Deprecate checkdep_ps_distiller.

anntzer · anntzer · commit 968f9795cb93 · 2019-04-26T11:41:01.000+02:00
We may as well move it to the corresponding rc validator and always
validate when assigning to that rcParam, not just at import time.
diff --git a/doc/api/next_api_changes/2019-04-26-AL.rst b/doc/api/next_api_changes/2019-04-26-AL.rst
@@ -0,0 +1,4 @@
+Deprecations
+````````````
+
+``matplotlib.checkdep_ps_distiller`` is deprecated.
diff --git a/lib/matplotlib/__init__.py b/lib/matplotlib/__init__.py
@@ -460,6 +460,7 @@ def checkdep_inkscape():
 checkdep_inkscape.version = None
 
 
+@cbook.deprecated("3.2")
 def checkdep_ps_distiller(s):
     if not s:
         return False
@@ -1014,9 +1015,6 @@ def rc_params_from_file(fname, fail_on_error=False, use_default_template=True):
                                 defaultParams.items()
                                 if key not in _all_deprecated])
 
-rcParams['ps.usedistiller'] = checkdep_ps_distiller(
-                      rcParams['ps.usedistiller'])
-
 if rcParams['axes.formatter.use_locale']:
     locale.setlocale(locale.LC_ALL, '')
 
diff --git a/lib/matplotlib/rcsetup.py b/lib/matplotlib/rcsetup.py
@@ -15,10 +15,12 @@
 """
 from collections.abc import Iterable, Mapping
 from functools import reduce
+import logging
 import operator
 import os
 import re
 
+import matplotlib as mpl
 from matplotlib import cbook
 from matplotlib.cbook import ls_mapper
 from matplotlib.fontconfig_pattern import parse_fontconfig_pattern
@@ -28,6 +30,7 @@
 from cycler import Cycler, cycler as ccycler
 
 
+_log = logging.getLogger(__name__)
 # The capitalized forms are needed for ipython at present; this may
 # change for later versions.
 interactive_bk = ['GTK3Agg', 'GTK3Cairo',
@@ -534,11 +537,22 @@ def update_savefig_format(value):
 def validate_ps_distiller(s):
     if isinstance(s, str):
         s = s.lower()
-    if s in ('none', None):
+    if s in ('none', None, 'false', False):
         return None
-    elif s in ('false', False):
-        return False
     elif s in ('ghostscript', 'xpdf'):
+        try:
+            mpl._get_executable_info("gs")
+        except FileNotFoundError:
+            _log.warning("Setting rcParams['ps.usedistiller'] requires "
+                         "ghostscript.")
+            return None
+        if s == "xpdf":
+            try:
+                mpl._get_executable_info("pdftops")
+            except FileNotFoundError:
+                _log.warning("Setting rcParams['ps.usedistiller'] to 'xpdf' "
+                             "requires xpdf.")
+                return None
         return s
     else:
         raise ValueError('matplotlibrc ps.usedistiller must either be none, '
