A script to make inactive windows transparent

Sway has ability to apply transparency to arbitrary windows. This script
wires up this functional to one of popular use-cases from
i3+<compositor_name>.

Signed-off-by: Konstantin Kharlamov <Hi-Angel@yandex.ru>

contrib/inactive-windows-transparency.py

@@ -0,0 +1,28 @@
+#!/usr/bin/python
+
+# This script requires i3ipc-python package (install it from a system package manager
+# or pip).
+# It makes inactive windows transparent. Use `transparency_val` variable to control
+# transparency strength in range of 0…1.
+
+import i3ipc
+
+transparency_val = '0.8';
+ipc              = i3ipc.Connection()
+prev_focused     = None
+
+for window in ipc.get_tree():
+    if window.focused:
+        prev_focused = window
+    else:
+        window.command('opacity ' + transparency_val)
+
+def on_window_focus(ipc, focused):
+    global prev_focused
+    if focused.container.id != prev_focused.id: # https://github.com/swaywm/sway/issues/2859
+        focused.container.command('opacity 1')
+        prev_focused.command('opacity ' + transparency_val)
+        prev_focused = focused.container
+
+ipc.on("window::focus", on_window_focus)
+ipc.main()