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Optimize ImageStat.Stat.extrema #7593

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merged 5 commits into from Dec 6, 2023
Merged

Optimize ImageStat.Stat.extrema #7593

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1b8f9d3
Optimize ImageStat.Stat._getextrema function
florath Dec 1, 2023
7762dd3
Fixed spacing in _getextrema method
florath Dec 1, 2023
96fe0a1
Merge branch 'main' into ImageStat_getextrema_opt
radarhere Dec 2, 2023
ac47b75
Update src/PIL/ImageStat.py
florath Dec 4, 2023
ed03954
Merge branch 'main' into ImageStat_getextrema_opt
florath Dec 5, 2023
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18 changes: 12 additions & 6 deletions src/PIL/ImageStat.py
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Expand Up @@ -53,17 +53,23 @@
"""Get min/max values for each band in the image"""

def minmax(histogram):
n = 255
x = 0
res_min, res_max = 255, 0
for i in range(256):
if histogram[i]:
n = min(n, i)
x = max(x, i)
return n, x # returns (255, 0) if there's no data in the histogram
res_min = i
break
for i in range(255, -1, -1):
if histogram[i]:
res_max = i
break
if res_max >= res_min:
return res_min, res_max
else:
return (255, 0)

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v = []
for i in range(0, len(self.h), 256):
v.append(minmax(self.h[i:]))
v.append(minmax(self.h[i : i + 256]))
return v
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you can also use list comprehension

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My idea was to have a minimal patch set.

If you want, we could go with

return [minmax(self.h[i:i+256]) for i in range(0, len(self.h), 256)]

My tests showed that from the performance point of view the two solutions are mostly the same. But if my other patch gets accepted #7599 the list comprehension might be the way to go to have the same style.

What do you think?

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#7597 has actually just been merged to use list comprehension here. Would you like to resolve the conflict?

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Done.


def _getcount(self):
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