Xrhrft

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

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}

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).