- Fixed FillBetweenItem to force PlotCurveItem to generate path

- Added FillBetweenItem.setCurves()
- Added FillBetweenItem example

CHANGELOG

@@ -23,6 +23,7 @@ pyqtgraph-0.9.9  [unreleased]
         - Get, set current value
     - Added Flowchart.sigChartChanged
     - ImageItem.getHistogram is more clever about constructing histograms
+    - Added FillBetweenItem.setCurves()
 
   Bugfixes:
     - PlotCurveItem now has correct clicking behavior--clicks within a few px
@@ -42,6 +43,7 @@ pyqtgraph-0.9.9  [unreleased]
     - Prevent divide-by-zero in AxisItem
     - Major speedup when using ScatterPlotItem in pxMode
     - PlotCurveItem ignores clip-to-view when auto range is enabled
+    - FillBetweenItem now forces PlotCurveItem to generate path
 
 pyqtgraph-0.9.8  2013-11-24
 

examples/__main__.py

@@ -37,6 +37,7 @@ examples = OrderedDict([
         ('IsocurveItem', 'isocurve.py'),
         ('GraphItem', 'GraphItem.py'),
         ('ErrorBarItem', 'ErrorBarItem.py'),
+        ('FillBetweenItem', 'FillBetweenItem.py'),
         ('ImageItem - video', 'ImageItem.py'),
         ('ImageItem - draw', 'Draw.py'),
         ('Region-of-Interest', 'ROIExamples.py'),

pyqtgraph/graphicsItems/FillBetweenItem.py

@@ -1,24 +1,70 @@
 from ..Qt import QtGui
 from .. import functions as fn
+from .PlotDataItem import PlotDataItem
+from .PlotCurveItem import PlotCurveItem
 
 class FillBetweenItem(QtGui.QGraphicsPathItem):
     """
     GraphicsItem filling the space between two PlotDataItems.
     """
-    def __init__(self, p1, p2, brush=None):
+    def __init__(self, curve1=None, curve2=None, brush=None):
         QtGui.QGraphicsPathItem.__init__(self)
-        self.p1 = p1
-        self.p2 = p2
-        p1.sigPlotChanged.connect(self.updatePath)
-        p2.sigPlotChanged.connect(self.updatePath)
+        self.curves = None
+        if curve1 is not None and curve2 is not None:
+            self.setCurves(curve1, curve2)
+        elif curve1 is not None or curve2 is not None:
+            raise Exception("Must specify two curves to fill between.")
+        
         if brush is not None:
             self.setBrush(fn.mkBrush(brush))
-        self.setZValue(min(p1.zValue(), p2.zValue())-1)
+        self.updatePath()
+
+    def setCurves(self, curve1, curve2):
+        """Set the curves to fill between.
+        
+        Arguments must be instances of PlotDataItem or PlotCurveItem."""
+        
+        if self.curves is not None:
+            for c in self.curves:
+                try:
+                    c.sigPlotChanged.disconnect(self.curveChanged)
+                except TypeError:
+                    pass
+        
+        curves = [curve1, curve2]
+        for c in curves:
+            if not isinstance(c, PlotDataItem) and not isinstance(c, PlotCurveItem):
+                raise TypeError("Curves must be PlotDataItem or PlotCurveItem.")
+        self.curves = curves
+        curve1.sigPlotChanged.connect(self.curveChanged)
+        curve2.sigPlotChanged.connect(self.curveChanged)
+        self.setZValue(min(curve1.zValue(), curve2.zValue())-1)
+        self.curveChanged()
+        
+    def setBrush(self, *args, **kwds):
+        """Change the fill brush. Acceps the same arguments as pg.mkBrush()"""
+        QtGui.QGraphicsPathItem.setBrush(self, fn.mkBrush(*args, **kwds))
+
+    def curveChanged(self):
         self.updatePath()
 
     def updatePath(self):
-        p1 = self.p1.curve.path
-        p2 = self.p2.curve.path
+        if self.curves is None:
+            self.setPath(QtGui.QPainterPath())
+            return
+        paths = []
+        for c in self.curves:
+            if isinstance(c, PlotDataItem):
+                paths.append(c.curve.getPath())
+            elif isinstance(c, PlotCurveItem):
+                paths.append(c.getPath())
+            
         path = QtGui.QPainterPath()
-        path.addPolygon(p1.toSubpathPolygons()[0] + p2.toReversed().toSubpathPolygons()[0])
+        p1 = paths[0].toSubpathPolygons()
+        p2 = paths[1].toReversed().toSubpathPolygons()
+        if len(p1) == 0 or len(p2) == 0:
+            self.setPath(QtGui.QPainterPath())
+            return
+            
+        path.addPolygon(p1[0] + p2[0])
         self.setPath(path)

pyqtgraph/graphicsItems/PlotDataItem.py

@@ -15,7 +15,7 @@ class PlotDataItem(GraphicsObject):
     GraphicsItem for displaying plot curves, scatter plots, or both. 
     While it is possible to use :class:`PlotCurveItem <pyqtgraph.PlotCurveItem>` or
     :class:`ScatterPlotItem <pyqtgraph.ScatterPlotItem>` individually, this class
-    provides a unified interface to both. Inspances of :class:`PlotDataItem` are 
+    provides a unified interface to both. Instances of :class:`PlotDataItem` are 
     usually created by plot() methods such as :func:`pyqtgraph.plot` and
     :func:`PlotItem.plot() <pyqtgraph.PlotItem.plot>`.