RGB image is flipped a different way depending on whether it is PNG or JPG about matplotlib HOT 7 CLOSED

JPG loading is handled through PIL, and the pil_to_array code explicitly flips the image upside down. This seems like a bug, but I'm hesitant to fix it since it's been that way for at least 3 years in a commit by @jdh2358 -- I'm surprised we're just finding it now -- and this isn't an area I'm terribly familiar with.

diff --git a/lib/matplotlib/image.py b/lib/matplotlib/image.py
index f2d9984..93402d4 100644
--- a/lib/matplotlib/image.py
+++ b/lib/matplotlib/image.py
@@ -1257,7 +1257,7 @@ def pil_to_array( pilImage ):
     """
     def toarray(im):
         'return a 1D array of floats'
-        x_str = im.tostring('raw',im.mode,0,-1)
+        x_str = im.tostring()
         x = np.fromstring(x_str,np.uint8)
         return x
 

from matplotlib.

I think the thread below is related with this issue. I don't think we actually made any action though.

http://old.nabble.com/Question-about-imshow-ts23578564.html

from matplotlib.

Changing assignment to Andrew, since I don't quite understand the history and backward incompatibility issues.

from matplotlib.

I can verify that this is a bug. Here's the much simplified version we use in scikits.image:

https://github.com/scikits-image/scikits.image/blob/master/scikits/image/io/_plugins/pil_plugin.py#L12

from matplotlib.

I believe this is fixed by #616.

from matplotlib.

I can confirm that this was fixed 5 days ago.

from matplotlib.

Just a note: as this is a pretty significant backward-incompatible change, it is only on master, and won't be in the 1.1.2rc.

from matplotlib.