Merge pull request pyqtgraph#3006 from j9ac9k/fix-fillbetween-regression

Allow users to specify FillRule for FillBetweenItem, undo regressionfrom pyqtgraph#2971

Author: j9ac9k

pyqtgraph/graphicsItems/FillBetweenItem.py

@@ -1,5 +1,7 @@
+from typing import Union
+
 from .. import functions as fn
-from ..Qt import QtGui, QtWidgets
+from ..Qt import QtGui, QtWidgets, QtCore
 from .PlotCurveItem import PlotCurveItem
 from .PlotDataItem import PlotDataItem
 
@@ -9,33 +11,104 @@ class FillBetweenItem(QtWidgets.QGraphicsPathItem):
     """
     GraphicsItem filling the space between two PlotDataItems.
     """
-    def __init__(self, curve1=None, curve2=None, brush=None, pen=None):
-        QtWidgets.QGraphicsPathItem.__init__(self)
+    def __init__(
+        self,
+        curve1: Union[PlotDataItem, PlotCurveItem],
+        curve2: Union[PlotDataItem, PlotCurveItem],
+        brush=None,
+        pen=None,
+        fillRule: QtCore.Qt.FillRule=QtCore.Qt.FillRule.OddEvenFill
+    ):
+        """FillBetweenItem fills a region between two curves with a specified
+        :class:`~QtGui.QBrush`. 
+
+        Parameters
+        ----------
+        curve1 : :class:`~pyqtgraph.PlotDataItem` | :class:`~pyqtgraph.PlotCurveItem`
+            Line to draw fill from
+        curve2 : :class:`~pyqtgraph.PlotDataItem` | :class:`~pyqtgraph.PlotCurveItem`
+            Line to draw fill to
+        brush : color_like, optional
+            Arguments accepted by :func:`~pyqtgraph.mkBrush`, used
+            to create the :class:`~QtGui.QBrush` instance used to draw the item
+            by default None
+        pen : color_like, optional
+            Arguments accepted by :func:`~pyqtgraph.mkColor`, used
+            to create the :class:`~QtGui.QPen` instance used to draw the item
+            by default ``None``
+        fillRule : QtCore.Qt.FillRule, optional
+            FillRule to be applied to the underlying :class:`~QtGui.QPainterPath`
+            instance, by default ``QtCore.Qt.FillRule.OddEvenFill``
+
+        Raises
+        ------
+        ValueError
+            Raised when ``None`` is passed in as either ``curve1``
+            or ``curve2``
+        TypeError
+            Raised when either ``curve1`` or ``curve2`` is not either
+            :class:`~pyqtgraph.PlotDataItem` or :class:`~pyqtgraph.PlotCurveItem`
+        """
+        super().__init__()
         self.curves = None
+        self._fillRule = fillRule
         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.")
+            raise ValueError("Must specify two curves to fill between.")
 
         if brush is not None:
             self.setBrush(brush)
         self.setPen(pen)
         self.updatePath()
+
+    def fillRule(self):
+        return self._fillRule
+
+    def setFillRule(self, fillRule: QtCore.Qt.FillRule=QtCore.Qt.FillRule.OddEvenFill):
+        """Set the underlying :class:`~QtGui.QPainterPath` to the specified 
+        :class:`~QtCore.Qt.FillRule`
+
+        This can be useful for allowing in the filling of voids.
+
+        Parameters
+        ----------
+        fillRule : QtCore.Qt.FillRule
+            A member of the :class:`~QtCore.Qt.FillRule` enum
+        """
+        self._fillRule = fillRule
+        self.updatePath()
 
     def setBrush(self, *args, **kwds):
-        """Change the fill brush. Accepts the same arguments as pg.mkBrush()"""
+        """Change the fill brush. Accepts the same arguments as :func:`~pyqtgraph.mkBrush`
+        """
         QtWidgets.QGraphicsPathItem.setBrush(self, fn.mkBrush(*args, **kwds))
 
     def setPen(self, *args, **kwds):
+        """Change the fill pen. Accepts the same arguments as :func:`~pyqtgraph.mkColor`
+        """
         QtWidgets.QGraphicsPathItem.setPen(self, fn.mkPen(*args, **kwds))
 
-    def setCurves(self, curve1, curve2):
-        """Set the curves to fill between.
-        
-        Arguments must be instances of PlotDataItem or PlotCurveItem.
-        
-        Added in version 0.9.9
-        """
+    def setCurves(
+        self,
+        curve1: Union[PlotDataItem, PlotCurveItem],
+        curve2: Union[PlotDataItem, PlotCurveItem]
+    ):
+        """Method to set the Curves to draw the FillBetweenItem between
+
+        Parameters
+        ----------
+        curve1 : :class:`~pyqtgraph.PlotDataItem` | :class:`~pyqtgraph.PlotCurveItem`
+            Line to draw fill from
+        curve2 : :class:`~pyqtgraph.PlotDataItem` | :class:`~pyqtgraph.PlotCurveItem`
+            Line to draw fill to
+    
+        Raises
+        ------
+        TypeError
+            Raised when input arguments are not either :class:`~pyqtgraph.PlotDataItem` or
+            :class:`~pyqtgraph.PlotCurveItem`
+        """        
         if self.curves is not None:
             for c in self.curves:
                 try:
@@ -45,7 +118,7 @@ def setCurves(self, curve1, curve2):
 
         curves = [curve1, curve2]
         for c in curves:
-            if not isinstance(c, PlotDataItem) and not isinstance(c, PlotCurveItem):
+            if not isinstance(c, (PlotDataItem, PlotCurveItem)):
                 raise TypeError("Curves must be PlotDataItem or PlotCurveItem.")
         self.curves = curves
         curve1.sigPlotChanged.connect(self.curveChanged)
@@ -55,6 +128,7 @@ def setCurves(self, curve1, curve2):
 
     def curveChanged(self):
         self.updatePath()
+    
     def updatePath(self):
         if self.curves is None:
             self.setPath(QtGui.QPainterPath())
@@ -67,19 +141,17 @@ def updatePath(self):
                 paths.append(c.getPath())
 
         path = QtGui.QPainterPath()
-        transform = QtGui.QTransform()
+        path.setFillRule(self.fillRule())   
 
-        ps1 = paths[0].toSubpathPolygons(transform)
-        ps2 = paths[1].toReversed().toSubpathPolygons(transform)
+        ps1 = paths[0].toSubpathPolygons()
+        ps2 = paths[1].toReversed().toSubpathPolygons()
         ps2.reverse()
 
         if len(ps1) == 0 or len(ps2) == 0:
             self.setPath(QtGui.QPainterPath())
             return
-        
+
         for p1, p2 in zip(ps1, ps2):
-            intersection = p1.intersected(p2)
-            if not intersection.isEmpty():
-                path.addPolygon(intersection)
-            path.addPolygon(p1 + p2)       
+            path.addPolygon(p1 + p2)
+
         self.setPath(path)