fix ipynbplotutils.Plot3D

meshgrid is in numpy now.
PIL now correctly refuses to store an RGBA as JPEG,
see python-pillow/Pillow#2609.

pyoptools/gui/ipynbplotutils.py

@@ -165,12 +165,13 @@ def show(self):
         '''Show the PIL image with the default viewer'''
         self.image.show()
 
-    def _repr_jpeg_(self):
-        '''Ipython can embed the jpg image directly
-        from http://ipython.org/ipython-doc/dev/config/integrating.html
+    def _repr_png_(self):
+        '''return a png image
+        to be embedded directly by Ipython:
+        https://ipython.readthedocs.io/en/stable/config/integrating.html
         '''
         temppng = six.BytesIO()
-        self.image.save(temppng, "JPEG")
+        self.image.save(temppng, "PNG")
         data = temppng.getvalue()
         temppng.close()
         return data

pyoptools/raytrace/surface/surface.pyx

@@ -31,13 +31,12 @@ from warnings import warn
 from sys import exit
 from numpy import absolute, arccos, array, cos as npcos, dot, isinf as npisinf,inf, isnan as npisnan, \
                 power, sqrt as npsqrt, sometrue,  zeros_like, ones_like,  histogram2d, \
-                linspace, abs,  indices, argwhere, tan, polyfit,arange,where
+                linspace, meshgrid, abs, indices, argwhere, tan, polyfit, arange, where
 from numpy.fft import fft2,  ifft2
 from numpy.ma import array as ma_array
 
 from scipy.signal import medfilt2d
 from scipy import interpolate
-from pylab import meshgrid
 
 from inspect import getmembers, isroutine