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ndarray indexing is faster than np.take

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KIU Shueng Chuan 2021-04-09 20:24:56 +08:00
parent 29ad432f5a
commit f59097a484
1 changed files with 18 additions and 8 deletions
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26
pyqtgraph/graphicsItems/ImageItem.py
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@ -455,14 +455,24 @@ class ImageItem(GraphicsObject):
lut = self._effectiveLut
levels = None
if image.dtype == self._xp.uint16 or (image.ndim == 3 and image.shape[2] == 3):
# apply the effective lut early for the following types:
# 1) uint16 mono
# 2) {uint8, uint16} rgb
# this converts the input image to an uint8 image of shape
# (h, w) or (h, w, 3) or (h, w, 4), depending on the lut's shape.
# we don't do it for uint8 mono so that it will use Format_Indexed8
image = fn.applyLookupTable(image, lut)
# apply the effective lut early for the following types:
if image.dtype == self._xp.uint16 and (image.ndim == 2 or image.shape[2] == 1):
# 1) uint16 mono
if lut.ndim == 2:
if lut.shape[1] == 3: # rgb
# convert rgb lut to rgba so that it is 32-bits
lut = numpy.column_stack([lut, numpy.full(lut.shape[0], 255, dtype=numpy.uint8)])
if lut.shape[1] == 4: # rgba
lut = lut.view(numpy.uint32)
image = lut.ravel()[image]
lut = None
# now both levels and lut are None
if image.dtype == numpy.uint32:
image = image.view(numpy.uint8).reshape(image.shape + (4,))
elif image.ndim == 3 and image.shape[2] == 3:
# 2) {uint8, uint16} rgb
# for rgb images, the lut will be 1d
image = lut.ravel()[image]
lut = None
# now both levels and lut are None