Hcfyk

This question is related to Strange behavior in TikZ draw command but is not the same.

While working with coordinates and nodes in TikZ, I was expecting that:

  coordinate (x) at (4,0) node[right] {$x$};

  coordinate (y) at (0,3) node[above] {$y$}; 

and

  node[right] at (x) {$x$};

  node[above] at (y) {$y$};

would yield the same result. But they don't. I get the following output:

With coordinate (x) at (4,0) node[right] {$x$};, I meant, the system will create a node at (4,0) and will place the text $x$ to its right.

Based on the output, I see the text $x$ is placed at (0,0), with the above command.

Why does this happen.

MWE:

documentclass{article}

usepackage{tikz}

usetikzlibrary{intersections}

begin{document}

begin{tikzpicture}

  coordinate (x) at (4,0) node[right] {$x$};

  coordinate (y) at (0,3) node[above] {$y$};



  node[right] at (x) {$x$};

  node[above] at (y) {$y$};



  draw[<->,thick] (0,3) |- (4,0);

end{tikzpicture}

end{document} 

try the following:

documentclass{article}

usepackage{tikz}

%usetikzlibrary{intersections} not used in this mwe



begin{document}

begin{tikzpicture}

  coordinate[label=right:$x$] (x) at (4,0);

  coordinate[label=above:$y$] (y) at (0,3);



  draw[<->,thick] (y) |- (x);

end{tikzpicture}

end{document}

In section 17.2.1 of the TikZ manual, the commands for such works are shown:

• 
  

  path ... node ... (1.1)

  
  
  

  or node ... (1.2)

  
  


• 
  

  path ... coordinate ... (2.1)

  
  
  

  or coordinate ... (2.2)

  
  

coordinate ... node ... are not present for the same job! In fact, since coordinate is the same as path coordinate so coordinate (x) at (4,0) node[right] {$x$}; is understood as

path coordinate (x) at (4,0);  % or `coordinate (x) at (4,0);

path node[right] {$x$}; % (0,0) in case no coordinates are specified

This makes the outputs of coordinate (x) at (4,0) node[right] {$x$}; and node[right] at (x) {$x$}; not the same at all.

That is why we get

with this code

documentclass[tikz]{standalone}

begin{document}

begin{tikzpicture}

coordinate (x) at (2,0) node[draw,right] {world};

fill (x) circle (1pt)

    (0,0) circle (1pt);

end{tikzpicture}

end{document}

and we get

with this code

documentclass[tikz]{standalone}

begin{document}

begin{tikzpicture}

node[draw] (x) at (2,0) {Hello} node[draw,right] {world};

fill (0,0) circle (1pt);

end{tikzpicture}

end{document}

So how to solve it? We can't combine (2.2) or (1.2) with ... node ..., but we can do it with (1.1) or (2.1):

path (4,0) coordinate (x) node[right] {$x$};

Remember that draw, fill, filldraw... are all daughters of path, so they are all valid. But node and coordinate are not – they are less general versions of path..

I found this using the draw powerful trick :)

It doesn't give you the expected result because the syntax is not appropriate. (At which level do you expect an explanation? Does it help that in coordinate (x) at (4,0) node[right] {$x$}; at (4,0) got "absorbed" by coordinate (x) so that TikZ adds the default coordinate (0,0) to interpret node[right] {$x$}?) You can condense all statements to one line.

documentclass[tikz,border=3.14mm]{standalone}

begin{document}

begin{tikzpicture}

  draw[<->,thick] (0,3) coordinate (y) node[above] {$y$} |- (4,0) coordinate (x)  node[right] {$x$};

end{tikzpicture}

end{document}