lincolnloop/python-qrcode

============================= Pure python QR Code generator

Generate QR codes.

A standard install uses pypng_ to generate PNG files and can also render QR codes directly to the console. A standard install is just::

pip install qrcode

For more image functionality, install qrcode with the pil dependency so that pillow_ is installed and can be used for generating images::

pip install "qrcode[pil]"

.. _pypng: https://pypi.python.org/pypi/pypng .. _pillow: https://pypi.python.org/pypi/Pillow

What is a QR Code?

A Quick Response code is a two-dimensional pictographic code used for its fast readability and comparatively large storage capacity. The code consists of black modules arranged in a square pattern on a white background. The information encoded can be made up of any kind of data (e.g., binary, alphanumeric, or Kanji symbols)

Usage

From the command line, use the installed qr script::

qr "Some text" > test.png

Or in Python, use the make shortcut function:

.. code:: python

import qrcode
img = qrcode.make('Some data here')
type(img)  # qrcode.image.pil.PilImage
img.save("some_file.png")

Advanced Usage

For more control, use the QRCode class. For example:

.. code:: python

import qrcode
qr = qrcode.QRCode(
    version=1,
    error_correction=qrcode.constants.ERROR_CORRECT_L,
    box_size=10,
    border=4,
)
qr.add_data('Some data')
qr.make(fit=True)

img = qr.make_image(fill_color="black", back_color="white")

The version parameter is an integer from 1 to 40 that controls the size of the QR Code (the smallest, version 1, is a 21x21 matrix). Set to None and use the fit parameter when making the code to determine this automatically.

fill_color and back_color can change the background and the painting color of the QR, when using the default image factory. Both parameters accept RGB color tuples.

.. code:: python

img = qr.make_image(back_color=(255, 195, 235), fill_color=(55, 95, 35))

The error_correction parameter controls the error correction used for the QR Code. The following four constants are made available on the qrcode package:

ERROR_CORRECT_L About 7% or less errors can be corrected. ERROR_CORRECT_M (default) About 15% or less errors can be corrected. ERROR_CORRECT_Q About 25% or less errors can be corrected. ERROR_CORRECT_H. About 30% or less errors can be corrected.

The box_size parameter controls how many pixels each "box" of the QR code is.

The border parameter controls how many boxes thick the border should be (the default is 4, which is the minimum according to the specs).

Other image factories

You can encode as SVG, or use a new pure Python image processor to encode to PNG images.

The Python examples below use the make shortcut. The same image_factory keyword argument is a valid option for the QRCode class for more advanced usage.

SVG

You can create the entire SVG or an SVG fragment. When building an entire SVG image, you can use the factory that combines as a path (recommended, and default for the script) or a factory that creates a simple set of rectangles.

From your command line::

qr --factory=svg-path "Some text" > test.svg
qr --factory=svg "Some text" > test.svg
qr --factory=svg-fragment "Some text" > test.svg

Or in Python:

.. code:: python

import qrcode
import qrcode.image.svg

method = input("What method? (basic, fragment, path): ")

if method == 'basic':
    # Simple factory, just a set of rects.
    factory = qrcode.image.svg.SvgImage
elif method == 'fragment':
    # Fragment factory (no standalone header)
    factory = qrcode.image.svg.SvgFragmentImage
else:
    # Combined path factory, fixes white space that may occur when zooming
    factory = qrcode.image.svg.SvgPathImage

img = qrcode.make('Some data here', image_factory=factory)

img.save('some_file.svg')

Two other related factories are available that work the same, but also fill the background of the SVG with white::

qrcode.image.svg.SvgFillImage
qrcode.image.svg.SvgPathFillImage

The QRCode.make_image() method forwards additional keyword arguments to the underlying ElementTree XML library. This helps to fine tune the root element of the resulting SVG:

.. code:: python

import qrcode
qr = qrcode.QRCode(image_factory=qrcode.image.svg.SvgPathImage)
qr.add_data('Some data')
qr.make(fit=True)

img = qr.make_image(attrib={'class': 'some-css-class'})

You can convert the SVG image into strings using the to_string() method. Additional keyword arguments are forwarded to ElementTrees tostring():

.. code:: python

img.to_string(encoding='unicode')

Pure Python PNG

If Pillow is not installed, the default image factory will be a pure Python PNG encoder that uses pypng.

You can use the factory explicitly from your command line::

qr --factory=png "Some text" > test.png

Or in Python:

.. code:: python

import qrcode
from qrcode.image.pure import PyPNGImage
img = qrcode.make('Some data here', image_factory=PyPNGImage)

Styled Image

Works only with versions_ >=7.2 (SVG styled images require 7.4).

.. _versions: https://github.com/lincolnloop/python-qrcode/blob/master/CHANGES.rst#72-19-july-2021

To apply styles to the QRCode, use the StyledPilImage or one of the standard SVG_ image factories. These accept an optional module_drawer parameter to control the shape of the QR Code.

These QR Codes are not guaranteed to work with all readers, so do some experimentation and set the error correction to high (especially if embedding an image).

Other PIL module drawers:

.. image:: doc/module_drawers.png

For SVGs, use SvgSquareDrawer, SvgCircleDrawer, SvgPathSquareDrawer, or SvgPathCircleDrawer.

These all accept a size_ratio argument which allows for "gapped" squares or circles by reducing this less than the default of Decimal(1).

The StyledPilImage additionally accepts an optional color_mask parameter to change the colors of the QR Code, and an optional embedded_image_path to embed an image in the center of the code.

Other color masks:

.. image:: doc/color_masks.png

Here is a code example to draw a QR code with rounded corners, radial gradient and an embedded image:

.. code:: python

import qrcode
from qrcode.image.styledpil import StyledPilImage
from qrcode.image.styles.moduledrawers.pil import RoundedModuleDrawer
from qrcode.image.styles.colormasks import RadialGradiantColorMask

qr = qrcode.QRCode(error_correction=qrcode.constants.ERROR_CORRECT_H)
qr.add_data('Some data')

img_1 = qr.make_image(image_factory=StyledPilImage, module_drawer=RoundedModuleDrawer())
img_2 = qr.make_image(image_factory=StyledPilImage, color_mask=RadialGradiantColorMask())
img_3 = qr.make_image(image_factory=StyledPilImage, embedded_image_path="/path/to/image.png")

Examples

Get the text content from print_ascii:

.. code:: python

import io
import qrcode
qr = qrcode.QRCode()
qr.add_data("Some text")
f = io.StringIO()
qr.print_ascii(out=f)
f.seek(0)
print(f.read())

The add_data method will append data to the current QR object. To add new data by replacing previous content in the same object, first use clear method:

.. code:: python

import qrcode
qr = qrcode.QRCode()
qr.add_data('Some data')
img = qr.make_image()
qr.clear()
qr.add_data('New data')
other_img = qr.make_image()

Pipe ascii output to text file in command line::

qr --ascii "Some data" > "test.txt"
cat test.txt

Alternative to piping output to file to avoid PowerShell issues::

# qr "Some data" > test.png
qr --output=test.png "Some data"