[Tex/LaTex] How to make a thick line connect completely with the side of a box in TikZ

arrowsboxestikz-pgf

In my figure, I have a thick line that connects with the side of a box. However, the line does not connect completely with the box. Also, the line covers part of the box (which I don't want).

So, I want the lower edge of the line to connect completely with the box, and prevent the upper edge of the line to cover part of the box. It probably says how to deal with this in the PGF manual but I can't find it (and since I don't know the terminology for this, I can't search for it either).

enter image description here

Here is minimal example for the figure above.

\documentclass{standalone}

\usepackage{tikz}

\begin{document}
\begin{tikzpicture}
  \node [draw, minimum size = 1cm] (box) {};
  \draw [line width = 5pt] (2cm, 2cm) -- (box.east);
\end{tikzpicture}
\end{document}

Best Answer

\documentclass{standalone}   
\usepackage{tikz}
\usetikzlibrary{calc} 
\begin{document} 

  \tikzset{%
    add/.style args={#1 and #2}{to path={%
 ($(\tikztostart)!-#1!(\tikztotarget)$)--($(\tikztotarget)!-#2!(\tikztostart)$)%
  \tikztonodes}}
}                

\begin{tikzpicture}  
   \node [ minimum size = 1cm] (box) {};  
   \draw [line width = 5pt,add=0 and .1] (2cm, 2cm) to (box.east);   
   \node [draw, fill=white,minimum size = 1cm]  {};

\end{tikzpicture}
\end{document}

enter image description here

second solution

\documentclass{standalone}
\usepackage{tikz}
\usetikzlibrary{calc} 
\begin{document} 

  \tikzset{%
    add/.style args={#1 and #2}{to path={%
 ($(\tikztostart)!-#1!(\tikztotarget)$)--($(\tikztotarget)!-#2!(\tikztostart)$)%
  \tikztonodes}}
}                

\begin{tikzpicture}  
   \node [draw, fill=white,minimum size = 1cm] (box) {};  
   \clip (box.south east) rectangle (2.1cm, 2.1cm);   
   \draw [line width = 5pt,add=0 and .1] (2cm, 2cm) to (box.east);   
\end{tikzpicture}
\end{document}

Third solution

\documentclass{article}   
\usepackage{tikz}
\usetikzlibrary{calc,backgrounds} 
\begin{document} 

  \tikzset{%
    add/.style args={#1 and #2}{to path={%
 ($(\tikztostart)!-#1!(\tikztotarget)$)--($(\tikztotarget)!-#2!(\tikztostart)$)%
  \tikztonodes}}
}                

\begin{tikzpicture}
   \draw[help lines] (0,0) grid (2,2);    
   \node [draw,minimum size = 1cm,fill=white] (box) {}; 
   \begin{pgfonlayer}{background}
      \draw [line width = 5pt,add=0 and .1] (2cm, 2cm) to (box.east);      
   \end{pgfonlayer}
\end{tikzpicture}

\end{document}

Fourth version With reverseclip

\documentclass{article}
\usepackage{tikz}

\begin{document}

\begin{tikzpicture}[remember picture]

% A path that follows the edges of the current page
\tikzstyle{reverseclip}=[insert path={(current page.north east) --
  (current page.south east) --
  (current page.south west) --
  (current page.north west) --
  (current page.north east)}
]

\node [draw, minimum size = 1cm,inner sep=0pt,ultra thick,red] (box) at (.5cm,.5cm){};
\coordinate (D) at (box.north west);
\coordinate (C) at (box.north east);
\coordinate (B) at (box.south east);
\coordinate (A) at (box.south west);

\begin{pgfinterruptboundingbox} 
\path [clip] (A) -- (B) -- (C) -- (D) -- cycle [reverseclip];
\end{pgfinterruptboundingbox}

\draw [line width = 15pt] (.5cm, 1.5cm) to (.8cm,-.5cm);
\end{tikzpicture}
\end{document}

enter image description here

Related Solutions

[Tex/LaTex] TikZ: how to find the intersection of two extended lines

You're right, the shorten > syntax doesn't "actually" extend the line, but works on a lower level. In your case, I would use \usetikzlibrary{calc}, which gives you access to a lot of nifty coordinate calculations.

Your desired result could be achieved with the syntax

\draw (A) -- ($(B)!-1cm!(A)$) coordinate (C);

where the ($...$) encloses the calc syntax, and the (<first node>)!<distance>!(<second node>) specifies the coordinate that lies at <distance> along the line from <first node> to <second node>.

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{calc,intersections}
\begin{document}
\begin{tikzpicture}
\fill (0,0) circle [radius=2pt] node (A) [label=A] {};
\fill (2,1) circle [radius=2pt] node (B) [label=B] {};
\fill (3.2,1) circle [radius=2pt] node (C) [label=C] {};
\fill (4,0.5) circle [radius=2pt] node (D) [label=D] {};
\draw [name path=AB] (A) -- ($(B)!-1cm!(A)$);
\draw [name path=CD] (D) -- ($(C)!-1cm!(D)$);

\fill [red,name intersections={of={AB and CD}}] (intersection-1) circle [radius=2pt];
\end{tikzpicture}
\end{document}

[Tex/LaTex] Rotate a node but not its content: the case of the ellipse decoration

The source of the difficulty is that ellipses are constructed in a particular way in TikZ. They are paths that start from the x-axis and proceed counter-clockwise around their centre. The vast majority of the time, the exact parametrisation doesn't matter. You appear to have found the one situation where it does!

In the actual question, you only want to be able to mirror the ellipse, and so draw it starting from the negative x-axis (the title of the question suggests a more flexible approach). That's actually not too hard since we can exploit the symmetry of the ellipse. The key is to provide it with a negative x-radius, since then it will start from the negative x-axis (and proceed clockwise, but we could correct for that by negating the y-radius as well). To do this, we interrupt the call from the node shape to the drawing command and flip the sign of the x-radius. The simplest way to do this is to redefine the \pgfpathellipse macro to do the negation and then call the original macro. The following code does this.

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{decorations,shapes,decorations.markings}
\makeatletter
\let\origpgfpathellipse=\pgfpathellipse
\def\revpgfpathellipse#1#2#3{%
  #2%
  \pgf@xa=-\pgf@x
  \origpgfpathellipse{#1}{\pgfqpoint{\pgf@xa}{0pt}}{#3}}
\makeatother

\tikzset{
  reversed ellipse/.style={
    ellipse,
    reverse the ellipse%
  },
  reverse the ellipse/.code={
    \let\pgfpathellipse=\revpgfpathellipse
  }
}
\begin{document}
\begin{tikzpicture}
\node[ellipse,
  draw,
  postaction={
    decorate,
    decoration={
      markings,
      mark=at position 1 with {
        \arrow[line width=5pt,blue]{>}
      }
    }
  }
] at (0,0) {hello world};

\node[reversed ellipse,
  draw,
  postaction={
    decorate,
    decoration={
      markings,
      mark=at position 1 with {
        \arrow[line width=5pt,blue]{>}
      }
    }
  }
] at (0,-2) {hello world};
\end{tikzpicture}

\end{document}

Here's the result:

rotated ellipse

(the arrow got clipped, but you can see where it lies)

Best Answer

Related Solutions

[Tex/LaTex] TikZ: how to find the intersection of two extended lines

[Tex/LaTex] Rotate a node but not its content: the case of the ellipse decoration

Related Question