sway: Enable screencasts via xdg-desktop-portal-wlr

This also adds a blinking indicator to the status bar so it is obvious
when the screen is shared.

modules/gui.nix

@@ -8,6 +8,17 @@ lib.mkIf config.sbruder.gui.enable {
     extraPackages = [ ];
   };
 
+  xdg = {
+    portal = {
+      enable = true;
+      extraPortals = with pkgs; [
+        xdg-desktop-portal-wlr
+        xdg-desktop-portal-gtk
+      ];
+      gtkUsePortal = true;
+    };
+  };
+
   # steam (and other high quality software) still ships 32 bit binaries
   hardware.opengl.driSupport32Bit = lib.mkDefault pkgs.stdenv.isx86_64;
 

users/simon/files/waybar/style.css

@@ -156,3 +156,13 @@ window#waybar {
   background-color: @base3@;
   color: @base03@;
 }
+
+#custom-screencast {
+  background-color: @red@;
+  color: @base03@;
+  animation-name: blink;
+  animation-duration: 0.5s;
+  animation-timing-function: cubic-bezier(1, 0, 0, 1);
+  animation-iteration-count: infinite;
+  animation-direction: alternate;
+}

users/simon/modules/sway.nix

@@ -343,9 +343,9 @@ lib.mkIf nixosConfig.sbruder.gui.enable {
       ];
       modules-right = [
         "tray"
+        "custom/screencast"
         "custom/redshift"
         "idle_inhibitor"
-        "custom/notification_inhibitor"
         "backlight"
         "mpd"
         "pulseaudio"
@@ -386,6 +386,38 @@ lib.mkIf nixosConfig.sbruder.gui.enable {
           deactivated = " ";
         };
       };
+      "custom/screencast" = {
+        exec = pkgs.writeScript "screencast-monitor" ''
+          #!${pkgs.python3}/bin/python3
+          import subprocess
+          import sys
+
+          active_outputs = 0
+
+          with subprocess.Popen(
+              ["${pkgs.coreutils}/bin/stdbuf", "-o0", "${nixosConfig.services.pipewire.package}/bin/pw-link", "-m", "-o", "xdg-desktop-portal-wlr"],
+              stdout=subprocess.PIPE,
+              text=True,
+          ) as proc:
+              for line in proc.stdout:
+                  action = line.split(" ")[0]
+                  if action == "=" or action == "+":
+                      active_outputs += 1
+                  elif action == "-":
+                      active_outputs -= 1
+                  else:
+                      print(f"Invalid action {action} (in line {line})", file=sys.stderr)
+
+                  if active_outputs > 0:
+                      print("${lrm} ")
+                  else:
+                      print()
+
+                  sys.stdout.flush()
+        '';
+        format = "{}";
+        tooltip = false;
+      };
       backlight = {
         format = "{percent}% {icon}";
         format-icons = [ " " " " " " " " " " " " " " ];
@@ -596,4 +628,13 @@ lib.mkIf nixosConfig.sbruder.gui.enable {
       night = 3500;
     };
   };
+
+  # screen recording/sharing with pipewire
+  xdg.configFile."xdg-desktop-portal-wlr/config".text = lib.generators.toINI { } {
+    screencast = {
+      max_fps = 30;
+      chooser_type = "simple";
+      chooser_cmd = "slurp -f %o -or";
+    };
+  };
 }