Perform finiteCheck on PlotCurveItem.setData

The check for NaN values in arrayToQPath is expensive, this change
attempts to do the check one time, and if no NaN values are present,
an optional flag is passed along telling arrayToQPath that the check
can be skipped

pyqtgraph/functions.py

@@ -1678,7 +1678,7 @@ def downsample(data, n, axis=0, xvals='subsample'):
         return MetaArray(d2, info=info)
 
 
-def arrayToQPath(x, y, connect='all'):
+def arrayToQPath(x, y, connect='all', finiteCheck=True):
     """Convert an array of x,y coordinats to QPainterPath as efficiently as possible.
     The *connect* argument may be 'all', indicating that each point should be
     connected to the next; 'pairs', indicating that each pair of points
@@ -1735,7 +1735,7 @@ def arrayToQPath(x, y, connect='all'):
     # Qt version 5.12.3; these must now be manually cleaned out.
     isfinite = None
     qtver = [int(x) for x in QtVersion.split('.')]
-    if qtver >= [5, 12, 3]:
+    if qtver >= [5, 12, 3] and finiteCheck:
         isfinite = np.isfinite(x) & np.isfinite(y)
         if not np.all(isfinite):
             # credit: Divakar https://stackoverflow.com/a/41191127/643629

pyqtgraph/graphicsItems/PlotCurveItem.py

@@ -65,6 +65,7 @@ class PlotCurveItem(GraphicsObject):
             'connect': 'all',
             'mouseWidth': 8, # width of shape responding to mouse click
             'compositionMode': None,
+            'skipFiniteCheck': True
         }
         if 'pen' not in kargs:
             self.opts['pen'] = fn.mkPen('w')
@@ -336,6 +337,11 @@ class PlotCurveItem(GraphicsObject):
                         connectivity, specify an array of boolean values.
         compositionMode See :func:`setCompositionMode
                         <pyqtgraph.PlotCurveItem.setCompositionMode>`.
+        skipFiniteCheck Optimization parameter that can speed up plot time by
+                        telling the painter to not check and compensate for NaN
+                        values.  If set to True, and NaN values exist, the data
+                        may not be displayed or your plot will take a
+                        significant performance hit.  Defaults to False.
         =============== ========================================================
 
         If non-keyword arguments are used, they will be interpreted as
@@ -373,6 +379,7 @@ class PlotCurveItem(GraphicsObject):
             if data.dtype.kind == 'c':
                 raise Exception("Can not plot complex data types.")
 
+
         profiler("data checks")
 
         #self.setCacheMode(QtGui.QGraphicsItem.NoCache)  ## Disabling and re-enabling the cache works around a bug in Qt 4.6 causing the cached results to display incorrectly
@@ -421,6 +428,8 @@ class PlotCurveItem(GraphicsObject):
         if 'antialias' in kargs:
             self.opts['antialias'] = kargs['antialias']
 
+        self.opts['skipFiniteCheck'] = kargs.get('skipFiniteCheck', False)
+
         profiler('set')
         self.update()
         profiler('update')
@@ -458,10 +467,12 @@ class PlotCurveItem(GraphicsObject):
                 y[0] = self.opts['fillLevel']
                 y[-1] = self.opts['fillLevel']
 
-        path = fn.arrayToQPath(x, y, connect=self.opts['connect'])
+        return fn.arrayToQPath(
-
+            x,
-        return path
+            y,
-
+            connect=self.opts['connect'],
+            finiteCheck=not self.opts['skipFiniteCheck']
+        )
 
     def getPath(self):
         if self.path is None:

pyqtgraph/graphicsItems/PlotDataItem.py

@@ -140,6 +140,11 @@ class PlotDataItem(GraphicsObject):
                               at any time.
             dynamicRangeLimit (float or None) Limit off-screen positions of data points at large
                               magnification to avoids display errors. Disabled if None.
+            skipFiniteCheck   (bool) Optimization parameter that can speed up plot time by
+                              telling the painter to not check and compensate for NaN
+                              values.  If set to True, and NaN values exist, the data
+                              may not be displayed or your plot will take a
+                              significant performance hit.  Defaults to False.
             identical         *deprecated*
             ================= =====================================================================
 
@@ -210,7 +215,7 @@ class PlotDataItem(GraphicsObject):
             'clipToView': False,
             'dynamicRangeLimit': 1e6,
             'dynamicRangeHyst': 3.0,
-
+            'skipFiniteCheck': False,
             'data': None,
         }
         self.setCurveClickable(kargs.get('clickable', False))
@@ -605,11 +610,29 @@ class PlotDataItem(GraphicsObject):
         scatterArgs = {}
 
         if styleUpdate: # repeat style arguments only when changed
-            for k,v in [('pen','pen'), ('shadowPen','shadowPen'), ('fillLevel','fillLevel'), ('fillOutline', 'fillOutline'), ('fillBrush', 'brush'), ('antialias', 'antialias'), ('connect', 'connect'), ('stepMode', 'stepMode')]:
+            for k, v in [
+                ('pen','pen'),
+                ('shadowPen','shadowPen'),
+                ('fillLevel','fillLevel'),
+                ('fillOutline', 'fillOutline'),
+                ('fillBrush', 'brush'),
+                ('antialias', 'antialias'),
+                ('connect', 'connect'),
+                ('stepMode', 'stepMode'),
+                ('skipFiniteCheck', 'skipFiniteCheck')
+            ]:
                 if k in self.opts:
                     curveArgs[v] = self.opts[k]
 
-            for k,v in [('symbolPen','pen'), ('symbolBrush','brush'), ('symbol','symbol'), ('symbolSize', 'size'), ('data', 'data'), ('pxMode', 'pxMode'), ('antialias', 'antialias')]:
+            for k, v in [
+                ('symbolPen','pen'),
+                ('symbolBrush','brush'),
+                ('symbol','symbol'),
+                ('symbolSize', 'size'),
+                ('data', 'data'),
+                ('pxMode', 'pxMode'),
+                ('antialias', 'antialias')
+            ]:
                 if k in self.opts:
                     scatterArgs[v] = self.opts[k]