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Fix arrayToPath

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Use the correct format for streaming QByteArray to QPainterPath.
This commit is contained in:
zhujun98 2020-06-28 21:23:06 +02:00
parent 4110b3e539
commit 7016d1c6c3
1 changed files with 14 additions and 11 deletions
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25
pyqtgraph/functions.py
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@ -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: