From 7016d1c6c36a4c9a0052f5d2f4c6d2485124e651 Mon Sep 17 00:00:00 2001
From: zhujun98 <zhujun981661@gmail.com>
Date: Sun, 28 Jun 2020 21:23:06 +0200
Subject: [PATCH 1/2] Fix arrayToPath

Use the correct format for streaming QByteArray to QPainterPath.
---
 pyqtgraph/functions.py | 25 ++++++++++++++-----------
 1 file changed, 14 insertions(+), 11 deletions(-)

diff --git a/pyqtgraph/functions.py b/pyqtgraph/functions.py
index 75318bbc..2147fb86 100644
--- a/pyqtgraph/functions.py
+++ b/pyqtgraph/functions.py
@@ -1471,12 +1471,14 @@ def arrayToQPath(x, y, connect='all'):
 
     ## Speed this up using >> operator
     ## Format is:
-    ##    numVerts(i4)   0(i4)
-    ##    x(f8)   y(f8)   0(i4)    <-- 0 means this vertex does not connect
-    ##    x(f8)   y(f8)   1(i4)    <-- 1 means this vertex connects to the previous vertex
+    ##    numVerts(i4)
+    ##    0(i4)   x(f8)   y(f8)    <-- 0 means this vertex does not connect
+    ##    1(i4)   x(f8)   y(f8)    <-- 1 means this vertex connects to the previous vertex
     ##    ...
-    ##    0(i4)
+    ##    cStart(i4)   fillRule(i4)
     ##
+    ## see: https://github.com/qt/qtbase/blob/dev/src/gui/painting/qpainterpath.cpp
+
     ## All values are big endian--pack using struct.pack('>d') or struct.pack('>i')
 
     path = QtGui.QPainterPath()
@@ -1484,12 +1486,12 @@ def arrayToQPath(x, y, connect='all'):
     #profiler = debug.Profiler()
     n = x.shape[0]
     # create empty array, pad with extra space on either end
-    arr = np.empty(n+2, dtype=[('x', '>f8'), ('y', '>f8'), ('c', '>i4')])
+    arr = np.empty(n+2, dtype=[('c', '>i4'), ('x', '>f8'), ('y', '>f8')])
     # write first two integers
     #profiler('allocate empty')
     byteview = arr.view(dtype=np.ubyte)
-    byteview[:12] = 0
-    byteview.data[12:20] = struct.pack('>ii', n, 0)
+    byteview[:16] = 0
+    byteview.data[16:20] = struct.pack('>i', n)
     #profiler('pack header')
     # Fill array with vertex values
     arr[1:-1]['x'] = x
@@ -1508,17 +1510,18 @@ def arrayToQPath(x, y, connect='all'):
     else:
         raise Exception('connect argument must be "all", "pairs", "finite", or array')
 
+    arr[1]['c'] = 0  # the first vertex has no previous vertex to connect
+
     #profiler('fill array')
-    # write last 0
-    lastInd = 20*(n+1)
-    byteview.data[lastInd:lastInd+4] = struct.pack('>i', 0)
+    byteview.data[-20:-16] = struct.pack('>i', 0)  # cStart
+    byteview.data[-16:-12] = struct.pack('>i', 0)  # fillRule (Qt.OddEvenFill)
     #profiler('footer')
     # create datastream object and stream into path
 
     ## Avoiding this method because QByteArray(str) leaks memory in PySide
     #buf = QtCore.QByteArray(arr.data[12:lastInd+4])  # I think one unnecessary copy happens here
 
-    path.strn = byteview.data[12:lastInd+4] # make sure data doesn't run away
+    path.strn = byteview.data[16:-12]  # make sure data doesn't run away
     try:
         buf = QtCore.QByteArray.fromRawData(path.strn)
     except TypeError:

From b61c7c1e39dbaf81071b70ce696811ff76dfd582 Mon Sep 17 00:00:00 2001
From: zhujun98 <zhujun981661@gmail.com>
Date: Mon, 29 Jun 2020 23:17:47 +0200
Subject: [PATCH 2/2] Fix the cases with connect being 'pairs' and 'finite'

---
 pyqtgraph/functions.py | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/pyqtgraph/functions.py b/pyqtgraph/functions.py
index 2147fb86..98cf301e 100644
--- a/pyqtgraph/functions.py
+++ b/pyqtgraph/functions.py
@@ -1501,10 +1501,14 @@ def arrayToQPath(x, y, connect='all'):
     if eq(connect, 'all'):
         arr[1:-1]['c'] = 1
     elif eq(connect, 'pairs'):
-        arr[1:-1]['c'][::2] = 1
-        arr[1:-1]['c'][1::2] = 0
+        arr[1:-1]['c'][::2] = 0
+        arr[1:-1]['c'][1::2] = 1  # connect every 2nd point to every 1st one
     elif eq(connect, 'finite'):
-        arr[1:-1]['c'] = np.isfinite(x) & np.isfinite(y)
+        # Let's call a point with either x or y being nan is an invalid point.
+        # A point will anyway not connect to an invalid point regardless of the
+        # 'c' value of the invalid point. Therefore, we should set 'c' to 0 for
+        # the next point of an invalid point.
+        arr[2:]['c'] = np.isfinite(x) & np.isfinite(y)
     elif isinstance(connect, np.ndarray):
         arr[1:-1]['c'] = connect
     else: