Opacity in PDF not rendered the same between Adobe Reader and TeXworks

Question

When producing a PDF from the following example using pdflatex, I get different results between Adobe Reader and TeXworks. I think this is a bug in the way that Reader handles opacity/transparency.

My goal is to have just a small space between the black node and each edge (like how TeXworks is rendering it), and the way I'm doing that is by setting a black fill and color=transparent/opacity=0 edge for each node.

Can anyone suggest a nice workaround to get consistent results? I have many trees I am trying to render that suffer from this issue and I would like to have the space between the edge and node be transparent rather than white.

Maybe I can draw fully transparent nodes, and then draw a smaller black node on top of each of these. Can this be automated as part of the state syle? Or can I set a gap between the start and end of every edge? (How would I do this?)

\documentclass{article}
\usepackage{tikz}

\tikzstyle{lts}=[
  state/.style={circle,draw,minimum size=4pt,inner sep=0pt,line width=2pt,draw opacity=0,color=transparent,fill=black},
  edge from parent/.style={-stealth,draw},
  obs/.style={edge from parent/.style={-stealth,draw,very thick}},
]

\begin{document}
    \begin{tikzpicture}[lts]
      \node[state] {}
        child[obs] {node[state] {}
        edge from parent node {}}
        child[obs] {node[state] {}
        edge from parent node {}};
    \end{tikzpicture}
\end{document}

Comparing the rendering in TeXworks to Reader:

Answer 1

Using draw=none instead of color=transparent seems to properly display it in Acrobat. The image on the left is the one with color=transparent, and the one on the right is with draw=noneas viewed in Acrobat:

Notes:

• I used tikzset instead of tikzstyle as per Should \tikzset or \tikzstyle be used to define TikZ styles?

Code:

\documentclass{article}
\usepackage{tikz}

\tikzstyle{lts}=[
  state/.style={circle,draw,minimum size=4pt,inner sep=0pt,line width=2pt,draw opacity=0,color=transparent,fill=black},
  edge from parent/.style={-stealth,draw},
  obs/.style={edge from parent/.style={-stealth,draw,very thick}},
]

\tikzset{MyState/.style={circle,draw,minimum size=4pt,inner sep=0pt,line width=2pt,draw opacity=0,draw=none,fill=black}}
\tikzset{MyObs/.style={edge from parent/.style={-stealth,draw,very thick}}}

\begin{document}
    \begin{tikzpicture}[lts]
      \node[state] {}
        child[obs] {node[state] {}
        edge from parent node {}}
        child[obs] {node[state] {}
        edge from parent node {}};
    \end{tikzpicture}%
    \begin{tikzpicture}
      \node[MyState] {}
        child[MyObs] {node[MyState] {}
        edge from parent node {}}
        child[MyObs] {node[MyState] {}
        edge from parent node {}};
    \end{tikzpicture}
\end{document}