#!/usr/bin/perl
use warnings;
use Tk;
use Tk::JPEG;
use Tk::Zinc;
use MIME::Base64;

#my $imagein = shift || '1z-squatch.jpg';
my $imagein = shift || "No Image $!\n" ;

my $mw = MainWindow->new();
$mw->idletasks;

my $jscreen = $mw->screenwidth - 500;
my $kscreen = $mw->screenheight - 500;

$mw->geometry( "$jscreen" . "x" . "$kscreen" . "+20+20" );

# Only tested with jpeg.
open( PIC, $imagein ) or die print "Need a jpeg \n";
binmode(PIC);

my $buffer = '';
while (<PIC>) { $buffer .= $_; }
close(PIC);
my $image = encode_base64($buffer);

my $zinc = $mw->Scrolled(
    'Zinc',
    -scrollbars  => 'osoe',
    -borderwidth => 0
)->pack( -side => 'left', -fill => 'both', -expand => 1 );

my $zoomframe = $mw->Frame()->pack( -side => 'left', -fill => 'y' );

my $label1 = $zoomframe->Label( -text => 'Zoom' )->pack(
    -side => 'top',
    -pady => 5
);

my $button1 = $zoomframe->Button(
    -text    => '+',
    -command => [ \&zoom, 1 ]
)->pack( -side => 'top', -pady => 5, -fill => 'x' );

my $button2 = $zoomframe->Button(
    -text    => '-',
    -command => [ \&zoom, 0 ]
)->pack( -side => 'top', -pady => 5, -fill => 'x' );

my $scale   = 0;
my $radio1 = $zoomframe->Radiobutton(
    -text     => 'Resize',
    -variable => \$scale,
    -value    => 0,
    -command  => \&reset
  )->pack(
    -side => 'top',
    -pady => 5,
    -fill => 'x'
  );

my $radio2 = $zoomframe->Radiobutton(
    -text     => 'Scale',
    -variable => \$scale,
    -value    => 1,
    -command  => \&reset
  )->pack(
    -side => 'top',
    -pady => 5,
    -fill => 'x'
  );

my $percent   = '100%';
my $label2 = $zoomframe->Label( -textvariable => \$percent )->pack(
    -side => 'top',
    -pady => 5
);


my $factor1 = 4;
my $factor2 = 4;
my $photo     = $zinc->Photo( -data => $image, -format => 'jpeg' );
my $group     = $zinc->add( 'group', 1 );
my $realimage = $zinc->add(
    'icon', $group,
    -position => [ 0, 0 ],
    -image    => $photo,
    -tags     => 'image'
);
$zinc->configure( -scrollregion => [ $zinc->bbox('image') ] );

MainLoop;

sub reset {
    $factor1 = 4;
    $factor2 = 4;
    $percent = '100%';
    $zinc->remove('image');
    $zinc->xview( 'moveto', 0 );
    $zinc->yview( 'moveto', 0 );
    $zinc->remove( 'group', 1 );
    $group = $zinc->add( 'group', 1 );
    $realimage = $zinc->add(
        'icon', $group,
        -position => [ 0, 0 ],
        -image    => $photo,
        -tags     => 'image'
    );
    $zinc->configure( -scrollregion => [ $zinc->bbox('image') ] );
}

sub zoom {
    my ($zoomer) = @_;

    if ( $zoomer == 0 && $factor1 == 1 ) { return; }

    $mw->Busy;

    if ( $scale == 0 ) {

        if ($realimage)   { $zinc->remove('image'); undef($realimage); }
        if ($zoomimage)   { $zoomimage->delete;     undef($zoomimage); }
        if ($subbedimage) { $subbedimage->delete;   undef($subbedimage); }

        $zoomimage   = $zinc->Photo;
        $subbedimage = $zinc->Photo;
        $zoomimage->blank;
        $subbedimage->blank;

        if ( $zoomer == 1 ) { $factor1++; }
        else { $factor1--; }

        $zoomimage->copy( $photo,       -zoom      => $factor1 );
        $subbedimage->copy( $zoomimage, -subsample => $factor2 );

        $zinc->xview( 'moveto', 0 );
        $zinc->yview( 'moveto', 0 );
        $realimage = $zinc->add(
            'icon', $group,
            -position => [ 0, 0 ],
            -image    => $subbedimage,
            -tags     => 'image'
        );
        $zinc->configure( -scrollregion => [ $zinc->bbox('image') ] );

    }
    else {
        if ( $zoomer == 1 ) { $factor1++; }
        else { $factor1--; }

        my $newscale = $factor1 / $factor2;
        $zinc->xview( 'moveto', 0 );
        $zinc->yview( 'moveto', 0 );
        $zinc->scale( $group, $newscale, $newscale );
        $zinc->configure( -scrollregion => [ $zinc->bbox('image') ] );
    }

    $mw->Unbusy;
    $mw->update;
    $percent = ( ( $factor1 / $factor2 ) * 100 ) . '%';
}