Don't set savefig.facecolor/edgecolor in dark_background/538 styles.

anntzer · anntzer · commit 3d758e2dfdda · 2024-05-01T21:49:13.000+02:00
Previously, the dark_background and fivethirtyeight styles would set the
savefig.facecolor and savefig.edgecolor rcParams to the same values as
figure.facecolor and figure.edgecolor; i.e., if a user uses a style but
tweaks the figure facecolor, this tweak is lost (overridden) when saving
the figure.  A concrete example would be using the dark_background style
but wanting a dark gray background instead of a black one, e.g.
`mpl.style.use(["dark_background", {"figure.facecolor": ".2"}]); plot();
savefig(...)`.

In all likelihood these values were set because the styles
predate the ability to set these savefig rcParams to "auto", which means
"don't change the figure facecolor, just use it as is" (a feature
introduced exactly because this auto-switching of color by savefig was
confusing users).  Now we can just remove these rcParams from the two
styles (which are the only ones affected by the issue -- the grayscale
style also sets savefig.facecolor but to a value different from
figure.facecolor) and let them inherit the global default value, "auto".
diff --git a/doc/api/next_api_changes/behavior/28156-AL.rst b/doc/api/next_api_changes/behavior/28156-AL.rst
@@ -0,0 +1,12 @@
+dark_background and fivethirtyeight styles no longer set ``savefig.facecolor`` and ``savefig.edgecolor``
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+When using these styles, :rc:`savefig.facecolor` and :rc:`savefig.edgecolor`
+now inherit the global default value of "auto", which means that the actual
+figure colors will be used.  Previously, these rcParams were set to the same
+values as :rc:`figure.facecolor` and :rc:`figure.edgecolor`, i.e. a saved
+figure would always use the theme colors even if the user manually overrode
+them; this is no longer the case.
+
+This change should have no impact for users that do not manually set the figure
+face and edge colors.
diff --git a/lib/matplotlib/mpl-data/stylelib/dark_background.mplstyle b/lib/matplotlib/mpl-data/stylelib/dark_background.mplstyle
@@ -18,9 +18,6 @@ grid.color: white
 figure.facecolor: black
 figure.edgecolor: black
 
-savefig.facecolor: black
-savefig.edgecolor: black
-
 ### Boxplots
 boxplot.boxprops.color: white
 boxplot.capprops.color: white
diff --git a/lib/matplotlib/mpl-data/stylelib/fivethirtyeight.mplstyle b/lib/matplotlib/mpl-data/stylelib/fivethirtyeight.mplstyle
@@ -29,10 +29,7 @@ xtick.minor.size: 0
 ytick.major.size: 0
 ytick.minor.size: 0
 
-font.size:14.0
-
-savefig.edgecolor: f0f0f0
-savefig.facecolor: f0f0f0
+font.size: 14.0
 
 figure.subplot.left: 0.08
 figure.subplot.right: 0.95
