LabelsGen

Utility to generate labels that include QR codes for generic products

Below few examples:

Sequence	File	Schema

Examples above refers to 1x1inch pages, used for Dymo labelwrites printers. The page size can be configured.

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Setup

Before proceeding with the setup, ensure that the following prerequisites are satisfied by your system:

• Python3
• Python PIP
• Virtualenv

Python3

Most modern operating systems are already providing Python3 interpreter. Verify its presence executing from a console the command python3 --version. If the python interpeter is not available, please refer to the python download page.

Python PIP

To verify that PIP is available in your system just execute pip --version. In no PIP is present, just execute below commands:

curl https://bootstrap.pypa.io/get-pip.py -o get-pip.py
python3 get-pip.py

In case curl command is not available, download the get-pip.py file manually.

Virtualenv

To check the presence of the virtualenv, just execute python3 -m venv, it sould report che usage of the tool. If the virtualenv is not present, use PIP to install it:

pip install virtualenv

labelsgen command installation

To install 'labelsgen' command, just execute the commands below:

cd <labelsgen path>
python3 -venv venv
. venv/bin/activate
pip install .

Usage

The labelsgen command foresees different options, as reported by its usage instructions:

$ labelsgen 
This utility creates a PDF file containing label pages including products QR codes 
    Usage: labelsgen <first_product_number> [number_of_products=1]
                 -v
                 -f <file_labels>
                 -s <schema_labels>
                 -h|--help show this page

    Where:
      -v open the generated QR labels file
      'file_labels' is a text file containing a single product data and optionally a text placed on the right side
      'schema_labels' file containing the description of the labels to generate

    The utility can be configured changing the 'labelsgen_conf.json' file

• Generate a sequence of labels containing QE codes of products providing the first serial number and the number of successive products

  labelsgen <first_product_number> [number_of_products=1]

• Generate QRs specified into an input file

  labelsgen -f <file_labels>

  where <file_labels> contains UPI line records in the format:

  <product url> [<product serial>]

• Generate a custom page providing a shema file

  labelsgen -s <schema_labels>

  The schema file consists of a json file containing instrucitons to generate cusstom pages. To see how to configure the page, see the chapter Page schema composition

  Page schema composition

  The schema file consists of a json array of objects in which each element specifies instructions to generate a single page. Each object contains one or more graphic elements being part of the page using the strucure:

  {
   "<name of the element 1>": {
     <description of the element 1>
   },
   "<name of the element 2>": {
     <description of the element 2>
   }
  }

  The name of the element has only informative purposes, while each element is characterized by a "type" attribute value. Each type foresees different properties. Object property names are self explanatory, just consider that values are expressed in terms of page percentage and objects will be centered respect to the specified position.

  The schema supports the following element types:

  label

  To specify a label (a texutal element), specify the object:

  "product_code": {
    "type": "label",
    "font": "Helvetica",
    "font_size": 6,
    "text": "4.7.6/ACTIVE/3.XX",
    "x": 0.50,
    "y": 0.08[,
    "rotation": 90
    ]
  },

  The rotation property is not mandatory.

  qr

  This type represent the given text into a QR code image having specified position and size.

  "product_qr": {
    "type": "qr",
    "qr_size": 0.68,
    "text": "https://<mysite>/products/3.XX",
    "x": 0.50,
    "y": 0.52
  }

  image

  "company_logo": {
    "type": "image",
    "path": "images/company_logo.png",
    "width": 0.3,
    "height": 0.3,
    "x": 0.50,
    "y": 0.20
  }

All different execution modes can be specified in a single command line:

labelsgen -f file_labels.txt -s schema_labels.json 2000 5 -v

Configuration

The labelsgen command can be configured changing the configuration file labelsgen_conf.json. Below the default settings:

{
  "page": "Multipurpose Labels",
  "qr_url_prefix": "https://<mycompany>/product/",
  "qr_url_product_prefix": "<product>/4.",
  "sequence_labels": "sequence_labels.pdf",
  "file_labels": "file_labels.pdf",
  "schema_labels": "schema_labels.pdf",
  "qr_size": 0.78,
  "text_left_x": 0.12,
  "text_right_x": 0.92,
  "text_bottom_y": 0.06,
  "font": "Helvetica",
  "font_size": 6,
  "pages": [
    { "name": "Multipurpose Labels",
      "width": 1.0,
      "height": 1.0
    },
    { "name": "24x48 labels",
      "width": 1.0,
      "height": 2.0
    }
  ]
}

Configuration options are self explanatory and they principally affect the QR generation in sequence and using the configuration file. The pages array and page define the page size. The *_labels.pdf are the PDF file names produced using numeric sequence, input file or schema