def __init__(self, modelStrand, virtualHelixItem, viewroot):
"""The parent should be a VirtualHelixItem."""
super(StrandItem, self).__init__(virtualHelixItem)
self._modelStrand = modelStrand
self._virtualHelixItem = virtualHelixItem
self._viewroot = viewroot
self._activeTool = virtualHelixItem.activeTool()
self._controller = StrandItemController(self, modelStrand)
isDrawn5to3 = modelStrand.strandSet().isDrawn5to3()
self._strandFilter = modelStrand.strandFilter()
self._insertionItems = {}
# caps
self._lowCap = EndpointItem(self, 'low', isDrawn5to3)
self._highCap = EndpointItem(self, 'high', isDrawn5to3)
self._dualCap = EndpointItem(self, 'dual', isDrawn5to3)
# orientation
self._isDrawn5to3 = isDrawn5to3
# self._isOnTop = virtualHelixItem.isStrandOnTop(modelStrand)
# label
self._seqLabel = QGraphicsSimpleTextItem(self)
self.refreshInsertionItems(modelStrand)
self._updateSequenceText()
# create a larger click area rect to capture mouse events
self._clickArea = cA = QGraphicsRectItem(_defaultRect, self)
cA.mousePressEvent = self.mousePressEvent
cA.setPen(_noPen)
self.setAcceptHoverEvents(True)
cA.setAcceptHoverEvents(True)
cA.hoverMoveEvent = self.hoverMoveEvent
self.setZValue(styles.ZSTRANDITEM)
# xover comming from the 3p end
self._xover3pEnd = XoverItem(self, virtualHelixItem)
# initial refresh
self._updateColor(modelStrand)
self._updateAppearance(modelStrand)
self.setZValue(styles.ZSTRANDITEM)
self.setFlag(QGraphicsItem.ItemIsSelectable)
