For individual signs, the area of a sign shall be computed by delineating the smallest square, circle, rectangle, triangle, or combination thereof that will encompass the extreme limits of the writing, representation, emblem, or other display, together with any material or color forming an integral part of the background of the display or used to differentiate the sign from the backdrop or structure against which it is placed, but not including any supporting framework, bracing, or decorative fence or wall when such fence or wall otherwise meets the regulations of this chapter and is clearly incidental to the display itself. In the case of a facade or freestanding sign, the entire face shall be measured in computing the sign area.