+class MeasurementDataModel(QtGui.QStandardItemModel):
+ '''Model to hold the measured values.'''
+
+ '''Role used to identify and find the item.'''
+ _idRole = QtCore.Qt.UserRole + 1
+
+ '''Role used to store the device vendor and model.'''
+ descRole = QtCore.Qt.UserRole + 2
+
+ def __init__(self, parent):
+ super(self.__class__, self).__init__(parent)
+
+ # Use the description text to sort the items for now, because the
+ # _idRole holds tuples, and using them to sort doesn't work.
+ self.setSortRole(MeasurementDataModel.descRole)
+
+ # Used in 'format_mag()' to check against.
+ self.inf = float('inf')
+
+ def format_unit(self, u):
+ units = {
+ sr.Unit.VOLT: 'V',
+ sr.Unit.AMPERE: 'A',
+ sr.Unit.OHM: u'\u03A9',
+ sr.Unit.FARAD: 'F',
+ sr.Unit.KELVIN: 'K',
+ sr.Unit.CELSIUS: u'\u00B0C',
+ sr.Unit.FAHRENHEIT: u'\u00B0F',
+ sr.Unit.HERTZ: 'Hz',
+ sr.Unit.PERCENTAGE: '%',
+ # sr.Unit.BOOLEAN
+ sr.Unit.SECOND: 's',
+ sr.Unit.SIEMENS: 'S',
+ sr.Unit.DECIBEL_MW: 'dBu',
+ sr.Unit.DECIBEL_VOLT: 'dBV',
+ # sr.Unit.UNITLESS
+ sr.Unit.DECIBEL_SPL: 'dB',
+ # sr.Unit.CONCENTRATION
+ sr.Unit.REVOLUTIONS_PER_MINUTE: 'rpm',
+ sr.Unit.VOLT_AMPERE: 'VA',
+ sr.Unit.WATT: 'W',
+ sr.Unit.WATT_HOUR: 'Wh',
+ sr.Unit.METER_SECOND: 'm/s',
+ sr.Unit.HECTOPASCAL: 'hPa',
+ sr.Unit.HUMIDITY_293K: '%rF',
+ sr.Unit.DEGREE: u'\u00B0',
+ sr.Unit.HENRY: 'H'
+ }
+
+ return units.get(u, '')
+
+ def format_mqflags(self, mqflags):
+ if sr.QuantityFlag.AC in mqflags:
+ return 'AC'
+ elif sr.QuantityFlag.DC in mqflags:
+ return 'DC'
+ else:
+ return ''
+
+ def format_mag(self, mag):
+ if mag == self.inf:
+ return u'\u221E'
+ return '{:f}'.format(mag)
+
+ def getItem(self, device, channel):
+ '''Returns the item for the device + channel combination from the model,
+ or creates a new item if no existing one matches.'''
+
+ # unique identifier for the device + channel
+ # TODO: isn't there something better?
+ uid = (
+ device.vendor,
+ device.model,
+ device.serial_number(),
+ device.connection_id(),
+ channel.index
+ )
+
+ # find the correct item in the model
+ for row in range(self.rowCount()):
+ item = self.item(row)
+ rid = item.data(MeasurementDataModel._idRole)
+ rid = tuple(rid) # PySide returns a list
+ if uid == rid:
+ return item
+
+ # nothing found, create a new item
+ desc = '{} {}, channel "{}"'.format(
+ device.vendor, device.model, channel.name)
+
+ item = QtGui.QStandardItem()
+ item.setData(uid, MeasurementDataModel._idRole)
+ item.setData(desc, MeasurementDataModel.descRole)
+ self.appendRow(item)
+ self.sort(0)
+ return item
+
+ @QtCore.Slot(object, object)
+ def update(self, device, payload):
+ '''Updates the data for the device (+channel) with the most recent
+ measurement from the given payload.'''
+
+ if not len(payload.channels):
+ return
+
+ # TODO: find a device with multiple channels in one packet
+ channel = payload.channels[0]
+
+ item = self.getItem(device, channel)
+
+ # the most recent value
+ mag = payload.data[0][-1]
+
+ unit_str = self.format_unit(payload.unit)
+ mqflags_str = self.format_mqflags(payload.mq_flags)
+ mag_str = self.format_mag(mag)
+ disp = ' '.join([mag_str, unit_str, mqflags_str])
+ item.setData(disp, QtCore.Qt.DisplayRole)
+
+class MultimeterDelegate(QtGui.QStyledItemDelegate):
+ '''Delegate to show the data items from a MeasurementDataModel.'''
+
+ def __init__(self, parent, font):
+ '''Initializes the delegate.
+
+ :param font: Font used for the description text, the value is drawn
+ with a slightly bigger and bold variant of the font.
+ '''
+
+ super(self.__class__, self).__init__(parent)
+
+ self._nfont = font
+ self._bfont = QtGui.QFont(self._nfont)
+
+ self._bfont.setBold(True)
+ if self._bfont.pixelSize() != -1:
+ self._bfont.setPixelSize(self._bfont.pixelSize() * 1.8)
+ else:
+ self._bfont.setPointSizeF(self._bfont.pointSizeF() * 1.8)
+
+ fi = QtGui.QFontInfo(self._nfont)
+ self._nfontheight = fi.pixelSize()
+
+ fm = QtGui.QFontMetrics(self._bfont)
+ r = fm.boundingRect('-XX.XXXXXX X XX')
+ self._size = QtCore.QSize(r.width() * 1.2, r.height() * 3.5)
+
+ def sizeHint(self, option=None, index=None):
+ return self._size
+
+ def paint(self, painter, options, index):
+ value = index.data(QtCore.Qt.DisplayRole)
+ desc = index.data(MeasurementDataModel.descRole)
+
+ # description in the top left corner
+ painter.setFont(self._nfont)
+ p = options.rect.topLeft()
+ p += QtCore.QPoint(self._nfontheight, 2 * self._nfontheight)
+ painter.drawText(p, desc)
+
+ # value in the center
+ painter.setFont(self._bfont)
+ r = options.rect.adjusted(self._nfontheight, 2.5 * self._nfontheight,
+ 0, 0)
+ painter.drawText(r, QtCore.Qt.AlignCenter, value)
+
+class EmptyMessageListView(QtGui.QListView):
+ '''List view that shows a message if the model im empty.'''
+
+ def __init__(self, message, parent=None):
+ super(self.__class__, self).__init__(parent)
+
+ self._message = message
+
+ def paintEvent(self, event):
+ m = self.model()
+ if m and m.rowCount():
+ super(self.__class__, self).paintEvent(event)
+ return
+
+ painter = QtGui.QPainter(self.viewport())
+ painter.drawText(self.rect(), QtCore.Qt.AlignCenter, self._message)
+