Tikz - Overlapping arrows make them too big

Question

I'm pretty new to Tikz and I'm facing a little issue.

I'd like to draw arrows that are overlapping, all going in same directions, but it's getting wider and wider and is pretty horrible. How could I face it ? Here is the code :

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{tikz}
\usetikzlibrary{shapes.geometric, arrows, calc}

\begin{document}
    \begin{tikzpicture}[node distance=2.3cm]
    % Style
    \tikzstyle{cell} = [rectangle, minimum width=1.5cm, minimum height=1.5cm, text centered, draw=black, fill=green!20]
    \tikzstyle{tensor} = [circle, minimum width=1cm, text centered, draw=black, fill=green!10]

    \tikzstyle{arrow} = [thick,->,>=stealth]

    % Nodes

    \node (he)   [tensor] {$h^e$};

    \node (d1)   [cell, right of=he, below of=he, xshift=1.5cm, yshift=-2cm] {$d$};
    \node (d2)   [cell, right of=d1, xshift=1.5cm] {$d$};
    \node (dn)   [cell, right of=d2, xshift=2cm] {$d$};

    \node (w1)   [tensor, above of=d1, left of=d1, minimum width=1.25cm] {$w_1$};
    \node (w2)   [tensor, above of=d2, left of=d2, minimum width=1.25cm] {$w_2$};
    \node (wn)   [tensor, above of=dn, left of=dn, minimum width=1.25cm] {$w_n$};


    % Arrows
    \draw[arrow] (w1) -| (d1);
    \draw[arrow] (w2) -| (d2);
    \draw[arrow] (wn) -| (dn);

    \draw[arrow] (d1) -- (d2);
    \draw[arrow] (he) |- (d1);

    \draw[arrow] (he) -| (d1);
    \draw[arrow] (he) -| (d2);
    \draw[arrow] (he) -| (dn);

\end{tikzpicture}
\end{document}

If you render the figure, you'll see arrows getting darker, how can I fix it ?

Thanks, Cheers

Welcome to TeX.Stackexchange! Can you make your example compilable? When I try to run your code I get errors. I can debug them, but how would I know if this still reproduces the problem you are asking about? — samcarter_is_at_topanswers.xyz, Jan 23 '19 at 10:26
Actually, as I know, if two lines overlapping each other in TikZ, they are darkened. — , Jan 23 '19 at 10:28
@joulev That's exactly my problem, I don't want arrows being darkened — Ricocotam, Jan 23 '19 at 10:35
Have you tried to print it? There are often aliasing problems with PDF viewers, and the line can seems darker or not depending on the zoom level. — Rmano, Jan 23 '19 at 10:45
@Rmano You're right, when I zoom there's no difference. But it's a numerical report so the "pdf view" issue is actually an issue. I can't print it right now, I'll try. — Ricocotam, Jan 23 '19 at 10:48

samcarter_is_at_topanswers.xyz · Accepted Answer · 2019-01-23T14:42:36.807

The following example uses the calc library to print each line only once. If you still experience problems with varying line widths this is most probably an issue of your pdf viewer.

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{tikz}
\usetikzlibrary{shapes.geometric, arrows, calc}

\begin{document}
    \begin{tikzpicture}[node distance=2.3cm]
    % Style
    \tikzset{
        cell/.style={rectangle, minimum width=1.5cm, minimum height=1.5cm, text centered, draw=black, fill=green!20}, 
        tensor/.style={circle, minimum width=1cm, text centered, draw=black, fill=green!10}, arrow/.style={thick,->,>=stealth},
        arrow/.style={thick,->,>=stealth}
    }

    % Nodes

    \node (he)   [tensor] {$h^e$};

    \node (d1)   [cell, right of=he, below of=he, xshift=1.5cm, yshift=-2cm] {$d$};
    \node (d2)   [cell, right of=d1, xshift=1.5cm] {$d$};
    \node (dn)   [cell, right of=d2, xshift=2cm] {$d$};

    \node (w1)   [tensor, above of=d1, left of=d1, minimum width=1.25cm] {$w_1$};
    \node (w2)   [tensor, above of=d2, left of=d2, minimum width=1.25cm] {$w_2$};
    \node (wn)   [tensor, above of=dn, left of=dn, minimum width=1.25cm] {$w_n$};


    % Arrows
    \draw[arrow] (w1) -| (d1);
    \draw[arrow] (w2) -| (d2);
    \draw[arrow] (wn) -| (dn);

    \draw[arrow] (d1) -- (d2);
    \draw[arrow] (he) |- (d1);

    \draw[arrow] (he) -| (d1);
    \draw[arrow] let \p1 = (he), \p2 = (d1) in (\x2,\y1) -| (d2);
    \draw[arrow] let \p1 = (he), \p2 = (d2) in (\x2,\y1) -| (dn);

\end{tikzpicture}
\end{document}

Thanks to @marmot for suggesting this calc free version:

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{tikz}
\usetikzlibrary{shapes.geometric, arrows}

\begin{document}
    \begin{tikzpicture}[node distance=2.3cm]
    % Style
    \tikzset{
        cell/.style={rectangle, minimum width=1.5cm, minimum height=1.5cm, text centered, draw=black, fill=green!20}, 
        tensor/.style={circle, minimum width=1cm, text centered, draw=black, fill=green!10}, arrow/.style={thick,->,>=stealth},
        arrow/.style={thick,->,>=stealth}
    }

    % Nodes

    \node (he)   [tensor] {$h^e$};

    \node (d1)   [cell, right of=he, below of=he, xshift=1.5cm, yshift=-2cm] {$d$};
    \node (d2)   [cell, right of=d1, xshift=1.5cm] {$d$};
    \node (dn)   [cell, right of=d2, xshift=2cm] {$d$};

    \node (w1)   [tensor, above of=d1, left of=d1, minimum width=1.25cm] {$w_1$};
    \node (w2)   [tensor, above of=d2, left of=d2, minimum width=1.25cm] {$w_2$};
    \node (wn)   [tensor, above of=dn, left of=dn, minimum width=1.25cm] {$w_n$};


    % Arrows
    \draw[arrow] (w1) -| (d1);
    \draw[arrow] (w2) -| (d2);
    \draw[arrow] (wn) -| (dn);

    \draw[arrow] (d1) -- (d2);
    \draw[arrow] (he) |- (d1);

    \draw[arrow] (he) -| (d1);
        \draw[arrow] (d1|-he) -| (d2); 
        \draw[arrow] (d2|-he) -| (dn);

\end{tikzpicture}
\end{document}

Thanks a lot, you're awsome ! Could you give a bit background or give some resources so I understand how to reuse this kind of things ? — Ricocotam, Jan 23 '19 at 10:51
@Ricocotam See https://tex.stackexchange.com/a/18393/36296 for a short example how the calc library works — samcarter_is_at_topanswers.xyz, Jan 23 '19 at 12:53
@marmot Thanks for your suggestions! I just fixed the \tikzset and will soon post a second example without calc. — samcarter_is_at_topanswers.xyz, Jan 23 '19 at 14:43

score 2 · Answer 2 · answered Jan 23 '19 at 10:49

2

This is what I see (okular) at 100% zoom:

so I can't see any "darkening". Now, zooming in:

This is a rendering/aliasing problem for subpixel zooms, and it is mostly unsolvable (it depends on the anti-aliasing algorithm of the viewer).

answered Jan 23 '19 at 10:49

Rmano

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Tikz - Overlapping arrows make them too big

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