Merge pull request matplotlib#3795 from chebee7i/style-rcparams

ENH : RcParams/dict as input to matplotlib.style.use

Author: tacaswell

lib/matplotlib/style/core.py

@@ -39,53 +39,88 @@ def is_style_file(filename):
     return STYLE_FILE_PATTERN.match(filename) is not None
 
 
-def use(name):
-    """Use matplotlib style settings from a known style sheet or from a file.
+def use(style):
+    """Use matplotlib style settings from a style specification.
 
     Parameters
     ----------
-    name : str or list of str
-        Name of style or path/URL to a style file. For a list of available
-        style names, see `style.available`. If given a list, each style is
-        applied from first to last in the list.
+    style : str, dict, or list
+        A style specification. Valid options are:
+
+        +------+-------------------------------------------------------------+
+        | str  | The name of a style or a path/URL to a style file. For a    |
+        |      | list of available style names, see `style.available`.       |
+        +------+-------------------------------------------------------------+
+        | dict | Dictionary with valid key/value pairs for                   |
+        |      | `matplotlib.rcParams`.                                      |
+        +------+-------------------------------------------------------------+
+        | list | A list of style specifiers (str or dict) applied from first |
+        |      | to last in the list.                                        |
+        +------+-------------------------------------------------------------+
+
+
     """
-    if cbook.is_string_like(name):
-        name = [name]
+    if cbook.is_string_like(style) or hasattr(style, 'keys'):
+        # If name is a single str or dict, make it a single element list.
+        styles = [style]
+    else:
+        styles = style
+
+    for style in styles:
+        if not cbook.is_string_like(style):
+            mpl.rcParams.update(style)
+            continue
 
-    for style in name:
         if style in library:
             mpl.rcParams.update(library[style])
         else:
             try:
                 rc = rc_params_from_file(style, use_default_template=False)
                 mpl.rcParams.update(rc)
-            except:
+            except IOError:
                 msg = ("'%s' not found in the style library and input is "
                        "not a valid URL or path. See `style.available` for "
                        "list of available styles.")
-                raise ValueError(msg % style)
+                raise IOError(msg % style)
 
 
 @contextlib.contextmanager
-def context(name, after_reset=False):
+def context(style, after_reset=False):
     """Context manager for using style settings temporarily.
 
     Parameters
     ----------
-    name : str or list of str
-        Name of style or path/URL to a style file. For a list of available
-        style names, see `style.available`. If given a list, each style is
-        applied from first to last in the list.
+    style : str, dict, or list
+        A style specification. Valid options are:
+
+        +------+-------------------------------------------------------------+
+        | str  | The name of a style or a path/URL to a style file. For a    |
+        |      | list of available style names, see `style.available`.       |
+        +------+-------------------------------------------------------------+
+        | dict | Dictionary with valid key/value pairs for                   |
+        |      | `matplotlib.rcParams`.                                      |
+        +------+-------------------------------------------------------------+
+        | list | A list of style specifiers (str or dict) applied from first |
+        |      | to last in the list.                                        |
+        +------+-------------------------------------------------------------+
+
     after_reset : bool
         If True, apply style after resetting settings to their defaults;
         otherwise, apply style on top of the current settings.
     """
     initial_settings = mpl.rcParams.copy()
     if after_reset:
         mpl.rcdefaults()
-    use(name)
-    yield
-    mpl.rcParams.update(initial_settings)
+    try:
+        use(style)
+    except:
+        # Restore original settings before raising errors during the update.
+        mpl.rcParams.update(initial_settings)
+        raise
+    else:
+        yield
+    finally:
+        mpl.rcParams.update(initial_settings)
 
 
 def load_base_library():

lib/matplotlib/tests/test_style.py

@@ -2,17 +2,20 @@
                         unicode_literals)
 
 import os
+import sys
 import shutil
 import tempfile
 from contextlib import contextmanager
 
+from nose import SkipTest
+from nose.tools import assert_raises
+
 import matplotlib as mpl
 from matplotlib import style
 from matplotlib.style.core import USER_LIBRARY_PATHS, STYLE_EXTENSION
 
 import six
 
-
 PARAM = 'image.cmap'
 VALUE = 'pink'
 DUMMY_SETTINGS = {PARAM: VALUE}
@@ -68,6 +71,70 @@ def test_context():
     assert mpl.rcParams[PARAM] == 'gray'
 
 
+def test_context_with_dict():
+    original_value = 'gray'
+    other_value = 'blue'
+    mpl.rcParams[PARAM] = original_value
+    with style.context({PARAM: other_value}):
+        assert mpl.rcParams[PARAM] == other_value
+    assert mpl.rcParams[PARAM] == original_value
+
+
+def test_context_with_dict_after_namedstyle():
+    # Test dict after style name where dict modifies the same parameter.
+    original_value = 'gray'
+    other_value = 'blue'
+    mpl.rcParams[PARAM] = original_value
+    with temp_style('test', DUMMY_SETTINGS):
+        with style.context(['test', {PARAM: other_value}]):
+            assert mpl.rcParams[PARAM] == other_value
+    assert mpl.rcParams[PARAM] == original_value
+
+
+def test_context_with_dict_before_namedstyle():
+    # Test dict before style name where dict modifies the same parameter.
+    original_value = 'gray'
+    other_value = 'blue'
+    mpl.rcParams[PARAM] = original_value
+    with temp_style('test', DUMMY_SETTINGS):
+        with style.context([{PARAM: other_value}, 'test']):
+            assert mpl.rcParams[PARAM] == VALUE
+    assert mpl.rcParams[PARAM] == original_value
+
+
+def test_context_with_union_of_dict_and_namedstyle():
+    # Test dict after style name where dict modifies the a different parameter.
+    original_value = 'gray'
+    other_param = 'text.usetex'
+    other_value = True
+    d = {other_param: other_value}
+    mpl.rcParams[PARAM] = original_value
+    mpl.rcParams[other_param] = (not other_value)
+    with temp_style('test', DUMMY_SETTINGS):
+        with style.context(['test', d]):
+            assert mpl.rcParams[PARAM] == VALUE
+            assert mpl.rcParams[other_param] == other_value
+    assert mpl.rcParams[PARAM] == original_value
+    assert mpl.rcParams[other_param] == (not other_value)
+
+
+def test_context_with_badparam():
+    if sys.version_info[:2] >= (2, 7):
+        from collections import OrderedDict
+    else:
+        m = "Test can only be run in Python >= 2.7 as it requires OrderedDict"
+        raise SkipTest(m)
+
+    original_value = 'gray'
+    other_value = 'blue'
+    d = OrderedDict([(PARAM, original_value), ('badparam', None)])
+    with style.context({PARAM: other_value}):
+        assert mpl.rcParams[PARAM] == other_value
+        x = style.context([d])
+        assert_raises(KeyError, x.__enter__)
+        assert mpl.rcParams[PARAM] == other_value
+
+
 if __name__ == '__main__':
     from numpy import testing
     testing.run_module_suite()