gears: Add a geometry modules

Add an abstract geometry module to `gears`

lib/gears/geometry.lua

@@ -0,0 +1,60 @@
+---------------------------------------------------------------------------
+--
+-- Helper functions used to compute geometries.
+--
+-- When this module refer to a geometry table, this assume a table with at least
+-- an *x*, *y*, *width* and *height* keys and numeric values.
+--
+-- @author Julien Danjou <julien@danjou.info>
+-- @copyright 2008 Julien Danjou
+-- @release @AWESOME_VERSION@
+-- @module gears.geometry
+---------------------------------------------------------------------------
+local math = math
+
+local gears = {geometry = {rectangle = {} } }
+
+--- Get the square distance between a rectangle and a point.
+-- @tparam table geom A rectangle
+-- @tparam number geom.x The horizontal coordinate
+-- @tparam number geom.y The vertical coordinate
+-- @tparam number geom.width The rectangle width
+-- @tparam number geom.height The rectangle height
+-- @tparam number x X coordinate of point
+-- @tparam number y Y coordinate of point
+-- @treturn number The squared distance of the rectangle to the provided point
+function gears.geometry.rectangle.get_square_distance(geom, x, y)
+    local dist_x, dist_y = 0, 0
+    if x < geom.x then
+        dist_x = geom.x - x
+    elseif x >= geom.x + geom.width then
+        dist_x = x - geom.x - geom.width + 1
+    end
+    if y < geom.y then
+        dist_y = geom.y - y
+    elseif y >= geom.y + geom.height then
+        dist_y = y - geom.y - geom.height + 1
+    end
+    return dist_x * dist_x + dist_y * dist_y
+end
+
+--- Return the closest rectangle from `list` for a given point.
+-- @tparam table list A list of geometry tables.
+-- @tparam number x The x coordinate
+-- @tparam number y The y coordinate
+-- @return The key from the closest geometry.
+function gears.geometry.rectangle.get_closest_by_coord(list, x, y)
+    local dist = math.huge
+    local ret = nil
+
+    for k, v in pairs(list) do
+        local d = gears.geometry.rectangle.get_square_distance(v, x, y)
+        if d < dist then
+            ret, dist = k, d
+        end
+    end
+
+    return ret
+end
+
+return gears.geometry

lib/gears/init.lua

@@ -19,6 +19,7 @@ return
     shape = require("gears.shape");
     protected_call = require("gears.protected_call");
     screen = require("gears.screen");
+    geometry = require("gears.geometry");
 }
 
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