Python：如何在PyQt中的图像上绘制对象

Question

我通过GridLabel制作应用程序和位置对象。我的细胞中有灰色的藻类。现在我想只在这个灰色单元格上绘制矩形。但它只能在这张灰色图片下淹没，并且也会从这个细胞的边界中划出。我是如何编写这部分代码的，它可以让我在这个灰色图像上绘制而不是从它的边界出来？

from PyQt4 import QtGui, QtCore
import sys, os

class Example(QtGui.QWidget):

def __init__(self,parent):
    super(Example, self).__init__()
    self.main_image_name="main_image.png"
    self.mode = 5

    self.initUI()

def initUI(self):
    File_name = QtGui.QLabel('Setup file name')
    File_name_edit = QtGui.QLineEdit()
    QtGui.QToolTip.setFont(QtGui.QFont('SansSerif', 10))
    #QMainWindow.statusBar().showMessage('Ready')
    self.setGeometry(300, 300, 250, 150)        
    self.resize(640, 360)
    self.center()
    self.main_image = QtGui.QLabel(self)
    self.main_image.setPixmap(QtGui.QPixmap(self.main_image_name))        
    btn = QtGui.QPushButton("Make setup file")    
    btn.setToolTip('Press <b>Detect</b> button for detecting objects by your settings')
    btn.resize(btn.sizeHint())
    btn.clicked.connect(QtCore.QCoreApplication.instance().quit)
    btn_browse = QtGui.QPushButton("Browse")
    btn_browse.clicked.connect(self.browse)
    btn_set = QtGui.QPushButton("Set name")
    #fullscreen
    #self.main_image.setScaledContents(True)
    #just centered
    self.main_image.setAlignment(QtCore.Qt.AlignCenter)



    #Layout
    box_File_name = QtGui.QHBoxLayout()
    box_File_name.addWidget(File_name)
    box_File_name.addWidget(File_name_edit)
    box_File_name.addWidget(btn_set)
    grid = QtGui.QGridLayout()
    grid.setSpacing(10)
    grid.addLayout(box_File_name, 1, 0)
    #grid.addWidget(File_name_edit, 1, 1)
    grid.addWidget(self.main_image, 2, 0)
    grid.addWidget(btn_browse, 3 , 0)
    grid.addWidget(btn, 4, 0)

    box_number = QtGui.QVBoxLayout()
    number_group=QtGui.QButtonGroup() # Number group
    r0=QtGui.QRadioButton("Traffic Lights")
    number_group.addButton(r0)
    r1=QtGui.QRadioButton("Direction")
    number_group.addButton(r1)
    r2=QtGui.QRadioButton("Traffic Lines H")
    number_group.addButton(r2)
    r3=QtGui.QRadioButton("Traffic Lines V")
    number_group.addButton(r3)
    box_number.addWidget(r0)
    box_number.addWidget(r1)
    box_number.addWidget(r2)
    box_number.addWidget(r3)

    r0.toggled.connect(self.radio0_clicked)
    r1.toggled.connect(self.radio1_clicked)
    r2.toggled.connect(self.radio2_clicked)
    r3.toggled.connect(self.radio3_clicked)

    box_road_sign = QtGui.QHBoxLayout()
    road_sign_label = QtGui.QLabel('Road signs', self)
    road_sign = QtGui.QComboBox()
    road_sign.addItem("None")
    road_sign.addItem("ex1")
    road_sign.addItem("ex2")
    road_sign.addItem("ex3")
    road_sign.addItem("ex4")
    road_sign.addItem("ex5")
    box_road_sign.addWidget(road_sign_label)
    box_road_sign.addWidget(road_sign)
    grid.addLayout(box_road_sign, 1, 1)
    grid.addLayout(box_number, 2, 1)
    self.setLayout(grid)

    self.show()
def browse(self):
    w = QtGui.QWidget()
    w.resize(320, 240)
    w.setWindowTitle("Select Picture")
    filename = QtGui.QFileDialog.getOpenFileName(w, 'Open File', '/')
    self.main_image_name = filename
    self.main_image.setPixmap(QtGui.QPixmap(self.main_image_name))

def center(self):

    qr = self.frameGeometry()
    cp = QtGui.QDesktopWidget().availableGeometry().center()
    qr.moveCenter(cp)
    self.move(qr.topLeft())


def radio0_clicked(self, enabled):
    if enabled:
        print "0"
        self.mode=0

def radio1_clicked(self, enabled):
    if enabled:
        print "1"
        self.mode=1

def radio2_clicked(self, enabled):
    if enabled:
        print "2"
        self.mode=2

def radio3_clicked(self, enabled):
    if enabled:
        print "3"
        self.mode=3

def paintEvent( self, event) :

                    ????

class menubarex(QtGui.QMainWindow):
    def __init__(self, parent=None):
        super(menubarex, self).__init__(parent)
        self.form_widget = Example(self) 
        self.setCentralWidget(self.form_widget)

    self.initUI()

def initUI(self):        
    exitAction = QtGui.QAction(QtGui.QIcon('exit.png'), '&Exit', self)        
    exitAction.setShortcut('Ctrl+Q')
    exitAction.setStatusTip('Exit application')
    exitAction.triggered.connect(QtGui.qApp.quit)
    menubar = self.menuBar()
    fileMenu = menubar.addMenu('&File')
    fileMenu.addAction(exitAction)

    #self.toolbar = self.addToolBar('Exit')
    #self.toolbar.addAction(exitAction)

    self.statusBar().showMessage('Ready')
    self.setWindowTitle('mi ban')        
    self.setWindowIcon(QtGui.QIcon('icon.png'))

def closeEvent(self, event):

    reply = QtGui.QMessageBox.question(self, 'Message',
        "Are you sure to quit?", QtGui.QMessageBox.Yes | 
        QtGui.QMessageBox.No)

    if reply == QtGui.QMessageBox.Yes:
        event.accept()
    else:
        event.ignore()

def main():

app = QtGui.QApplication(sys.argv)
#ex = Example()
menubar = menubarex()
menubar.show()
sys.exit(app.exec_())
main()

Answer 1

您应该编写自己的Qlabel类：

class myQLabel(QLabel):
   def __init__(self,parent=None):
        super(myQLabel, self).__init__(parent)

    def paintEvent(self, QPaintEvent):
        super(myQLabel, self).paintEvent(QPaintEvent)
        painter = QPainter(self)
        painter.setPen(QPen(Qt.red))
        painter.drawArc(QRectF(50, 50, 10, 10), 0, 5760)
        painter.drawRect(QRectF(50, 50, 100, 100) )

然后使用它：

self.main_image = myQLabel(self)

还删除了def paintEvent（self，event）：在Example类

中

我使用pyqt5所以我改变了一点代码：

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

class myQLabel(QLabel):
    def __init__(self,parent=None):
        super(myQLabel, self).__init__(parent)

    def paintEvent(self, QPaintEvent):
        super(myQLabel, self).paintEvent(QPaintEvent)
        painter = QPainter(self)
        painter.setPen(QPen(Qt.red))
        painter.drawArc(QRectF(50, 50, 10, 10), 0, 5760)
        painter.drawRect(QRectF(50, 50, 100, 100) )

class Example(QWidget):

    def __init__(self,parent):
        super(Example, self).__init__()
        self.main_image_name="icons\\add.png"
        self.mode = 5

        self.initUI()

    def initUI(self):
        File_name = QLabel('Setup file name')
        File_name_edit = QLineEdit()
        QToolTip.setFont(QFont('SansSerif', 10))
        #QMainWindow.statusBar().showMessage('Ready')
        self.setGeometry(300, 300, 250, 150)
        self.resize(640, 360)
        self.center()
        self.main_image = myQLabel(self)
        self.main_image.setPixmap(QPixmap(self.main_image_name))
        btn = QPushButton("Make setup file")
        btn.setToolTip('Press <b>Detect</b> button for detecting objects by your settings')
        btn.resize(btn.sizeHint())
        btn.clicked.connect(QCoreApplication.instance().quit)
        btn_browse = QPushButton("Browse")
        btn_browse.clicked.connect(self.browse)
        btn_set = QPushButton("Set name")
        #fullscreen
        #self.main_image.setScaledContents(True)
        #just centered
        self.main_image.setAlignment(Qt.AlignCenter)



        #Layout
        box_File_name = QHBoxLayout()
        box_File_name.addWidget(File_name)
        box_File_name.addWidget(File_name_edit)
        box_File_name.addWidget(btn_set)
        grid = QGridLayout()
        grid.setSpacing(10)
        grid.addLayout(box_File_name, 1, 0)
        #grid.addWidget(File_name_edit, 1, 1)
        grid.addWidget(self.main_image, 2, 0)
        grid.addWidget(btn_browse, 3 , 0)
        grid.addWidget(btn, 4, 0)

        box_number = QVBoxLayout()
        number_group=QButtonGroup() # Number group
        r0=QRadioButton("Traffic Lights")
        number_group.addButton(r0)
        r1=QRadioButton("Direction")
        number_group.addButton(r1)
        r2=QRadioButton("Traffic Lines H")
        number_group.addButton(r2)
        r3=QRadioButton("Traffic Lines V")
        number_group.addButton(r3)
        box_number.addWidget(r0)
        box_number.addWidget(r1)
        box_number.addWidget(r2)
        box_number.addWidget(r3)

        r0.toggled.connect(self.radio0_clicked)
        r1.toggled.connect(self.radio1_clicked)
        r2.toggled.connect(self.radio2_clicked)
        r3.toggled.connect(self.radio3_clicked)

        box_road_sign = QHBoxLayout()
        road_sign_label = QLabel('Road signs', self)
        road_sign = QComboBox()
        road_sign.addItem("None")
        road_sign.addItem("ex1")
        road_sign.addItem("ex2")
        road_sign.addItem("ex3")
        road_sign.addItem("ex4")
        road_sign.addItem("ex5")
        box_road_sign.addWidget(road_sign_label)
        box_road_sign.addWidget(road_sign)
        grid.addLayout(box_road_sign, 1, 1)
        grid.addLayout(box_number, 2, 1)
        self.setLayout(grid)

        self.show()
    def browse(self):
        w = QWidget()
        w.resize(320, 240)
        w.setWindowTitle("Select Picture")
        filename = QFileDialog.getOpenFileName(w, 'Open File', '/')
        self.main_image_name = filename
        self.main_image.setPixmap(QPixmap(self.main_image_name))

    def center(self):

        qr = self.frameGeometry()
        cp = QDesktopWidget().availableGeometry().center()
        qr.moveCenter(cp)
        self.move(qr.topLeft())


    def radio0_clicked(self, enabled):
        if enabled:
            print("0")
            self.mode=0

    def radio1_clicked(self, enabled):
        if enabled:
            print("1")
            self.mode=1

    def radio2_clicked(self, enabled):
        if enabled:
            print("2")
            self.mode=2

    def radio3_clicked(self, enabled):
        if enabled:
            print("3")
            self.mode=3

    # def paintEvent( self, event) :
    #     pass

class menubarex(QMainWindow):
    def __init__(self, parent=None):
        super(menubarex, self).__init__(parent)
        self.form_widget = Example(self)
        self.setCentralWidget(self.form_widget)

        self.initUI()

    def initUI(self):
        exitAction = QAction(QIcon('exit.png'), '&Exit', self)
        exitAction.setShortcut('Ctrl+Q')
        exitAction.setStatusTip('Exit application')
        exitAction.triggered.connect(qApp.quit)
        menubar = self.menuBar()
        fileMenu = menubar.addMenu('&File')
        fileMenu.addAction(exitAction)

        #self.toolbar = self.addToolBar('Exit')
        #self.toolbar.addAction(exitAction)

        self.statusBar().showMessage('Ready')
        self.setWindowTitle('mi ban')
        self.setWindowIcon(QIcon('icon.png'))

    def closeEvent(self, event):

        reply = QMessageBox.question(self, 'Message',
            "Are you sure to quit?", QMessageBox.Yes |
            QMessageBox.No)

        if reply == QMessageBox.Yes:
            event.accept()
        else:
            event.ignore()

def main():
    app = QApplication(sys.argv)
    #ex = Example()
    menubar = menubarex()
    menubar.show()
    sys.exit(app.exec_())

if __name__ == '__main__':
    main()

给我：