Building QR Code Generator Application using PyQt5
Last Updated :
05 Sep, 2024
In this article, we will see how we can make a QR code generator application using PyQt5. A QR code is a type of matrix barcode first designed in 1994 for the automotive industry in Japan. A barcode is a machine-readable optical label that contains information about the item to which it is attached. Below is how the application will look like
Required Installation
PyQt5 is a cross-platform GUI toolkit, a set of Python bindings for PyQt v5. One can develop an interactive desktop application with so much ease because of the tools and simplicity provided by this library. Below is the command to install the PyQt5
pip install PyQt5
qrcode: For generating 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). Below is the command to install the qrcode module:
pip install qrcode
Steps to Build QR Code Generator in Python
- Create a Image class which inherits qrcode base image
- Inside the Image class, get the size from the border and width and override the painter event and create a initial image and fill it with white color
- Create a main window class
- Inside the window class create a label which will show the QR code image
- Create a line edit to receive the text from the user
- Add label and line edit to the vertical layout and set layout to the window
- Add action to the line edit when entered is pressed
- Inside the line edit action get the text of the line edit
- Create a pixmap image of the line edit text and use Image class as image_factory
- Set the pixmap i.e QR code image to the label
Python
# importing libraries
from PyQt5.QtWidgets import *
from PyQt5 import QtCore, QtGui
from PyQt5.QtGui import *
from PyQt5.QtCore import *
import qrcode
import sys
# Image class for QR code
class Image(qrcode.image.base.BaseImage):
# constructor
def __init__(self, border, width, box_size, qrcode_modules):
# assigning border
self.border = border
# assigning width
self.width = width
# assigning box size
self.box_size = box_size
# creating size
size = (width + border * 2) * box_size
# image
self._image = QImage(size, size, QImage.Format_RGB16)
# initial image as white
self._image.fill(Qt.white)
# pixmap method
def pixmap(self):
# returns image
return QPixmap.fromImage(self._image)
# drawrect method for drawing rectangle
def drawrect(self, row, col):
# creating painter object
painter = QPainter(self._image)
# drawing rectangle
painter.fillRect(
(col + self.border) * self.box_size,
(row + self.border) * self.box_size,
self.box_size, self.box_size,
QtCore.Qt.black)
# Main Window class
class Window(QMainWindow):
# constructor
def __init__(self):
QMainWindow.__init__(self)
# setting window title
self.setWindowTitle("QR Code")
# setting geometry
self.setGeometry(100, 100, 300, 300)
# creating a label to show the qr code
self.label = QLabel(self)
# creating a line edit to receive text
self.edit = QLineEdit(self)
# adding action when entered is pressed
self.edit.returnPressed.connect(self.handleTextEntered)
# setting font to the line edit
self.edit.setFont(QFont('Times', 9))
# setting alignment
self.edit.setAlignment(Qt.AlignCenter)
# creating a vertical layout
layout = QVBoxLayout(self)
# adding label to the layout
layout.addWidget(self.label)
# adding line edit to the layout
layout.addWidget(self.edit)
# creating a QWidget object
widget = QWidget()
# setting layout to the widget
widget.setLayout(layout)
# setting widget as central widget to the main window
self.setCentralWidget(widget)
# method called by the line edit
def handleTextEntered(self):
# get the text
text = self.edit.text()
# creating a pix map of qr code
qr_image = qrcode.make(text, image_factory = Image).pixmap()
# set image to the label
self.label.setPixmap(qr_image)
# create pyqt5 app
app = QApplication(sys.argv)
# create the instance of our Window
window = Window()
# showing window
window.show()
# start the app
sys.exit(app.exec_())
Output:
When user entered the text in the line edit and press enter key, QR code will be displayed and window size will get adjusted according to the size of QR code