summaryrefslogtreecommitdiff
path: root/graphics/pgf/base/doc/pgfmanual-en-library-trees.tex
diff options
context:
space:
mode:
Diffstat (limited to 'graphics/pgf/base/doc/pgfmanual-en-library-trees.tex')
-rw-r--r--graphics/pgf/base/doc/pgfmanual-en-library-trees.tex196
1 files changed, 196 insertions, 0 deletions
diff --git a/graphics/pgf/base/doc/pgfmanual-en-library-trees.tex b/graphics/pgf/base/doc/pgfmanual-en-library-trees.tex
new file mode 100644
index 0000000000..ccb5eb53dc
--- /dev/null
+++ b/graphics/pgf/base/doc/pgfmanual-en-library-trees.tex
@@ -0,0 +1,196 @@
+% Copyright 2019 by Till Tantau
+%
+% This file may be distributed and/or modified
+%
+% 1. under the LaTeX Project Public License and/or
+% 2. under the GNU Free Documentation License.
+%
+% See the file doc/generic/pgf/licenses/LICENSE for more details.
+
+
+\section{Tree Library}
+\label{section-tree-library}
+
+\begin{tikzlibrary}{trees}
+ This packages defines styles to be used when drawing trees.
+\end{tikzlibrary}
+
+
+\subsection{Growth Functions}
+
+The package |trees| defines two new growth functions. They are installed using
+the following options:
+
+\begin{key}{/tikz/grow via three points=\texttt{one child at (}\meta{x}
+ \texttt{) and two children at (}\meta{y}\texttt{) and (}\meta{z}|)|%
+}
+ This option installs a growth function that works as follows: If a parent
+ node has just one child, this child is placed at \meta{x}. If the parent
+ node has two children, these are placed at \meta{y} and \meta{z}. If the
+ parent node has more than two children, the children are placed at points
+ that are linearly extrapolated from the three points \meta{x}, \meta{y},
+ and \meta{z}. In detail, the position is $x + \frac{n-1}{2}(y-x) +
+ (c-1)(z-y)$, where $n$ is the number of children and $c$ is the number of
+ the current child (starting with~$1$).
+
+ The net effect of all this is that if you have a certain ``linear
+ arrangement'' in mind and use this option to specify the placement of a
+ single child and of two children, then any number of children will be
+ placed correctly.
+
+ Here are some arrangements based on this growth function. We start with a
+ simple ``above'' arrangement:
+ %
+\begin{codeexample}[preamble={\usetikzlibrary{trees}}]
+\begin{tikzpicture}[grow via three points={%
+ one child at (0,1) and two children at (-.5,1) and (.5,1)}]
+ \node at (0,0) {one} child;
+ \node at (0,-1.5) {two} child child;
+ \node at (0,-3) {three} child child child;
+ \node at (0,-4.5) {four} child child child child;
+\end{tikzpicture}
+\end{codeexample}
+
+ The next arrangement places children above, but ``grows only to the
+ right''.
+ %
+\begin{codeexample}[preamble={\usetikzlibrary{trees}}]
+\begin{tikzpicture}[grow via three points={%
+ one child at (0,1) and two children at (0,1) and (1,1)}]
+ \node at (0,0) {one} child;
+ \node at (0,-1.5) {two} child child;
+ \node at (0,-3) {three} child child child;
+ \node at (0,-4.5) {four} child child child child;
+\end{tikzpicture}
+\end{codeexample}
+
+ In the final arrangement, the children are placed along a line going down
+ and right.
+\begin{codeexample}[preamble={\usetikzlibrary{trees}}]
+\begin{tikzpicture}[grow via three points={%
+ one child at (-1,-.5) and two children at (-1,-.5) and (0,-.75)}]
+ \node at (0,0) {one} child;
+ \node at (0,-1.5) {two} child child;
+ \node at (0,-3) {three} child child child;
+ \node at (0,-4.5) {four} child child child child;
+\end{tikzpicture}
+\end{codeexample}
+
+ These examples should make it clear how you can create new styles to
+ arrange your children along a line.
+\end{key}
+
+\begin{key}{/tikz/grow cyclic}
+ This style causes the children to be arranged ``on a circle''. For this,
+ the children are placed at distance |\tikzleveldistance| from the parent
+ node, but not on a straight line, but on points on a circle. Instead of a
+ sibling distance, there is a |sibling angle| that denotes the angle between
+ two given children.
+ %
+ \begin{key}{/tikz/sibling angle=\meta{angle}}
+ Sets the angle between siblings in the |grow cyclic| style.
+ \end{key}
+ %
+ Note that this function will rotate the coordinate system of the children
+ to ensure that the grandchildren will grow in the right direction.
+ %
+\begin{codeexample}[preamble={\usetikzlibrary{trees}}]
+\begin{tikzpicture}
+ [grow cyclic,
+ level 1/.style={level distance=8mm,sibling angle=60},
+ level 2/.style={level distance=4mm,sibling angle=45},
+ level 3/.style={level distance=2mm,sibling angle=30}]
+ \coordinate [rotate=-90] % going down
+ child foreach \x in {1,2,3}
+ {child foreach \x in {1,2,3}
+ {child foreach \x in {1,2,3}}};
+\end{tikzpicture}
+\end{codeexample}
+ %
+\end{key}
+
+\begin{key}{/tikz/clockwise from=\meta{angle}}
+ This option also causes children to be arranged on a circle. However, the
+ rule for placing children is simpler than with the |grow cyclic| style: The
+ first child is placed at \meta{angle} at a distance of
+ |\tikzleveldistance|. The second child is placed at the same distance from
+ the parent, but at angle \meta{angle}${}-{}$|\tikzsiblingangle|. The third
+ child is displaced by another |\tikzsiblingangle| in a clockwise fashion,
+ and so on.
+
+ Note that this function will not rotate the coordinate system.
+ %
+\begin{codeexample}[preamble={\usetikzlibrary{trees}}]
+\begin{tikzpicture}
+ \node {root}
+ [clockwise from=30,sibling angle=30]
+ child {node {$30$}}
+ child {node {$0$}}
+ child {node {$-30$}}
+ child {node {$-60$}};
+\end{tikzpicture}
+\end{codeexample}
+ %
+\end{key}
+
+\begin{key}{/tikz/counterclockwise from=\meta{angle}}
+ Works the same way as |clockwise from|, but sibling angles are added
+ instead of subtracted.
+\end{key}
+
+
+\subsection{Edges From Parent}
+
+The following styles can be used to modify how the edges from parents are
+drawn:
+
+\begin{stylekey}{/tikz/edge from parent fork down}
+ This style will draw a line from the parent downwards (for half the level
+ distance) and then on to the child using only horizontal and vertical
+ lines.
+ %
+\begin{codeexample}[preamble={\usetikzlibrary{trees}}]
+\begin{tikzpicture}
+ \node {root}
+ [edge from parent fork down]
+ child {node {left}}
+ child {node {right}
+ child[child anchor=north east] {node {child}}
+ child {node {child}}
+ };
+\end{tikzpicture}
+\end{codeexample}
+ %
+\end{stylekey}
+
+\begin{stylekey}{/tikz/edge from parent fork right}
+ This style behaves similarly, only it will first draw its edge to the
+ right.
+ %
+\begin{codeexample}[preamble={\usetikzlibrary{trees}}]
+\begin{tikzpicture}
+ \node {root}
+ [edge from parent fork right,grow=right]
+ child {node {left}}
+ child {node {right}
+ child {node {child}}
+ child {node {child}}
+ };
+\end{tikzpicture}
+\end{codeexample}
+ %
+\end{stylekey}
+
+\begin{stylekey}{/tikz/edge from parent fork left}
+ Behaves similarly to the previous styles.
+\end{stylekey}
+
+\begin{stylekey}{/tikz/edge from parent fork up}
+ Behaves similarly to the previous styles.
+\end{stylekey}
+
+
+%%% Local Variables:
+%%% mode: latex
+%%% TeX-master: "pgfmanual-pdftex-version"
+%%% End: