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authorNorbert Preining <norbert@preining.info>2019-09-02 13:46:59 +0900
committerNorbert Preining <norbert@preining.info>2019-09-02 13:46:59 +0900
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+% Copyright 2006 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{Actions on Paths}
+
+\subsection{Overview}
+
+Once a path has been constructed, different things can be done with it. It can
+be drawn (or stroked) with a ``pen'', it can be filled with a color or shading,
+it can be used for clipping subsequent drawing, it can be used to specify the
+extend of the picture -- or any combination of these actions at the same time.
+
+To decide what is to be done with a path, two methods can be used. First, you
+can use a special-purpose command like |\draw| to indicate that the path should
+be drawn. However, commands like |\draw| and |\fill| are just abbreviations for
+special cases of the more general method: Here, the |\path| command is used to
+specify the path. Then, options encountered on the path indicate what should be
+done with the path.
+
+For example, |\path (0,0) circle (1cm);| means: ``This is a path consisting of
+a circle around the origin. Do not do anything with it (throw it away).''
+However, if the option |draw| is encountered anywhere on the path, the circle
+will be drawn. ``Anywhere'' is any point on the path where an option can be
+given, which is everywhere where a path command like |circle (1cm)| or
+|rectangle (1,1)| or even just |(0,0)| would also be allowed. Thus, the
+following commands all draw the same circle:
+%
+\begin{codeexample}[code only]
+\path [draw] (0,0) circle (1cm);
+\path (0,0) [draw] circle (1cm);
+\path (0,0) circle (1cm) [draw];
+\end{codeexample}
+%
+Finally, |\draw (0,0) circle (1cm);| also draws a path, because |\draw| is an
+abbreviation for |\path [draw]| and thus the command expands to the first line
+of the above example.
+
+Similarly, |\fill| is an abbreviation for |\path[fill]| and |\filldraw| is an
+abbreviation for the command |\path[fill,draw]|. Since options accumulate, the
+following commands all have the same effect:
+%
+\begin{codeexample}[code only]
+\path [draw,fill] (0,0) circle (1cm);
+\path [draw] [fill] (0,0) circle (1cm);
+\path [fill] (0,0) circle (1cm) [draw];
+\draw [fill] (0,0) circle (1cm);
+\fill (0,0) [draw] circle (1cm);
+\filldraw (0,0) circle (1cm);
+\end{codeexample}
+
+In the following subsection the different actions that can be performed on a
+path are explained. The following commands are abbreviations for certain sets
+of actions, but for many useful combinations there are no abbreviations:
+
+\begin{command}{\draw}
+ Inside |{tikzpicture}| this is an abbreviation for |\path[draw]|.
+\end{command}
+
+\begin{command}{\fill}
+ Inside |{tikzpicture}| this is an abbreviation for |\path[fill]|.
+\end{command}
+
+\begin{command}{\filldraw}
+ Inside |{tikzpicture}| this is an abbreviation for |\path[fill,draw]|.
+\end{command}
+
+\begin{command}{\pattern}
+ Inside |{tikzpicture}| this is an abbreviation for |\path[pattern]|.
+\end{command}
+
+\begin{command}{\shade}
+ Inside |{tikzpicture}| this is an abbreviation for |\path[shade]|.
+\end{command}
+
+\begin{command}{\shadedraw}
+ Inside |{tikzpicture}| this is an abbreviation for |\path[shade,draw]|.
+\end{command}
+
+\begin{command}{\clip}
+ Inside |{tikzpicture}| this is an abbreviation for |\path[clip]|.
+\end{command}
+
+\begin{command}{\useasboundingbox}
+ Inside |{tikzpicture}| this is an abbreviation for |\path[use as bounding box]|.
+\end{command}
+
+
+\subsection{Specifying a Color}
+
+The most unspecific option for setting colors is the following:
+%
+\begin{key}{/tikz/color=\meta{color name}}
+ \indexoption{color option}%
+ This option sets the color that is used for fill, drawing, and text inside
+ the current scope. Any special settings for filling colors or drawing
+ colors are immediately ``overruled'' by this option.
+
+ The \meta{color name} is the name of a previously defined color. For
+ \LaTeX\ users, this is just a normal ``\LaTeX-color'' and the |xcolor|
+ extensions are allowed. Here is an example:
+ %
+\begin{codeexample}[]
+\tikz \fill[color=red!20] (0,0) circle (1ex);
+\end{codeexample}
+
+ It is possible to ``leave out'' the |color=| part and you can also write:
+ %
+\begin{codeexample}[]
+\tikz \fill[red!20] (0,0) circle (1ex);
+\end{codeexample}
+ %
+ What happens is that every option that \tikzname\ does not know, like
+ |red!20|, gets a ``second chance'' as a color name.
+
+ For plain \TeX\ users, it is not so easy to specify colors since plain
+ \TeX\ has no ``standardized'' color naming mechanism. Because of this,
+ \pgfname\ emulates the |xcolor| package, though the emulation is
+ \emph{extremely basic} (more precisely, what I could hack together in two
+ hours or so). The emulation allows you to do the following:
+ %
+ \begin{itemize}
+ \item Specify a new color using |\definecolor|. Only the two color
+ models |gray| and |rgb| are supported\footnote{Con\TeX t users
+ should be aware that \texttt{\textbackslash definecolor} has a
+ different meaning in Con\TeX t. There is a low-level equivalent
+ named \texttt{\textbackslash pgfutil@definecolor} which can be
+ used instead.}.
+ %
+ \example |\definecolor{orange}{rgb}{1,0.5,0}|
+ \item Use |\colorlet| to define a new color based on an old one.
+ Here, the |!| mechanism is supported, though only ``once'' (use
+ multiple |\colorlet| for more fancy colors).
+ %
+ \example |\colorlet{lightgray}{black!25}|
+ \item Use |\color|\marg{color name} to set the color in the current
+ \TeX\ group. |\aftergroup|-hackery is used to restore the color
+ after the group.
+ \end{itemize}
+\end{key}
+
+As pointed out above, the |color=| option applies to ``everything'' (except to
+shadings), which is not always what you want. Because of this, there are
+several more specialized color options. For example, the |draw=| option sets
+the color used for drawing, but does not modify the color used for filling.
+These color options are documented where the path action they influence is
+described.
+
+
+\subsection{Drawing a Path}
+
+You can draw a path using the following option:
+%
+\begin{key}{/tikz/draw=\meta{color} (default \normalfont is scope's color setting)}
+ Causes the path to be drawn. ``Drawing'' (also known as ``stroking'') can
+ be thought of as picking up a pen and moving it along the path, thereby
+ leaving ``ink'' on the canvas.
+
+ There are numerous parameters that influence how a line is drawn, like the
+ thickness or the dash pattern. These options are explained below.
+
+ If the optional \meta{color} argument is given, drawing is done using the
+ given \meta{color}. This color can be different from the current filling
+ color, which allows you to draw and fill a path with different colors. If
+ no \meta{color} argument is given, the last usage of the |color=| option is
+ used.
+
+ If the special color name |none| is given, this option causes drawing to be
+ ``switched off''. This is useful if a style has previously switched on
+ drawing and you locally wish to undo this effect.
+
+ Although this option is normally used on paths to indicate that the path
+ should be drawn, it also makes sense to use the option with a |{scope}| or
+ |{tikzpicture}| environment. However, this will \emph{not} cause all paths
+ to be drawn. Instead, this just sets the \meta{color} to be used for
+ drawing paths inside the environment.
+ %
+\begin{codeexample}[]
+\begin{tikzpicture}
+ \path[draw=red] (0,0) -- (1,1) -- (2,1) circle (10pt);
+\end{tikzpicture}
+\end{codeexample}
+ %
+\end{key}
+
+The following subsections list the different options that influence how a path
+is drawn. All of these options only have an effect if the |draw| option is
+given (directly or indirectly).
+
+
+\subsubsection{Graphic Parameters: Line Width, Line Cap, and Line Join}
+\label{section-cap-joins}
+
+\begin{key}{/tikz/line width=\meta{dimension} (initially 0.4pt)}
+ Specifies the line width. Note the space.
+ %
+\begin{codeexample}[]
+ \tikz \draw[line width=5pt] (0,0) -- (1cm,1.5ex);
+\end{codeexample}
+ %
+\end{key}
+
+There are a number of predefined styles that provide more ``natural'' ways of
+setting the line width. You can also redefine these styles.
+
+\begin{stylekey}{/tikz/ultra thin}
+ Sets the line width to 0.1pt.
+ %
+\begin{codeexample}[]
+ \tikz \draw[ultra thin] (0,0) -- (1cm,1.5ex);
+\end{codeexample}
+ %
+\end{stylekey}
+
+\begin{stylekey}{/tikz/very thin}
+ Sets the line width to 0.2pt.
+ %
+\begin{codeexample}[]
+ \tikz \draw[very thin] (0,0) -- (1cm,1.5ex);
+\end{codeexample}
+ %
+\end{stylekey}
+
+\begin{stylekey}{/tikz/thin}
+ Sets the line width to 0.4pt.
+ %
+\begin{codeexample}[]
+ \tikz \draw[thin] (0,0) -- (1cm,1.5ex);
+\end{codeexample}
+ %
+\end{stylekey}
+
+\begin{stylekey}{/tikz/semithick}
+ Sets the line width to 0.6pt.
+ %
+\begin{codeexample}[]
+ \tikz \draw[semithick] (0,0) -- (1cm,1.5ex);
+\end{codeexample}
+ %
+\end{stylekey}
+
+\begin{stylekey}{/tikz/thick}
+ Sets the line width to 0.8pt.
+ %
+\begin{codeexample}[]
+ \tikz \draw[thick] (0,0) -- (1cm,1.5ex);
+\end{codeexample}
+ %
+\end{stylekey}
+
+\begin{stylekey}{/tikz/very thick}
+ Sets the line width to 1.2pt.
+ %
+\begin{codeexample}[]
+ \tikz \draw[very thick] (0,0) -- (1cm,1.5ex);
+\end{codeexample}
+ %
+\end{stylekey}
+
+\begin{stylekey}{/tikz/ultra thick}
+ Sets the line width to 1.6pt.
+ %
+\begin{codeexample}[]
+ \tikz \draw[ultra thick] (0,0) -- (1cm,1.5ex);
+\end{codeexample}
+ %
+\end{stylekey}
+
+ \label{section-line-cap}
+\begin{key}{/tikz/line cap=\meta{type} (initially butt)}
+ Specifies how lines ``end''. Permissible \meta{type} are |round|, |rect|,
+ and |butt|. They have the following effects:
+ %
+\begin{codeexample}[]
+\begin{tikzpicture}
+ \begin{scope}[line width=10pt]
+ \draw[line cap=round] (0,1 ) -- +(1,0);
+ \draw[line cap=butt] (0,.5) -- +(1,0);
+ \draw[line cap=rect] (0,0 ) -- +(1,0);
+ \end{scope}
+ \draw[white,line width=1pt]
+ (0,0 ) -- +(1,0) (0,.5) -- +(1,0) (0,1 ) -- +(1,0);
+\end{tikzpicture}
+\end{codeexample}
+ %
+\end{key}
+
+\begin{key}{/tikz/line join=\meta{type} (initially miter)}
+ Specifies how lines ``join''. Permissible \meta{type} are |round|, |bevel|,
+ and |miter|. They have the following effects:
+ %
+\begin{codeexample}[]
+\begin{tikzpicture}[line width=10pt]
+ \draw[line join=round] (0,0) -- ++(.5,1) -- ++(.5,-1);
+ \draw[line join=bevel] (1.25,0) -- ++(.5,1) -- ++(.5,-1);
+ \draw[line join=miter] (2.5,0) -- ++(.5,1) -- ++(.5,-1);
+ \useasboundingbox (0,1.5); % enlarge bounding box
+\end{tikzpicture}
+\end{codeexample}
+
+ \begin{key}{/tikz/miter limit=\meta{factor} (initially 10)}
+ When you use the miter join and there is a very sharp corner (a small
+ angle), the miter join may protrude very far over the actual joining
+ point. In this case, if it were to protrude by more than \meta{factor}
+ times the line width, the miter join is replaced by a bevel join.
+ %
+\begin{codeexample}[]
+\begin{tikzpicture}[line width=5pt]
+ \draw (0,0) -- ++(5,.5) -- ++(-5,.5);
+ \draw[miter limit=25] (6,0) -- ++(5,.5) -- ++(-5,.5);
+ \useasboundingbox (14,0); % make bounding box bigger
+\end{tikzpicture}
+\end{codeexample}
+ \end{key}
+\end{key}
+
+
+\subsubsection{Graphic Parameters: Dash Pattern}
+
+\begin{key}{/tikz/dash pattern=\meta{dash pattern}}
+ Sets the dashing pattern. The syntax is the same as in \textsc{metafont}.
+ For example following pattern |on 2pt off 3pt on 4pt off 4pt| means ``draw
+ 2pt, then leave out 3pt, then draw 4pt once more, then leave out 4pt again,
+ repeat''.
+ %
+\begin{codeexample}[]
+\begin{tikzpicture}[dash pattern=on 2pt off 3pt on 4pt off 4pt]
+ \draw (0pt,0pt) -- (3.5cm,0pt);
+\end{tikzpicture}
+\end{codeexample}
+ %
+\end{key}
+
+\begin{key}{/tikz/dash phase=\meta{dash phase} (initially 0pt)}
+ Shifts the start of the dash pattern by \meta{phase}.
+ %
+\begin{codeexample}[]
+\begin{tikzpicture}[dash pattern=on 20pt off 10pt]
+ \draw[dash phase=0pt] (0pt,3pt) -- (3.5cm,3pt);
+ \draw[dash phase=10pt] (0pt,0pt) -- (3.5cm,0pt);
+\end{tikzpicture}
+\end{codeexample}
+ %
+\end{key}
+
+\begin{key}{/tikz/dash=\meta{dash pattern}|phase|\meta{dash phase}}
+ Sets the dashing pattern and phase at the same time.
+ %
+\begin{codeexample}[]
+\begin{tikzpicture}
+ \draw [dash=on 20pt off 10pt phase 0pt] (0pt,3pt) -- (3.5cm,3pt);
+ \draw [dash=on 20pt off 10pt phase 10pt] (0pt,0pt) -- (3.5cm,0pt);
+\end{tikzpicture}
+\end{codeexample}
+ %
+\end{key}
+
+\begin{key}{/tikz/dash expand off}
+ Makes the |off| part of a dash pattern expandable such that it can stretch.
+ This only works when there is a single |on| and a single |off| field and
+ requires the |decorations| library. Right now this option has to be
+ specified on the path where it is supposed to take effect after the |dash
+ pattern| option because the dash pattern has to be known at the point where
+ it is applied.
+ %
+\begin{codeexample}[]
+\begin{tikzpicture}[|-|, dash pattern=on 4pt off 2pt]
+ \draw [dash expand off] (0pt,30pt) -- (26pt,30pt);
+ \draw [dash expand off] (0pt,20pt) -- (24pt,20pt);
+ \draw [dash expand off] (0pt,10pt) -- (22pt,10pt);
+ \draw [dash expand off] (0pt, 0pt) -- (20pt, 0pt);
+\end{tikzpicture}
+\end{codeexample}
+ %
+\end{key}
+
+As for the line thickness, some predefined styles allow you to set the dashing
+conveniently.
+
+\begin{stylekey}{/tikz/solid}
+ Shorthand for setting a solid line as ``dash pattern''. This is the default.
+ %
+\begin{codeexample}[]
+\tikz \draw[solid] (0pt,0pt) -- (50pt,0pt);
+\end{codeexample}
+ %
+\end{stylekey}
+
+\begin{stylekey}{/tikz/dotted}
+ Shorthand for setting a dotted dash pattern.
+ %
+\begin{codeexample}[]
+\tikz \draw[dotted] (0pt,0pt) -- (50pt,0pt);
+\end{codeexample}
+ %
+\end{stylekey}
+
+\begin{stylekey}{/tikz/densely dotted}
+ Shorthand for setting a densely dotted dash pattern.
+ %
+\begin{codeexample}[]
+\tikz \draw[densely dotted] (0pt,0pt) -- (50pt,0pt);
+\end{codeexample}
+ %
+\end{stylekey}
+
+\begin{stylekey}{/tikz/loosely dotted}
+ Shorthand for setting a loosely dotted dash pattern.
+ %
+\begin{codeexample}[]
+\tikz \draw[loosely dotted] (0pt,0pt) -- (50pt,0pt);
+\end{codeexample}
+ %
+\end{stylekey}
+
+\begin{stylekey}{/tikz/dashed}
+ Shorthand for setting a dashed dash pattern.
+ %
+\begin{codeexample}[]
+\tikz \draw[dashed] (0pt,0pt) -- (50pt,0pt);
+\end{codeexample}
+ %
+\end{stylekey}
+
+\begin{stylekey}{/tikz/densely dashed}
+ Shorthand for setting a densely dashed dash pattern.
+ %
+\begin{codeexample}[]
+\tikz \draw[densely dashed] (0pt,0pt) -- (50pt,0pt);
+\end{codeexample}
+ %
+\end{stylekey}
+
+\begin{stylekey}{/tikz/loosely dashed}
+ Shorthand for setting a loosely dashed dash pattern.
+ %
+\begin{codeexample}[]
+\tikz \draw[loosely dashed] (0pt,0pt) -- (50pt,0pt);
+\end{codeexample}
+ %
+\end{stylekey}
+
+\begin{stylekey}{/tikz/dash dot}
+ Shorthand for setting a dashed and dotted dash pattern.
+ %
+\begin{codeexample}[]
+\tikz \draw[dash dot] (0pt,0pt) -- (50pt,0pt);
+\end{codeexample}
+ %
+\end{stylekey}
+
+\begin{stylekey}{/tikz/densely dash dot}
+ Shorthand for setting a densely dashed and dotted dash pattern.
+ %
+\begin{codeexample}[]
+\tikz \draw[densely dash dot] (0pt,0pt) -- (50pt,0pt);
+\end{codeexample}
+ %
+\end{stylekey}
+
+\begin{stylekey}{/tikz/loosely dash dot}
+ Shorthand for setting a loosely dashed and dotted dash pattern.
+ %
+\begin{codeexample}[]
+\tikz \draw[loosely dash dot] (0pt,0pt) -- (50pt,0pt);
+\end{codeexample}
+ %
+\end{stylekey}
+
+\begin{stylekey}{/tikz/dash dot dot}
+ Shorthand for setting a dashed and dotted dash pattern with more dots.
+ %
+\begin{codeexample}[]
+\tikz \draw[dash dot dot] (0pt,0pt) -- (50pt,0pt);
+\end{codeexample}
+ %
+\end{stylekey}
+
+\begin{stylekey}{/tikz/densely dash dot dot}
+ Shorthand for setting a densely dashed and dotted dash pattern with more dots.
+ %
+\begin{codeexample}[]
+\tikz \draw[densely dash dot dot] (0pt,0pt) -- (50pt,0pt);
+\end{codeexample}
+ %
+\end{stylekey}
+
+\begin{stylekey}{/tikz/loosely dash dot dot}
+ Shorthand for setting a loosely dashed and dotted dash pattern with more dots.
+ %
+\begin{codeexample}[]
+\tikz \draw[loosely dash dot dot] (0pt,0pt) -- (50pt,0pt);
+\end{codeexample}
+ %
+\end{stylekey}
+
+
+\subsubsection{Graphic Parameters: Draw Opacity}
+
+When a line is drawn, it will normally ``obscure'' everything behind it as if
+you had used perfectly opaque ink. It is also possible to ask \tikzname\ to use
+an ink that is a little bit (or a big bit) transparent using the |draw opacity|
+option. This is explained in Section~\ref{section-tikz-transparency} on
+transparency in more detail.
+
+
+\subsubsection{Graphic Parameters: Double Lines and Bordered Lines}
+
+\begin{key}{/tikz/double=\meta{core color} (default white)}
+ This option causes ``two'' lines to be drawn instead of a single one.
+ However, this is not what really happens. In reality, the path is drawn
+ twice. First, with the normal drawing color, secondly with the \meta{core
+ color}, which is normally |white|. Upon the second drawing, the line width
+ is reduced. The net effect is that it appears as if two lines had been
+ drawn and this works well even with complicated, curved paths:
+ %
+\begin{codeexample}[]
+\tikz \draw[double]
+ plot[smooth cycle] coordinates{(0,0) (1,1) (1,0) (0,1)};
+\end{codeexample}
+
+ You can also use the doubling option to create an effect in which a line
+ seems to have a certain ``border'':
+ %
+\begin{codeexample}[]
+\begin{tikzpicture}
+ \draw (0,0) -- (1,1);
+ \draw[draw=white,double=red,very thick] (0,1) -- (1,0);
+\end{tikzpicture}
+\end{codeexample}
+ %
+\end{key}
+
+\begin{key}{/tikz/double distance=\meta{dimension} (initially 0.6pt)}
+ Sets the distance the ``two'' lines are spaced apart. In reality, this is
+ the thickness of the line that is used to draw the path for the second
+ time. The thickness of the \emph{first} time the path is drawn is twice the
+ normal line width plus the given \meta{dimension}. As a side-effect, this
+ option ``selects'' the |double| option.
+ %
+\begin{codeexample}[]
+\begin{tikzpicture}
+ \draw[very thick,double] (0,0) arc (180:90:1cm);
+ \draw[very thick,double distance=2pt] (1,0) arc (180:90:1cm);
+ \draw[thin,double distance=2pt] (2,0) arc (180:90:1cm);
+\end{tikzpicture}
+\end{codeexample}
+ %
+\end{key}
+
+\begin{key}{/tikz/double distance between line centers=\meta{dimension}}
+ This option works like |double distance|, only the distance is not the
+ distance between (inner) borders of the two main lines, but between their
+ centers. Thus, the thickness the \emph{first} time the path is drawn is the
+ normal line width plus the given \meta{dimension}, while the line width of
+ the \emph{second} line that is drawn is \meta{dimension} minus the normal
+ line width. As a side-effect, this option ``selects'' the |double| option.
+ %
+\begin{codeexample}[]
+\begin{tikzpicture}[double distance between line centers=3pt]
+ \foreach \lw in {0.5,1,1.5,2,2.5}
+ \draw[line width=\lw pt,double] (\lw,0) -- ++(4mm,0);
+\end{tikzpicture}
+\end{codeexample}
+ %
+\begin{codeexample}[]
+\begin{tikzpicture}[double distance=3pt]
+ \foreach \lw in {0.5,1,1.5,2,2.5}
+ \draw[line width=\lw pt,double] (\lw,0) -- ++(4mm,0);
+\end{tikzpicture}
+\end{codeexample}
+ %
+\end{key}
+
+\begin{stylekey}{/tikz/double equal sign distance}
+ This style selects a double line distance such that it corresponds to the
+ distance of the two lines in an equal sign.
+ %
+\begin{codeexample}[]
+\Huge $=\implies$\tikz[baseline,double equal sign distance]
+ \draw[double,thick,-implies](0,0.55ex) --++(3ex,0);
+\end{codeexample}
+ %
+\begin{codeexample}[]
+\normalsize $=\implies$\tikz[baseline,double equal sign distance]
+ \draw[double,-implies](0,0.6ex) --++(3ex,0);
+\end{codeexample}
+ %
+\begin{codeexample}[]
+\tiny $=\implies$\tikz[baseline,double equal sign distance]
+ \draw[double,very thin,-implies](0,0.5ex) -- ++(3ex,0);
+\end{codeexample}
+ %
+\end{stylekey}
+
+
+\subsection{Adding Arrow Tips to a Path}
+\label{section-arrow-tip-action}
+
+In different situations, \tikzname\ will add arrow tips to the end of a path.
+For this to happen, a number of different things need to be specified:
+%
+\begin{enumerate}
+ \item You must have used the |arrows| key, explained in detail in
+ Section~\ref{section-tikz-arrows}, to setup which kinds of arrow tips
+ you would like.
+ \item The path may not be closed (like a circle or a rectangle) and, if
+ it consists of several subpath, further restrictions apply as
+ explained in Section~\ref{section-tikz-arrows}.
+ \item The |tips| key must be set to an appropriate value, see
+ Section~\ref{section-tikz-arrows} once more.
+\end{enumerate}
+
+For the current section on paths, it is only important that when you add the
+|tips| option to a path that is not drawn, arrow tips will still be added at
+the beginning and at the end of the current path. This is true even when
+``only'' arrow tips get drawn for a path without drawing the path itself. Here
+is an example:
+%
+\begin{codeexample}[width=2cm]
+\tikz \path[tips, -{Latex[open,length=10pt,bend]}] (0,0) to[bend left] (1,0);
+\end{codeexample}
+%
+\begin{codeexample}[width=2cm]
+\tikz \draw[tips, -{Latex[open,length=10pt,bend]}] (0,0) to[bend left] (1,0);
+\end{codeexample}
+
+
+\subsection{Filling a Path}
+\label{section-rules}
+
+To fill a path, use the following option:
+%
+\begin{key}{/tikz/fill=\meta{color} (default \normalfont is scope's color setting)}
+ This option causes the path to be filled. All unclosed parts of the path
+ are first closed, if necessary. Then, the area enclosed by the path is
+ filled with the current filling color, which is either the last color set
+ using the general |color=| option or the optional color \meta{color}. For
+ self-intersection paths and for paths consisting of several closed areas,
+ the ``enclosed area'' is somewhat complicated to define and two different
+ definitions exist, namely the nonzero winding number rule and the even odd
+ rule, see the explanation of these options, below.
+
+ Just as for the |draw| option, setting \meta{color} to |none| disables
+ filling locally.
+ %
+\begin{codeexample}[]
+\begin{tikzpicture}
+ \fill (0,0) -- (1,1) -- (2,1);
+ \fill (4,0) circle (.5cm) (4.5,0) circle (.5cm);
+ \fill[even odd rule] (6,0) circle (.5cm) (6.5,0) circle (.5cm);
+ \fill (8,0) -- (9,1) -- (10,0) circle (.5cm);
+\end{tikzpicture}
+\end{codeexample}
+
+ If the |fill| option is used together with the |draw| option (either
+ because both are given as options or because a |\filldraw| command is
+ used), the path is filled \emph{first}, then the path is drawn
+ \emph{second}. This is especially useful if different colors are selected
+ for drawing and for filling. Even if the same color is used, there is a
+ difference between this command and a plain |fill|: A ``filldrawn'' area
+ will be slightly larger than a filled area because of the thickness of the
+ ``pen''.
+ %
+\begin{codeexample}[]
+\begin{tikzpicture}[fill=yellow!80!black,line width=5pt]
+ \filldraw (0,0) -- (1,1) -- (2,1);
+ \filldraw (4,0) circle (.5cm) (4.5,0) circle (.5cm);
+ \filldraw[even odd rule] (6,0) circle (.5cm) (6.5,0) circle (.5cm);
+ \filldraw (8,0) -- (9,1) -- (10,0) circle (.5cm);
+\end{tikzpicture}
+\end{codeexample}
+ %
+\end{key}
+
+
+\subsubsection{Graphic Parameters: Fill Pattern}
+\label{section-fill-pattern}
+
+Instead of filling a path with a single solid color, it is also possible to
+fill it with a \emph{tiling pattern}. Imagine a small tile that contains a
+simple picture like a star. Then these tiles are (conceptually) repeated
+infinitely in all directions, but clipped against the path.
+
+Tiling patterns come in two variants: \emph{inherently colored patterns} and
+\emph{form-only patterns}. An inherently colored pattern is, say, a red star
+with a black border and will always look like this. A form-only pattern may
+have a different color each time it is used, only the form of the pattern will
+stay the same. As such, form-only patterns do not have any colors of their own,
+but when it is used the current \emph{pattern color} is used as its color.
+
+Patterns are not overly flexible. In particular, it is not possible to change
+the size or orientation of a pattern without declaring a new pattern. For
+complicated cases, it may be easier to use two nested |\foreach| statements to
+simulate a pattern, but patterns are rendered \emph{much} more quickly than
+simulated ones.
+
+\begin{key}{/tikz/pattern=\meta{name} (default \normalfont is scope's pattern)}
+ This option causes the path to be filled with a pattern. If the \meta{name}
+ is given, this pattern is used, otherwise the pattern set in the enclosing
+ scope is used. As for the |draw| and |fill| options, setting \meta{name} to
+ |none| disables filling locally.
+
+ The pattern works like a fill color. In particular, setting a new fill
+ color will fill the path with a solid color once more.
+
+ Strangely, no \meta{name}s are permissible by default. You need to load for
+ instance the |patterns| library, see
+ Section~\ref{section-library-patterns}, to install predefined patterns.
+ %
+\begin{codeexample}[]
+\begin{tikzpicture}
+ \draw[pattern=dots] (0,0) circle (1cm);
+ \draw[pattern=fivepointed stars] (0,0) rectangle (3,1);
+\end{tikzpicture}
+\end{codeexample}
+ %
+\end{key}
+
+\begin{key}{/tikz/pattern color=\meta{color}}
+ This option is used to set the color to be used for form-only patterns.
+ This option has no effect on inherently colored patterns.
+ %
+\begin{codeexample}[]
+\begin{tikzpicture}
+ \draw[pattern color=red,pattern=fivepointed stars] (0,0) circle (1cm);
+ \draw[pattern color=blue,pattern=fivepointed stars] (0,0) rectangle (3,1);
+\end{tikzpicture}
+\end{codeexample}
+
+\begin{codeexample}[]
+\begin{tikzpicture}
+ \def\mypath{(0,0) -- +(0,1) arc (180:0:1.5cm) -- +(0,-1)}
+ \fill [red] \mypath;
+ \pattern[pattern color=white,pattern=bricks] \mypath;
+\end{tikzpicture}
+\end{codeexample}
+ %
+\end{key}
+
+
+\subsubsection{Graphic Parameters: Interior Rules}
+
+The following two options can be used to decide how interior points should be
+determined:
+%
+\begin{key}{/tikz/nonzero rule}
+ If this rule is used (which is the default), the following method is used
+ to determine whether a given point is ``inside'' the path: From the point,
+ shoot a ray in some direction towards infinity (the direction is chosen
+ such that no strange borderline cases occur). Then the ray may hit the
+ path. Whenever it hits the path, we increase or decrease a counter, which
+ is initially zero. If the ray hits the path as the path goes ``from left to
+ right'' (relative to the ray), the counter is increased, otherwise it is
+ decreased. Then, at the end, we check whether the counter is nonzero (hence
+ the name). If so, the point is deemed to lie ``inside'', otherwise it is
+ ``outside''. Sounds complicated? It is.
+ %
+\begin{codeexample}[]
+\begin{tikzpicture}
+ \filldraw[fill=yellow!80!black]
+ % Clockwise rectangle
+ (0,0) -- (0,1) -- (1,1) -- (1,0) -- cycle
+ % Counter-clockwise rectangle
+ (0.25,0.25) -- (0.75,0.25) -- (0.75,0.75) -- (0.25,0.75) -- cycle;
+
+ \draw[->] (0,1) -- (.4,1);
+ \draw[->] (0.75,0.75) -- (0.3,.75);
+
+ \draw[->] (0.5,0.5) -- +(0,1) node[above] {crossings: $-1+1 = 0$};
+
+ \begin{scope}[yshift=-3cm]
+ \filldraw[fill=yellow!80!black]
+ % Clockwise rectangle
+ (0,0) -- (0,1) -- (1,1) -- (1,0) -- cycle
+ % Clockwise rectangle
+ (0.25,0.25) -- (0.25,0.75) -- (0.75,0.75) -- (0.75,0.25) -- cycle;
+
+ \draw[->] (0,1) -- (.4,1);
+ \draw[->] (0.25,0.75) -- (0.4,.75);
+
+ \draw[->] (0.5,0.5) -- +(0,1) node[above] {crossings: $1+1 = 2$};
+ \end{scope}
+\end{tikzpicture}
+\end{codeexample}
+ %
+\end{key}
+
+\begin{key}{/tikz/even odd rule}
+ This option causes a different method to be used for determining the inside
+ and outside of paths. While it is less flexible, it turns out to be more
+ intuitive.
+
+ With this method, we also shoot rays from the point for which we wish to
+ determine whether it is inside or outside the filling area. However, this
+ time we only count how often we ``hit'' the path and declare the point to
+ be ``inside'' if the number of hits is odd.
+
+ Using the even-odd rule, it is easy to ``drill holes'' into a path.
+ %
+\begin{codeexample}[]
+\begin{tikzpicture}
+ \filldraw[fill=yellow!80!black,even odd rule]
+ (0,0) rectangle (1,1) (0.5,0.5) circle (0.4cm);
+ \draw[->] (0.5,0.5) -- +(0,1) [above] node{crossings: $1+1 = 2$};
+\end{tikzpicture}
+\end{codeexample}
+ %
+\end{key}
+
+
+\subsubsection{Graphic Parameters: Fill Opacity}
+\label{section-fill-opacity}
+
+Analogously to the |draw opacity|, you can also set the fill opacity. Please
+see Section~\ref{section-tikz-transparency} for more details.
+
+
+\subsection{Generalized Filling: Using Arbitrary Pictures to Fill a Path}
+
+Sometimes you wish to ``fill'' a path with something even more complicated than
+a pattern, let alone a single color. For instance, you might wish to use an
+image to fill the path or some other, complicated drawing. In principle, this
+effect can be achieved by first using the path for clipping and then,
+subsequently, drawing the desired image or picture. However, there is an option
+that makes this process much easier:
+
+\begin{key}{/tikz/path picture=\meta{code}}
+ When this option is given on a path and when the \meta{code} is not empty,
+ the following happens: After all other ``filling'' operations are done with
+ the path, which are caused by the options |fill|, |pattern| and |shade|, a
+ local scope is opened and the path is temporarily installed as a clipping
+ path. Then, the \meta{code} is executed, which can now draw something.
+ Then, the local scope ends and, possibly, the path is stroked, provided the
+ |draw| option has been given.
+
+ As with other keys like |fill| or |draw| this option needs to be given on a
+ path, setting the |path picture| outside a path has no effect (the path
+ picture is cleared at the beginning of each path).
+
+ The \meta{code} can be any normal \tikzname\ code like |\draw ...| or
+ |\node ...|. As always, when you include an external graphic, you need to
+ put it inside a |\node|.
+
+ Note that no special actions are taken to transform the origin in any way.
+ This means that the coordinate |(0,0)| is still where is was when the path
+ was being constructed and not -- as one might expect -- at the lower left
+ corner of the path. However, you can use the following special node to
+ access the size of the path:
+ %
+ \begin{predefinednode}{path picture bounding box}
+ This node is of shape |rectangle|. Its size and position are those of
+ |current path bounding box| just before the \meta{code} of the path
+ picture started to be executed. The \meta{code} can construct its own
+ paths, so accessing the |current path bounding box| inside the
+ \meta{code} yields the bounding box of any path that is currently being
+ constructed inside the \meta{code}.
+ \end{predefinednode}
+ %
+\begin{codeexample}[]
+\begin{tikzpicture}
+ \draw [help lines] (0,0) grid (3,2);
+ \filldraw [fill=blue!10,draw=blue,thick] (1.5,1) circle (1)
+ [path picture={
+ \node at (path picture bounding box.center) {
+ This is a long text.
+ };}
+ ];
+\end{tikzpicture}
+\end{codeexample}
+
+\begin{codeexample}[]
+\begin{tikzpicture}[cross/.style={path picture={
+ \draw[black]
+ (path picture bounding box.south east) --
+ (path picture bounding box.north west)
+ (path picture bounding box.south west) --
+ (path picture bounding box.north east);
+ }}]
+ \draw [help lines] (0,0) grid (3,2);
+ \filldraw [cross,fill=blue!10,draw=blue,thick] (1,1) circle (1);
+ \path [cross,top color=red,draw=red,thick] (2,0) -- (3,2) -- (3,0);
+\end{tikzpicture}
+\end{codeexample}
+
+\begin{codeexample}[]
+ \begin{tikzpicture}[path image/.style={
+ path picture={
+ \node at (path picture bounding box.center) {
+ \includegraphics[height=3cm]{#1}
+ };}}]
+ \draw [help lines] (0,0) grid (3,2);
+
+ \draw [path image=brave-gnu-world-logo,draw=blue,thick]
+ (0,1) circle (1);
+ \draw [path image=brave-gnu-world-logo,draw=red,very thick,->]
+ (1,0) parabola[parabola height=2cm] (3,0);
+
+\end{tikzpicture}
+\end{codeexample}
+ %
+\end{key}
+
+
+\subsection{Shading a Path}
+
+You can shade a path using the |shade| option. A shading is like a filling,
+only the shading changes its color smoothly from one color to another.
+
+\begin{key}{/tikz/shade}
+ Causes the path to be shaded using the currently selected shading (more on
+ this later). If this option is used together with the |draw| option, then
+ the path is first shaded, then drawn.
+
+ It is not an error to use this option together with the |fill| option, but
+ it makes no sense.
+ %
+\begin{codeexample}[]
+\tikz \shade (0,0) circle (1ex);
+\end{codeexample}
+
+\begin{codeexample}[]
+\tikz \shadedraw (0,0) circle (1ex);
+\end{codeexample}
+ %
+\end{key}
+
+For some shadings it is not really clear how they can ``fill'' the path. For
+example, the |ball| shading normally looks like this:
+\tikz \shade[shading=ball] (0,0) circle (0.75ex);. How is this supposed to
+shade a rectangle? Or a triangle?
+
+To solve this problem, the predefined shadings like |ball| or |axis| fill a
+large rectangle completely in a sensible way. Then, when the shading is used to
+``shade'' a path, what actually happens is that the path is temporarily used
+for clipping and then the rectangular shading is drawn, scaled and shifted such
+that all parts of the path are filled.
+
+The default shading is a smooth transition from gray to white and from top to
+bottom. However, other shadings are also possible, for example a shading that
+will sweep a color from the center to the corners outward. To choose the
+shading, you can use the |shading=| option, which will also automatically
+invoke the |shade| option. Note that this does \emph{not} change the shading
+color, only the way the colors sweep. For changing the colors, other options
+are needed, which are explained below.
+
+\begin{key}{/tikz/shading=\meta{name}}
+ This selects a shading named \meta{name}. The following shadings are
+ predefined: |axis|, |radial|, and |ball|.
+ %
+\begin{codeexample}[]
+\tikz \shadedraw [shading=axis] (0,0) rectangle (1,1);
+\tikz \shadedraw [shading=radial] (0,0) rectangle (1,1);
+\tikz \shadedraw [shading=ball] (0,0) circle (.5cm);
+\end{codeexample}
+
+ The shadings as well as additional shadings are described in more detail in
+ Section~\ref{section-library-shadings}.
+
+ To change the color of a shading, special options are needed like
+ |left color|, which sets the color of an axis shading from left to right.
+ These options implicitly also select the correct shading type, see the
+ following example
+ %
+\begin{codeexample}[]
+\tikz \shadedraw [left color=red,right color=blue]
+ (0,0) rectangle (1,1);
+\end{codeexample}
+
+ For a complete list of the possible options see
+ Section~\ref{section-library-shadings} once more.
+
+ \begin{key}{/tikz/shading angle=\meta{degrees} (initially 0)}
+ This option rotates the shading (not the path!) by the given angle. For
+ example, we can turn a top-to-bottom axis shading into a left-to-right
+ shading by rotating it by $90^\circ$.
+ %
+\begin{codeexample}[]
+\tikz \shadedraw [shading=axis,shading angle=90] (0,0) rectangle (1,1);
+\end{codeexample}
+ \end{key}
+\end{key}
+
+You can also define new shading types yourself. However, for this, you need to
+use the basic layer directly, which is, well, more basic and harder to use.
+Details on how to create a shading appropriate for filling paths are given in
+Section~\ref{section-shading-a-path}.
+
+
+\subsection{Establishing a Bounding Box}
+
+\pgfname\ is reasonably good at keeping track of the size of your picture and
+reserving just the right amount of space for it in the main document. However,
+in some cases you may want to say things like ``do not count this for the
+picture size'' or ``the picture is actually a little large''. For this you can
+use the option |use as bounding box| or the command |\useasboundingbox|, which
+is just a shorthand for |\path[use as bounding box]|.
+
+\begin{key}{/tikz/use as bounding box}
+ Normally, when this option is given on a path, the bounding box of the
+ present path is used to determine the size of the picture and the size of
+ all \emph{subsequent} paths are ignored. However, if there were previous
+ path operations that have already established a larger bounding box, it
+ will not be made smaller by this operation (consider the
+ |\pgfresetboundingbox| command to reset the previous bounding box).
+
+ In a sense, |use as bounding box| has the same effect as clipping all
+ subsequent drawing against the current path -- without actually doing the
+ clipping, only making \pgfname\ treat everything as if it were clipped.
+
+ The first application of this option is to have a |{tikzpicture}| overlap
+ with the main text:
+ %
+\begin{codeexample}[]
+Left of picture\begin{tikzpicture}
+ \draw[use as bounding box] (2,0) rectangle (3,1);
+ \draw (1,0) -- (4,.75);
+\end{tikzpicture}right of picture.
+\end{codeexample}
+
+ In a second application this option can be used to get better control over
+ the white space around the picture:
+ %
+\begin{codeexample}[]
+Left of picture
+\begin{tikzpicture}
+ \useasboundingbox (0,0) rectangle (3,1);
+ \fill (.75,.25) circle (.5cm);
+\end{tikzpicture}
+right of picture.
+\end{codeexample}
+
+ Note: If this option is used on a path inside a \TeX\ group (scope), the
+ effect ``lasts'' only until the end of the scope. Again, this behavior is
+ the same as for clipping.
+
+ Consider using |\useasboundingbox| together with |\pgfresetboundingbox| in
+ order to replace the bounding box with a new one.
+\end{key}
+
+There is a node that allows you to get the size of the current bounding box.
+The |current bounding box| node has the |rectangle| shape and its size is
+always the size of the current bounding box.
+
+Similarly, the |current path bounding box| node has the |rectangle| shape and
+the size of the bounding box of the current path.
+%
+\begin{codeexample}[]
+\begin{tikzpicture}
+ \draw[red] (0,0) circle (2pt);
+ \draw[red] (2,1) circle (3pt);
+
+ \draw (current bounding box.south west) rectangle
+ (current bounding box.north east);
+
+ \draw[red] (3,-1) circle (4pt);
+
+ \draw[thick] (current bounding box.south west) rectangle
+ (current bounding box.north east);
+\end{tikzpicture}
+\end{codeexample}
+
+Occasionally, you may want to align multiple |tikzpicture| environments
+horizontally and/or vertically at some prescribed position. The vertical
+alignment can be realized by means of the |baseline| option since \TeX\
+supports the concept of box depth natively. For horizontal alignment, things
+are slightly more involved. The following approach is realized by means of
+negative |\hspace|s before and/or after the picture, thereby removing parts of
+the picture. However, the actual amount of negative horizontal space is
+provided by means of image coordinates using the |trim left| and |trim right|
+keys:
+
+\begin{key}{/tikz/trim left=\meta{dimension or coordinate or \texttt{default}} (default 0pt)}
+ The |trim left| key tells \pgfname\space to discard everything which is
+ left of the provided \meta{dimension or coordinate}. Here, \meta{dimension}
+ is a single $x$ coordinate of the picture and \meta{coordinate} is a point
+ with $x$ and $y$ coordinates (but only its $x$ coordinate will be used).
+ The effect is the same as if you issue |\hspace{-s}| where |s| is the
+ difference of the picture's bounding box lower left $x$ coordinate and the
+ $x$ coordinate specified as \meta{dimension or coordinate}:
+ %
+\begin{codeexample}[]
+Text before image.%
+ \begin{tikzpicture}[trim left]
+ \draw (-1,-1) grid (3,2);
+ \fill (0,0) circle (5pt);
+ \end{tikzpicture}%
+Text after image.
+\end{codeexample}
+ %
+ Since |trim left| uses the default |trim left=0pt|, everything left of
+ $x=0$ is removed from the bounding box.
+
+ The following example has once the relative long label $-1$ and once the
+ shorter label $1$. Horizontal alignment is established with |trim left|:
+ %
+\begin{codeexample}[pre={\vbox\bgroup\hsize=5cm},post=\egroup,width=8cm]
+\begin{tikzpicture}
+ \draw (0,1) -- (0,0) -- (1,1) -- cycle;
+ \fill (0,0) circle (2pt);
+ \node[left] at (0,0) {$-1$};
+\end{tikzpicture}
+\par
+\begin{tikzpicture}
+ \draw (0,1) -- (0,0) -- (1,1) -- cycle;
+ \fill (0,0) circle (2pt);
+ \node[left] at (0,0) {$1$};
+\end{tikzpicture}
+\par
+\begin{tikzpicture}[trim left]
+ \draw (0,1) -- (0,0) -- (1,1) -- cycle;
+ \fill (0,0) circle (2pt);
+ \node[left] at (0,0) {$-1$};
+\end{tikzpicture}
+\par
+\begin{tikzpicture}[trim left]
+ \draw (0,1) -- (0,0) -- (1,1) -- cycle;
+ \fill (0,0) circle (2pt);
+ \node[left] at (0,0) {$1$};
+\end{tikzpicture}
+\end{codeexample}
+
+ Use |trim left=default| to reset the value.
+\end{key}
+
+\begin{key}{/tikz/trim right=\meta{dimension or coordinate or \texttt{default}}}
+ This key is similar to |trim left|: it discards everything which is right
+ of the provided \meta{dimension or coordinate}. As for |trim left|,
+ \meta{dimension} denotes a single $x$ coordinate of the picture and
+ \meta{coordinate} a coordinate with $x$ and $y$ value (although only its
+ $x$ component will be used).
+
+ We use the same example from above and add |trim right|:
+ %
+\begin{codeexample}[]
+Text before image.%
+ \begin{tikzpicture}[trim left, trim right=2cm, baseline]
+ \draw (-1,-1) grid (3,2);
+ \fill (0,0) circle (5pt);
+ \end{tikzpicture}%
+Text after image.
+\end{codeexample}
+ %
+ In addition to |trim left=0pt|, we also discard everything which is right
+ of $x$|=2cm|. Furthermore, the |baseline| key supports vertical alignment
+ as well (using the $y$|=0cm| baseline).
+
+ Use |trim right=default| to reset the value.
+\end{key}
+
+Note that |baseline|, |trim left| and |trim right| are currently the
+\emph{only} supported way of truncated bounding boxes which are compatible with
+image externalization (see the |external| library for details).
+
+\begin{key}{/pgf/trim lowlevel=\mchoice{true,false} (initially false)}
+ This affects only the basic level image externalization: the initial
+ configuration |trim lowlevel=false| stores the normal image, without
+ trimming, and the trimming into a separate file. This allows reduced
+ bounding boxes without clipping the rest away. The |trim lowlevel=true|
+ information causes the image externalization to store the trimmed image,
+ possibly resulting in clipping.
+\end{key}
+
+
+\subsection{Clipping and Fading (Soft Clipping)}
+
+\emph{Clipping path} means that all painting on the page is restricted to a
+certain area. This area need not be rectangular, rather an arbitrary path can
+be used to specify this area. The |clip| option, explained below, is used to
+specify the region that is to be used for clipping.
+
+A \emph{fading} (a term that I propose, fadings are commonly known as soft
+masks, transparency masks, opacity masks or soft clips) is similar to clipping,
+but a fading allows parts of the picture to be only ``half clipped''. This
+means that a fading can specify that newly painted pixels should be partly
+transparent. The specification and handling of fadings is a bit complex and it
+is detailed in Section~\ref{section-tikz-transparency}, which is devoted to
+transparency in general.
+
+\begin{key}{/tikz/clip}
+ This option causes all subsequent drawings to be clipped against the
+ current path and the size of subsequent paths will not be important for the
+ picture size. If you clip against a self-intersecting path, the even-odd
+ rule or the nonzero winding number rule is used to determine whether a
+ point is inside or outside the clipping region.
+
+ The clipping path is a graphic state parameter, so it will be reset at the
+ end of the current scope. Multiple clippings accumulate, that is, clipping
+ is always done against the intersection of all clipping areas that have
+ been specified inside the current scopes. The only way of enlarging the
+ clipping area is to end a |{scope}|.
+ %
+\begin{codeexample}[]
+\begin{tikzpicture}
+ \draw[clip] (0,0) circle (1cm);
+ \fill[red] (1,0) circle (1cm);
+\end{tikzpicture}
+\end{codeexample}
+
+ It is usually a \emph{very} good idea to apply the |clip| option only to
+ the first path command in a scope.
+
+ If you ``only wish to clip'' and do not wish to draw anything, you can use
+ the |\clip| command, which is a shorthand for |\path[clip]|.
+ %
+\begin{codeexample}[]
+\begin{tikzpicture}
+ \clip (0,0) circle (1cm);
+ \fill[red] (1,0) circle (1cm);
+\end{tikzpicture}
+\end{codeexample}
+
+ To keep clipping local, use |{scope}| environments as in the following
+ example:
+ %
+\begin{codeexample}[]
+\begin{tikzpicture}
+ \draw (0,0) -- ( 0:1cm);
+ \draw (0,0) -- (10:1cm);
+ \draw (0,0) -- (20:1cm);
+ \draw (0,0) -- (30:1cm);
+ \begin{scope}[fill=red]
+ \fill[clip] (0.2,0.2) rectangle (0.5,0.5);
+
+ \draw (0,0) -- (40:1cm);
+ \draw (0,0) -- (50:1cm);
+ \draw (0,0) -- (60:1cm);
+ \end{scope}
+ \draw (0,0) -- (70:1cm);
+ \draw (0,0) -- (80:1cm);
+ \draw (0,0) -- (90:1cm);
+\end{tikzpicture}
+\end{codeexample}
+
+ There is a slightly annoying catch: You cannot specify certain graphic
+ options for the command used for clipping. For example, in the above code
+ we could not have moved the |fill=red| to the |\fill| command. The reasons
+ for this have to do with the internals of the \pdf\ specification. You do
+ not want to know the details. It is best simply not to specify any options
+ for these commands.
+\end{key}
+
+
+\subsection{Doing Multiple Actions on a Path}
+
+If more than one of the basic actions like drawing, clipping and filling are
+requested, they are automatically applied in a sensible order: First, a path is
+filled, then drawn, and then clipped (although it took Apple two mayor
+revisions of their operating system to get this right\dots). Sometimes,
+however, you need finer control over what is done with a path. For instance,
+you might wish to first fill a path with a color, then repaint the path with a
+pattern and then repaint it with yet another pattern. In such cases you can use
+the following two options:
+
+\begin{key}{/tikz/preaction=\meta{options}}
+ This option can be given to a |\path| command (or to derived commands like
+ |\draw| which internally call |\path|). Similarly to options like |draw|,
+ this option only has an effect when given to a |\path| or as part of the
+ options of a |node|; as an option to a |{scope}| it has no effect.
+
+ When this option is used on a |\path|, the effect is the following: When
+ the path has been completely constructed and is about to be used, a scope
+ is created. Inside this scope, the path is used but not with the original
+ path options, but with \meta{options} instead. Then, the path is used in
+ the usual manner. In other words, the path is used twice: Once with
+ \meta{options} in force and then again with the normal path options in
+ force.
+
+ Here is an example in which the path consists of a rectangle. The main
+ action is to draw this path in red (which is why we see a red rectangle).
+ However, the preaction is to draw the path in blue, which is why we see a
+ blue rectangle behind the red rectangle.
+ %
+\begin{codeexample}[]
+\begin{tikzpicture}
+ \draw[help lines] (0,0) grid (3,2);
+
+ \draw
+ [preaction={draw,line width=4mm,blue}]
+ [line width=2mm,red] (0,0) rectangle (2,2);
+\end{tikzpicture}
+\end{codeexample}
+
+ Note that when the preactions are preformed, then the path is already
+ ``finished''. In particular, applying a coordinate transformation to the
+ path has no effect. By comparison, applying a canvas transformation does
+ have an effect. Let us use this to add a ``shadow'' to a path. For this, we
+ use the preaction to fill the path in gray, shifted a bit to the right and
+ down:
+ %
+\begin{codeexample}[]
+\begin{tikzpicture}
+ \draw[help lines] (0,0) grid (3,2);
+ \draw
+ [preaction={fill=black,opacity=.5,
+ transform canvas={xshift=1mm,yshift=-1mm}}]
+ [fill=red] (0,0) rectangle (1,2)
+ (1,2) circle (5mm);
+\end{tikzpicture}
+\end{codeexample}
+
+ Naturally, you would normally create a style |shadow| that contains the
+ above code. The shadow library, see Section~\ref{section-libs-shadows},
+ contains predefined shadows of this kind.
+
+ It is possible to use the |preaction| option multiple times. In this case,
+ for each use of the |preaction| option, the path is used again (thus, the
+ \meta{options} do not accumulate in a single usage of the path). The path
+ is used in the order of |preaction| options given.
+
+ In the following example, we use one |preaction| to add a shadow and
+ another to provide a shading, while the main action is to use a pattern.
+ %
+\begin{codeexample}[]
+\begin{tikzpicture}
+ \draw[help lines] (0,0) grid (3,2);
+ \draw [pattern=fivepointed stars]
+ [preaction={fill=black,opacity=.5,
+ transform canvas={xshift=1mm,yshift=-1mm}}]
+ [preaction={top color=blue,bottom color=white}]
+ (0,0) rectangle (1,2)
+ (1,2) circle (5mm);
+\end{tikzpicture}
+\end{codeexample}
+
+ A complicated application is shown in the following example, where the path
+ is used several times with different fadings and shadings to create a
+ special visual effect:
+ %
+\begin{codeexample}[]
+\begin{tikzpicture}
+ [
+ % Define an interesting style
+ button/.style={
+ % First preaction: Fuzzy shadow
+ preaction={fill=black,path fading=circle with fuzzy edge 20 percent,
+ opacity=.5,transform canvas={xshift=1mm,yshift=-1mm}},
+ % Second preaction: Background pattern
+ preaction={pattern=#1,
+ path fading=circle with fuzzy edge 15 percent},
+ % Third preaction: Make background shiny
+ preaction={top color=white,
+ bottom color=black!50,
+ shading angle=45,
+ path fading=circle with fuzzy edge 15 percent,
+ opacity=0.2},
+ % Fourth preaction: Make edge especially shiny
+ preaction={path fading=fuzzy ring 15 percent,
+ top color=black!5,
+ bottom color=black!80,
+ shading angle=45},
+ inner sep=2ex
+ },
+ button/.default=horizontal lines light blue,
+ circle
+ ]
+
+ \draw [help lines] (0,0) grid (4,3);
+
+ \node [button] at (2.2,1) {\Huge Big};
+ \node [button=crosshatch dots light steel blue,
+ text=white] at (1,1.5) {Small};
+\end{tikzpicture}
+\end{codeexample}
+ %
+\end{key}
+
+\begin{key}{/tikz/postaction=\meta{options}}
+ The postactions work in the same way as the preactions, only they are
+ applied \emph{after} the main action has been taken. Like preactions,
+ multiple |postaction| options may be given to a |\path| command, in which
+ case the path is reused several times, each time with a different set of
+ options in force.
+
+ If both pre- and postactions are specified, then the preactions are taken
+ first, then the main action, and then the post actions.
+
+ In the first example, we use a postaction to draw the path, after it has
+ already been drawn:
+ %
+\begin{codeexample}[]
+\begin{tikzpicture}
+ \draw[help lines] (0,0) grid (3,2);
+
+ \draw
+ [postaction={draw,line width=2mm,blue}]
+ [line width=4mm,red,fill=white] (0,0) rectangle (2,2);
+\end{tikzpicture}
+\end{codeexample}
+
+ In another example, we use a postaction to ``colorize'' a path:
+ %
+\begin{codeexample}[]
+\begin{tikzpicture}
+ \draw[help lines] (0,0) grid (3,2);
+ \draw
+ [postaction={path fading=south,fill=white}]
+ [postaction={path fading=south,fading angle=45,fill=blue,opacity=.5}]
+ [left color=black,right color=red,draw=white,line width=2mm]
+ (0,0) rectangle (1,2)
+ (1,2) circle (5mm);
+\end{tikzpicture}
+\end{codeexample}
+ %
+\end{key}
+
+
+\subsection{Decorating and Morphing a Path}
+
+Before a path is used, it is possible to first ``decorate'' and/or ``morph''
+it. Morphing means that the path is replaced by another path that is slightly
+varied. Such morphings are a special case of the more general ``decorations''
+described in detail in Section~\ref{section-tikz-decorations}. For instance, in
+the following example the path is drawn twice: Once normally and then in a
+morphed (=decorated) manner.
+%
+\begin{codeexample}[]
+\begin{tikzpicture}
+ \draw (0,0) rectangle (3,2);
+ \draw [red, decorate, decoration=zigzag]
+ (0,0) rectangle (3,2);
+\end{tikzpicture}
+\end{codeexample}
+
+Naturally, we could have combined this into a single command using pre- or
+postaction. It is also possible to deform shapes:
+%
+\begin{codeexample}[]
+\begin{tikzpicture}
+ \node [circular drop shadow={shadow scale=1.05},minimum size=3.13cm,
+ decorate, decoration=zigzag,
+ fill=blue!20,draw,thick,circle] {Hello!};
+\end{tikzpicture}
+\end{codeexample}