Python 如何在PyQt5图像上用画笔画线

我想在已经打开的图像上画一条线（或绘画）。我可以打开图像，但不能在图像上画画。但如果我不打开任何图像，我可以在空白处画任何我想要的东西

那么，我如何用画笔在图像上画画呢？就目前而言，橡皮擦之类的东西并不重要。我只想用画笔在图像上做点什么，我已经在电脑上打开了

我没有得到任何错误或什么。所以我不能具体搜索

这是我的密码

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)

        closeAction = QAction('Exit', self)
        closeAction.triggered.connect(self.close)
        fileMenu.addAction(closeAction)
        self.label = QLabel()
        self.setCentralWidget(self.label)


        saveAction = QAction(QIcon("icons/save.png"), "Save",self)
        saveAction.setShortcut("Ctrl+S")
        fileMenu.addAction(saveAction)
        saveAction.triggered.connect(self.save)

        clearAction = QAction(QIcon("icons/clear.png"), "Clear", self)
        clearAction.setShortcut("Ctrl+C")
        fileMenu.addAction(clearAction)
        clearAction.triggered.connect(self.clear)

        threepxAction = QAction( QIcon("icons/threepx.png"), "3px", self)
        brushSize.addAction(threepxAction)
        threepxAction.triggered.connect(self.threePixel)

        fivepxAction = QAction(QIcon("icons/fivepx.png"), "5px", self)
        brushSize.addAction(fivepxAction)
        fivepxAction.triggered.connect(self.fivePixel)

        sevenpxAction = QAction(QIcon("icons/sevenpx.png"),"7px", self)
        brushSize.addAction(sevenpxAction)
        sevenpxAction.triggered.connect(self.sevenPixel)

        ninepxAction = QAction(QIcon("icons/ninepx.png"), "9px", self)
        brushSize.addAction(ninepxAction)
        ninepxAction.triggered.connect(self.ninePixel)

        blackAction = QAction(QIcon("icons/black.png"), "Black", self)
        blackAction.setShortcut("Ctrl+B")
        brushColor.addAction(blackAction)
        blackAction.triggered.connect(self.blackColor)


        whitekAction = QAction(QIcon("icons/white.png"), "White", self)
        whitekAction.setShortcut("Ctrl+W")
        brushColor.addAction(whitekAction)
        whitekAction.triggered.connect(self.whiteColor)


        redAction = QAction(QIcon("icons/red.png"), "Red", self)
        redAction.setShortcut("Ctrl+R")
        brushColor.addAction(redAction)
        redAction.triggered.connect(self.redColor)

        greenAction = QAction(QIcon("icons/green.png"), "Green", self)
        greenAction.setShortcut("Ctrl+G")
        brushColor.addAction(greenAction)
        greenAction.triggered.connect(self.greenColor)

        yellowAction = QAction(QIcon("icons/yellow.png"), "Yellow", self)
        yellowAction.setShortcut("Ctrl+Y")
        brushColor.addAction(yellowAction)
        yellowAction.triggered.connect(self.yellowColor)


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

    def mousePressEvent(self, event):
        if event.button() == Qt.LeftButton:
            self.drawing = True
            self.lastPoint = event.pos()
            #print(self.lastPoint)


    def mouseMoveEvent(self, event):
        if(event.buttons() & Qt.LeftButton) & self.drawing:
            painter = QPainter(self.image)
            painter.setPen(QPen(self.brushColor, self.brushSize, Qt.SolidLine, Qt.RoundCap, Qt.RoundJoin))
            painter.drawLine(self.lastPoint, event.pos())
            self.lastPoint = event.pos()
            self.update()



    def mouseReleaseEvent(self, event):

        if event.button() == Qt.LeftButton:
            self.drawing = False


    def paintEvent(self, event):
        canvasPainter  = QPainter(self)
        canvasPainter.drawImage(self.rect(),self.image, self.image.rect() )





    def save(self):
        filePath, _ = QFileDialog.getSaveFileName(self, "Save Image", "", "PNG(*.png);;JPEG(*.jpg *.jpeg);;All Files(*.*) ")

        if filePath == "":
            return
        self.image.save(filePath)



    def clear(self):
        self.image.fill(Qt.white)
        self.update()


    def threePixel(self):
        self.brushSize = 3

    def fivePixel(self):
        self.brushSize = 5

    def sevenPixel(self):
        self.brushSize = 7

    def ninePixel(self):
        self.brushSize = 9


    def blackColor(self):
        self.brushColor = Qt.black

    def whiteColor(self):
        self.brushColor = Qt.white

    def redColor(self):
        self.brushColor = Qt.red

    def greenColor(self):
        self.brushColor = Qt.green

    def yellowColor(self):
        self.brushColor = Qt.yellow




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

---

与其从文件路径构造QPixmap，不如构造一个QImage并将其分配给变量

self.image

。您无需更改任何其他内容，因为

paintEvent

将绘制由

self.image

指向的QImage对象

def openImage(self):
    imagePath, _ = QFileDialog.getOpenFileName()
    self.image = QImage(imagePath)
    self.resize(self.image.size())