Color count in PIL

[Larry]

I've been walking up, down, and around instances in the object model
of PIL trying to figure out how to easily calculate how many unique
colors are used in an image, specifically a bitmap (mode "P"). Am I
missing something?

Thanks python friends!

 

[Larry]

I've been walking up, down, and around instances in the object model
of PIL trying to figure out how to easily calculate how many unique
colors are used in an image, specifically a bitmap (mode "P"). Am I
missing something?

Thanks python friends!

So far I have: colors=len(sets.Set(list(im.getdata())))

That makes me want to throw up.

 

[David M. Cooke]

So far I have: colors=len(sets.Set(list(im.getdata())))

That makes me want to throw up.

Probably very inefficient. Have a look at im.histogram(). Something
like:

colours = sum( [ 1 for h in im.histogram() if h != 0 ] )

 

[Fredrik Lundh]

I've been walking up, down, and around instances in the object model
of PIL trying to figure out how to easily calculate how many unique
colors are used in an image, specifically a bitmap (mode "P"). Am I
missing something?

colors = len(filter(None, im.histogram()))

</F>