Re: [Matplotlib-users] weird matplotlib imread question for png

[Fabrice S. <si...@lm...>]

Le mardi 14 avril 2015 à 18:15 +0800, oyster a écrit :
> I am using anaconda(Python 2.7.6 |Anaconda 1.9.2 (32-bit)| (default,
> Nov 11 2013, 10:50:31) [MSC v.1500 32 bit (Intel)] on win32) on
> windows 7 64 bits
> And the matplotlib is 1.4.3, numpy is 1.9.2, and scipy is 0.15.1,
> which are all been updated by 'conda update xx'
> 
> As http://matplotlib.org/api/pyplot_api.html says
> [quote]
> matplotlib.pyplot.imread(*args, **kwargs) Read an image from a file
> into an array.
> 
> Return value is a numpy.array. For grayscale images, the return array
> is MxN. For RGB images, the return value is MxNx3. For RGBA images the
> return value is MxNx4.
> [/quote]
> 
> But if I read a 128*128*8 BPP gray PNG file, the array.shape is (128,
> 128, 3); if I read a 128*128*24BPP color PNG file, the array.shape is
> (128, 128, 4)

Are you sure your png "24bpp" does not have a transparency channel?

-- 
Fabrice