python3+PyQt5实现自定义分数滑块部件

#!/usr/bin/env python3import platformfrom PyQt5.QtCore import (QPointF, QRectF, QSize, Qt,pyqtSignal)from PyQt5.QtWidgets import (QApplication, QDialog,QSizePolicy,     QGridLayout, QLCDNumber, QLabel,    QSpinBox, QWidget)from PyQt5.QtGui import QColor,QFont,QPainter,QFontMetricsF,QPalette, QPolygonFX11 = Truetry:  from PyQt5.QtGui import qt_x11_wait_for_window_managerexcept ImportError:  X11 = Falseclass FractionSlider(QWidget):  XMARGIN = 12.0  YMARGIN = 5.0  WSTRING = "999"  valueChanged = pyqtSignal(int,int)   def __init__(self, numerator=0, denominator=10, parent=None):    super(FractionSlider, self).__init__(parent)    self.__numerator = numerator    self.__denominator = denominator    self.setFocusPolicy(Qt.WheelFocus)    self.setSizePolicy(QSizePolicy(QSizePolicy.MinimumExpanding,                    QSizePolicy.Fixed))  def decimal(self):    return self.__numerator / float(self.__denominator)  def fraction(self):    return self.__numerator, self.__denominator  def sizeHint(self):    return self.minimumSizeHint()  def minimumSizeHint(self):    font = QFont(self.font())    font.setPointSize(font.pointSize() - 1)    fm = QFontMetricsF(font)    return QSize(fm.width(FractionSlider.WSTRING) *           self.__denominator,           (fm.height() * 4) + FractionSlider.YMARGIN)  def setFraction(self, numerator, denominator=None):    if denominator is not None:      if 3 <= denominator <= 60:        self.__denominator = denominator      else:        raise ValueError("denominator out of range")    if 0 <= numerator <= self.__denominator:      self.__numerator = numerator    else:      raise ValueError("numerator out of range")    self.update()    self.updateGeometry()  def mousePressEvent(self, event):    if event.button() == Qt.LeftButton:      self.moveSlider(event.x())      event.accept()    else:      QWidget.mousePressEvent(self, event)  def mouseMoveEvent(self, event):    self.moveSlider(event.x())  def moveSlider(self, x):    span = self.width() - (FractionSlider.XMARGIN * 2)    offset = span - x + FractionSlider.XMARGIN    numerator = int(round(self.__denominator *            (1.0 - (offset / span))))    numerator = max(0, min(numerator, self.__denominator))    if numerator != self.__numerator:      self.__numerator = numerator      #self.emit(SIGNAL("valueChanged(int,int)"),      #     self.__numerator, self.__denominator)      self.valueChanged.emit(self.__numerator, self.__denominator)      self.update()  def keyPressEvent(self, event):    change = 0    if event.key() == Qt.Key_Home:      change = -self.__denominator    elif event.key() in (Qt.Key_Up, Qt.Key_Right):      change = 1    elif event.key() == Qt.Key_PageUp:      change = (self.__denominator // 10) + 1    elif event.key() in (Qt.Key_Down, Qt.Key_Left):      change = -1    elif event.key() == Qt.Key_PageDown:      change = -((self.__denominator // 10) + 1)    elif event.key() == Qt.Key_End:      change = self.__denominator    if change:      numerator = self.__numerator      numerator += change      numerator = max(0, min(numerator, self.__denominator))      if numerator != self.__numerator:        self.__numerator = numerator        #self.emit(SIGNAL("valueChanged(int,int)"),        #     self.__numerator, self.__denominator)        self.valueChanged.emit(self.__numerator, self.__denominator)        self.update()      event.accept()    else:      QWidget.keyPressEvent(self, event)  def paintEvent(self, event=None):    font = QFont(self.font())    font.setPointSize(font.pointSize() - 1)    fm = QFontMetricsF(font)    fracWidth = fm.width(FractionSlider.WSTRING)    indent = fm.boundingRect("9").width() / 2.0    if not X11:      fracWidth *= 1.5    span = self.width() - (FractionSlider.XMARGIN * 2)    value = self.__numerator / float(self.__denominator)    painter = QPainter(self)    painter.setRenderHint(QPainter.Antialiasing)    painter.setRenderHint(QPainter.TextAntialiasing)    painter.setPen(self.palette().color(QPalette.Mid))    painter.setBrush(self.palette().brush(        QPalette.AlternateBase))    painter.drawRect(self.rect())    segColor = QColor(Qt.green).darker(120)    segLineColor = segColor.darker()    painter.setPen(segLineColor)    painter.setBrush(segColor)    painter.drawRect(FractionSlider.XMARGIN,             FractionSlider.YMARGIN, span, fm.height())    textColor = self.palette().color(QPalette.Text)    segWidth = span / self.__denominator    segHeight = fm.height() * 2    nRect = fm.boundingRect(FractionSlider.WSTRING)    x = FractionSlider.XMARGIN    yOffset = segHeight + fm.height()    for i in range(self.__denominator + 1):      painter.setPen(segLineColor)      painter.drawLine(x, FractionSlider.YMARGIN, x, segHeight)      painter.setPen(textColor)      y = segHeight      rect = QRectF(nRect)      rect.moveCenter(QPointF(x, y + fm.height() / 2.0))      #painter.drawText(rect, Qt.AlignCenter,               #QString.number(i))      painter.drawText(rect, Qt.AlignCenter,str(i))            y = yOffset      rect.moveCenter(QPointF(x, y + fm.height() / 2.0))      painter.drawText(rect, Qt.AlignCenter,               str(self.__denominator))      painter.drawLine(QPointF(rect.left() + indent, y),               QPointF(rect.right() - indent, y))      x += segWidth    span = int(span)    y = FractionSlider.YMARGIN - 0.5    triangle = [QPointF(value * span, y),          QPointF((value * span) +              (2 * FractionSlider.XMARGIN), y),          QPointF((value * span) +              FractionSlider.XMARGIN, fm.height())]    painter.setPen(Qt.yellow)    painter.setBrush(Qt.darkYellow)    painter.drawPolygon(QPolygonF(triangle))if __name__ == "__main__":  import sys  app = QApplication(sys.argv)  form = QDialog()  sliderLabel = QLabel("&Fraction")  slider = FractionSlider(denominator=12)  sliderLabel.setBuddy(slider)  denominatorLabel = QLabel("&Denominator")  denominatorSpinBox = QSpinBox()  denominatorLabel.setBuddy(denominatorSpinBox)  denominatorSpinBox.setRange(3, 60)  denominatorSpinBox.setValue(slider.fraction()[1])  denominatorSpinBox.setAlignment(Qt.AlignRight|Qt.AlignVCenter)  numeratorLabel = QLabel("Numerator")  numeratorLCD = QLCDNumber()  numeratorLCD.setSegmentStyle(QLCDNumber.Flat)  layout = QGridLayout()  layout.addWidget(sliderLabel, 0, 0)  layout.addWidget(slider, 0, 1, 1, 5)  layout.addWidget(numeratorLabel, 1, 0)  layout.addWidget(numeratorLCD, 1, 1)  layout.addWidget(denominatorLabel, 1, 2)  layout.addWidget(denominatorSpinBox, 1, 3)  form.setLayout(layout)  def valueChanged(denominator):    numerator = int(slider.decimal() * denominator)    slider.setFraction(numerator, denominator)    numeratorLCD.display(numerator)  #form.connect(slider, SIGNAL("valueChanged(int,int)"),         #numeratorLCD, SLOT("display(int)"))  slider.valueChanged[int,int].connect(numeratorLCD.display)  #form.connect(denominatorSpinBox, SIGNAL("valueChanged(int)"),         #valueChanged)  denominatorSpinBox.valueChanged[int].connect(valueChanged)  form.setWindowTitle("Fraction Slider")  form.show()  app.exec_()