Label near start when using myncbar

Question

My problem is quite simple, yet i can't find answer. Pre:

\usepackage{tikz}
\usetikzlibrary{matrix, shapes, arrows, positioning, fit, calc}

Styles:

\tikzstyle{decision} = [diamond, draw, fill=blue!20, 
                        text width=6em, text badly centered, node distance=3cm, inner sep=0pt]
    \tikzstyle{block} = [rectangle, draw, fill=blue!20, text width=9em, text centered, rounded corners, minimum height=2.5em]
    \tikzstyle{label} = [draw=white!0, minimum size=2ems]
    \tikzstyle{line} = [draw, -latex']
    \tikzstyle{cloud} = [draw, ellipse,fill=red!20, node distance=3cm,
        minimum height=2em]
    \tikzstyle{box}=[rectangle,
                    thick,
                    minimum size=1cm,
                    draw=black!80,
                    fill=gray!01]
    \tikzstyle{connector} = [->,thick]
    \tikzstyle{pusty}=[draw=white, minimum size=2em]

Im using myncbar macro to create C-like shapes:

\def\myarm{1cm}
    \def\myangle{0}
    \tikzset{
      arm/.default=1cm,
      arm/.code={\def\myarm{#1}}, % store value in \myarm
      angle/.default=0,
      angle/.code={\def\myangle{#1}} % store value in \myangle
    }

\tikzset{
    myncbar/.style = {to path={
        % We need to calculate a couple of coordinates to help us draw
        % the path. 
        let
            % Same as (\tikztotarget)++(\myangle:\myarm)
            \p1=($(\tikztotarget)+(\myangle:\myarm)$)
        in
            -- ++(\myangle:\myarm) coordinate (tmp)
            % Find the projection of the (tmp) coordinate
            % on the line from the target to p1
            -- ($(\tikztotarget)!(tmp)!(\p1)$)
            -- (\tikztotarget)\tikztonodes
    }}
}

And my code is:

\begin{figure}[H]
    \begin{center}
        \begin{tikzpicture}[node distance = 2cm, auto]
            % Place nodes
            \node [decision] (init) {Minął określony czas?};
            \node [block, below of=init, node distance = 3cm] (oblicz) {Oblicz różnicę temperatur};
            \node [decision, below of=oblicz, node distance=3.5cm] (roznica) {Róznica powyżej zadanego poziomu?};
            \node [decision, below of=roznica, node distance=5.5cm] (otwarte) {Przepustnice otwarte maksymalnie i temperatura spada?};
            \node [block, right of=otwarte, node distance=5.5cm] (ostrzezenie) {Wyświetl ostrzeżenie o kończącym się paliwie};
            \node [block, below of=otwarte, node distance=4cm] (kat) {Oblicz kąt otwarcia przepustnic};
            \node [block, below of=kat, node distance=2cm] (servo) {Ustaw serwomechanizmy};
            \node [block, below of=servo, node distance=2cm] (koniec) {Koniec};

            % Draw edges
            \path [line] (init) -- node [near start] {Tak} (oblicz);
            \path [line] (init.west) to[myncbar,angle=0,arm=-2cm] node [near start] {Nie} (koniec.west);
            \path [line] (oblicz) -- (roznica);
            \path [line] (roznica) -- node [near start] {Tak} (otwarte);
            \path [line] (roznica.east) to[myncbar,angle=0,arm=6cm] node [near start] {Nie} (koniec.east);
            \path [line] (otwarte) -- node [near start] {Tak} (ostrzezenie);
            \path [line] (otwarte) -- node [near start] {Nie} (kat);
            \path [line] (kat) -- (servo);
            \path [line] (servo) -- (koniec);
            \path [line] (ostrzezenie) -- (koniec);
        \end{tikzpicture}
        \caption{Algorytm obsługi kotła}
     \end{center}
\end{figure}

And my problem is in this line:

\path [line] (init.west) to[myncbar,angle=0,arm=-2cm] node [near start] {Nie} (koniec.west);
...
\path [line] (roznica.east) to[myncbar,angle=0,arm=6cm] node [near start] {Nie} (koniec.east);

Text labels are not near start. They are near the start of the last line. Is it possible to make them near start of the first line?

Answer 1

I guess it's hardly possible to easily refer to the first part of such a composite path. However, you could use near start with an invisible copy of the first part.

You could replace

\path [line] (roznica.east) to[myncbar,angle=0,arm=6cm]
      node [near start] {Nie} (koniec.east);

by

\path [line] (roznica.east) to[myncbar,angle=0,arm=6cm] (koniec.east);
\path (roznica.east) -- node [near start] {Nie} ++(6cm,0);