input: implement follow_mouse_shrink (#13707)

* input: implement follow_mouse_shrink

Add a new config option `input:follow_mouse_shrink` (INT, 0-300, default 0)
that shrinks inactive window hitboxes by the specified number of pixels for
focus detection purposes. This creates a dead zone in gaps between windows
where moving the cursor will not trigger a focus change.

The shrink only applies to inactive (non-focused) windows and only during
mouse-move focus checks (follow_mouse = 1). Click and scroll interactions
are unaffected — clicking on a window in the shrunk area still works
normally once the window is focused.

Closes #9973

* tests: add integration test for follow_mouse_shrink

1 files changed, 1 insertions, 0 deletions

diff --git a/src/config/legacy/ConfigManager.cpp b/src/config/legacy/ConfigManager.cpp
index bfe8fef3..310d2710 100644
--- a/src/config/legacy/ConfigManager.cpp
+++ b/src/config/legacy/ConfigManager.cpp
@@ -684,6 +684,7 @@ CConfigManager::CConfigManager() {
     registerConfigVar("animations:workspace_wraparound", Hyprlang::INT{0});
 
     registerConfigVar("input:follow_mouse", Hyprlang::INT{1});
+    registerConfigVar("input:follow_mouse_shrink", Hyprlang::INT{0});
     registerConfigVar("input:follow_mouse_threshold", Hyprlang::FLOAT{0});
     registerConfigVar("input:focus_on_close", Hyprlang::INT{0});
     registerConfigVar("input:mouse_refocus", Hyprlang::INT{1});