Btukfyl

As part of a larger diagram I've written the following, which does basically what I want:

documentclass{report}

usepackage{tikz}

usetikzlibrary{arrows,positioning}

begin{document}



begin{tikzpicture}[box/.style={rectangle,draw=black},

                    vh path/.style={to path={|- (tikztotarget)}}

                   ]

  node[box] (ReadQueryParametersJSON) at (0,0) {ReadQueryParametersJSON};

  node[box] (ParseParametricLine) [below=of ReadQueryParametersJSON,anchor=west,xshift=-1cm] {ParseParametricLine};

  node[box] (ReadJSONFile) [below=of ParseParametricLine.west,anchor=west] {ReadJSONFile};

  node[box] (GUIMapping) [below=of ReadJSONFile.west,anchor=west] {GUIMapping};



  path [->] (node cs:name=ReadQueryParametersJSON,angle=-169.69) edge [vh path] (GUIMapping)

             (node cs:name=ReadQueryParametersJSON,angle=-168.69) edge [vh path] (ReadJSONFile)

             (node cs:name=ReadQueryParametersJSON,angle=-167.47) edge [vh path] (ParseParametricLine);



  %node[box] (root) at (0,-4) {root};

  %foreach name in {aa,bb,cc,dd}

  %   node[box] (name) at ++(0,-1) {name};

end{tikzpicture} 





end{document}

The only mechanism I could find to offset the starting point for the arrows was to use the angle, which means that for even spacing, the parameter depends on the arctan and the dimensions of the box. That's sort of complicated. Is there a better way?

I need to make a structure like this several times, so I tried write a loop to generate this structure automatically, starting with the code that is commented out. This code places the root node down at (1,-4) and all of the listed nodes on top of each other at the absolute location (1,-1) even though I used ++ to get relative location. Why doesn't this work? How can I write this loop (without absolute coordinates so that the child nodes are positioned relative to the parent)?

If I understood your question correctly, you can use the above of= key in this way:

documentclass{report}

usepackage{tikz}

usetikzlibrary{arrows,positioning}

begin{document}



begin{tikzpicture}[

box/.style={draw=black},

vh path/.style={to path={|- (tikztotarget)}}

                   ]



  node[box] (root) at (0,-4) {root};

  foreach name [remember= name as n (initially root)]in {aa,bb,cc,dd}

     node[box, above=of n] (name) {name};

end{tikzpicture} 





end{document}

R you looking for the good old xshift?

documentclass{report}

usepackage{tikz}

usetikzlibrary{arrows,positioning}

begin{document}



begin{tikzpicture}[box/.style={rectangle,draw=black},

                    vh path/.style={to path={|- (tikztotarget)}}

                   ]

  node[box] (ReadQueryParametersJSON) at (0,0) {ReadQueryParametersJSON};

  node[box] (ParseParametricLine) [below=of ReadQueryParametersJSON,anchor=west,xshift=-1cm] {ParseParametricLine};

  node[box] (ReadJSONFile) [below=of ParseParametricLine.west,anchor=west] {ReadJSONFile};

  node[box] (GUIMapping) [below=of ReadJSONFile.west,anchor=west] {GUIMapping};



  path [->] ([xshift=4mm]ReadQueryParametersJSON.south west) edge [vh path] (GUIMapping)

             ([xshift=6mm]ReadQueryParametersJSON.south west) edge [vh path] (ReadJSONFile)

             ([xshift=8mm]ReadQueryParametersJSON.south west) edge [vh path] (ParseParametricLine);



  %node[box] (root) at (0,-4) {root};

  %foreach name in {aa,bb,cc,dd}

  %   node[box] (name) at ++(0,-1) {name};

end{tikzpicture}