Ben Bullock

NAME

Image::PNG::QRCode - make a PNG containing a QR code

SYNOPSIS

    use Image::PNG::QRCode 'qrpng';
    qrpng (text => 'boom shake shake shake the room', out => 'shake.png');

DESCRIPTION

This module converts input text to a PNG image of a QR code containing the text. The PNG image can either be stored to a file or it can be a scalar.

FUNCTIONS

qrpng

    my $png = qrpng (text => 'this is my text');

This makes a scalar PNG data in $png containing the QR code PNG.

    qrpng (in => 'file.txt', out => 'file.png');

This makes a PNG file file.png from the contents of file.txt.

qrpng options

text

Text to convert to a QR code.

in

in specifies an input file of text to convert to a QR code.

out

out specifies an output file or a scalar to put the PNG data into.

     qrpng (out => 'file.png');

writes to file.png, but

     qrpng (out => \$s);

writes the PNG data into a scalar $s.

version (NOT IMPLEMENTED YET)

Specify the "version" of the QR code. The "version" is like the size of the code. Maximum value is 40. If no version is specified, the program chooses one using the length of the text.

level (NOT IMPLEMENTED YET)

Specify the amount of error checking code (ECC) to use. The default is level one, which corresponds to 7% error tolerance. The level can go up to 4, which corresponds to 30% error tolerance.

quiet

Specify the size of the "quiet zone". The default is 4.

scale

Specify how many pixels one "module" (one block of the QR code) occupies. The default is 3. You can't use fractional values.

DIAGNOSTICS

%!$#"@*

This message is produced in the case of errors.

SCRIPT AND EXAMPLES

There is a script "qrpng" installed with the module:

    qrpng "earphone pad" 

makes qrcode.png. Try

    qrpng --help

for more options.

There is an example script qrpng.cgi in examples.

It makes a QR code for HTML:

SEE ALSO

Other QR code generators

On CPAN

That::QR::Module
Another::QR::Module

Non-CPAN

Google Charts QR code generator

The QR codes generated by this generator are about 2/5 the size of the Google charts ones.

BUGS

This module uses various tricks to make the PNG file very small, so it doesn't work with Image::PNG::Libpng. If you want to manipulate the output PNG file you'll need to read it in again and operate on it.

The module isn't optimized for repeated uses, it builds up and tears down everyting.

The QR encoding is not checked for correctness. The QR code library comes from the "qrduino" project, but the contents have been worked on so it's not clear whether it's still correct. Also there was a bug in the original thing leading to reading uninitialized memory.

COPYRIGHT AND LICENCE

The QR code creation part (the contents of qrencode.c in the distribution) is copyright 2010, tz@execpc.com. The rest of the module is copyright by Ben Bullock 2014.

This Perl module is licensed under the Gnu General Public Licence version 3.

1 POD Error

The following errors were encountered while parsing the POD:

Around line 132:

Expected text after =item, not a bullet