PyQt5实现鼠标绘制的界面

 功能：使用户能够使用鼠标绘制数字，当按下鼠标按钮时，应用程序将开始绘制，直到释放按钮为止，同时实时显示鼠标所在的位置。

class Drawer(QWidget):
    newPoint = pyqtSignal(QPoint)
    def __init__(self, parent=None):
        QWidget.__init__(self, parent)
        self.path = QPainterPath()    

    def paintEvent(self, event):
        painter = QPainter(self)
        painter.drawPath(self.path)

    def mousePressEvent(self, event):
        self.path.moveTo(event.pos())
        self.update()

    def mouseMoveEvent(self, event):
        self.path.lineTo(event.pos())
        self.newPoint.emit(event.pos())
        self.update()

    def sizeHint(self):
        return QSize(400, 400)

class MyWidget(QWidget):
    def __init__(self, parent=None):
        QWidget.__init__(self, parent)
        self.setLayout(QVBoxLayout())
        label = QLabel(self)
        drawer = Drawer(self)
        drawer.newPoint.connect(lambda p: label.setText('Coordinates: ( %d : %d )' % (p.x(), p.y())))
        self.layout().addWidget(label)
        self.layout().addWidget(drawer)

if __name__ == '__main__':
    app = QApplication(sys.argv)
    w = MyWidget()
    w.show()
    sys.exit(app.exec_())

效果图：