NAME

Imager::zxing - decode barcodes from Imager images using libzxing

SYNOPSIS

use Imager::zxing;
my $decoder = Imager::zxing::Decoder->new;
# list accepted formats separated by '|'
print $decoder->formats;
# list available formats
print $decoder->avail_formats
# set the accepted formats
$decoder->set_formats("DataMatrix|QRCode")
  or die $decoder->error;

# decode any barcodes
my $im = Imager->new(file => "somefile.png");
my @results = $decoder->decode($im);

for my $result (@results) {
  print $result->text, "\n";
}

DESCRIPTION

A primitive wrapper around zxing-cpp

This requires at least 1.4.0 of zxing-cpp, but 2.1.0 is preferable.

Currently only supports decoding and doesn't expose much of the interface.

To use this:

1. Create a decoder object:

   use Imager::zxing;
   my $decoder = Imager::zxing::Decoder->new;

2. Configure it if needed, most likely by setting the accepted barcode encodings:

   $decoder->set_formats("DataMatrix|QRCode");

3. Load an image using Imager:

   my $img = Imager->new(file => "somename.png")
     or die "Cannot load image ", Imager->errstr;

   The available file formats depends on the libraries Imager was built with.

4. Decode the barcode:

   my @results = $decoder->decode($img)
     or die "No barcodes found";

5. Process the results:

   for my $r (@results) {
     print $r->format, ": ", $r->text, "\n";
   }

Imager::zxing::Decoder class methods

• new

  my $decoder = Imager::zxing::Decoder->new;

  Create a new decoder object, does not accept any parameters.

  Default is to process all available barcode formats.

• avail_formats

  my @formats = Imager::zxing::Decoder->avail_formats

  Returns a list of the barcode formats that are decodable.

Decoder object methods

Create a decoder with:

my $decoder = Imager::zxing::Decoder->new;

Decoding

• decode(image)

  Attempts to decode barcodes from the supplied Imager image object.

  Returns a list of result objects, or an empty list if none are found.

  my $img = Imager->new(file => "somefile.png") or die Imager->errstr;
  my @results = $decoder->decode($img);

Settings

• formats()

  Returns the formats the decoder accepts as a | separated string.

  print $decoder->formats
  # default output:
  # Aztec|Codabar|Code39|Code93|Code128|DataBar|DataBarExpanded|DataMatrix|EAN-8|EAN-13|ITF|MaxiCode|PDF417|QRCode|UPC-A|UPC-E|MicroQRCode

• set_formats(formats)

  Sets the barcode formats that the decoder will decode, as a space, | or comma separated string.

  $decoder->set_formats("DataMatrix|QRCode");

• set_return_errors($bool)

  Set to non-zero to include results with soft errors such as checksum errors.

  $decoder->set_return_errors(1);

• set_pure($bool)

  Set to non-zero to only accept results where the image is an aligned image where the image is only the barcode.

  Note: this appears to be non-functional in my testing, this accepted a rotated image.

  $decoder->set_pure(1);

Result object methods

Result objects are returned by the decoder decode() method:

my @results = $decoder->decode($image);

• text()

  Returns the decoded text.

  my $text = $result->text;

• is_valid()

  True if the result represents a valid decoded barcode.

• is_mirrored()

  True if the result is from a mirrored barcode.

• is_inverted()

  True if the barcode image has inverted dark/light. Requires zxing 2.0.0 to be valid.

• format()

  The format of the decoded barcode.

• position()

  The co-ordinates of the top left, top right, bottom left and bottom right points of the decoded barcode in the supplied image, as a list.

• orientation()

  The rotation of the barcode image in degrees.

LICENSE

Imager::zxing is licensed under the same terms as perl itself.