text: #!/usr/bin/python3
  # -*- coding: utf-8 -*-
  
  """
  ZetCode PyQt5 tutorial
  
  In this example, we create a custom widget.
  
  Author: Jan Bodnar
  Website: zetcode.com
  Last edited: August 2017
  """
  
  from PyQt5.QtWidgets import (QWidget, QSlider, QApplication,
      QHBoxLayout, QVBoxLayout)
  from PyQt5.QtCore import QObject, Qt, pyqtSignal
  from PyQt5.QtGui import QPainter, QFont, QColor, QPen
  import sys
  
  class Communicate(QObject):
  
      updateBW = pyqtSignal(int)
  
  
  class BurningWidget(QWidget):
  
      def __init__(self):
          super().__init__()
  
          self.initUI()
  
  
      def initUI(self):
  
          self.setMinimumSize(1, 30)
          self.value = 75
          self.num = [75, 150, 225, 300, 375, 450, 525, 600, 675]
  
  
      def setValue(self, value):
  
          self.value = value
  
  
      def paintEvent(self, e):
  
          qp = QPainter()
          qp.begin(self)
          self.drawWidget(qp)
          qp.end()
  
  
      def drawWidget(self, qp):
  
          MAX_CAPACITY = 700
          OVER_CAPACITY = 750
  
          font = QFont('Serif', 7, QFont.Light)
          qp.setFont(font)
  
          size = self.size()
          w = size.width()
          h = size.height()
  
          step = int(round(w / 10))
  
  
          till = int(((w / OVER_CAPACITY) * self.value))
          full = int(((w / OVER_CAPACITY) * MAX_CAPACITY))
  
          if self.value >= MAX_CAPACITY:
  
              qp.setPen(QColor(255, 255, 255))
              qp.setBrush(QColor(255, 255, 184))
              qp.drawRect(0, 0, full, h)
              qp.setPen(QColor(255, 175, 175))
              qp.setBrush(QColor(255, 175, 175))
              qp.drawRect(full, 0, till-full, h)
  
          else:
  
              qp.setPen(QColor(255, 255, 255))
              qp.setBrush(QColor(255, 255, 184))
              qp.drawRect(0, 0, till, h)
  
  
          pen = QPen(QColor(20, 20, 20), 1,
              Qt.SolidLine)
  
          qp.setPen(pen)
          qp.setBrush(Qt.NoBrush)
          qp.drawRect(0, 0, w-1, h-1)
  
          j = 0
  
          for i in range(step, 10*step, step):
  
              qp.drawLine(i, 0, i, 5)
              metrics = qp.fontMetrics()
              fw = metrics.width(str(self.num[j]))
              qp.drawText(i-fw/2, h/2, str(self.num[j]))
              j = j + 1
  
  
  class Example(QWidget):
  
      def __init__(self):
          super().__init__()
  
          self.initUI()
  
  
      def initUI(self):
  
          OVER_CAPACITY = 750
  
          sld = QSlider(Qt.Horizontal, self)
          sld.setFocusPolicy(Qt.NoFocus)
          sld.setRange(1, OVER_CAPACITY)
          sld.setValue(75)
          sld.setGeometry(30, 40, 150, 30)
  
          self.c = Communicate()
          self.wid = BurningWidget()
          self.c.updateBW[int].connect(self.wid.setValue)
  
          sld.valueChanged[int].connect(self.changeValue)
          hbox = QHBoxLayout()
          hbox.addWidget(self.wid)
          vbox = QVBoxLayout()
          vbox.addStretch(1)
          vbox.addLayout(hbox)
          self.setLayout(vbox)
  
          self.setGeometry(300, 300, 390, 210)
          self.setWindowTitle('Burning widget')
          self.show()
  
  
      def changeValue(self, value):
  
          self.c.updateBW.emit(value)
          self.wid.repaint()
  
  
  if __name__ == '__main__':
  
      app = QApplication(sys.argv)
      ex = Example()
      sys.exit(app.exec_())
  