@@ -53,6 +53,8 @@ def __init__(
5353 )# type: ignore[no-untyped-call]
5454self ._replace_toolbar_icons ()
5555# callback to update when napari theme changed
56+ # TODO: this isn't working completely (see issue #140)
57+ # most of our styling respects the theme change but not all
5658self .viewer .events .theme .connect (self ._on_theme_change )
5759
5860self .setLayout (QVBoxLayout ())
@@ -77,22 +79,22 @@ def apply_napari_colorscheme(self, ax: Axes) -> None:
7779"""Apply napari-compatible colorscheme to an Axes."""
7880# get the foreground colours from current theme
7981theme = napari .utils .theme .get_theme (self .viewer .theme ,as_dict = False )
80- fg = theme .foreground .as_hex ()# fg is a muted contrast to bg
81- tx = theme .text .as_hex ()# text is high contrast to bg
82+ fg_colour = theme .foreground .as_hex ()# fg is a muted contrast to bg
83+ text_colour = theme .text .as_hex ()# text is high contrast to bg
8284
8385# changing color of axes background to transparent
8486ax .set_facecolor ("none" )
8587
8688# changing colors of all axes
8789for spine in ax .spines :
88- ax .spines [spine ].set_color (fg )
90+ ax .spines [spine ].set_color (fg_colour )
8991
90- ax .xaxis .label .set_color (tx )
91- ax .yaxis .label .set_color (tx )
92+ ax .xaxis .label .set_color (text_colour )
93+ ax .yaxis .label .set_color (text_colour )
9294
9395# changing colors of axes labels
94- ax .tick_params (axis = "x" ,colors = tx )
95- ax .tick_params (axis = "y" ,colors = tx )
96+ ax .tick_params (axis = "x" ,colors = text_colour )
97+ ax .tick_params (axis = "y" ,colors = text_colour )
9698
9799def _on_theme_change (self )-> None :
98100"""Update MPL toolbar and axis styling when `napari.Viewer.theme` is changed.
@@ -104,15 +106,24 @@ def _on_theme_change(self) -> None:
104106if self .figure .gca ():
105107self .apply_napari_colorscheme (self .figure .gca ())
106108
109+ def _theme_has_light_bg (self )-> bool :
110+ """
111+ Does this theme have a light background?
112+
113+ Returns
114+ -------
115+ bool
116+ True if theme's background colour has hsl lighter than 50%, False if darker.
117+ """
118+ theme = napari .utils .theme .get_theme (self .viewer .theme ,as_dict = False )
119+ _ ,_ ,bg_lightness = theme .background .as_hsl_tuple ()
120+ return bg_lightness > 0.5
121+
107122def _get_path_to_icon (self )-> Path :
108123"""
109124 Get the icons directory (which is theme-dependent).
110125 """
111- # TODO: can make this more robust by doing some RGB tricks to figure out
112- # whether white or black icons are going to be more visible given the
113- # theme.background
114- islight = self .viewer .theme == "light"
115- if islight :
126+ if self ._theme_has_light_bg ():
116127return ICON_ROOT / "black"
117128else :
118129return ICON_ROOT / "white"