def __init__(self, parent, imagescene2d):
"""
Constructs a view upon a ImageScene2D
imagescene2d -- a ImgeScene2D instance
"""
QGraphicsView.__init__(self, parent)
self.setScene(imagescene2d)
self.mousePos = QPointF(0, 0)
# FIXME: These int members shadow QWidget.x() and QWidget.y(), which can lead to confusion when debugging...
self.x, self.y = (0, 0)
self.setHorizontalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
self.setVerticalScrollBarPolicy(Qt.ScrollBarAlwaysOff)
self._isRubberBandZoom = False
self._cursorBackup = None
#these attributes are exposed as public properties above
self._sliceShape = None #2D shape of this view's shown image
self._slices = None #number of slices that are stacked
self._hud = None
self._crossHairCursor = None
self._sliceIntersectionMarker = None
self._ticker = QTimer(self)
self._ticker.timeout.connect(self._tickerEvent)
#
# Setup the Viewport for fast painting
#
#With these flags turned on we could handle the drawing of the
#white background ourselves thus removing the flicker
#when scrolling fast through the slices
#self.viewport().setAttribute(Qt.WA_OpaquePaintEvent)
#self.viewport().setAttribute(Qt.WA_NoSystemBackground)
#self.viewport().setAttribute(Qt.WA_PaintOnScreen)
#self.viewport().setAutoFillBackground(False)
self.setViewportUpdateMode(QGraphicsView.MinimalViewportUpdate)
#as rescaling images is slow if done in software,
#we use Qt's built-in background caching mode so that the cached
#image need only be blitted on the screen when we only move
#the cursor
self.setCacheMode(QGraphicsView.CacheBackground)
self.setRenderHint(QPainter.Antialiasing, False)
self._crossHairCursor = CrossHairCursor(self.scene())
self._crossHairCursor.setZValue(99)
self._sliceIntersectionMarker = SliceIntersectionMarker(self.scene())
self._sliceIntersectionMarker.setZValue(100)
self._sliceIntersectionMarker.setVisibility(True)
#FIXME: this should be private, but is currently used from
# within the image scene renderer
self.tempImageItems = []
self._zoomFactor = 1.0
#for panning
self._lastPanPoint = QPoint()
self._dragMode = False
self._deltaPan = QPointF(0, 0)
#FIXME: Is there are more elegant way to handle this?
self.setMouseTracking(True)
# invisible cursor to enable custom cursor
self._hiddenCursor = QCursor(Qt.BlankCursor)
