Dear Bretheren, I've created a zoom function that lets a user select a rectangle area on a chart (such as http://pashanoid.ru/charts.png) and the script selects that area of the database timeline (http://pashanoid.ru/sqlite.db) and re-draws the chart with that area being not only zoomed in, but also re-defined via the timeline. However, I'm unable to get rid of the rectangle boxes that I originally use to show the selection. Please help.

#!/usr/bin/perl
use strict;
use warnings;
use Tk;
use Tk::Chart;
use Tk::Chart::Lines;
use Tk::Canvas::GradientColor;
use DBI;
use utf8;

my (@timeline, @v_out, @v_in, @v_ac, @v_acc);
my $mw = MainWindow->new();

$mw->title('U in, U out');
$mw->optionAdd("*font", "*utf-8");
$mw->fontCreate('giant_rus', -family => 'nimbus sans l', -weight => 'n
+ormal', -size=>int(-13*13/10));
$mw->fontCreate('tiny_rus', -family => 'nimbus sans l', -weight => 'no
+rmal', -size=>int(-12*12/10));
my $chart = $mw->Lines(
    -title  => 'U in and U out (volts)',
    -titlefont => 'giant_rus',
    -xlabelfont => 'tiny_rus',
    -ylabelfont => 'tiny_rus',
    -boxaxis => 1,
    -yticknumber => 10,
    -linewidth => 2,
    -bezier => 1,
    -alltickview => 1,
    -pointline => 0,
    -markers => [10, 9, 9],
    -xtickheight => 5,
    -ylongticks => 1,
    -ylongtickscolor => 'white',
    -xlongticks => 1,
    -xlongtickscolor => 'white',
    -width => 700,
    -height => 350,
    -yminvalue => 0,
    -ymaxvalue => 260,
     -xlabelskip => 150,
)->pack(qw / -fill both -expand 1/);

$chart->enabled_gradientcolor();
$chart->set_gradientcolor(
    -start_color => '#bdbebe',
    -end_color   => '#aed5e2',
    -type => 'linear_vertical',
);
my $chart2 = $mw->Lines(
        -title  => 'U batt',
        -titlefont => 'giant_rus',
        -xlabelfont => 'tiny_rus',
        -ylabelfont => 'tiny_rus',
        -boxaxis => 1,
        -yticknumber => 10,
        -linewidth => 2,
        -bezier => 1,
        -alltickview => 1,
        -pointline => 0,
        -markers => [10, 9, 9],
        -xtickheight => 5,
        -ylongticks => 1,
        -ylongtickscolor => 'white',
        -xlongticks => 1,
        -xlongtickscolor => 'white',
    -width => 700,
        -height => 350,
        -yminvalue => 9,
    -ymaxvalue =>17,
     -xlabelskip => 150,
)->pack(qw / -fill both -expand 1 /);

$chart2->enabled_gradientcolor();
$chart2->set_gradientcolor(
        -start_color => '#bdbebe',
        -end_color   => '#aed5e2',
        -type => 'linear_vertical',
);

my (@data, @data2);

my ($d, $e) = (0.001, 1);
&update_data($d, $e);

$chart->plot( \@data );
$chart2->plot(\@data2 );

my ($chart_width, $x_begin, $y_begin, $x_now, $y_now, $rec, $rec2);

$mw->bind('<ButtonPress>' => 
    sub {
        $x_begin = $Tk::event->x; 
        $y_begin = $Tk::event->y;
        print "x_begin = $x_begin y_begin=$y_begin\n";
        $mw->bind('<Motion>' => 
            sub { 
                $x_now = $Tk::event->x;
                        $y_now = $Tk::event->y;
                print "x_now = $x_now y_now=$y_now\n";
                $rec = $chart->createRectangle($x_begin, $y_begin, $x_
+now, $y_now, -width => 2, -outline => 'yellow');
                $rec2 = $chart2->createRectangle($x_begin, $y_begin, $
+x_now, $y_now, -width => 2, -outline => 'orange');
            });
    }
);
$mw->bind('<ButtonRelease>' => sub { 
            print "ButtonReleased\n"; #$chart->delete($rec);
            $mw->bind('<Motion>', "");
            $chart_width = $chart->width;
            $chart->delete($rec);
                    $chart2->delete($rec2);
            $d = $x_begin/$chart_width;
            $e = $x_now/$chart_width;
            print "draw next chart at $d percent of timeline, end at $
+e percent of timeline\n";
            $chart->clearchart;
                        $chart2->clearchart;
                        &update_data($d, $e);
                        $chart->plot(\@data);
                        $chart2->plot(\@data2);

         }
);



MainLoop();


sub update_data{
    my ($d, $e) = @_;
    my ($mindate, $maxdate);
    @timeline = ();
    @v_in =();
    @v_out =();
    @v_acc =();
    @data =();
    @data2=();
        my $dbfile = 'sqlite.db';
        my $dbh = DBI->connect("dbi:SQLite:dbname=$dbfile","",""); #
    my $sth = $dbh->prepare("SELECT min(strftime('%s',date)) FROM mapl
+og");
        $sth->execute();
        while (my @result = $sth->fetchrow_array()) {
                $mindate = $result[0]
        }
    $sth = $dbh->prepare("SELECT max(strftime('%s',date)) FROM maplog"
+);
    $sth->execute();

    while (my @result = $sth->fetchrow_array()) {
                $maxdate = $result[0]
        }
        $sth->finish;
    my $interval = ($maxdate - $mindate);
    print "d=$d e=$e interval=$interval maxdate = $maxdate\n";
    print "converted = ". &convert_dates($maxdate);
    $d = &convert_dates($mindate+$interval*$d);
    $e = &convert_dates($mindate+$interval*$e);
    
    print " d=$d e=$e\n";
    my $phrase = "SELECT strftime(\'%H-%MN%m-%d\',date), v_in, v_out, 
+v_acc FROM maplog WHERE (date > \'$d\' and date < \'$e\')";
    print "phrase = $phrase\n";  
          $sth = $dbh->prepare($phrase); 
    $sth->execute();
        while (my @result = $sth->fetchrow_array()) {
                $result[0] =~ s/N/\n/g;
                push (@timeline,$result[0]);
                push (@v_in,$result[1]);
                push (@v_out,$result[2]);
                push (@v_acc,$result[3]);
        }
        $sth->finish;
        $dbh->disconnect;

        @data = (\@timeline, \@v_in, \@v_out);
        @data2 = (\@timeline, \@v_acc);
}

sub convert_dates{
    my $date = shift;
    my ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) = localti
+me($date);
        $year += 1900;
        $sec = sprintf("%02d", $sec);
        $min = sprintf("%02d", $min);
        $hour = sprintf("%02d", $hour);
        $mon = sprintf("%02d", $mon+1);
        my $sqlite_date = "$year-$mon-$mday $hour:$min:$sec"; #SQLite 
+date old->#my $sqlite_date = "$mday/$mon/$year $hour:$min:$sec";
        return($sqlite_date);
}
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