Sets the line cap style.
type
TLineCapStyle = ( lcButtEnd, lcRoundEnd, lcProjectSquareEnd );
Sintaxis Delphi:
procedure SetLineCap ( Linecap: TLineCapStyle );
Sintaxis C++:
void __fastcall SetLineCap ( TLineCapStyle Linecap );
Descripción:
Establece el estilo de extremo de línea en el estado gráfico
Value Meaning
lcButtEnd Butt cap. The stroke is squared off at the endpoint of the path.
There is no projection beyond the end of the path.
lcRoundEnd Round cap. A semicircular arc with a diameter equal to the line width
is drawn around the endpoint and filled in. 
lcProjectSquareEnd Projecting square cap. The stroke continues beyond the endpoint of the path
for a distance equal to half the line width and is then squared off. 