Small cleanups to animation.

anntzer · anntzer · commit 3229acfff88f · 2022-06-29T22:40:09.000+02:00
- Don't hard-code/expose CREATE_NO_WINDOW on Windows (I'll aggressively
  remove the global without a deprecation here), taking advantage of the
  fact that the subprocess module now exposes the constant on Windows.
- Clarify the documentation in the rcParams for ffmpeg_path and
  convert_path.  1) subprocess.Popen (which is really what we're using)
  is not exactly just searching in the $PATH -- see the big warning to
  that respect in the CPython docs.  2) One doesn't actually need to put
  an absolute path for convert on Windows -- Matplotlib now handles this
  transparently.
diff --git a/lib/matplotlib/animation.py b/lib/matplotlib/animation.py
@@ -44,13 +44,9 @@
 _log = logging.getLogger(__name__)
 
 # Process creation flag for subprocess to prevent it raising a terminal
-# window. See for example:
-# https://stackoverflow.com/q/24130623/
-if sys.platform == 'win32':
-    subprocess_creation_flags = CREATE_NO_WINDOW = 0x08000000
-else:
-    # Apparently None won't work here
-    subprocess_creation_flags = 0
+# window. See for example https://stackoverflow.com/q/24130623/
+subprocess_creation_flags = (
+    subprocess.CREATE_NO_WINDOW if sys.platform == 'win32' else 0)
 
 # Other potential writing methods:
 # * http://pymedia.org/
diff --git a/lib/matplotlib/mpl-data/matplotlibrc b/lib/matplotlib/mpl-data/matplotlibrc
@@ -768,12 +768,18 @@
 #animation.bitrate: -1            # Controls size/quality trade-off for movie.
                                   # -1 implies let utility auto-determine
 #animation.frame_format: png      # Controls frame format used by temp files
-#animation.ffmpeg_path:  ffmpeg   # Path to ffmpeg binary. Without full path
-                                  # $PATH is searched
-#animation.ffmpeg_args:           # Additional arguments to pass to ffmpeg
-#animation.convert_path: convert  # Path to ImageMagick's convert binary.
-                                  # On Windows use the full path since convert
-                                  # is also the name of a system tool.
-#animation.convert_args:          # Additional arguments to pass to convert
+
+## Path to ffmpeg binary.  Unqualified paths are resolved by subprocess.Popen.
+#animation.ffmpeg_path:  ffmpeg
+## Additional arguments to pass to ffmpeg.
+#animation.ffmpeg_args:
+
+## Path to ImageMagick's convert binary.  Unqualified paths are resolved by
+## subprocess.Popen, except that on Windows, we look up an install of
+## ImageMagick in the registry (as convert is also the name of a system tool).
+#animation.convert_path: convert
+## Additional arguments to pass to convert.
+#animation.convert_args:
+#
 #animation.embed_limit:  20.0     # Limit, in MB, of size of base64 encoded
                                   # animation in HTML (i.e. IPython notebook)
