mouse: Add an `awful.mouse.snap.aerosnap_distance` global variable.

The distance to snap clients to each other was already something which
could be configured. The distance to enable screen edge wasn't.

Fixes #3025

lib/awful/mouse/init.lua

@@ -31,11 +31,16 @@ local mouse = {
 mouse.object = {}
 mouse.wibox = {}
 
---- The default snap distance.
+--- The default distance before snapping clients together.
 -- @tfield integer awful.mouse.snap.default_distance
 -- @tparam[opt=8] integer default_distance
 -- @see awful.mouse.snap
 
+--- The default distance before activating screen edge snap.
+-- @tfield integer awful.mouse.snap.aerosnap_distance
+-- @tparam[opt=16] integer default_distance
+-- @see awful.mouse.snap
+
 --- Enable screen edges snapping.
 -- @tfield[opt=true] boolean awful.mouse.snap.edge_enabled
 
@@ -57,9 +62,9 @@ mouse.wibox = {}
 -- @beautiful beautiful.snap_shape
 -- @tparam function shape A `gears.shape` compatible function
 
---- The gap between snapped contents.
+--- The gap between snapped clients.
 -- @beautiful beautiful.snapper_gap
--- @tparam number (default: 0)
+-- @tparam[opt=0] number snapper_gap
 
 --- Get the client object under the pointer.
 -- @deprecated awful.mouse.client_under_pointer

lib/awful/mouse/snap.lua

@@ -25,7 +25,8 @@ local capi = {
 }
 
 local module = {
-    default_distance = 8
+    default_distance  = 8,
+    aerosnap_distance = 16
 }
 
 local placeholder_w = nil
@@ -258,7 +259,7 @@ resize.add_move_callback(function(c, geo, args)
     -- Screen edge snapping (areosnap)
     if (module.edge_enabled ~= false)
       and args and (args.snap == nil or args.snap) then
-        detect_areasnap(c, 16)
+        detect_areasnap(c, module.aerosnap_distance)
     end
 
     -- Snapping between clients