jsteng has asked for the wisdom of the Perl Monks concerning the following question:

Hi
I am trying to make a customized TK::Listbox using TK::canvas because I need the ability to change text color and font when <double-1>
here is my initial work: 
#!/usr/bin/perl
use warnings;
use strict;
use Tk;

my ($DimX,$DimY)=(400,600);
my ($mX,$mY) = (2,2);

my $mw = MainWindow->new( -bg=> "#000000", -borderwidth=> 0);
$mw->minsize( $DimX, $DimY );
$mw->maxsize( $DimX, $DimY );
my %canvas;
my $fontsize=int(20);
$canvas{'canvas'} = $mw->Scrolled(
    'Canvas', 
    -width => $DimX-2*$mX,
    -height => 2*$DimY,
    -bg => '#60C8BC',
    -borderwidth => 2,
    -relief => 'raised',
    -scrollbars => 'e',
    )->pack();

$canvas{'canvas'}->CanvasBind("<Button-1>", [ \&print_xy, Ev('x'), Ev(
+'y') ]);
sub print_xy {
    my ($canv, $x, $y) = @_;
    my $sel = int($canvas{'canvas'}->canvasy($y) / (1.4*$fontsize+2));
    printf "Selected: %d, (%d,%d)\n", $sel, $canvas{'canvas'}->canvasx
+($x),$canvas{'canvas'}->canvasy($y);

    $canvas{'text'}{$sel}->itemconfigure(
        -fill => '#0000FF',
        -font => "Courier $fontsize bold",
    );
}

for (my $y=0; $y<200; $y++) {
    $canvas{'text'}{$y} = $canvas{'canvas'}->createText( 5, 4+$y*(1.4*
+$fontsize+2),
        -fill => '#000000',
        -text => "GgYy".$y x 20,
        -font => "Courier $fontsize normal",
        -anchor => 'nw',
    );
}

MainLoop;

[download]
Problems:
1. I could not make the scrollbar scroll.
2. How do I change the selected item's font/color?
I tried doing this: 
    $canvas{'text'}{$sel}->itemconfigure(
        -fill => '#0000FF',
        -font => "Courier $fontsize bold",
    );

[download]
But it is not working.
3. lastly, how do I retrieve a particular selected text's font/color? Sorry folks, I am very rusty with perl after years of not programming.

Thanks BTW: My original (>10 years ago) script used TK::ROText; however in that version, the windows' size is fixed, and all entry in the ROText are space padded to cover the whole line (sprintf "%-50s", $text). Then using tag for each line. That was a nightmare, it was ugly programming. I am redoing that script to use Listbox; it was alot cleaner but I could not change font of selected text (line) thus I am redoing it with Canvas.

Replies are listed 'Best First'.
Re: tk canvas text
by tybalt89 (Monsignor) on Apr 16, 2018 at 20:13 UTC

    Just for fun, here's a sort-of-listbox that changes item color and font and is scrollable constructed out of a pane and labels. 

    #!/usr/bin/perl

# http://perlmonks.org/?node_id=1212975

use strict;
use warnings;
use Tk;
use Tk::Pane;

my $mw = MainWindow->new;
$mw->geometry( '500x400+300+300' );

my @items;
my $selectedtext = '';

$mw->Button( -text => 'Exit', -command => sub { $mw->destroy },
  )->pack( -side => 'bottom', -expand => 0, -fill => 'x' );

$mw->Label( -textvariable => \$selectedtext,
  -width => 10,
  -font => 'courier 30', -fg => 'navy',
  )->pack( -side => 'right', -fill => 'y' );

my $pane = $mw->Scrolled(Pane => -scrollbars => 'oe',
  -sticky => 'nsew',
  )->pack(-fill => 'both', -expand => 1);

for my $text ( qw( one two three four five six seven eight nine ten ) 
+)
  {
  my $label = $pane->Label( -text => $text,
    -fg => 'red', -font => 'courier 40',
    )->pack(-fill => 'both', -expand => 1);
  push @items, $label;
  $label->bind('<ButtonRelease-1>' => sub {
    $_->configure( -fg => 'red', -font => 'courier 40' ) for @items;
    $selectedtext = $text;
    $label->configure( -fg => 'green', -font => 'times 80' );
    } );
  }

MainLoop;

    [download]
[reply]
[d/l]
      Are these Labels within a scrollable frame?
      If so, how come I could not use -justify=>'left' option?
      what options can I use to align the text?
      thanks
[reply]
        #!/usr/bin/perl

# http://perlmonks.org/?node_id=1212975

use strict;
use warnings;
use Tk;
use Tk::Pane;

my $mw = MainWindow->new;
$mw->geometry( '500x400+300+300' );

my @items;
my $selectedtext = '';

$mw->Button( -text => 'Exit', -command => sub { $mw->destroy },
  )->pack( -side => 'bottom', -expand => 0, -fill => 'x' );

$mw->Label( -textvariable => \$selectedtext,
  -width => 10,
  -font => 'courier 30', -fg => 'navy',
  )->pack( -side => 'right', -fill => 'y' );

my $pane = $mw->Scrolled(Pane => -scrollbars => 'oe',
  -sticky => 'nsew',
  )->pack(-fill => 'both', -expand => 1);

for my $text ( qw( one two three four five six seven eight nine ten ) 
+)
  {
  my $label = $pane->Label( -text => $text,
    -anchor => 'w',
    -fg => 'red', -font => 'courier 40',
    )->pack(-fill => 'both', -expand => 1);
  push @items, $label;
  $label->bind('<ButtonRelease-1>' => sub {
    $_->configure( -fg => 'red', -font => 'courier 40' ) for @items;
    $selectedtext = $text;
    $label->configure( -fg => 'green', -font => 'times 80' );
    } );
  }

MainLoop;

        [download]
[reply]
[d/l]
Re: tk canvas text
by Anonymous Monk on Apr 16, 2018 at 10:17 UTC
    Tags
[reply]
      what about tag? a sample script would be helpful. thanks!
[reply]
        Read about it in tk docs
[reply]

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