njari / qrgen

Basic bulk QR Code Generator in Python; can overlay an image on the QR code

qrgen

Basic bulk QR Code Generator in Python.

I wrote this tool to generate QR Codes for PaperCut Mobile Release printers. It's provided as is, without any warranty or support. If it's useful to you, great!

Installation

This tool requires PIL or pillow, and pyqrcode. In a virtualenv on Ubuntu, you can run:

pip install pillow qrcode

However, pip and virtualenv aren't always installed by default, so

sudo apt-get install python-pip; sudo pip install pillow qrcode

might be required.

I have no idea about PIL on Windows; I assume there are binary builds available... I would look into compiling this for Windows if anyone was ever interested.

Usage

Help can be output with the -h flag.

usage: qrgen.py [-h] [--overlay OVERLAY] [--prefix PREFIX] [--suffix SUFFIX]
                [--format {png,jpg,bmp}] [--size SIZE] [--border BORDER]
                [text [text ...]]

Generate QR codes as PNG files

positional arguments:
  text                  Text to encode in the QR code.

optional arguments:
  -h, --help            show this help message and exit
  --overlay OVERLAY     a PNG file to overlay in the centre of the code. Test
                        your codes work!
  --prefix PREFIX, --url PREFIX, -p PREFIX
                        Optional text added to the start of the code's text,
                        e.g. http://server/qr/
  --suffix SUFFIX, -s SUFFIX
                        Optional text added to the end of the code's text.
  --format {png,jpg,bmp}, -f {png,jpg,bmp}
                        Image format (default: PNG)
  --size SIZE           Pixel width per "box" of the QR (default: 5)
  --border BORDER       Border width in "boxes" (at least 4 is required by the
                        standards)

This tool is provided AS-IS and no support or warranty is given or implied.

Overlay Images

The tool will overlay a suitably sized PNG file over your QR code. You specify the file to overlay from the command line, e.g. --overlay overlay.png.

Important: The overlay is placed AS IS, not resized at ALL. If it is too large, the QR code may not work. Test a few codes to make sure it's not interfering - the amount of text in the QR code controls how well the image will work.

For --size=4, I found a 60x60 image worked quite well. Transparency is preserved.

Images in QR codes work because of QR code error correction. They're obscuring a bit of the code, but with error correction on, the code keeps repeating itself as many times as will fit, to ensure the code can be read.

Size / Border

The --size parameter controls how many pixels make up the width of a QR's "pixel". The default size is 5; experiment and see. See the pyqrcode docs for more info.

Changing the --size parameter will not scale your image.

According to the specifications, the QR code needs a border to work properly. The default setting should suffice.

Input

The text to generate is specified either as one or more arguments, or by using the special syntax @filename to read them from a file.

You can use the switch --prefix "sometext" to prepend something to the text, and --suffix to add something to the end.

For example, you can do:

python qrgen.py make-this-code another-code "this one has a space" "hello there" etc

Or you could also do this:

python qrgen.py --prefix "http://print-server/mr/" @printers.txt

Where the contents of printers.txt is one printer name per line.

Output

One QR code is generated per inputted filename. The filename is the same as the string generated, with some unsafe characters removed. The --prefix isn't included in the name of the file.

--format controls the format of the file. The default is PNG.

Example

To generate a bunch of QR codes going to http://print-server:9191/mr/this-printer from the file printers.txt, at size 4, with the image overlay.png embedded in the center:

python qrgen.py --prefix "http://print-server:9191/mr/" --overlay overlay.png --size 4 @printers.txt

It will write out one PNG per line in printers.txt to the current directory.

Good luck!