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I am trying to produce a sequence/time diagram showing the synchronisation process of a master and slave in the Precision Time Protocol using TikZ. Being very new to TikZ I don't know much more than the primitives for drawing lines and placing nodes, which seems almost enough for such a simple diagram.

The problem I am having is that I cannot figure out how to make lines and arrows converge precisely in a single point on an axis. Here is what it looks like now (not the actual diagram but close):

Up close:

As you can see there is quite a gap between the three lines converging on the t-axis. How do I remove such gaps and have the lines converge precisely in one point on the t-axis?

Or is there a better way to draw such diagrams?

Here is a MWE:

\documentclass[]{article}

\usepackage{tikz}

\begin{document}
\begin{tikzpicture}
    \draw [->,thick] (0,8) node (Master) [above] {Master} -- (0,0) node [below right] {t};
    \draw [->,thick] (5,8) node (Slave) [above] {Slave} -- (5,0) node [below right] {t};

    \node (t1) at (0,7) [left] {$t_1$};
    \node (t2) at (5,6) [right] {$t_2$};
    \node (t3) at (0,3) [left] {$t_3$};
    \node (t4) at (5,1) [right] {$t_4$};


    \draw[->] (t1) -- (t2);
    \draw[->] (t2) -- (t3);
    \draw[->] (t3) -- (t4);

    \draw[very thin,dashed] (t2) -- ++(-6,0);
    \draw[very thin,dashed] (t3) -- ++(6,0);
    \draw[very thin,dashed] (t1) -- ++(6,0);
    \draw[very thin,dashed] (t4) -- ++(-6,0);
\end{tikzpicture}
\end{document}

Thanks in advance!

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  • 1
    This happens because with the (node) syntax (as opposed to (node.anchor)), TikZ stops the line at the border of the node (which contains the text plus a margin of size inner sep). – Caramdir Jun 4 '11 at 16:47
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I suggest you this:

\draw[->] (t1.east) -- (t2.west);
\draw[->] (t2.west) -- (t3.east);
\draw[->] (t3.east) -- (t4.west);

The result is the following

enter image description here

I suggest you to use latex 45 arrow style. Bye

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  • Thank you, that's it! But I can't seem to find a "latex 45" arrow style, only "latex" and variants and various "triangle 45" or "angle 45" styles. But the "latex" style is quite adequate I think. – daff Jun 4 '11 at 5:01
  • 4
    Maybe he meant arrow 45 accessible by usetikzlibrary{arrows}? Anyway, choose the tip you prefer! You should also consider a different strategy of building your picture: You actually want to draw an arrow to a point (you can use node[shape=coordinate]) on the vertical line, not to the text. The text can be placed as a label next to that coordinate. – Christoph Jun 4 '11 at 7:12
  • Yeah, I meant arrow 45, sorry!! – Azoun Jun 4 '11 at 13:55

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