Tikz equivalent for pst-rputover

Question

For pstricks the package pst-rputover (new on ctan since 2017-03-28) has been created to solve following problem

In brief, I'm looking for a version of \rput* that blocks out lines but not fill colors.

raised here: Is there a variant of \rput* in PSTricks that preserves background fill colors?

I am interested in a solution for tikz. I have recreated the minimal example with tikz:

\documentclass[tikz]{standalone}
\begin{document}
\begin{tikzpicture}
  \fill[blue!40] (0,0) rectangle (2,2);
  \fill[red] plot [smooth] coordinates {(0,2)(1,1)(2,2)} -- cycle;
  \draw(1,0)--(1,2);
  \node at (1,1) {\Large\sf label};
\end{tikzpicture}
\end{document}

The expected output should be

I am evaluating following options in tikz:

• draw/fill/text opacity
• transparency groups
• \begin{scope}
• \begin{pgfonlayer}

Note the knockout feature is not supported by all PDF Viewer. I can confirm that it does not work in Skim and Preview on macOS.

However, I have not figured out yet how to solve this.

UPDATE I want to add parts of the picture I am working on to clarify that lines might cross several nodes which is a priori not clear:

pst-rputover doc details

The style combines two ideas. The first idea, suggested by the StackExchange user Werner on this page, is to use \psDefBoxNodes in pst-node.sty to get the coordinates of the corners of the box occupied by each label. The second idea is to use these coordinates and \psclip to remove the parts of the objects in the argument of \coverable that overlap with the labels. The only subtlety in implementing this second idea is that we want to do a ‘reverse clip’: we want to keep the areas outside the labels, not the ones inside.

Related questions

• Relative transparency in TikZ?
• TikZ: Node fill which is opaque to entities in tikzpicture but transparent to background color/image?

Answer 1

Just for completeness: this is a version which also takes into account rounded corners or, more generally, arbitrary node shapes. And it spares you from typing a lot of coordinates.

\documentclass[tikz]{standalone}
\usetikzlibrary{shapes.geometric}
\makeatletter % https://tex.stackexchange.com/a/38995/121799
\tikzset{
  use path/.code={\pgfsyssoftpath@setcurrentpath{#1}}
}
\makeatother
\tikzset{remember path/.style={save path=\tmprotect}}
% https://tex.stackexchange.com/a/12033/121799
\tikzset{reverseclip/.style={insert path={(current bounding box.north
        east) rectangle (current bounding box.south west)}}}

\begin{document}
\begin{tikzpicture}
  \fill[blue!40] (0,0) rectangle (2,2);
  \fill[red] plot [smooth] coordinates {(0,2)(1,1)(2,2)} -- cycle;
  \node[remember path,font=\Large\sf] at (1,1) {label};
  \clip[use path=\tmprotect,reverseclip];
  \draw(1,0)--(1,2);
\end{tikzpicture}

\begin{tikzpicture}
  \fill[blue!40] (-1,0) rectangle (3,4);
  \fill[red] plot [smooth] coordinates {(-1,4)(0,2)(1,1)(2,2)(3,4)} -- cycle;
  \node[remember path,font=\Large\sf,rounded corners] at (1,1) {label};
  \clip[use path=\tmprotect,reverseclip];
  \node[remember path,font=\Large\sf,shape=diamond] at (2,2) {label 3};
  \clip[use path=\tmprotect,reverseclip];
  \node[remember path,font=\Large\sf,shape=ellipse] at (0,2) {label 2};
  \clip[use path=\tmprotect,reverseclip];
  \fill[gray,opacity=0.2] (-1,0) rectangle (3,4);
  \draw [blue,thick] (-1,4) -- (1,0) -- (3,4);
\end{tikzpicture}
\end{document}

Answer 2

You can clip against the labels:

\documentclass[tikz]{standalone}
\begin{document}
\begin{tikzpicture}

  \fill[color=blue!40] (0,0) rectangle (2,2);
  \fill[red] plot [smooth] coordinates {(0,2)(1,1)(2,2)} -- cycle;

  \node at (1,1) (mynodeA){\Large\sffamily label};
  \node at (0.5,1.5) (mynodeB){\sffamily label};

  \begin{scope}
  \foreach \n in {mynodeA, mynodeB}{
    \path [clip] 
          (\n.north east) -- 
          (\n.south east) --
          (\n.south west) -- 
          (\n.north west) -- cycle
          (current bounding box.south east) --
          (current bounding box.north east) --
          (current bounding box.north west) --
          (current bounding box.south west) -- cycle;
  }

  \draw(1,0)--(1,2);
  \draw(0.5,0)--(0.5,2);
  \draw(0,1.8)--(2,0.5);
  \end{scope}

\end{tikzpicture}
\end{document}

Answer 3

with drawing line in two parts?

\documentclass[tikz, margin=3.141592]{standalone}
\begin{document}
\begin{tikzpicture}
  \fill[blue!40] (0,0) rectangle (2,2);
  \fill[red] plot [smooth] coordinates {(0,2)(1,1)(2,2)} -- cycle;
  \node at (1,1)  (label) {\Large\sf label};
  \draw (1,0) -- (label) (label) -- (1,2);
\end{tikzpicture}
\end{document}