Adding space to a center line

Question

How to draw for instance a beam (or even fancier forms) from a given center line? Here is what i mean but with a rather not so good solution. I would like to add pattern, etc.

\documentclass[12pt,tikz,border=5pt]{standalone}
\usetikzlibrary{calc}


\begin{document}

\begin{tikzpicture}
% grid to see the coordinates

% Point A with circle and label
\coordinate [label={[label distance=3mm]below:A}] (A) at (1,3);

% Point B with circle and label
\coordinate [label={[label distance=3mm]right:B}](B) at (6,6);

% Point C with circle and label
\coordinate [label={[label distance=3mm]below:C}](C) at (7,4);

% Point D with circle and label
\coordinate [label={[label distance=3mm]right:D}](D) at (9,4);
\draw (D) circle [radius=3pt];

\draw[line width=20pt,line cap=round] (A) -- (B) -- (C) -- (D); 
\draw[line width=14pt,white,line cap=round] (A) -- (B) -- (C) -- (D);    
\draw (A) -- (B) -- (C) -- (D);

% grid to see the coordinates
\draw[help lines, step=1] (0,0) grid (10,8);

\draw (A) circle [radius=3pt];
\draw (B) circle [radius=3pt];
\draw (C) circle [radius=3pt];
\draw (D) circle [radius=3pt];

\end{tikzpicture}
\end{document}

enter image description here

Do you mean TikZ decorations? Have a look at chapter 24 of the current TikZ/PGF documentation. — Turion, Jan 07 '15 at 22:25
i know about the decoration library and i will look at this library. but from the idea: i want a knew path around the given skeleton line and than make fancy things (decorations) to this new path. — Nik, Jan 09 '15 at 14:34

score 1 · Answer 1 · answered Jan 08 '15 at 03:15

Use pgf-blur. The documentation says that the shadow is always black. But it is not hard to find out that black and replace it by our \blurcolor

\documentclass[tikz]{standalone}
\usetikzlibrary{shadows.blur}
\makeatletter
\tikzset{
    /tikz/render blur shadow/.code={
        \pgfbs@savebb
        \pgfsyssoftpath@getcurrentpath{\pgfbs@input@path}%
        \pgfbs@compute@shadow@bbox
        \pgfbs@process@rounding{\pgfbs@input@path}{\pgfbs@fadepath}%
        \pgfbs@apply@canvas@transform
        \colorlet{pstb@shadow@color}{white!\pgfbs@opacity!black}%
        \pgfdeclarefading{shadowfading}{\pgfbs@paint@fading}%
        \pgfsetfillcolor{\blurcolor}%
        \pgfsetfading{shadowfading}%
            {\pgftransformshift{\pgfpoint{\pgfbs@midx}{\pgfbs@midy}}}%
        \pgfbs@usebbox{fill}%
        \pgfbs@restorebb
    }
}
\begin{document}
    \begin{tikzpicture}
        \fill[black](0,2)rectangle(10,7);
        \def\blurcolor{yellow}
        \path[blur shadow,shadow xshift=0,shadow yshift=0,
              shadow blur radius=20pt,shadow opacity=100,shadow blur steps=100]
            (1,3)--(6,6)--cycle(6,6)--(7,4)--cycle(7,4)--(9,4)--cycle;
    \end{tikzpicture}
\end{document}

@Nik when you like one answer, a good practice is to upvote it. — Kpym, Jan 09 '15 at 14:54
sorry. done. ok i get this @ here but not at the beginning of the comment? — Nik, Jan 09 '15 at 16:22

score 1 · Accepted Answer · edited Apr 13 '17 at 12:34

1

You can adapt my previous answer like this:

\documentclass[tikz,border=5]{standalone}
\usetikzlibrary{calc}
\usetikzlibrary{patterns}
\tikzset{
  rect/.style= { to path={ let \n1={sqrt(2)*#1},
    \p1=($(\tikztostart)!\n1!-135:(\tikztotarget)$), \p2=($(\tikztostart)!\n1!135:(\tikztotarget)$),
    \p3=($(\tikztotarget)!\n1!-135:(\tikztostart)$), \p4=($(\tikztotarget)!\n1!135:(\tikztostart)$)
    in (\p1) -- (\p2) -- (\p3) -- (\p4) --cycle (\tikztotarget)}
  },
  round/.style={rounded corners=#1,rect/.default=#1}
}
\begin{document}
  \begin{tikzpicture}
    \draw[help lines] (0,0) grid (7,5);

    \def\mypath{(1,2) foreach \a in {30,-45,0,90} {to[rect] ++(\a:2)}}
    \fill[round=4mm,black] \mypath;
    \shade[round=3mm,left color=red, right color=blue] \mypath;
    \pattern[round=3mm,pattern color=white,pattern=bricks] \mypath;

  \end{tikzpicture}
\end{document}

enter image description here

edited Apr 13 '17 at 12:34

Community

1

answered Jan 08 '15 at 04:59

Kpym

23,002

that ist what I had in mind. i will later explore your code. but can i ask you to make a picture with everywhere rounded corners? to get the body of a snake :-) ? – Nik Jan 09 '15 at 14:30
@Nik probably you want another patern too, but I'll let you do this by yourself. Putting a circle is not so hard ;) – Kpym Jan 09 '15 at 14:53
Kpym ok ok ok ok – Nik Jan 09 '15 at 16:21
i want to write: @Kpym but i don't get this. not at the beginning of the comment. – Nik Jan 09 '15 at 16:24
You don't need @ for the author of the answer/question. It is automaticaly informed. You can add only one @ to informe somebody else too. Here for more info : http://meta.stackexchange.com/a/43020 – Kpym Jan 09 '15 at 16:38

Adding space to a center line

2 Answers2

Linked