How to make widgets scale with the window in PyQt5?

Question

I'm trying to set up a GUI which will include multiple pages in PyQt5. The window will have a minimum size of 800x600, but is customisable beyond that. I want most, but not all, elements on the window to scale along with it. I have a solution already, but I feel that it is not very elegant.

Here is an example of the window at 800x600:

And here's another example after scaling

I've tried using QVBoxLayout, but with that system, I can't manage to keep the layout as it is here (not to say that it's impossible), rather the widgets all become centred and of the same width. At a later date, I might also be looking at adding widgets to the side that will be at the same y-value as some of the existing widgets, which is another thing that I'm not sure on how to do with the box layout.

Here's the relevant code:

class CreatePage(QWidget):
    def __init__(self, parent=None):
        super().__init__()
        self.initUI()

    def initUI(self):
        self.homeBtn = QPushButton("Home", self)
        self.homeBtn.move(10, 10)

        self.frontLabel = QLabel("Front", self)
        self.frontLabel.setFont(QFont("Decorative", 20))

        self.frontEdit = QTextEdit(self)
        self.frontEdit.setFont(QFont("Decorative", 11))

        self.backLabel = QLabel("Back", self)
        self.backLabel.setFont(QFont("Decorative", 20))

        self.backEdit = QTextEdit(self)
        self.backEdit.setFont(QFont("Decorative", 11))

    def paintEvent(self, e):
        qp = QPainter()
        qp.setFont(QFont("Decorative", 20))

        size = self.size()
        h = size.height()
        w = size.width()

        frontW = qp.fontMetrics().width("Front")
        self.frontLabel.move((w/2) - (frontW/2) , h/15)
        #I use fontMetrics to determine the width of the text
        #I then use this information to centre the text

        self.frontEdit.move(50, h/15 + 40)
        self.frontEdit.resize(w-100, h/3)

        backW = qp.fontMetrics().width("Back")
        self.backLabel.move((w/2) - (backW/2), h/2)

        self.backEdit.move(50, h/2 + 40)
        self.backEdit.resize(w-100, h/3)

Apologies for any general sloppiness, I am new to PyQt and to GUI programming on the whole. Anyway, the formulas I've used for resizing and moving widgets are quite arbitrary. Does anyone know a better way of achieving this effect?

Answer 1

Try it:

import sys
from PyQt5.QtWidgets import *
from PyQt5.QtCore    import *
from PyQt5.QtGui     import *

class CreatePage(QWidget):
    def __init__(self, parent=None):
        super().__init__()
        self.initUI()

    def initUI(self):
        self.homeBtn = QPushButton("Home") 

        self.frontLabel = QLabel("Front") 
        self.frontLabel.setFont(QFont("Decorative", 20))
        self.frontEdit = QTextEdit(placeholderText="frontEdit") 
        self.frontEdit.setFont(QFont("Decorative", 11))

        self.backLabel = QLabel("Back") 
        self.backLabel.setFont(QFont("Decorative", 20))
        self.backEdit = QTextEdit(placeholderText="backEdit") 
        self.backEdit.setFont(QFont("Decorative", 11))

        grid = QGridLayout()
        grid.addWidget(self.homeBtn,    0, 0, alignment=Qt.AlignTop | Qt.AlignLeft)
        grid.addWidget(self.frontLabel, 1, 0, alignment=Qt.AlignCenter)
        grid.addWidget(self.frontEdit,  2, 0)
        grid.addWidget(self.backLabel,  3, 0, alignment=Qt.AlignCenter)
        grid.addWidget(self.backEdit,   4, 0)

        self.setLayout(grid)

if __name__=="__main__":
    app = QApplication(sys.argv)
    myapp = CreatePage()
    myapp.show()
    sys.exit(app.exec_())