Tikz: drawing border or line with shade

Question

I want to draw a line with a shade, not a big rectangle.

As per the documentation,

Shading is caused by the shade option (there are \shade and \shadedraw abbreviations).

Shouldn't therefore something like this work?

\documentclass[border=1mm]{standalone}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
\draw [shade, left color=red, right color=blue] (0,0) -- (1,0);
\end{tikzpicture}
\end{document}

But I cannot get it to be shaded. It always shows up like this:

In actuality, what I want to draw is a rectangle where the end of the borders are shaded this way:

There is probably a simple way to do this, but I only see forms of doing filled shade, not border shades or single lines...

Related/possible duplicate: Tikz: Shading a path without any filling — Claudio Fiandrino, Jun 23 '18 at 10:18
Shading is only for areas, not lines. Edit: Also from the documentation: "A shading is like a filling, ..." — Torbjørn T., Jun 23 '18 at 10:23
@ClaudioFiandrino I saw that solution, but it's overkill for my case. I don't want to use more than 100 lines when I just need a straight line. I will just draw lines as rectangles, as the answer below. — Ricardo Cruz, Jun 23 '18 at 13:25

Kpym · Answer 1 · 2018-06-23T13:07:10.267

5

You can use path fading from fadings library.

\documentclass[tikz,border=7pt]{standalone}
\usetikzlibrary{fadings}
\begin{document}
  \tikz
    \draw[blue,thick,path fading=east] (0,0) rectangle (4,1);
\end{document}

edited Jun 23 '18 at 13:07

answered Jun 23 '18 at 12:57

Kpym

23,002

1

Thank you. I had tried that, but it also didn't work. I see now that solution doesn't work in the PDF viewer I use (Evince). I will go with the answer I posted in the comments (for interoperability's sake). – Ricardo Cruz Jun 23 '18 at 13:22

score 3 · Answer 2 · answered Jun 23 '18 at 13:19

As @Torbjørn T. pointed out, shading is a filling.

I have decided to just use rectangles of the size of a line (\pgflinewidth).

i.e.

\documentclass[border=1mm]{standalone}
\usepackage{tikz}

\newcommand{\fadehline}[3]{
    \fill (#1,#3) rectangle ++(#2, \pgflinewidth);
    \shade[left color=black, right color=white] (#2,#3) rectangle ++(0.5, \pgflinewidth);
}

\begin{document}
\begin{tikzpicture}

\fadehline{0}{1}{0};
\fadehline{0}{1}{0.8};
\fill (0,0) rectangle ++(\pgflinewidth, 0.8);

\end{tikzpicture}
\end{document}

Tikz: drawing border or line with shade

2 Answers2