[Python practical basis] Introduction to QPen of PyQt6 in Python

Table of contents

1. The actual combat scene

2. Main points of knowledge

file read and write

Basic grammar

PyQt6

QPen

Three, rookie combat

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1. The actual combat scene

Practical scenario: Introduction to QPen of PyQt6 in Python

2. Main points of knowledge

• file read and write

• Basic grammar

• PyQt6

• QPen

Three, rookie combat

QPen Is a basic graphics object that can draw lines, curves and outlines of shapes such as rectangles, ellipses, polygons, etc.

from PyQt6.QtWidgets import QWidget, QApplication
from PyQt6.QtGui import QPainter, QPen
from PyQt6.QtCore import Qt
import sys


class Example(QWidget):

    def __init__(self):
        super().__init__()

        self.initUI()


    def initUI(self):

        self.setGeometry(300, 300, 280, 270)
        self.setWindowTitle('Pen styles')
        self.show()


    def paintEvent(self, e):

        qp = QPainter()
        qp.begin(self)
        self.drawLines(qp)
        qp.end()


    def drawLines(self, qp):

        pen = QPen(Qt.GlobalColor.black, 2, Qt.PenStyle.SolidLine)

        qp.setPen(pen)
        qp.drawLine(20, 40, 250, 40)

        pen.setStyle(Qt.PenStyle.DashLine)
        qp.setPen(pen)
        qp.drawLine(20, 80, 250, 80)

        pen.setStyle(Qt.PenStyle.DashDotLine)
        qp.setPen(pen)
        qp.drawLine(20, 120, 250, 120)

        pen.setStyle(Qt.PenStyle.DotLine)
        qp.setPen(pen)
        qp.drawLine(20, 160, 250, 160)

        pen.setStyle(Qt.PenStyle.DashDotDotLine)
        qp.setPen(pen)
        qp.drawLine(20, 200, 250, 200)

        pen.setStyle(Qt.PenStyle.CustomDashLine)
        pen.setDashPattern([1, 4, 5, 4])
        qp.setPen(pen)
        qp.drawLine(20, 240, 250, 240)


def main():

    app = QApplication(sys.argv)
    ex = Example()
    sys.exit(app.exec())


if __name__ == '__main__':
    main()

In the example, we have drawn 6 lines. Lines are styled with six different stroke styles. There are five predefined strokes. We can also create custom stroke styles. The last line is styled using a custom stroke style.

pen = QPen(Qt.GlobalColor.black, 2, Qt.PenStyle.SolidLine)

Here an  QPen object is created, the color is black, and the width is 2 pixels, so that the different strokes can be distinguished. Qt.SolidLine is a predefined stroke.

pen.setStyle(Qt.PenStyle.CustomDashLine) pen.setDashPattern([1, 4, 5, 4]) qp.setPen(pen) 

Here we customize a stroke. The style is set to  Qt.PenStyle。CustomDashLine, use the  setDashPattern method to set the specific style, the parameters must be an even number, the odd number defines the dash, and the even number defines the space. The larger the number, the larger the space or dash. The settings here are 1px horizontal line, 4px space, 5px horizontal line, 4px space and so on.

Rookie combat, keep learning!