Open Image & Draw on it

Question

I'm trying to create an application with functionality similar to MS paint using Python 3.8. However, I am unable to upon up the image in the MainWindow. This is the code that I have so far:

from PyQt5.QtWidgets import QMainWindow, QApplication, QMenu, QMenuBar, QAction, QFileDialog
from PyQt5.QtGui import QIcon, QImage, QPainter, QPen, QBrush
from PyQt5.QtCore import Qt, QPoint
import sys


class Window(QMainWindow):
    def __init__(self):
        super().__init__()

        title = "Paint Application"
        top = 400
        left = 400
        width = 800
        height = 600

        icon = "icons/pain.png"

        self.setWindowTitle(title)
        self.setGeometry(top, left, width, height)
        self.setWindowIcon(QIcon(icon))

        self.image = QImage(self.size(), QImage.Format_RGB32)
        self.image.fill(Qt.white)

        self.drawing = False
        self.brushSize = 2
        self.brushColor = Qt.black
        self.lastPoint = QPoint()

        mainMenu = self.menuBar()
        fileMenu = mainMenu.addMenu("File")
        brushSize = mainMenu.addMenu("Brush Size")
        brushColor = mainMenu.addMenu("Brush Color")

        openAction = QAction('Open Image', self)
        openAction.triggered.connect(self.openImage)
        fileMenu.addAction(openAction)

    def openImage(self):
        imagePath, _ = QFileDialog.getOpenFileName()
        pixmap = QPixmap(imagePath)
        self.label.setPixmap(pixmap)
        self.resize(pixmap.size())
        self.adjustSize()


if __name__ == "__main__":
    app = QApplication(sys.argv)
    window = Window()
    window.show()
    app.exec()

However, the program does not open the images, as instructed by QAction. What am I doing wrong?

Answer 1

A few things:

• Use app.exec_(), not app.exec()
• Create the label before showing the window
• Resize the label after loading the image

This code will show the image:

from PyQt5.QtWidgets import QMainWindow, QApplication, QMenu, QMenuBar, QAction, QFileDialog, QLabel
from PyQt5.QtGui import QIcon, QImage, QPainter, QPen, QBrush, QPixmap
from PyQt5.QtCore import Qt, QPoint
import sys

class Window(QMainWindow):
    def __init__(self):
        super().__init__()

        title = "Paint Application"
        top = 400
        left = 400
        width = 800
        height = 600

        icon = "icons/pain.png"

        self.setWindowTitle(title)
        self.setGeometry(top, left, width, height)
        self.setWindowIcon(QIcon(icon))

        self.image = QImage(self.size(), QImage.Format_RGB32)
        self.image.fill(Qt.white)

        self.drawing = False
        self.brushSize = 2
        self.brushColor = Qt.black
        self.lastPoint = QPoint()

        mainMenu = self.menuBar()
        fileMenu = mainMenu.addMenu("File")
        brushSize = mainMenu.addMenu("Brush Size")
        brushColor = mainMenu.addMenu("Brush Color")

        openAction = QAction('Open Image', self)
        openAction.triggered.connect(self.openImage)
        fileMenu.addAction(openAction)
        self.label = QLabel(self)
        self.show()

    def openImage(self):
        imagePath, _ = QFileDialog.getOpenFileName()
        pixmap = QPixmap(imagePath)
        self.label.setPixmap(pixmap)
        self.resize(pixmap.size().width(),pixmap.size().height()+20) # 20 for menu
        self.label.setFixedSize(pixmap.size())
        self.label.move(0,20)  # below menu
        

if __name__ == "__main__":
    app = QApplication(sys.argv)
    window = Window()
    app.exec_()