moby: lift background into sway config

hosts/by-name/moby/polyfill.nix

@@ -9,13 +9,6 @@
 # - <https://itsfoss.com/content/images/2023/04/nixos-tutorials.png>
 
 { lib, pkgs, sane-lib, ... }:
-let
-  # TODO: generate this from the .svg
-  # bg = ./nixos-bg-02.png;
-  bg = pkgs.runCommand "nixos-bg.png" { nativeBuildInputs = [ pkgs.inkscape ]; } ''
-    inkscape ${./nixos-bg-02.svg} -o $out
-  '';
-in
 {
   sane.programs.firefox.config = {
     # compromise impermanence for the sake of usability
@@ -134,7 +127,6 @@ in
       # - close is 16th entry
       SXMO_BEMENU_LANDSCAPE_LINES = "11";  # default 8
       SXMO_BEMENU_PORTRAIT_LINES = "16";  # default 16
-      SXMO_BG_IMG = "${bg}";
       SXMO_LOCK_IDLE_TIME = "15";  # how long between screenoff -> lock -> back to screenoff (default: 8)
       # gravity: how far to tilt the device before the screen rotates
       # for a given setting, normal <-> invert requires more movement then left <-> right

hosts/modules/gui/default.nix

@@ -7,6 +7,7 @@
     ./phosh.nix
     ./sway
     ./sxmo
+    ./theme
   ];
 
   sane.programs.guiApps = {

hosts/modules/gui/sway/default.nix

@@ -46,6 +46,9 @@ in
           default font (for e.g. window titles)
         '';
       };
+      background = mkOption {
+        type = types.path;
+      };
       mod = mkOption {
         type = types.string;
         default = "Mod4";

hosts/modules/gui/sway/sway-config

@@ -32,6 +32,8 @@ client.focused_inactive #1f5e54 #5f676a #ffffff
 client.unfocused        #1f5e54 #1f554c #b4b4b4
 client.urgent           #ff8080 #ff8080 #ffffff
 
+output '*' bg "@background@" fill
+
 ### pixel boundary between windows
 hide_edge_borders smart
 default_border pixel 1

hosts/modules/gui/sway/sway-config.nix

@@ -36,6 +36,7 @@ in pkgs.substituteAll {
     xwayland
   ;
   inherit (config)
+    background
     brightness_down_cmd
     brightness_up_cmd
     extra_lines

hosts/modules/gui/theme/default.nix

@@ -0,0 +1,28 @@
+{ config, lib, pkgs, ... }:
+let
+  cfg = config.sane.gui.theme.background;
+in
+{
+  options = with lib; {
+    sane.gui.theme.background = {
+      svg = mkOption {
+        type = types.path;
+        default = ./nixos-bg-02.svg;
+      };
+      png = mkOption {
+        type = types.path;
+        default = pkgs.runCommand
+          "nixos-bg.png"
+          { nativeBuildInputs = [ pkgs.inkscape ]; }
+          ''
+            inkscape ${cfg.svg} -o $out
+          '';
+      };
+    };
+  };
+
+  config = {
+    sane.gui.sway.config.background = lib.mkDefault cfg.png;
+    sane.gui.sxmo.settings.SXMO_BG_IMG = lib.mkDefault (builtins.toString cfg.png);
+  };
+}