naughty: Add position "middle" to center notifications in screen (#2775)

Signed-off-by: Michael Beaumont <mjboamail@gmail.com>

lib/naughty/core.lua

@@ -151,6 +151,7 @@ screen.connect_for_each_screen(function(s)
         bottom_left = {},
         bottom_middle = {},
         bottom_right = {},
+        middle = {},
     }
 end)
 
@@ -537,7 +538,7 @@ end
 -- @tparam[opt=focused] integer|screen args.screen Target screen for the notification.
 -- @string[opt="top_right"] args.position Corner of the workarea displaying the popups.
 --   Values: `"top_right"`, `"top_left"`, `"bottom_left"`,
---   `"bottom_right"`, `"top_middle"`, `"bottom_middle"`.
+--   `"bottom_right"`, `"top_middle"`, `"bottom_middle"`, `"middle"`.
 -- @bool[opt=true] args.ontop Boolean forcing popups to display on top.
 -- @int[opt=`beautiful.notification_height` or auto] args.height Popup height.
 -- @int[opt=`beautiful.notification_width` or auto] args.width Popup width.

lib/naughty/layout/legacy.lua

@@ -54,14 +54,37 @@ screen.connect_for_each_screen(function(s)
         bottom_left = {},
         bottom_middle = {},
         bottom_right = {},
+        middle = {},
     }
 end)
 
+--- Sum heights of notifications at position
+--
+-- @param s Screen to use
+-- @param position top_right | top_left | bottom_right | bottom_left
+--   | top_middle | bottom_middle | middle
+-- @param[opt] idx Index of last notification
+-- @return Height of notification stack with spacing
+local function get_total_heights(s, position, idx)
+    local sum = 0
+    local notifications = current_notifications[s][position]
+    idx = idx or #notifications
+    for i = 1, idx, 1 do
+        local n = notifications[i]
+
+        -- `n` will not nil when there is too many notifications to fit in `s`
+        if n then
+            sum = sum + n.height + naughty.config.spacing
+        end
+    end
+    return sum
+end
+
 --- Evaluate desired position of the notification by index - internal
 --
 -- @param s Screen to use
 -- @param position top_right | top_left | bottom_right | bottom_left
---   | top_middle | bottom_middle
+--   | top_middle | bottom_middle | middle
 -- @param idx Index of the notification
 -- @param[opt] width Popup width.
 -- @param height Popup height
@@ -83,21 +106,16 @@ local function get_offset(s, position, idx, width, height)
     end
 
     -- calculate existing popups' height
-    local existing = 0
-    for i = 1, idx-1, 1 do
-        local n = current_notifications[s][position][i]
-
-        -- `n` will not nil when there is too many notifications to fit in `s`
-        if n then
-            existing = existing + n.height + naughty.config.spacing
-        end
-    end
+    local existing = get_total_heights(s, position, idx-1)
 
     -- calculate y
     if position:match("top") then
         v.y = ws.y + naughty.config.padding + existing
-    else
+    elseif position:match("bottom") then
         v.y = ws.y + ws.height - (naughty.config.padding + height + existing)
+    else
+        local total = get_total_heights(s, position)
+        v.y = ws.y + (ws.height - total) / 2 + naughty.config.padding + existing
     end
 
     -- Find old notification to replace in case there is not enough room.

lib/naughty/notification.lua

@@ -105,6 +105,7 @@ local notification = {}
 -- * *bottom_right*
 -- * *top_middle*
 -- * *bottom_middle*
+-- * *middle*
 --
 --@DOC_awful_notification_corner_EXAMPLE@
 --
@@ -414,7 +415,7 @@ end
 -- @tparam[opt=focused] integer|screen args.screen Target screen for the notification.
 -- @string[opt="top_right"] args.position Corner of the workarea displaying the popups.
 --   Values: `"top_right"`, `"top_left"`, `"bottom_left"`,
---   `"bottom_right"`, `"top_middle"`, `"bottom_middle"`.
+--   `"bottom_right"`, `"top_middle"`, `"bottom_middle"`, `"middle"`.
 -- @bool[opt=true] args.ontop Boolean forcing popups to display on top.
 -- @int[opt=`beautiful.notification_height` or auto] args.height Popup height.
 -- @int[opt=`beautiful.notification_width` or auto] args.width Popup width.

tests/examples/awful/notification/corner.lua

@@ -8,6 +8,7 @@ for _, pos in ipairs {
     "bottom_left",
     "bottom_middle",
     "bottom_right",
+    "middle",
 } do
     naughty.notify {
         title    = pos,

tests/test-naughty-legacy.lua

@@ -342,6 +342,7 @@ end
 local positions = {
     "top_left"      , "top_middle"    , "top_right"     ,
     "bottom_left"   , "bottom_middle" , "bottom_right"  ,
+    "middle"        ,
 }
 
 -- Test each corners.