ROBLOX-GUI -> DrawLine (Supports Rotation Property)

local StartPoint = script.Parent.StartPoint.AbsolutePosition;
local EndPoint = script.Parent.EndPoint.AbsolutePosition;

function DrawLine(Start, End, Width)
    local Start_O, End_O = Start, End
    if (Start.X > End.X) then
        End = Start_O
        Start = End_O
    end
    local Line = Instance.new("Frame");
    local XSize = (End-Start).magnitude;
    local XDistance = (End.X-Start.X);
    local YDistance = (End.Y-Start.Y);
    local DesiredAngle = math.atan2(YDistance,XDistance);
    local YPositionOffset = YDistance/2;
    local XOffset = (1 - math.cos(DesiredAngle)) * (XSize/2)

    print("Distances :: " .. XDistance .. ", " .. YDistance);
    print("Needed angle :: " .. math.deg(DesiredAngle));
    Line.Rotation = math.deg(DesiredAngle);
    Line.BorderSizePixel = 0;
    Line.Size = UDim2.new(0,XSize,0,Width);
    Line.Position = UDim2.new(0,Start.X-XOffset,0,Start.Y + YPositionOffset);
    Line.Parent = script.Parent
    print("Distance between GUIs :: " .. XSize);
    return Line;
end

DrawLine(StartPoint,EndPoint,2);