unattractive additive effect to opacity with pstricks

Question

I'm using pstricks to highlight by boxing or circling replacement text in my math equations. But, I don't want this highlighting to occlude what's behind it. So, I've been setting opacity or strokeopacity to accomplish this. Everything seemed to be working as I wanted it to until I started trying to connect the nodes. Then where the arrows and connects and boxes overlapped, I got annoying additive side effects from the opacity. What really surprised me was to learn that arrows and their lines are treated as two separated objects by pstricks.

Anyway, does anyone know a way around this? I'm open to any suggestions. I know pratically nothing about tikz: really only enough to make myself constantly frustrated. Nevertheless, I am open to tikz solutions too.

Here is my MWE:

\documentclass{article}
\usepackage{amsmath}
\usepackage{pst-node}
\pagestyle{empty}
\begin{document}
    \newcommand{\myboxn}[3][red!60]{%
            \rnode{#2}{\psframebox[boxsep=false,
                                   framesep=0.5pt,
                                   linewidth=3pt,
                                   strokeopacity=0.4,
                                   linecolor=#1]{#3}}}
    \begin{align*}
         \sqrt{2} - 1   & = \frac{1}{\sqrt{2}+1}                                   \\[2ex]
         \sqrt{2} - 1   & = \dfrac{1}{2 + \myboxn{A}{\sqrt{2}-1}}                  \\[2ex]
         \sqrt{2} - 1   & = \dfrac{1}{2 + \myboxn{B}{\dfrac{1}{2+\sqrt{2}-1}}}    
    \end{align*}

    \ncline[arrows=-D>,
            linecolor=red,
            linewidth=3pt,
            arrowscale=1.25,
            strokeopacity=.40]{A}{B}


\end{document}

By the way, I know I can set the parameters using \psset{...} but in the actually document, there is a lot going on with different different styles. So, I'd prefer to stick to passing the parameters individually to \ncline etc.

Answer 1

use arrowinset=0, in the settings: