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combine levels back with lut

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This commit is contained in:
KIU Shueng Chuan 2021-03-27 10:57:44 +08:00
parent 4650b66414
commit f8c30eb712
1 changed files with 33 additions and 8 deletions
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33
pyqtgraph/graphicsItems/ImageItem.py
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@ -418,17 +418,36 @@ class ImageItem(GraphicsObject):
# if the image data is a small int, then we can combine levels + lut
# into a single lut for better performance
scale = None
levels = self.levels
if levels is not None and lut is not None and levels.ndim == 1 and \
image.dtype in (self._xp.ubyte, self._xp.uint16):
while True:
if image.dtype not in (self._xp.ubyte, self._xp.uint16):
break
if levels is not None and levels.ndim != 1:
# can't handle multi-channel levels
break
if levels is None and lut is None:
# nothing to combine
break
if self._effectiveLut is None:
eflsize = 2**(image.itemsize*8)
ind = self._xp.arange(eflsize)
if levels is None:
info = numpy.iinfo(image.dtype)
minlev, maxlev = info.min, info.max
else:
minlev, maxlev = levels
levdiff = maxlev - minlev
levdiff = 1 if levdiff == 0 else levdiff # don't allow division by 0
if lut is None:
efflut = fn.rescaleData(ind, scale=255./levdiff,
offset=minlev, dtype=self._xp.ubyte)
else:
effscale = lut.shape[0] / levdiff
lutdtype = self._xp.min_scalar_type(lut.shape[0] - 1)
efflut = fn.rescaleData(ind, scale=(lut.shape[0]-1)/levdiff,
efflut = fn.rescaleData(ind, scale=effscale,
offset=minlev, dtype=lutdtype, clip=(0, lut.shape[0]-1))
efflut = lut[efflut]
@ -436,6 +455,12 @@ class ImageItem(GraphicsObject):
lut = self._effectiveLut
levels = None
# when calling makeARGB() with lut and no levels, we need to
# explicitly set scale. This ensures that makeARGB() will skip
# applying levels.
scale = lut.shape[0] - 1
break
# Convert single-channel image to 2D array
if image.ndim == 3 and image.shape[-1] == 1:
image = image[..., 0]
@ -448,7 +473,7 @@ class ImageItem(GraphicsObject):
if self._processingBuffer is None or self._processingBuffer.shape[:2] != image.shape[:2]:
self._buildQImageBuffer(image.shape)
fn.makeARGB(image, lut=lut, levels=levels, output=self._processingBuffer)
fn.makeARGB(image, lut=lut, levels=levels, scale=scale, output=self._processingBuffer)
if self._xp == self._cupy:
self._processingBuffer.get(out=self._displayBuffer)
self._renderRequired = False