Fix preview of PNG images (bz 1906363).

Add missing Recommends needed to preview images (bz 1906363).

sympy-png-decoder.patch

@@ -0,0 +1,13 @@
+--- sympy-sympy-1.7/sympy/printing/preview.py.orig	2020-11-29 04:02:22.000000000 -0700
++++ sympy-sympy-1.7/sympy/printing/preview.py	2020-12-10 10:55:53.290413553 -0700
+@@ -32,8 +32,8 @@ def _run_pyglet(fname, fmt):
+     from pyglet.window import key
+ 
+     if fmt == "png":
+-        from pyglet.image.codecs.png import PNGImageDecoder
+-        img = image.load(fname, decoder=PNGImageDecoder())
++        from pyglet.image.codecs.pil import PILImageDecoder
++        img = image.load(fname, decoder=PILImageDecoder())
+     else:
+         raise ValueError("pyglet preview works only for 'png' files.")
+ 

sympy.spec

@@ -1,6 +1,6 @@
 Name:           sympy
 Version:        1.7
-Release:        1%{?dist}
+Release:        2%{?dist}
 Summary:        A Python library for symbolic mathematics
 License:        BSD
 URL:            http://sympy.org/
@@ -11,6 +11,8 @@ Patch0:         %{name}-float.patch
 Patch1:         %{name}-python3.patch
 # Adapt to Theano-PyMC
 Patch2:         %{name}-theano-pymc.patch
+# Work around Fedora pyglet not including PNGImageDecoder
+Patch3:         %{name}-png-decoder.patch
 
 BuildArch:      noarch
 
@@ -61,6 +63,12 @@ Requires:       %{py3_dist gmpy2}
 Requires:       %{py3_dist matplotlib}
 Requires:       %{py3_dist pyglet}
 
+Recommends:     tex(latex)
+Recommends:     tex(amsfonts.sty)
+Recommends:     tex(amsmath.sty)
+Recommends:     tex(euler.sty)
+Recommends:     tex(eulervm.sty)
+Recommends:     tex(standalone.cls)
 Recommends:     %{py3_dist numexpr}
 Recommends:     %{py3_dist scipy}
 Recommends:     %{py3_dist theano-pymc}
@@ -143,7 +151,6 @@ find examples/ -name '*.py[co]' -print -delete
 # Do not run tests on 32-bit systems.
 %global maxpyint %(python3 -c 'import sys;print("%x" % sys.maxsize)')
 if [ "%{maxpyint}" != "7fffffff" ]; then
-  let "dnum = $RANDOM % 90 + 10"
   # Split into many small chunks to reduce waiting in the end-game
   jobs=%{?_smp_mflags}; jobs=${jobs#-j}; jobs=$((jobs * 3))
 
@@ -177,6 +184,10 @@ fi
 %{_docdir}/%{name}-doc/html
 
 %changelog
+* Thu Dec 10 2020 Jerry James <loganjerry@gmail.com> - 1.7-2
+- Fix preview of PNG images (bz 1906363)
+- Add missing Recommends needed to preview images (bz 1906363)
+
 * Sat Nov 28 2020 Jerry James <loganjerry@gmail.com> - 1.7-1
 - Version 1.7