Variable in foreach loop not updated

[llafriel]

Hi,

I'm having trouble getting a little Perl program to work. It doesn't want to update some variables inside a foreach loop. '$image->Read($listitem);' works in the first iteration, but isn't updated next time around.

Pardon if this the solution is obvious, this is my first attempt at perl.

#!/usr/local/bin/perl
use Image::Magick;

my $progdir = 'c:/CoverArt/';
my $origdir = 'c:/CoverArt/Originals/';
my $pdadir = 'c:/CoverArt/PDA/';

chdir( $progdir ) or die "Cant chdir to $dir $!";

unlink("nytt.jpg");


chdir;

my($image, $x);
$gradient = Image::Magick->new;
$bottombar = Image::Magick->new;
$shine = Image::Magick->new;
$shine2 = Image::Magick->new;
$main = Image::Magick->new;
$main2 = Image::Magick->new;
$image = Image::Magick->new;

$main->Read('main.jpg');
$shine->Read('shine.png');
$bottombar->Read('bottombar.png');
$gradient->Read('gradient.png');


chdir( $origdir ) or die "Cant chdir to $dir $!";

opendir MYDIR, ".";
@contents = grep !/^\.\.?$/, readdir MYDIR;
closedir MYDIR;


foreach my $listitem ( @contents )
{
print $listitem . "\n";


$shine2 = $shine;
$main2 = $main;

chdir( $origdir ) or die "Cant chdir to $dir $!";

$image->Read($listitem);

$width = $image->Get('columns');
$height = $image->Get('rows');
$width = (305/$height)*$width;
$image->AdaptiveResize(width=>$width,height=>305);
$shine2->AdaptiveResize(width=>$width);
$image->Composite(image=>$shine,compose=>'over');
$image->Border(bordercolor=>'white',width=>'1', height=>'1');
$reflection = $image->clone();
$reflection->Flip();
$main2->Composite(image=>$image,compose=>'over', y=>-20, gravity=>'center');
$main2->Composite(image=>$reflection,compose=>'blend', y=>285, gravity=>'center');
$main2->Composite(image=>$gradient,compose=>'over', gravity=>'south');
$main2->Composite(image=>$bottombar,compose=>'over', gravity=>'south');


chdir( $pdadir ) or die "Cant chdir to $dir $!";
$main2->Write($listitem);

}

 

[Kirsle]

You create $image as a new Image::Magick before the loop, and then on each loop iteration you call $image->Read.

According to the examples on the perlmagick page, I would assume that multiple Read calls actually adds the new image to a kind of stack of already loaded images (for example, to read multiple images and output them into an animated GIF image).

i.e. like this example from perlmagick:

  #!/usr/local/bin/perl
  use Image::Magick;

  my($image, $p, $q);

  $image = new Image::Magick;
  $image->Read('x1.png');
  $image->Read('j*.jpg');
  $image->Read('k.miff[1, 5, 3]');
  $image->Contrast();
  for ($x = 0; $image->[$x]; $x++)
  {
    $image->[$x]->Frame('100x200') if $image->[$x]->Get('magick') eq 'GIF';
    undef $image->[$x] if $image->[$x]->Get('columns') < 100;
  }
  $p = $image->[1];
  $p->Draw(stroke=>'red', primitive=>'rectangle', points=>20,20 100,100');
  $q = $p->Montage();
  undef $image;
  $q->Write('x.miff');

So, try creating $image = new Image::Magick inside your foreach loop, so that a *new* Image::Magick is created for each image you're looping through and then destroyed when the loop goes out of scope, instead of re-using the same object.

(to that end, your object probably *is* being updated, but you're probably writing to a format that doesn't support animation so it only writes the first image on the stack)

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