QRCodePlugin

Page contents

• Introduction
• Syntax Rules
• Examples
  • Small QR Code for URL
  • Encode URL of current topic
  • Pulldown menu with QR Code
  • Interactive example
• Plugin Installation & Configuration
• Plugin Info

Introduction

This plugin generates QR Code in TWiki pages. A QR Code is a specific matrix barcode (or two-dimensional code), readable by dedicated QR barcode readers and camera phones. The code consists of black modules arranged in a square pattern on a white background. The information encoded can be any text, such as phone numbers, URLs, gelocation, vCard, vCal and more.

Syntax Rules

%QRCODE{ "text" ... }%

QR Code has error correction capability (ECC) to restore data if the code is dirty or damaged:

• level "L" - about 7%
• level "M" - about 15%
• level "Q" - about 25%
• level "H" - about 30%

The length of text (number of bytes) and the ECC determine the symbol version (e.g. matrix size) required to encode some text. A version="auto" selects the version automatically based on text length and ECC. See "Attention" note in the "Plugin Installation & Configuration" section below before using "auto".

Overview of symbol version for default ECC level "M":

The size of the generated image depends on the symbol version and the module size. For example, version="2" and size="3" results in a 99x99 pixels image. Version 2 has matrix size 25x25. A module size 3 turns that into 3 times 25x25 pixels, or 75x75 pixels. There is some required whitespace, which results in a 99x99 pixels image size.

See also VarQRCODE documentation for TWikiVariables.

Examples

Small QR Code for URL http://twiki.org/

You type	You get (if installed)	Simulated example
%QRCODE{ "http://twiki.org/" version="2" size="3" }%	QRCode Plugin Error: Can't locate object method "new" via package "GD::Image" (perhaps you forgot to load "GD::Image"?) at /usr/local/share/perl5/GD/Barcode/QRcode.pm line 304.

Encode URL of current topic

The QR Code of the current topic can be placed in a TWiki skin so that the URL can easily be read by smart phones. We use symbol version 8, e.g. the URL cannot be longer than 152 characters.

You type	You get (if installed)	Simulated example
%QRCODE{ "%SCRIPTURL{view}%/%WEB%/%TOPIC%" version="8" size="4" }%	QRCode Plugin Error: Can't locate object method "new" via package "GD::Image" (perhaps you forgot to load "GD::Image"?) at /usr/local/share/perl5/GD/Barcode/QRcode.pm line 304.

Pulldown menu with QR Code

You can add a QR Code pulldown to the TopMenuSkin so that smartphone users can easily bookmark any TWiki page. Add the following to your TopMenuSkinTopicMenu after the Edit pulldown bullets:

You type	You get (if installed)	Simulated example
* [[%BASEWEB%.%BASETOPIC%][<img src="%PUBURLPATH%/%SYSTEMWEB%/QRCodePlugin/ qrcode.gif" alt="" width="16" height="16" /> %ICON{menu-down}%]] * [[%SYSTEMWEB%.QRCodePlugin][%QRCODE{ "%SCRIPTURL{view}%/%BASEWEB%/%BASETOPIC%" version="auto" size="4" }%]]	View Raw View Print version Find backlinks History More topic actions Edit Raw edit Attach file or image Edit topic preference settings Set new parent More topic actions QRCode Plugin Error: Can't locate object method "new" via package "GD::Image" (perhaps you forgot to load "GD::Image"?) at /usr/local/share/perl5/GD/Barcode/QRcode.pm line 304.

Interactive example

You can encode any text with this interactive form. The matrix size is set automatically using version="auto".

Plugin Installation & Configuration

Note: You do not need to install anything on the browser to use this plugin. The following instructions are for the administrator who installs the plugin on the TWiki server.

• For an automated installation, run the configure script and follow "Find More Extensions" in the in the Extensions section.

• Or, follow these manual installation steps:
  • Download the ZIP file from the Plugins home (see below).
  • Unzip QRCodePlugin.zip in your twiki installation directory. Content:

    File:	Description:
    data/TWiki/QRCodePlugin.txt	Plugin topic
    data/TWiki/VarQRCODE.txt	QRCODE variable documentation topic
    lib/TWiki/Plugins/QRCodePlugin.pm	Plugin Perl module
    lib/TWiki/Plugins/QRCodePlugin/Core.pm	Plugin core module
    pub/TWiki/QRCodePlugin/twiki-logo-80x40-t.gif	Logo file
    pub/TWiki/QRCodePlugin/qrcode-example-*.png	Example QR Code image files

  • Set the ownership of the extracted directories and files to the webserver user.
  • Install the dependencies.

• Plugin configuration and testing:
  • Run the configure script and enable the plugin in the Plugins section.
  • Test if the installation was successful: See example above.

Attention, CPAN:GD::Barcode::QRcode version 1.15 needs to be patched as follows before you can use version="auto":

--- /usr/lib/perl5/site_perl/5.8.0/GD/Barcode/QRcode.pm.save1   2004-04-23 23:35:34.000000000 -0700
+++ /usr/lib/perl5/site_perl/5.8.0/GD/Barcode/QRcode.pm   2011-02-11 22:37:13.000000000 -0800
@@ -37,7 +37,7 @@
     $oSelf->{text} = $sTxt;
     $oSelf->{Ecc} = $rhPrm->{Ecc} || ' ';
     $oSelf->{Ecc} =~ tr/LMHQ/M/c;    #Not /LMQH/ => M
-    $oSelf->{Version} = $rhPrm->{Version} || 1;
+    $oSelf->{Version} = $rhPrm->{Version} || 0;
     $oSelf->{ModuleSize} = $rhPrm->{ModuleSize} || 1;
     $oSelf->{ModuleSize} = int($oSelf->{ModuleSize});
 

Plugin Info

• One line description, is shown in the TextFormattingRules topic:
  • Set SHORTDESCRIPTION = Create QR Code (a matrix barcode) in TWiki pages, useful for mobile applications

Plugin Author:	TWiki:Main.PeterThoeny
Copyright:	© 2011-2018 TWiki:Main.PeterThoeny, TWiki.org © 2011-2018 TWiki:TWiki.TWikiContributor
License:	GPL (GNU General Public License)
Plugin Version:	2018-07-07
Change History:
2018-07-17:	TWikibug:Item7852: Make version="auto" work even if the 3rd part QR library does not support it; Remove newlines from error message so that code can be placed in a TWiki table -- TWiki:Main.PeterThoeny
2012-11-14:	TWikibug:Item7020: Categorize TWiki Variable QRCODE -- TWiki:Main.PeterThoeny
2012-09-03:	TWikibug:Item6837: Added missing example screenshot qrcode-example-4.png
2011-07-12:	TWikibug:Item6725: Change global package variables from "use vars" to "our"
2011-02-15:	TWikibug:Item6647: Added TopMenuSkin example; added qrcode.gif 16x16 pixels icon
2011-02-13:	TWikibug:Item6647: Added format=..."; XHTML fix for HTML img tag
2011-02-12:	TWikibug:Item6647: Lazy loading of core and CPAN modules for better performance when QRCODE is not used; adding interactive example
2011-02-11:	TWikibug:Item6647: Added version="auto"
2011-02-09:	TWikibug:Item6647: Initial version
TWiki Dependency:	$TWiki::Plugins::VERSION 1.1
CPAN Dependencies:	CPAN:GD, CPAN:GD::Barcode, CPAN:GD::Barcode::QRcode, CPAN:Digest::MD5
Other Dependencies:	gd (see http://www.libgd.org/)
Perl Version:	5.005
TWiki:Plugins.Benchmark:	GoodStyle nn%, FormattedSearch nn%, QRCodePlugin nn%
Plugin Home:	http://TWiki.org/cgi-bin/view/Plugins/QRCodePlugin
Feedback:	http://TWiki.org/cgi-bin/view/Plugins/QRCodePluginDev
Appraisal:	http://TWiki.org/cgi-bin/view/Plugins/QRCodePluginAppraisal

Related Topics: VarQRCODE, TWikiPlugins, DeveloperDocumentationCategory, AdminDocumentationCategory, TWikiPreferences