125 lines
4.6 KiB
Python
125 lines
4.6 KiB
Python
# -*- coding: utf-8 -*-
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from ..Qt import QtGui, QtCore, QT_LIB
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from .GraphicsObject import GraphicsObject
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if QT_LIB.startswith('PyQt'):
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from ..Qt import sip
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__all__ = ['UIGraphicsItem']
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class UIGraphicsItem(GraphicsObject):
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"""
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Base class for graphics items with boundaries relative to a GraphicsView or ViewBox.
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The purpose of this class is to allow the creation of GraphicsItems which live inside
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a scalable view, but whose boundaries will always stay fixed relative to the view's boundaries.
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For example: GridItem, InfiniteLine
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The view can be specified on initialization or it can be automatically detected when the item is painted.
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NOTE: Only the item's boundingRect is affected; the item is not transformed in any way. Use viewRangeChanged
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to respond to changes in the view.
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"""
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#sigViewChanged = QtCore.Signal(object) ## emitted whenever the viewport coords have changed
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def __init__(self, bounds=None, parent=None):
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"""
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============== =============================================================================
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**Arguments:**
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bounds QRectF with coordinates relative to view box. The default is QRectF(0,0,1,1),
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which means the item will have the same bounds as the view.
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============== =============================================================================
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"""
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GraphicsObject.__init__(self, parent)
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self.setFlag(self.GraphicsItemFlag.ItemSendsScenePositionChanges)
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if bounds is None:
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self._bounds = QtCore.QRectF(0, 0, 1, 1)
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else:
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self._bounds = bounds
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self._boundingRect = None
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self._updateView()
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def paint(self, *args):
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## check for a new view object every time we paint.
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#self.updateView()
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pass
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def itemChange(self, change, value):
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ret = GraphicsObject.itemChange(self, change, value)
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## workaround for pyqt bug:
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## http://www.riverbankcomputing.com/pipermail/pyqt/2012-August/031818.html
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if QT_LIB == 'PyQt5' and change == self.GraphicsItemChange.ItemParentChange and isinstance(ret, QtGui.QGraphicsItem):
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ret = sip.cast(ret, QtGui.QGraphicsItem)
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if change == self.GraphicsItemChange.ItemScenePositionHasChanged:
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self.setNewBounds()
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return ret
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#def updateView(self):
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### called to see whether this item has a new view to connect to
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### check for this item's current viewbox or view widget
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#view = self.getViewBox()
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#if view is None:
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##print " no view"
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#return
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#if self._connectedView is not None and view is self._connectedView():
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##print " already have view", view
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#return
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### disconnect from previous view
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#if self._connectedView is not None:
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#cv = self._connectedView()
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#if cv is not None:
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##print "disconnect:", self
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#cv.sigRangeChanged.disconnect(self.viewRangeChanged)
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### connect to new view
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##print "connect:", self
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#view.sigRangeChanged.connect(self.viewRangeChanged)
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#self._connectedView = weakref.ref(view)
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#self.setNewBounds()
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def boundingRect(self):
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if self._boundingRect is None:
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br = self.viewRect()
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if br is None:
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return QtCore.QRectF()
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else:
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self._boundingRect = br
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return QtCore.QRectF(self._boundingRect)
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def dataBounds(self, axis, frac=1.0, orthoRange=None):
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"""Called by ViewBox for determining the auto-range bounds.
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By default, UIGraphicsItems are excluded from autoRange."""
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return None
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def viewRangeChanged(self):
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"""Called when the view widget/viewbox is resized/rescaled"""
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self.setNewBounds()
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self.update()
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def setNewBounds(self):
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"""Update the item's bounding rect to match the viewport"""
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self._boundingRect = None ## invalidate bounding rect, regenerate later if needed.
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self.prepareGeometryChange()
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def setPos(self, *args):
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GraphicsObject.setPos(self, *args)
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self.setNewBounds()
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def mouseShape(self):
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"""Return the shape of this item after expanding by 2 pixels"""
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shape = self.shape()
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ds = self.mapToDevice(shape)
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stroker = QtGui.QPainterPathStroker()
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stroker.setWidh(2)
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ds2 = stroker.createStroke(ds).united(ds)
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return self.mapFromDevice(ds2)
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