add automatic transparency script

config/programs/theming.nix

@@ -261,7 +261,6 @@ in {
     '';
   };
   programs.kitty.settings = with theme; {
-    background_opacity = "0.85";
     background = color 0;
     foreground = color 15;
     cursor = color 15;
@@ -464,7 +463,6 @@ in {
       border = mkLiteral "3px";
       border-color = mkLiteral "@border-col";
       background-color = mkLiteral "@bg-col";
-      opacity = mkLiteral "0.9";
     };
     mainbox = {
       background-color = mkLiteral "@bg-col";
@@ -615,7 +613,16 @@ in {
       mantle = color 0;
       crust = color 0;
     };
-    "glassit.alpha" = 220;
-    "glassit.force_sway" = true;
+  };
+  systemd.user.services.transparency = {
+    Unit = {
+      Description = "transparency";
+      After = ["graphical-session-pre.target"];
+      PartOf = ["graphical-session.target"];
+    };
+    Install.WantedBy = ["graphical-session.target"];
+    Service = {
+      ExecStart = "${./transparency.py}";
+    };
   };
 }

config/programs/transparency.py

@@ -0,0 +1,65 @@
+#!/usr/bin/env nix-shell
+#!nix-shell -i python3 -p python3 python3Packages.i3ipc
+
+import i3ipc
+import signal
+import sys
+from functools import partial
+
+foreground_transparency = "0.9"
+background_transparency = "0.7"
+
+
+def on_window_focus(ipc, event):
+    global prev_focused
+
+    focused = event.container
+
+    if focused.id != prev_focused.id:  # https://github.com/swaywm/sway/issues/2859
+        if focused.fullscreen_mode > 0:
+            focused.command("opacity 1")
+        else:
+            focused.command("opacity " + foreground_transparency)
+        if prev_focused.fullscreen_mode == 0:
+            prev_focused.command("opacity " + background_transparency)
+        prev_focused = focused
+
+
+def on_fullscreen_mode(ipc, event):
+    global prev_focused
+    if event.container.id == prev_focused.id:
+        prev_focused = event.container
+
+    if event.container.fullscreen_mode > 0:
+        event.container.command("opacity 1")
+    elif event.container.focused:
+        event.container.command("opacity " + foreground_transparency)
+    else:
+        event.container.command("opacity " + background_transparency)
+
+
+def remove_opacity(ipc):
+    for workspace in ipc.get_tree().workspaces():
+        for w in workspace:
+            w.command("opacity 1")
+    ipc.main_quit()
+    sys.exit(0)
+
+
+if __name__ == '__main__':
+    ipc = i3ipc.Connection()
+    prev_args = None
+
+    for window in ipc.get_tree():
+        if window.fullscreen_mode > 0:
+            window.command("opacity 1")
+        elif window.focused:
+            prev_focused = window
+            window.command("opacity " + foreground_transparency)
+        else:
+            window.command("opacity " + background_transparency)
+    for sig in [signal.SIGINT, signal.SIGTERM]:
+        signal.signal(sig, lambda signal, frame: remove_opacity(ipc))
+    ipc.on("window::focus", on_window_focus)
+    ipc.on("window::fullscreen_mode", on_fullscreen_mode)
+    ipc.main()