Make light/dark mode work

src/gd_sophia_editor.erl

@@ -25,6 +25,7 @@
 -define(H, 255). % High
 -define(M, 192). % Medium
 -define(L, 128). % Low
+-define(X,  32). % X-Low
 -define(Z,   0). % Zilch
 
 
@@ -44,6 +45,7 @@
 -define(brown,         {?L, ?L, ?Z}).
 -define(magenta,       {?L, ?Z, ?L}).
 -define(cyan,          {?Z, ?L, ?L}).
+-define(not_black,     {?X, ?X, ?X}).
 -define(grey,          {?L, ?L, ?L}).
 -define(white,         {?M, ?M, ?M}).
 
@@ -63,7 +65,8 @@ palette(light) ->
       ?COMMENT    => ?grey,
       ?STRING     => ?red,
       ?NUMBER     => ?magenta,
-      ?OPERATOR   => ?brown};
+      ?OPERATOR   => ?brown,
+      bg          => ?high_white};
 palette(dark) ->
     #{?DEFAULT    => ?white,
       ?KEYWORD    => ?light_cyan,
@@ -71,10 +74,15 @@ palette(dark) ->
       ?COMMENT    => ?grey,
       ?STRING     => ?light_red,
       ?NUMBER     => ?light_magenta,
-      ?OPERATOR   => ?yellow}.
+      ?OPERATOR   => ?yellow,
+      bg          => ?not_black}.
 
 color_mode() ->
-    light.
+    {R, G, B, _} = wxSystemSettings:getColour(?wxSYS_COLOUR_WINDOW),
+    case (lists:sum([R, G, B]) div 3) > 128 of
+        true  -> light;
+        false -> dark
+    end.
 
 
 new(Parent) ->
@@ -104,13 +112,15 @@ set_text(STC, Text) ->
 %% ======================================================================
 
 set_colors(STC) ->
-    wxStyledTextCtrl:styleClearAll(STC),
-    Palette = palette(color_mode()),
+    ok = wxStyledTextCtrl:styleClearAll(STC),
+    Palette = #{bg := BGC} = palette(color_mode()),
     Colorize =
         fun(Style) ->
             Color = maps:get(Style, Palette),
-            wxStyledTextCtrl:styleSetForeground(STC, Style, Color)
+            ok = wxStyledTextCtrl:styleSetForeground(STC, Style, Color),
+            ok = wxStyledTextCtrl:styleSetBackground(STC, Style, BGC)
         end,
+    ok = wxStyledTextCtrl:styleSetBackground(STC, ?wxSTC_STYLE_DEFAULT, BGC),
     lists:foreach(Colorize, styles()).