PyQt 自定义窗口部件（三）

from PyQt5.QtWidgets import (QApplication,QFrame, QLabel,QSizePolicy, QSpinBox, QWidget)
from PyQt5.QtGui import QColor,QPainter,QFontMetricsF,QBrush,QLinearGradient,QPolygon,QPolygonF
from PyQt5.QtCore import QPointF, QSize, Qt,pyqtSignal

class YPipeWidget(QWidget):
    signal_valuechanged = pyqtSignal(int,int)
    def __init__(self, leftFlow=0, rightFlow=0, maxFlow=100, parent=None):
        super(YPipeWidget, self).__init__(parent)
        
        self.leftSpinBox = QSpinBox(self)
        self.leftSpinBox.setRange(0, maxFlow)
        self.leftSpinBox.setValue(leftFlow)
        self.leftSpinBox.setSuffix(" l/s")#设置后缀
        self.leftSpinBox.setAlignment(Qt.AlignRight|Qt.AlignVCenter)
        self.leftSpinBox.valueChanged.connect(self.valueChanged)
        
        self.rightSpinBox = QSpinBox(self)
        self.rightSpinBox.setRange(0, maxFlow)
        self.rightSpinBox.setValue(rightFlow)
        self.rightSpinBox.setSuffix(" l/s")#设置后缀
        self.rightSpinBox.setAlignment(Qt.AlignRight|Qt.AlignVCenter)
        self.rightSpinBox.valueChanged.connect(self.valueChanged)
        self.label = QLabel(self)
        self.label.setFrameStyle(QFrame.StyledPanel|QFrame.Sunken)
        self.label.setAlignment(Qt.AlignCenter)
        fm = QFontMetricsF(self.font())
        self.label.setMinimumWidth(fm.width(" 999 l/s "))
        self.setSizePolicy(QSizePolicy(QSizePolicy.Expanding,QSizePolicy.Expanding))#横向竖向均可放大
        self.setMinimumSize(self.minimumSizeHint())
        self.valueChanged()

    def valueChanged(self):
        a = self.leftSpinBox.value()
        b = self.rightSpinBox.value()
        self.label.setText("{0} l/s".format(a + b))
        self.signal_valuechanged.emit(a,b)
        self.update()

    def values(self):
        return self.leftSpinBox.value(), self.rightSpinBox.value()
    def minimumSizeHint(self):
        return QSize(self.leftSpinBox.width() * 3,self.leftSpinBox.height() * 5)
    def resizeEvent(self, event=None):
        fm = QFontMetricsF(self.font())
        x = (self.width() - self.label.width()) / 2
        y = self.height() - (fm.height() * 1.5)
        self.label.move(x, y)
        y = self.height() / 60.0
        x = (self.width() / 4.0) - self.leftSpinBox.width()
        self.leftSpinBox.move(x, y)
        x = self.width() - (self.width() / 4.0)
        self.rightSpinBox.move(x, y)
    def paintEvent(self, event=None):
        LogicalSize = 100.0
        
        def logicalFromPhysical(length, side):
            return (length / side) * LogicalSize
        
        fm = QFontMetricsF(self.font())
        ymargin = ((LogicalSize / 30.0) +logicalFromPhysical(self.leftSpinBox.height(),self.height()))
        ymax = (LogicalSize - logicalFromPhysical(fm.height() * 2, self.height()))
        width = LogicalSize / 4.0
        #设置Y形管 9 个角点的坐标
        cx, cy = LogicalSize / 2.0, LogicalSize / 3.0
        ax, ay = cx - (2 * width), ymargin
        bx, by = cx - width, ay
        dx, dy = cx + width, ay
        ex, ey = cx + (2 * width), ymargin
        fx, fy = cx + (width / 2), cx + (LogicalSize / 24.0)
        gx, gy = fx, ymax
        hx, hy = cx - (width / 2), ymax
        ix, iy = hx, fy
        painter = QPainter(self)# 创建QPainter实例，注意self！
        painter.setRenderHint(QPainter.Antialiasing)#抗锯齿
        side = min(self.width(), self.height())
        #设置绘图“视口”（使用物理坐标系），参数（整形）分别为左上角的x和y，以及视口的宽和高
        painter.setViewport((self.width() - side) / 2, (self.height() - side) / 2, side, side)
        #设置绘图“窗口”（使用逻辑坐标系），参数（整形）分别为左上角的x和y，以及“窗口”的宽和高
        #之后逻辑坐标系 (Qpainter自动会将逻辑坐标按比例映射到物理坐标)
        painter.setWindow(0, 0, LogicalSize, LogicalSize)
        
        painter.setPen(Qt.NoPen) #无线条
        gradient = QLinearGradient(QPointF(0, 0),QPointF(0, 100))#线性梯度
        gradient.setColorAt(0, Qt.white)
        a = self.leftSpinBox.value()
        gradient.setColorAt(1, (Qt.red if a != 0 else Qt.white)) #流速非零时，左边流体为红色
        painter.setBrush(QBrush(gradient)) #画刷
        #绘制左边多边形（4边形）
        painter.drawPolygon(QPolygonF([QPointF(ax, ay), QPointF(bx, by), QPointF(cx, cy), QPointF(ix, iy)]))
        gradient = QLinearGradient(QPointF(0, 0), QPointF(0, 100))
        gradient.setColorAt(0, Qt.white)
        b = self.rightSpinBox.value()
        gradient.setColorAt(1, (Qt.blue if b != 0 else Qt.white)) #流速非零时，右边流体为蓝色
        painter.setBrush(QBrush(gradient))
        #绘制右边多边形（4边形）
        painter.drawPolygon(QPolygonF([QPointF(cx, cy), QPointF(dx, dy),QPointF(ex, ey),QPointF(fx, fy)]))
        #计算混合流体的颜色
        if (a + b) == 0:
            color = QColor(Qt.white)
        else:
            ashare = (a / (a + b)) * 255.0
            bshare = 255.0 - ashare
            color = QColor(ashare, 0, bshare)
        gradient = QLinearGradient(QPointF(0, 0), QPointF(0, 100))
        gradient.setColorAt(0, Qt.white)
        gradient.setColorAt(1, color)
        painter.setBrush(QBrush(gradient))
        
        #绘制下部多边形（5边形）
        painter.drawPolygon(QPolygonF([QPointF(cx, cy),QPointF(fx, fy),QPointF(gx, gy), QPointF(hx, hy),QPointF(ix, iy)]))
        #绘制Y形管边界（黑色粗实线）
        painter.setPen(Qt.black)
        painter.drawPolyline(QPolygonF([QPointF(ax, ay), QPointF(ix, iy),QPointF(hx, hy)]))
        painter.drawPolyline(QPolygonF([QPointF(gx, gy), QPointF(fx, fy), QPointF(ex, ey)]))
        painter.drawPolyline(QPolygonF([QPointF(bx, by), QPointF(cx, cy), QPointF(dx, dy)]))

if __name__ == "__main__":
    import sys
    def valueChanged(a, b):
        print(a, b)
    app = QApplication(sys.argv)
    form = YPipeWidget()
    form.signal_valuechanged.connect(valueChanged)
    form.setWindowTitle("YPipe")
    form.move(0, 0)
    form.show()
    form.resize(400, 400)
    app.exec_()