This is not an answer to the question ”Is there a native way?”, but I think that there is a more elegant way:
def cm2inch(*tupl):
inch = 2.54
if isinstance(tupl[0], tuple):
return tuple(i/inch for i in tupl[0])
else:
return tuple(i/inch for i in tupl)
Then one can issue plt.figure(figsize=cm2inch(12.8, 9.6)), which I think is a much cleaner way. The implementation also allows us to use cm2inch((12.8, 9.6)), which I personally do not prefer, but some people may do.
Even though there isn’t any way of doing this natively at the moment, I found a discussion here.