
> open(C, "round2.bat 2>&1 |") or warn $!;
>
> round2.bat is a DOS batch file with a single line:
> perl round2.pl # (that is the way I run perl programs)
>
> round2.pl has:
>
> use strict;
> use warnings;
> my $number = 5.6278;
> my $rounded = sprintf '%.2f', $number;
> print "$rounded\n";
> $|++; # << SHOULD THIS LINE BE HERE?
>
> AND IT ALL WORKS!
>
> I can't just do
> open(C, "round2.pl 2>&1 |") or warn $!;
> because then it just opens round2.pl in my text editor,

> since that is the association I have ".pl" set to.

Why?!?! Why screw with something that works, unscrewed with, just fine? The
asscociations set up
by the ActivePerl install are the appropriate ones for making Perl run. If you
want associations to your
preferred editor, then:
Open Windows Explorer, or the abonminable kindergarten version My Computer
Click Folder Options on the Tools menu
Select File types
Find the PL extension.
Click the Advanced button.
Restore the Open association with the perl executable. The Open action should
read:

"C:\Perl\bin\perl.exe" "%1" %*

presuming that Perl is installed to the default location for Windows

Create an Edit action tied to your editor.

Changing the primary association is a bad hack, and a bad habit to be in as you
start learning a programming
language.

Actually, once you right-click on any registered file type in Win2K, and use the
Open with... option option to
select an alternate handler, that handler will thereafter be available on a list
under the Open with menu item.

In brief, there is no good reason to mess with a working file association

> I tried
> open(C, "'perl round2.pl' 2>&1 |") or warn $!;
> but that didn't work either.

open(C, "perl round2.pl 2>&1 |") or warn $!;
or simply:
open(CHILD, "perl round2.pl | ") or warn "Could not open pipe from child
process: $!";

>
> That "Got:" prompt isn't too cool, but I'm sure I'll
> learn how to turn that off later.
>
> Also, it's unfortunate that copy and paste don't work
> in that TK box.

If it is a Text widget, copy and paste will indeed work. Can you provide more
detail on
why you think it doesn't?

> Anyway, thanks a bunch. If there are other posts
> on the NG related to this, I'll see them when I get
> home.
>
> Mike Flannigan
> Houston, TX

Mike, I think you have a conceptual problem here. Seeking STDIN from a GUI
widget, hacking
and breaking working file associations, etc. indicate a bad habit that will
hobble your programming
efforts if unaddressed. *Let working systems be*, don't fix what ain't broke.

Joseph

[Mike Flannigan]

> > I was wondering if you could help me get this script
> > tied to one of my Perl programs on my Win2000 box.
> > After much experimentation, I've changed the line
> > open(C, "./read-own-stdout-piper 2>&1 |") or warn $!;
> > to
> > open(C, "round2.bat 2>&1 |") or warn $!;
> >
> > round2.bat is a DOS batch file with a single line:
> > perl round2.pl # (that is the way I run perl programs)
> >
> > round2.pl has:
> >
> > use strict;
> > use warnings;
> > my $number = 5.6278;
> > my $rounded = sprintf '%.2f', $number;
> > print "$rounded\n";
> > $|++; # << SHOULD THIS LINE BE HERE?
> >
> > AND IT ALL WORKS!
> >
> > I can't just do
> > open(C, "round2.pl 2>&1 |") or warn $!;
> > because then it just opens round2.pl in my text editor,

>

> > since that is the association I have ".pl" set to.

>
> Why?!?! Why screw with something that works, unscrewed with, just fine? The
> asscociations set up
> by the ActivePerl install are the appropriate ones for making Perl run.

Thanks for the response. Remember, I am using Windows on
this box. As others have recently pointed out, I need to run
Perl in a command prompt anyway, so it behooves me to
associate ".pl" with my text editor and not the Perl
executable.

> If you
> want associations to your
> preferred editor, then:
> Open Windows Explorer, or the abonminable kindergarten version My Computer
> Click Folder Options on the Tools menu
> Select File types
> Find the PL extension.
> Click the Advanced button.
> Restore the Open association with the perl executable. The Open action should
> read:
>
> "C:\Perl\bin\perl.exe" "%1" %*
>
> presuming that Perl is installed to the default location for Windows
>
> Create an Edit action tied to your editor.

I don't know what an "Edit action" is, but I am looking
into it.

>
> Changing the primary association is a bad hack, and a bad habit to be in as you
> start learning a programming
> language.
>
> Actually, once you right-click on any registered file type in Win2K, and use the
> Open with... option option to
> select an alternate handler, that handler will thereafter be available on a list
> under the Open with menu item.
>
> In brief, there is no good reason to mess with a working file association
>

> > I tried
> > open(C, "'perl round2.pl' 2>&1 |") or warn $!;
> > but that didn't work either.

>
> open(C, "perl round2.pl 2>&1 |") or warn $!;

I thought I tried that, but apparently not, because it
works perfectly. Not too smart on my part.

> or simply:
> open(CHILD, "perl round2.pl | ") or warn "Could not open pipe from child
> process: $!";
>

> >
> > That "Got:" prompt isn't too cool, but I'm sure I'll
> > learn how to turn that off later.
> >
> > Also, it's unfortunate that copy and paste don't work
> > in that TK box.

>
> If it is a Text widget, copy and paste will indeed work. Can you provide more
> detail on
> why you think it doesn't?

I changed round2.pl to include "print "Hello World\n";"

Now it's the nice, pretty Tk box with "Got: 5.63" on the
first line and "Got: Hello World" on the 2nd line. Clicking
on each line alternately highlights the entire line or
unhighlights the entire line with a dark blue line. You
can have both lines highlighted if you like.

In any case, hitting ctrl C does not copy anything to the
clipboard, and you cannot highlight just part of a line
of text.

> > Anyway, thanks a bunch. If there are other posts
> > on the NG related to this, I'll see them when I get
> > home.
> >
> > Mike Flannigan
> > Houston, TX

>
> Mike, I think you have a conceptual problem here.

Yeah, my main problem is I'm using Windows. I've been
trying to get a Linux box set up for quite some time now,
but it looks like it's going to be quite a bit longer before I
have it running.

> Seeking STDIN from a GUI
> widget,

Yeah, I thought you could do that. I need to study TK quite
a bit.

> hacking
> and breaking working file associations, etc. indicate a bad habit that will
> hobble your programming
> efforts if unaddressed. *Let working systems be*, don't fix what ain't broke.
>
> Joseph

[R. Joseph Newton]

Mike Flannigan wrote:

> In any case, hitting ctrl C does not copy anything to the
> clipboard, and you cannot highlight just part of a line
> of text.

Ah, but right clicking on the Text widget will--unless you have hacked the selection
activities.
If so, well--*Don't do that*--at least not until you have checked the unhacked
functionality of the widget. Tk::Text widgets have built-in copy-and-paste
functionality. If you manipualte the selection variables, though, you may be
generating side effects that disable this functionality.

Okay. I just checked it out. I brought up a project containing a Tk::Text widget,
whose editing functions I had done nothing with. Highlighted one phrase,
right-clicked and selected Copy. Pasted to Notepad from the clipboard, and got the
same phrase. Then I went down a line or two, selected another passage, used Ctl-c to
copied, and again the pasted text showed a successful copy.

I think something is going wrong with your highlighting routine. Or perhaps this is
ot a Text widget? If left alone, the Text widget will offer full copy-and-paste
functionality.

> > Houston, TX
> >
> > Mike, I think you have a conceptual problem here.

>
> Yeah, my main problem is I'm using Windows.

Nope. Windows certainly has its share of shortcomings, but they really don't seem to
bear on the issues you are presenting. The habit of low-level hacking will get you in
even more trouble on Linux.

> I've been
> trying to get a Linux box set up for quite some time now,
> but it looks like it's going to be quite a bit longer before I
> have it running.

>

> > Seeking STDIN from a GUI
> > widget,

>
> Yeah, I thought you could do that. I need to study TK quite
> a bit.

Yes. Tk is a complex, diverse, and somewhat uneven libary. It is really a ood idea
to read the documentation on each widget you use. Each widget has its own
characteristics and behaviorSome of them are pretty obvious, some are more subtle.

So I will reiterate:

> > hacking
> > and breaking working file associations, etc. indicate a bad habit that will
> > hobble your programming
> > efforts if unaddressed. *Let working systems be*, don't fix what ain't broke.

Joseph

[Mike Flannigan]

If I right click on the title bar, it gives "move", "size",
"minimize", "maximize", "close". If I right click anywhere else,
it doesn't do anything - produces no box. I don't recall
hacking anything to do with that, but perhaps I did.


Mike

> Ah, but right clicking on the Text widget will--unless you have hacked the selection
> activities.
> If so, well--*Don't do that*--at least not until you have checked the unhacked
> functionality of the widget. Tk::Text widgets have built-in copy-and-paste
> functionality. If you manipualte the selection variables, though, you may be
> generating side effects that disable this functionality.
>
> Okay. I just checked it out. I brought up a project containing a Tk::Text widget,
> whose editing functions I had done nothing with. Highlighted one phrase,
> right-clicked and selected Copy. Pasted to Notepad from the clipboard, and got the
> same phrase. Then I went down a line or two, selected another passage, used Ctl-c to
> copied, and again the pasted text showed a successful copy.
>
> I think something is going wrong with your highlighting routine. Or perhaps this is
> ot a Text widget? If left alone, the Text widget will offer full copy-and-paste
> functionality.
>

[R. Joseph Newton]

Mike Flannigan wrote:

> I> I think something is going wrong with your highlighting routine. Or perhaps this is

> > ot a Text widget? If left alone, the Text widget will offer full copy-and-paste
> > functionality.
> >

>
> f I right click on the title bar, it gives "move", "size",
> "minimize", "maximize", "close". If I right click anywhere else,
> it doesn't do anything - produces no box. I don't recall
> hacking anything to do with that, but perhaps I did.
>
> Mike

Mike,

That is because you are mixing threads. You pggybacked your issue on a thread initiated by
Vinesh Vargese, concerning the Tk::Text widget, as specified in the title bar. The sample
code you tried had do with getting standard output redirected to a Tk widget, though
Zentara chose a Listbox rather than a Text widget to display the text. The Listbox widget
does not have built-in copy-and-paste functionality. Such functionality would be much more
dificult to define in a generic sense for a listbox.

This is actualy the question I posed at the end of my post. I corrected your top-posting
above so you could see in context. No, this is not a Text widget. I think this is by
design. Zentara provided sample code to demonstrate the difference between Tk display text
and standard output. I don't think he had any intention of handing anyone a completed
assignment.

A simpler example, which does not deal with the original question, but which does show the
functionality you are interested in:

Greetings! E:\d_drive\perlStuff>perl -w
use Tk;

my $win = MainWindow->new(-title => 'This Text Copies Right');
my $text = $win->Text->pack(-expand => 'both');
MainLoop;
^Z

Joseph

[Mike Flannigan]

Ahhh. Not comparing apples to apples. That does make
a difference.

I need to get me a good Tk book and learn it proper, heh?


Mike

> Mike,
>
> That is because you are mixing threads. You pggybacked your issue on a thread initiated by
> Vinesh Vargese, concerning the Tk::Text widget, as specified in the title bar. The sample
> code you tried had do with getting standard output redirected to a Tk widget, though
> Zentara chose a Listbox rather than a Text widget to display the text. The Listbox widget
> does not have built-in copy-and-paste functionality. Such functionality would be much more
> dificult to define in a generic sense for a listbox.
>
> This is actualy the question I posed at the end of my post. I corrected your top-posting
> above so you could see in context. No, this is not a Text widget. I think this is by
> design. Zentara provided sample code to demonstrate the difference between Tk display text
> and standard output. I don't think he had any intention of handing anyone a completed
> assignment.
>
> A simpler example, which does not deal with the original question, but which does show the
> functionality you are interested in:
>
> Greetings! E:\d_drive\perlStuff>perl -w
> use Tk;
>
> my $win = MainWindow->new(-title => 'This Text Copies Right');
> my $text = $win->Text->pack(-expand => 'both');
> MainLoop;
> ^Z
>
> Joseph