read a png image with alpha gives uncorrect colors

Hi,

I have encountered a problem with this simplified code where I produce
a windrose with some alpha level.
Then read this png image to check.
Then discover that the colors are not correct.

What is the mistake ?
I am puzzled.

I use matplotlib 1.4.3

The correct windrose with alpha colors
<http://matplotlib.1069221.n5.nabble.com/file/n46131/windrose.png>

The read png image.
<http://matplotlib.1069221.n5.nabble.com/file/n46131/read.png>

Regards
Patrick

···

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I can't find it right now, but there is an issue on the scikit image issue
tracker which was a similar problem. I suspect the problem is that our png
read is not sophisticated enough and your png maybe encoded ckmy.

Tom

···

On Fri, Oct 9, 2015 at 7:19 AM PBrockmann <Patrick.Brockmann at lsce.ipsl.fr> wrote:

Hi,

I have encountered a problem with this simplified code where I produce
a windrose with some alpha level.
Then read this png image to check.
Then discover that the colors are not correct.

What is the mistake ?
I am puzzled.

I use matplotlib 1.4.3

The correct windrose with alpha colors
<http://matplotlib.1069221.n5.nabble.com/file/n46131/windrose.png>

The read png image.
<http://matplotlib.1069221.n5.nabble.com/file/n46131/read.png>

Regards
Patrick

--
View this message in context:
http://matplotlib.1069221.n5.nabble.com/read-a-png-image-with-alpha-gives-uncorrect-colors-tp46131.html
Sent from the matplotlib - users mailing list archive at Nabble.com.
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