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from ..Qt import QtCore, QtGui
from .GraphicsObject import GraphicsObject
__all__ = ['UIGraphicsItem']
class UIGraphicsItem(GraphicsObject):
"""
Base class for graphics items with boundaries relative to a GraphicsView or ViewBox.
The purpose of this class is to allow the creation of GraphicsItems which live inside
a scalable view, but whose boundaries will always stay fixed relative to the view's boundaries.
For example: GridItem, InfiniteLine
The view can be specified on initialization or it can be automatically detected when the item is painted.
NOTE: Only the item's boundingRect is affected; the item is not transformed in any way. Use viewRangeChanged
to respond to changes in the view.
"""
#sigViewChanged = QtCore.Signal(object) ## emitted whenever the viewport coords have changed
def __init__(self, bounds=None, parent=None):
"""
============== =============================================================================
**Arguments:**
bounds QRectF with coordinates relative to view box. The default is QRectF(0,0,1,1),
which means the item will have the same bounds as the view.
============== =============================================================================
"""
GraphicsObject.__init__(self, parent)
self.setFlag(self.GraphicsItemFlag.ItemSendsScenePositionChanges)
if bounds is None:
self._bounds = QtCore.QRectF(0, 0, 1, 1)
else:
self._bounds = bounds
self._boundingRect = None
self._updateView()
def paint(self, *args):
## check for a new view object every time we paint.
#self.updateView()
pass
def itemChange(self, change, value):
ret = GraphicsObject.itemChange(self, change, value)
if change == self.GraphicsItemChange.ItemScenePositionHasChanged:
self.setNewBounds()
return ret
#def updateView(self):
### called to see whether this item has a new view to connect to
### check for this item's current viewbox or view widget
#view = self.getViewBox()
#if view is None:
##print " no view"
#return
#if self._connectedView is not None and view is self._connectedView():
##print " already have view", view
#return
### disconnect from previous view
#if self._connectedView is not None:
#cv = self._connectedView()
#if cv is not None:
##print "disconnect:", self
#cv.sigRangeChanged.disconnect(self.viewRangeChanged)
### connect to new view
##print "connect:", self
#view.sigRangeChanged.connect(self.viewRangeChanged)
#self._connectedView = weakref.ref(view)
#self.setNewBounds()
def boundingRect(self):
if self._boundingRect is None:
br = self.viewRect()
if br is None:
return QtCore.QRectF()
else:
self._boundingRect = br
return QtCore.QRectF(self._boundingRect)
def dataBounds(self, axis, frac=1.0, orthoRange=None):
"""Called by ViewBox for determining the auto-range bounds.
By default, UIGraphicsItems are excluded from autoRange."""
return None
def viewRangeChanged(self):
"""Called when the view widget/viewbox is resized/rescaled"""
self.setNewBounds()
self.update()
def setNewBounds(self):
"""Update the item's bounding rect to match the viewport"""
self._boundingRect = None ## invalidate bounding rect, regenerate later if needed.
self.prepareGeometryChange()
def setPos(self, *args):
GraphicsObject.setPos(self, *args)
self.setNewBounds()
def mouseShape(self):
"""Return the shape of this item after expanding by 2 pixels"""
shape = self.shape()
ds = self.mapToDevice(shape)
stroker = QtGui.QPainterPathStroker()
stroker.setWidh(2)
ds2 = stroker.createStroke(ds).united(ds)
return self.mapFromDevice(ds2)
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