Defer parsing of palette into colors #6567
Merged
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Addresses #6561
The discussion points out that
Image.fromarray(a, "P")
is slower thanImage.fromarray(a, "L")
. The difference is that whenfromarray
callsfrombuffer
, for P mode an ImagePalette instance is created. Once ImagePalette assigns the initial palette, it parses the palette into acolors
dictionary. This parsing is the main difference in speed.I'm not convinced that
Image.fromarray(a, "P")
is a common enough to warrant speed optimization. However, the parsing of the initial ImagePalette palette string would be an operation shared through all P mode images, and depending on the series of operations from the user,colors
is not necessarily used afterwards.This PR defers the parsing of the palette into colors until the
colors
attribute is accessed.