How to find the nearest point in the perimeter of a rectangle to a given point?
bounding-box, geometry, math, rectangles
Solution
This time I'm trying to catch the minimum distance of the point toward any side of the rectangle.
local abs, min, max = math.abs, math.min, math.max
local function clamp(x, lower, upper)
return max(lower, min(upper, x))
end
local function getNearestPointInPerimeter(l,t,w,h, x,y)
local r, b = l+w, t+h
x, y = clamp(x, l, r), clamp(y, t, b)
local dl, dr, dt, db = abs(x-l), abs(x-r), abs(y-t), abs(y-b)
local m = min(dl, dr, dt, db)
if m == dt then return x, t end
if m == db then return x, b end
if m == dl then return l, y end
return r, y
end
Problem
This is a language-agnostic question. Given a rectangle's dimensions with `l,t,w,h` (left, top, width, height) and a point `x,y`, how do I find the nearest point on the perimeter of the rectangle to that point? I have tried to resolve it in Lua, but any other language would do. So far this is my best effort: ``` local function nearest(x, a, b) if a <= x and x <= b then return x elseif math.abs(a - x) < math.abs(b - x) then return a else return b end end local function getNearestPointInPerimeter(l,t,w,h, x,y) return nearest(x, l, l+w), nearest(y, t, t+h) end ``` This works for a point outside of the perimeter or in the perimeter itself. But for points inside of the perimeter it fails (it just returns `x,y`) My gut tells me that the solution should be simple, but I don't seem to find it.