cor de fundo do pstricks do texto \rput no gráfico

Question

Eu tenho o seguinte pst-plot. Como posso escrever A_{2}(usando \rput) com fundo branco?

todo o Código:

\begin{pspicture}(-2,-3.5)(6,3)
    \psgrid[griddots=10,gridlabels=0pt,subgriddiv=0,gridcolor=black!20]
    \psset{algebraic,linewidth=1.5pt}
    \psaxes[ticks=none,labels=none]{->}(0,0)(-2,-3.5)(6,3)[$x$,0][$y$,180]


    \pscustom[fillstyle=vlines,fillcolor=cyan,linestyle=none]{%
      \psline(-1,0)(*-1 {-0.5*(-1-2)^2+2})
      \psplot[algebraic]{-1}{0}{-0.5*(x-2)^2+2}
      \psline(0,0)(0,0)

      \psline(0,0)(0,0)
      \psplot[algebraic]{0}{4}{-0.5*(x-2)^2+2}
      \psline(4,0)(4,0)


      \psline(5,0)(*5 {-0.5*(5-2)^2+2})
      \psplot[algebraic]{4}{5}{-0.5*(x-2)^2+2}
      \psline(4,0)(4,0)
      }

     \rput{0}(2,1){$A_{2}$}

    %plotting:
    \psplot[linecolor=red]{-1}{5}{-0.5*(x-2)^2+2}
\end{pspicture}

Answer 1

Use a versão estrela de \rput:

\rput*(2,1){$A_2$}

Answer 2

Usar \rput{0}(2,1){\pscirclebox*[framesep=0pt]{$A_{2}$}}ou \rput{0}(2,1){\psframebox*[framesep=1pt]{$A_{2}$}}: