swayosd: add custom style option

modules/services/swayosd.nix

@@ -26,6 +26,15 @@ in {
       description = "OSD margin from top edge (0.5 would be screen center).";
     };
 
+    stylePath = mkOption {
+      type = types.nullOr types.path;
+      default = null;
+      example = "/etc/xdg/swayosd/style.css";
+      description = ''
+        Use a custom Stylesheet file instead of looking for one.
+      '';
+    };
+
     display = mkOption {
       type = types.nullOr types.str;
       default = null;
@@ -57,6 +66,8 @@ in {
           Type = "simple";
           ExecStart = "${cfg.package}/bin/swayosd-server"
             + (optionalString (cfg.display != null) " --display ${cfg.display}")
+            + (optionalString (cfg.stylePath != null)
+              " --style ${escapeShellArg cfg.stylePath}")
             + (optionalString (cfg.topMargin != null)
               " --top-margin ${toString cfg.topMargin}");
           Restart = "always";

tests/modules/services/swayosd/swayosd.nix

@@ -8,6 +8,7 @@
       outPath = "@swayosd@";
     };
     display = "DISPLAY";
+    stylePath = "/etc/xdg/swayosd/style.css";
     topMargin = 0.1;
   };
 
@@ -20,7 +21,7 @@
           WantedBy=graphical-session.target
 
           [Service]
-          ExecStart=@swayosd@/bin/swayosd-server --display DISPLAY --top-margin 0.100000
+          ExecStart=@swayosd@/bin/swayosd-server --display DISPLAY --style '/etc/xdg/swayosd/style.css' --top-margin 0.100000
           Restart=always
           Type=simple