\pgfpointanchor can insert spurious spaces if the anchor is an angle

[marmotghost]

Brief outline of the bug

\pgfpointanchor can insert spurious spaces if the anchor is an angle. This does not happen for "stringy" anchors like west.

Minimal working example (MWE)

\documentclass{article}
\usepackage{tikz}
\makeatletter
\pgfmathdeclarefunction*{x2d}{2}{%
\begingroup%
\pgf@process{\pgfpointanchor{#1}{#2}}%
\pgfmathparse{\pgf@x}%
\pgfmathsmuggle\pgfmathresult\endgroup%
}%
\pgfmathdeclarefunction*{test}{2}{%
\begingroup%
\pgfmathparse{0}%
\pgfmathsmuggle\pgfmathresult\endgroup%
}%
\makeatother
\begin{document}
\begin{tikzpicture} 
 \node[circle,draw,minimum size=2cm] (c) at (1,0) {};
 \draw (c.center)  -- ++ (0,2);
 \pgfmathparse{x2d("c","center")}
 \draw[blue,dashed] (c.center)  -- ++ (0,2);
 \pgfmathparse{x2d("c","20")}
 \draw[red,dashed] (c.center)  -- ++ (0,2);
\end{tikzpicture}
\begin{tikzpicture} 
 \node[circle,draw,minimum size=2cm] (c) at (1,0) {};
 \draw (c.center)  -- ++ (0,2);
 \pgfmathparse{test("c","center")}
 \draw[blue,dashed] (c.center)  -- ++ (0,2);
 \pgfmathparse{test("c","20")}
 \draw[red,dashed] (c.center)  -- ++ (0,2);
\end{tikzpicture}
\end{document}

As you can see, the dashed red line gets shifted. This is not because the function uses strings (which is why there is a second picture with a function test). The problem is also absent if one uses nonnumerical anchors.

[hmenke]

This is not a MWE.

[marmotghost]

Your fix does not work.

[hmenke]

Works on my machine.

[Qrrbrbirlbel]

There are multiple spaces in the definitions of the anchors, the most common is the space after the opening {, e.g.

pgf/tex/generic/pgf/modules/pgfmoduleshapes.code.tex

Line 1015 in 584b5ff

\anchor{center}{

Some libraries don't have those spaces at all, others have %ed some of those spaces but not all or also have them after } at the end of a line:

pgf/tex/generic/pgf/libraries/shapes/pgflibraryshapes.geometric.code.tex

Lines 84 to 92 in 584b5ff

	\anchor{west}
	{
	\pgf@process{\radius}
	\pgf@xa=\pgf@x%
	\pgf@process{\centerpoint}
	\advance\pgf@x by-\pgf@xa
	}%
	\anchor{mid west}
	{%

---

Here's a simpler MWE.

Uncommenting any of the commented lines will place the circle at the correct point again.

In my own code, I've chosen to use \nullfont since removing the spaces in all anchors of all shapes isn't practable.

\documentclass[tikz]{standalone}
\pgfmathdeclarefunction{anglebetweencoordinates}{2}{%
  \begingroup
%    \nullfont
    \pgfmathanglebetweenpoints
      {\pgfpointanchor{#1}{center}}%
      {\pgfpointanchor{#2}{center}}%
    \pgfmathsmuggle\pgfmathresult
  \endgroup
}
\usepackage{etoolbox}
\makeatletter
%\patchcmd\pgf@anchor@rectangle@center{ \pgf@process}{\pgf@process}{}{\PatchFailed}
\makeatother
\begin{document}
\begin{tikzpicture}[nodes=draw]
\node (A) at (0,0)  {A}
 node (B) at (30:1) {B};
\draw (A.{180+anglebetweencoordinates("A","B")}) circle[radius=2pt];
\end{tikzpicture}
\end{document}