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diff --git a/Master/texmf-dist/doc/generic/pgf/text-en/pgfmanual-en-tutorial.tex b/Master/texmf-dist/doc/generic/pgf/text-en/pgfmanual-en-tutorial.tex index 07f6784f54c..614177a7fa5 100644 --- a/Master/texmf-dist/doc/generic/pgf/text-en/pgfmanual-en-tutorial.tex +++ b/Master/texmf-dist/doc/generic/pgf/text-en/pgfmanual-en-tutorial.tex @@ -7,45 +7,43 @@ % % See the file doc/generic/pgf/licenses/LICENSE for more details. + \section{Tutorial: A Picture for Karl's Students} -This tutorial is intended for new users of \tikzname. It -does not give an exhaustive account of all the features of \tikzname, -just of those that you are likely to use right away. - -Karl is a math and chemistry high-school teacher. He used to create -the graphics in his worksheets and exams using \LaTeX's |{picture}| -environment. While the results were acceptable, creating the graphics -often turned out to be a lengthy process. Also, there tended to be -problems with lines having slightly wrong angles and circles also -seemed to be hard to get right. Naturally, his students could not care -less whether the lines had the exact right angles and they find -Karl's exams too difficult no matter how nicely they were drawn. But +This tutorial is intended for new users of \tikzname. It does not give an +exhaustive account of all the features of \tikzname, just of those that you are +likely to use right away. + +Karl is a math and chemistry high-school teacher. He used to create the +graphics in his worksheets and exams using \LaTeX's |{picture}| environment. +While the results were acceptable, creating the graphics often turned out to be +a lengthy process. Also, there tended to be problems with lines having slightly +wrong angles and circles also seemed to be hard to get right. Naturally, his +students could not care less whether the lines had the exact right angles and +they find Karl's exams too difficult no matter how nicely they were drawn. But Karl was never entirely satisfied with the result. -Karl's son, who was even less satisfied with the results (he did not -have to take the exams, after all), told Karl that he might wish -to try out a new package for creating graphics. A bit confusingly, -this package seems to have two names: First, Karl had to download and -install a package called \pgfname. Then it turns out that inside this -package there is another package called \tikzname, which is supposed to -stand for ``\tikzname\ ist \emph{kein} Zeichenprogramm.'' Karl finds this -all a bit strange and \tikzname\ seems to indicate that the package -does not do what he needs. However, having used \textsc{gnu} -software for quite some time and ``\textsc{gnu} not being Unix,'' +Karl's son, who was even less satisfied with the results (he did not have to +take the exams, after all), told Karl that he might wish to try out a new +package for creating graphics. A bit confusingly, this package seems to have +two names: First, Karl had to download and install a package called \pgfname. +Then it turns out that inside this package there is another package called +\tikzname, which is supposed to stand for ``\tikzname\ ist \emph{kein} +Zeichenprogramm''. Karl finds this all a bit strange and \tikzname\ seems to +indicate that the package does not do what he needs. However, having used +\textsc{gnu} software for quite some time and ``\textsc{gnu} not being Unix'', there seems to be hope yet. His son assures him that \tikzname's name is -intended to warn people that \tikzname\ is not a program that you can -use to draw graphics with your mouse or tablet. Rather, it is more -like a ``graphics language.'' +intended to warn people that \tikzname\ is not a program that you can use to +draw graphics with your mouse or tablet. Rather, it is more like a ``graphics +language''. \subsection{Problem Statement} -Karl wants to put a graphic on the next worksheet for his -students. He is currently teaching his students about sine and -cosine. What he would like to have is something that looks like this -(ideally): - +Karl wants to put a graphic on the next worksheet for his students. He is +currently teaching his students about sine and cosine. What he would like to +have is something that looks like this (ideally): +% \noindent \begin{tikzpicture} [scale=3,line cap=round, @@ -124,16 +122,16 @@ cosine. What he would like to have is something that looks like this \subsection{Setting up the Environment} -In \tikzname, to draw a picture, at the start of the picture -you need to tell \TeX\ or \LaTeX\ that you want to start a picture. In -\LaTeX\ this is done using the environment |{tikzpicture}|, in plain -\TeX\ you just use |\tikzpicture| to start the picture and -|\endtikzpicture| to end it. +In \tikzname, to draw a picture, at the start of the picture you need to tell +\TeX\ or \LaTeX\ that you want to start a picture. In \LaTeX\ this is done +using the environment |{tikzpicture}|, in plain \TeX\ you just use +|\tikzpicture| to start the picture and |\endtikzpicture| to end it. + \subsubsection{Setting up the Environment in \LaTeX} Karl, being a \LaTeX\ user, thus sets up his file as follows: - +% \begin{codeexample}[code only] \documentclass{article} % say \usepackage{tikz} @@ -146,9 +144,9 @@ We are working on \end{document} \end{codeexample} -When executed, that is, run via |pdflatex| or via |latex| followed by -|dvips|, the resulting will contain something that looks like this: - +When executed, that is, run via |pdflatex| or via |latex| followed by |dvips|, +the resulting will contain something that looks like this: +% \begin{codeexample}[width=7cm] We are working on \begin{tikzpicture} @@ -157,39 +155,38 @@ We are working on \end{tikzpicture}. \end{codeexample} -Admittedly, not quite the whole picture, yet, but we -do have the axes established. Well, not quite, but we have the lines -that make up the axes drawn. Karl suddenly has a sinking feeling -that the picture is still some way off. +Admittedly, not quite the whole picture, yet, but we do have the axes +established. Well, not quite, but we have the lines that make up the axes +drawn. Karl suddenly has a sinking feeling that the picture is still some way +off. -Let's have a more detailed look at the code. First, the package -|tikz| is loaded. This package is a so-called ``frontend'' to the -basic \pgfname\ system. The basic layer, which is also described in this -manual, is somewhat more, well, basic and thus harder to use. The -frontend makes things easier by providing a simpler syntax. +Let's have a more detailed look at the code. First, the package |tikz| is +loaded. This package is a so-called ``frontend'' to the basic \pgfname\ system. +The basic layer, which is also described in this manual, is somewhat more, +well, basic and thus harder to use. The frontend makes things easier by +providing a simpler syntax. -Inside the environment there are two |\draw| commands. They mean: -``The path, which is specified following the command up to the -semicolon, should be drawn.'' The first path is specified -as |(-1.5,0) -- (0,1.5)|, which means ``a straight line from the point -at position $(-1.5,0)$ to the point at position $(0,1.5)$.'' Here, the -positions are specified within a special coordinate system in which, -initially, one unit is 1cm. +Inside the environment there are two |\draw| commands. They mean: ``The path, +which is specified following the command up to the semicolon, should be +drawn.'' The first path is specified as |(-1.5,0) -- (0,1.5)|, which means ``a +straight line from the point at position $(-1.5,0)$ to the point at position +$(0,1.5)$''. Here, the positions are specified within a special coordinate +system in which, initially, one unit is 1cm. -Karl is quite pleased to note that the environment automatically -reserves enough space to encompass the picture. +Karl is quite pleased to note that the environment automatically reserves +enough space to encompass the picture. \subsubsection{Setting up the Environment in Plain \TeX} -Karl's wife Gerda, who also happens to be a math teacher, is not a -\LaTeX\ user, but uses plain \TeX\ since she prefers to do things -``the old way.'' She can also use \tikzname. Instead of -|\usepackage{tikz}| she has to write |\input tikz.tex| and instead of -|\begin{tikzpicture}| she writes |\tikzpicture| and instead of - |\end{tikzpicture}| she writes |\endtikzpicture|. +Karl's wife Gerda, who also happens to be a math teacher, is not a \LaTeX\ +user, but uses plain \TeX\ since she prefers to do things ``the old way''. She +can also use \tikzname. Instead of |\usepackage{tikz}| she has to write +|\input tikz.tex| and instead of |\begin{tikzpicture}| she writes +|\tikzpicture| and instead of |\end{tikzpicture}| she writes |\endtikzpicture|. Thus, she would use: +% \begin{codeexample}[code only] %% Plain TeX file \input tikz.tex @@ -204,24 +201,22 @@ We are working on \bye \end{codeexample} -Gerda can typeset this file using either |pdftex| or |tex| together -with |dvips|. \tikzname\ will automatically discern which driver she is -using. If she wishes to use |dvipdfm| together with |tex|, she -either needs to modify the file |pgf.cfg| or can write -|\def\pgfsysdriver{pgfsys-dvipdfm.def}| somewhere \emph{before} she -inputs |tikz.tex| or |pgf.tex|. - +Gerda can typeset this file using either |pdftex| or |tex| together with +|dvips|. \tikzname\ will automatically discern which driver she is using. If +she wishes to use |dvipdfm| together with |tex|, she either needs to modify the +file |pgf.cfg| or can write |\def\pgfsysdriver{pgfsys-dvipdfm.def}| somewhere +\emph{before} she inputs |tikz.tex| or |pgf.tex|. \subsubsection{Setting up the Environment in Con\TeX t} -Karl's uncle Hans uses Con\TeX t. Like Gerda, Hans can also use -\tikzname. Instead of |\usepackage{tikz}| he says -|\usemodule[tikz]|. Instead of |\begin{tikzpicture}| he writes - |\starttikzpicture| and instead of |\end{tikzpicture}| he writes -|\stoptikzpicture|. +Karl's uncle Hans uses Con\TeX t. Like Gerda, Hans can also use \tikzname. +Instead of |\usepackage{tikz}| he says |\usemodule[tikz]|. Instead of +|\begin{tikzpicture}| he writes |\starttikzpicture| and instead of +|\end{tikzpicture}| he writes |\stoptikzpicture|. His version of the example looks like this: +% \begin{codeexample}[code only] %% ConTeXt file \usemodule[tikz] @@ -235,55 +230,51 @@ His version of the example looks like this: \stoptext \end{codeexample} -Hans will now typeset this file in the usual way using -|texexec| or |context|. - +Hans will now typeset this file in the usual way using |texexec| or |context|. \subsection{Straight Path Construction} -The basic building block of all pictures in \tikzname\ is the path. -A \emph{path} is a series of straight lines and curves that are -connected (that is not the whole picture, but let us ignore the -complications for the moment). You start a path by specifying the -coordinates of the start position as a point in round brackets, as in -|(0,0)|. This is followed by a series of ``path extension -operations.'' The simplest is |--|, which we used already. It must be -followed by another coordinate and it extends the path in a straight -line to this new position. For example, if we were to turn the two -paths of the axes into one path, the following would result: - +The basic building block of all pictures in \tikzname\ is the path. A +\emph{path} is a series of straight lines and curves that are connected (that +is not the whole picture, but let us ignore the complications for the moment). +You start a path by specifying the coordinates of the start position as a point +in round brackets, as in |(0,0)|. This is followed by a series of ``path +extension operations''. The simplest is |--|, which we used already. It must be +followed by another coordinate and it extends the path in a straight line to +this new position. For example, if we were to turn the two paths of the axes +into one path, the following would result: +% \begin{codeexample}[] \tikz \draw (-1.5,0) -- (1.5,0) -- (0,-1.5) -- (0,1.5); \end{codeexample} Karl is a bit confused by the fact that there is no |{tikzpicture}| -environment, here. Instead, the little command |\tikz| is used. This -command either takes one argument (starting with an opening brace as in -|\tikz{\draw (0,0) -- (1.5,0)}|, which yields \tikz{\draw (0,0) - --(1.5,0);}) or collects everything up to the next semicolon and -puts it inside a |{tikzpicture}| environment. As a rule of thumb, all -\tikzname\ graphic drawing commands must occur as an argument of |\tikz| -or inside a |{tikzpicture}| environment. Fortunately, the command -|\draw| will only be defined inside this environment, so there is -little chance that you will accidentally do something wrong here. - +environment, here. Instead, the little command |\tikz| is used. This command +either takes one argument (starting with an opening brace as in +|\tikz{\draw (0,0) -- (1.5,0)}|, which yields \tikz{\draw (0,0) --(1.5,0);}) or +collects everything up to the next semicolon and puts it inside a +|{tikzpicture}| environment. As a rule of thumb, all \tikzname\ graphic drawing +commands must occur as an argument of |\tikz| or inside a |{tikzpicture}| +environment. Fortunately, the command |\draw| will only be defined inside this +environment, so there is little chance that you will accidentally do something +wrong here. \subsection{Curved Path Construction} -The next thing Karl wants to do is to draw the circle. For this, -straight lines obviously will not do. Instead, we need some way to -draw curves. For this, \tikzname\ provides a special syntax. One or two -``control points'' are needed. The math behind them is not quite -trivial, but here is the basic idea: Suppose you are at point $x$ and -the first control point is $y$. Then the curve will start ``going in -the direction of~$y$ at~$x$,'' that is, the tangent of the curve at $x$ -will point toward~$y$. Next, suppose the curve should end at $z$ and -the second support point is $w$. Then the curve will, indeed, end at -$z$ and the tangent of the curve at point $z$ will go through $w$. +The next thing Karl wants to do is to draw the circle. For this, straight lines +obviously will not do. Instead, we need some way to draw curves. For this, +\tikzname\ provides a special syntax. One or two ``control points'' are needed. +The math behind them is not quite trivial, but here is the basic idea: Suppose +you are at point $x$ and the first control point is $y$. Then the curve will +start ``going in the direction of~$y$ at~$x$'', that is, the tangent of the +curve at $x$ will point toward~$y$. Next, suppose the curve should end at $z$ +and the second support point is $w$. Then the curve will, indeed, end at $z$ +and the tangent of the curve at point $z$ will go through $w$. Here is an example (the control points have been added for clarity): +% \begin{codeexample}[] \begin{tikzpicture} \filldraw [gray] (0,0) circle [radius=2pt] @@ -294,14 +285,13 @@ Here is an example (the control points have been added for clarity): \end{tikzpicture} \end{codeexample} -The general syntax for extending a path in a ``curved'' way is -|.. controls| \meta{first control point} |and| \meta{second control - point} |..| \meta{end point}. You can leave out the |and| -\meta{second control point}, which causes the first one to be used -twice. +The general syntax for extending a path in a ``curved'' way is |.. controls| +\meta{first control point} |and| \meta{second control point} |..| +\meta{end point}. You can leave out the |and| \meta{second control point}, +which causes the first one to be used twice. So, Karl can now add the first half circle to the picture: - +% \begin{codeexample}[] \begin{tikzpicture} \draw (-1.5,0) -- (1.5,0); @@ -311,38 +301,38 @@ So, Karl can now add the first half circle to the picture: \end{tikzpicture} \end{codeexample} -Karl is happy with the result, but finds specifying circles in this -way to be extremely awkward. Fortunately, there is a much simpler way. +Karl is happy with the result, but finds specifying circles in this way to be +extremely awkward. Fortunately, there is a much simpler way. \subsection{Circle Path Construction} -In order to draw a circle, the path construction operation |circle| can -be used. This operation is followed by a radius in brackets as in -the following example: (Note that the previous position is used as the -\emph{center} of the circle.) - +In order to draw a circle, the path construction operation |circle| can be +used. This operation is followed by a radius in brackets as in the following +example: (Note that the previous position is used as the \emph{center} of the +circle.) +% \begin{codeexample}[] \tikz \draw (0,0) circle [radius=10pt]; \end{codeexample} -You can also append an ellipse to the path using the |ellipse| -operation. Instead of a single radius you can specify two of them: - +You can also append an ellipse to the path using the |ellipse| operation. +Instead of a single radius you can specify two of them: +% \begin{codeexample}[] \tikz \draw (0,0) ellipse [x radius=20pt, y radius=10pt]; \end{codeexample} -To draw an ellipse whose axes are not horizontal and vertical, but -point in an arbitrary direction (a ``turned ellipse'' like \tikz -\draw[rotate=30] (0,0) ellipse [x radius=6pt, y radius=3pt];) you can use -transformations, which are explained later. The code for the little -ellipse is |\tikz \draw[rotate=30] (0,0) ellipse [x radius=6pt, y radius=3pt];|, by -the way. +To draw an ellipse whose axes are not horizontal and vertical, but point in an +arbitrary direction (a ``turned ellipse'' like \tikz \draw[rotate=30] (0,0) +ellipse [x radius=6pt, y radius=3pt];) you can use transformations, which are +explained later. The code for the little ellipse is +|\tikz \draw[rotate=30] (0,0) ellipse [x radius=6pt, y radius=3pt];|, by the +way. So, returning to Karl's problem, he can write |\draw (0,0) circle [radius=1cm];| to draw the circle: - +% \begin{codeexample}[] \begin{tikzpicture} \draw (-1.5,0) -- (1.5,0); @@ -351,27 +341,24 @@ So, returning to Karl's problem, he can write \end{tikzpicture} \end{codeexample} - -At this point, Karl is a bit alarmed that the circle is so small when -he wants the final picture to be much bigger. He is pleased to learn -that \tikzname\ has powerful transformation options and scaling -everything by a factor of three is very easy. But let us leave the -size as it is for the moment to save some space. - - +At this point, Karl is a bit alarmed that the circle is so small when he wants +the final picture to be much bigger. He is pleased to learn that \tikzname\ has +powerful transformation options and scaling everything by a factor of three is +very easy. But let us leave the size as it is for the moment to save some +space. \subsection{Rectangle Path Construction} -The next things we would like to have is the grid in the background. -There are several ways to produce it. For example, one might draw lots of -rectangles. Since rectangles are so common, there is a special syntax -for them: To add a rectangle to the current path, use the |rectangle| -path construction operation. This operation should be followed by another -coordinate and will append a rectangle to the path such that the -previous coordinate and the next coordinates are corners of the -rectangle. So, let us add two rectangles to the picture: - +The next things we would like to have is the grid in the background. There are +several ways to produce it. For example, one might draw lots of rectangles. +Since rectangles are so common, there is a special syntax for them: To add a +rectangle to the current path, use the |rectangle| path construction operation. +This operation should be followed by another coordinate and will append a +rectangle to the path such that the previous coordinate and the next +coordinates are corners of the rectangle. So, let us add two rectangles to the +picture: +% \begin{codeexample}[] \begin{tikzpicture} \draw (-1.5,0) -- (1.5,0); @@ -382,31 +369,28 @@ rectangle. So, let us add two rectangles to the picture: \end{tikzpicture} \end{codeexample} -While this may be nice in other situations, this is not really leading -anywhere with Karl's problem: First, we would need an awful lot of -these rectangles and then there is the border that is not ``closed.'' - -So, Karl is about to resort to simply drawing four vertical and four -horizontal lines using the nice |\draw| command, when he learns that -there is a |grid| path construction operation. +While this may be nice in other situations, this is not really leading anywhere +with Karl's problem: First, we would need an awful lot of these rectangles and +then there is the border that is not ``closed''. +So, Karl is about to resort to simply drawing four vertical and four horizontal +lines using the nice |\draw| command, when he learns that there is a |grid| +path construction operation. \subsection{Grid Path Construction} -The |grid| path operation adds a grid to the current path. It will add -lines making up a grid that fills the rectangle whose one corner is -the current point and whose other corner is the point following the -|grid| operation. For example, the code -|\tikz \draw[step=2pt] (0,0) grid (10pt,10pt);| produces \tikz -\draw[step=2pt] (0,0) grid (10pt,10pt);. Note how the optional -argument for |\draw| can be used to specify a grid width (there are -also |xstep| and |ystep| to define the steppings independently). As -Karl will learn soon, there are \emph{lots} of things that can be -influenced using such options. +The |grid| path operation adds a grid to the current path. It will add lines +making up a grid that fills the rectangle whose one corner is the current point +and whose other corner is the point following the |grid| operation. For +example, the code |\tikz \draw[step=2pt] (0,0) grid (10pt,10pt);| produces +\tikz \draw[step=2pt] (0,0) grid (10pt,10pt);. Note how the optional argument +for |\draw| can be used to specify a grid width (there are also |xstep| and +|ystep| to define the steppings independently). As Karl will learn soon, there +are \emph{lots} of things that can be influenced using such options. For Karl, the following code could be used: - +% \begin{codeexample}[] \begin{tikzpicture} \draw (-1.5,0) -- (1.5,0); @@ -416,15 +400,14 @@ For Karl, the following code could be used: \end{tikzpicture} \end{codeexample} -Having another look at the desired picture, Karl notices that it would -be nice for the grid to be more subdued. (His son told him that grids -tend to be distracting if they are not subdued.) To subdue the grid, -Karl adds two more options to the |\draw| command that draws the -grid. First, he uses the color |gray| for the grid lines. Second, he -reduces the line width to |very thin|. Finally, he swaps the ordering -of the commands so that the grid is drawn first and everything else on -top. - +Having another look at the desired picture, Karl notices that it would be nice +for the grid to be more subdued. (His son told him that grids tend to be +distracting if they are not subdued.) To subdue the grid, Karl adds two more +options to the |\draw| command that draws the grid. First, he uses the color +|gray| for the grid lines. Second, he reduces the line width to |very thin|. +Finally, he swaps the ordering of the commands so that the grid is drawn first +and everything else on top. +% \begin{codeexample}[] \begin{tikzpicture} \draw[step=.5cm,gray,very thin] (-1.4,-1.4) grid (1.4,1.4); @@ -437,46 +420,47 @@ top. \subsection{Adding a Touch of Style} -Instead of the options |gray,very thin| Karl could also have -said |help lines|. \emph{Styles} are predefined sets of options -that can be used to organize how a graphic is drawn. By saying -|help lines| you say ``use the style that I (or someone else) -has set for drawing help lines.'' If Karl decides, at some later -point, that grids should be drawn, say, using the color |blue!50| -instead of |gray|, he could provide the following option somewhere: +Instead of the options |gray,very thin| Karl could also have said |help lines|. +\emph{Styles} are predefined sets of options that can be used to organize how a +graphic is drawn. By saying |help lines| you say ``use the style that I (or +someone else) has set for drawing help lines''. If Karl decides, at some later +point, that grids should be drawn, say, using the color |blue!50| instead of +|gray|, he could provide the following option somewhere: +% \begin{codeexample}[code only] help lines/.style={color=blue!50,very thin} \end{codeexample} -The effect of this ``style setter'' is that in the current -scope or environment the |help lines| option has the same effect as -|color=blue!50,very thin|. - -Using styles makes your graphics code more flexible. You can -change the way things look easily in a consistent manner. -Normally, styles are defined at the beginning of a picture. However, -you may sometimes wish to define a style globally, so that all -pictures of your document can use this style. Then you can easily -change the way all graphics look by changing this one style. In this -situation you can use the |\tikzset| command at the beginning of the -document as in +% +The effect of this ``style setter'' is that in the current scope or environment +the |help lines| option has the same effect as |color=blue!50,very thin|. + +Using styles makes your graphics code more flexible. You can change the way +things look easily in a consistent manner. Normally, styles are defined at the +beginning of a picture. However, you may sometimes wish to define a style +globally, so that all pictures of your document can use this style. Then you +can easily change the way all graphics look by changing this one style. In this +situation you can use the |\tikzset| command at the beginning of the document +as in +% \begin{codeexample}[code only] \tikzset{help lines/.style=very thin} \end{codeexample} -To build a hierarchy of styles you can have one style use -another. So in order to define a style |Karl's grid| that is based on -the |grid| style Karl could say +To build a hierarchy of styles you can have one style use another. So in order +to define a style |Karl's grid| that is based on the |grid| style Karl could +say +% \begin{codeexample}[code only] \tikzset{Karl's grid/.style={help lines,color=blue!50}} ... \draw[Karl's grid] (0,0) grid (5,5); \end{codeexample} -Styles are made even more powerful by parametrization. This means -that, like other options, styles can also be used with a -parameter. For instance, Karl could parameterize his grid so that, by -default, it is blue, but he could also use another color. - +Styles are made even more powerful by parametrization. This means that, like +other options, styles can also be used with a parameter. For instance, Karl +could parameterize his grid so that, by default, it is blue, but he could also +use another color. +% \begin{codeexample}[code only] \begin{tikzpicture} [Karl's grid/.style ={help lines,color=#1!50}, @@ -490,53 +474,46 @@ default, it is blue, but he could also use another color. \subsection{Drawing Options} -Karl wonders what other options there are that influence how a path is -drawn. He saw already that the |color=|\meta{color} option can be used -to set the line's color. The option |draw=|\meta{color} does nearly -the same, only it sets the color for the lines only and a different -color can be used for filling (Karl will need this when he fills the -arc for the angle). - -He saw that the style |very thin| yields very thin lines. Karl is not -really surprised by this and neither is he surprised to learn that |thin| -yields thin lines, |thick| yields thick lines, |very thick| yields -very thick lines, |ultra thick| yields really, really thick lines and -|ultra thin| yields lines that are so thin that low-resolution printers -and displays will have trouble showing them. He wonders what gives -lines of ``normal'' thickness. It turns out that |thin| is the correct -choice, since it gives the same thickness as \TeX's |\hrule| -command. Nevertheless, Karl would like to know whether there is -anything ``in the middle'' between |thin| and |thick|. There is: -|semithick|. - -Another useful thing one can do with lines is to dash or dot them. For -this, the two styles |dashed| and |dotted| can be used, yielding -\tikz[baseline] \draw[dashed] (0,.5ex) -- ++(2em,0pt); and -\tikz[baseline] \draw[dotted] (0,.5ex) --- ++(2em,0pt);. Both options also exist in a loose and a dense -version, called |loosely dashed|, |densely dashed|, |loosely dotted|, -and |densely dotted|. If he really, really needs to, Karl can also -define much more complex dashing patterns with the |dash pattern| -option, but his son insists that dashing is to be used with utmost -care and mostly distracts. Karl's son claims that complicated dashing -patterns are evil. Karl's students do not care about dashing patterns. - +Karl wonders what other options there are that influence how a path is drawn. +He saw already that the |color=|\meta{color} option can be used to set the +line's color. The option |draw=|\meta{color} does nearly the same, only it sets +the color for the lines only and a different color can be used for filling +(Karl will need this when he fills the arc for the angle). + +He saw that the style |very thin| yields very thin lines. Karl is not really +surprised by this and neither is he surprised to learn that |thin| yields thin +lines, |thick| yields thick lines, |very thick| yields very thick lines, +|ultra thick| yields really, really thick lines and |ultra thin| yields lines +that are so thin that low-resolution printers and displays will have trouble +showing them. He wonders what gives lines of ``normal'' thickness. It turns out +that |thin| is the correct choice, since it gives the same thickness as \TeX's +|\hrule| command. Nevertheless, Karl would like to know whether there is +anything ``in the middle'' between |thin| and |thick|. There is: |semithick|. + +Another useful thing one can do with lines is to dash or dot them. For this, +the two styles |dashed| and |dotted| can be used, yielding \tikz[baseline] +\draw[dashed] (0,.5ex) -- ++(2em,0pt); and \tikz[baseline] \draw[dotted] +(0,.5ex) -- ++(2em,0pt);. Both options also exist in a loose and a dense +version, called |loosely dashed|, |densely dashed|, |loosely dotted|, and +|densely dotted|. If he really, really needs to, Karl can also define much +more complex dashing patterns with the |dash pattern| option, but his son +insists that dashing is to be used with utmost care and mostly distracts. +Karl's son claims that complicated dashing patterns are evil. Karl's students +do not care about dashing patterns. \subsection{Arc Path Construction} -Our next obstacle is to draw the arc for the angle. For this, the -|arc| path construction operation is useful, which draws part of a -circle or ellipse. This |arc| operation is followed by options in -brackets that specify the arc. An example would be \texttt{arc[start - angle=10, end angle=80, radius=10pt]}, which means exactly what it -says. Karl obviously -needs an arc from $0^\circ$ to $30^\circ$. The radius should be -something relatively small, perhaps around one third of the circle's -radius. When one uses the arc path construction operation, the -specified arc will be added with its starting point at the current -position. So, we first have to ``get there.'' - +Our next obstacle is to draw the arc for the angle. For this, the |arc| path +construction operation is useful, which draws part of a circle or ellipse. This +|arc| operation is followed by options in brackets that specify the arc. An +example would be \texttt{arc[start angle=10, end angle=80, radius=10pt]}, which +means exactly what it says. Karl obviously needs an arc from $0^\circ$ to +$30^\circ$. The radius should be something relatively small, perhaps around one +third of the circle's radius. When one uses the arc path construction +operation, the specified arc will be added with its starting point at the +current position. So, we first have to ``get there''. +% \begin{codeexample}[] \begin{tikzpicture} \draw[step=.5cm,gray,very thin] (-1.4,-1.4) grid (1.4,1.4); @@ -547,12 +524,12 @@ position. So, we first have to ``get there.'' \end{tikzpicture} \end{codeexample} -Karl thinks this is really a bit small and he cannot continue unless -he learns how to do scaling. For this, he can add the |[scale=3]| -option. He could add this option to each |\draw| command, but that -would be awkward. Instead, he adds it to the whole environment, which -causes this option to apply to everything within. - +Karl thinks this is really a bit small and he cannot continue unless he learns +how to do scaling. For this, he can add the |[scale=3]| option. He could add +this option to each |\draw| command, but that would be awkward. Instead, he +adds it to the whole environment, which causes this option to apply to +everything within. +% \begin{codeexample}[] \begin{tikzpicture}[scale=3] \draw[step=.5cm,gray,very thin] (-1.4,-1.4) grid (1.4,1.4); @@ -563,25 +540,24 @@ causes this option to apply to everything within. \end{tikzpicture} \end{codeexample} -As for circles, you can specify ``two'' radii in order to get an -elliptical arc. - +As for circles, you can specify ``two'' radii in order to get an elliptical +arc. +% \begin{codeexample}[] - \tikz \draw (0,0) - arc [start angle=0, end angle=315, + \tikz \draw (0,0) + arc [start angle=0, end angle=315, x radius=1.75cm, y radius=1cm]; \end{codeexample} \subsection{Clipping a Path} -In order to save space in this manual, it would be nice to clip Karl's -graphics a bit so that we can focus on the ``interesting'' -parts. Clipping is pretty easy in \tikzname. You can use the |\clip| -command to clip all subsequent drawing. It works like |\draw|, only it -does not draw anything, but uses the given path to clip everything -subsequently. - +In order to save space in this manual, it would be nice to clip Karl's graphics +a bit so that we can focus on the ``interesting'' parts. Clipping is pretty +easy in \tikzname. You can use the |\clip| command to clip all subsequent +drawing. It works like |\draw|, only it does not draw anything, but uses the +given path to clip everything subsequently. +% \begin{codeexample}[] \begin{tikzpicture}[scale=3] \clip (-0.1,-0.2) rectangle (1.1,0.75); @@ -593,14 +569,13 @@ subsequently. \end{tikzpicture} \end{codeexample} -You can also do both at the same time: Draw \emph{and} clip a -path. For this, use the |\draw| command and add the |clip| -option. (This is not the whole picture: You can also use the |\clip| -command and add the |draw| option. Well, that is also not the whole -picture: In reality, |\draw| is just a shorthand for |\path[draw]| -and |\clip| is a shorthand for |\path[clip]| and you could also say -|\path[draw,clip]|.) Here is an example: - +You can also do both at the same time: Draw \emph{and} clip a path. For this, +use the |\draw| command and add the |clip| option. (This is not the whole +picture: You can also use the |\clip| command and add the |draw| option. Well, +that is also not the whole picture: In reality, |\draw| is just a shorthand for +|\path[draw]| and |\clip| is a shorthand for |\path[clip]| and you could also +say |\path[draw,clip]|.) Here is an example: +% \begin{codeexample}[] \begin{tikzpicture}[scale=3] \clip[draw] (0.5,0.5) circle (.6cm); @@ -615,27 +590,25 @@ and |\clip| is a shorthand for |\path[clip]| and you could also say \subsection{Parabola and Sine Path Construction} -Although Karl does not need them for his picture, he is pleased to -learn that there are |parabola| and |sin| and |cos| path operations for -adding parabolas and sine and cosine curves to the current path. For the -|parabola| operation, the current point will lie on the parabola as -well as the point given after the parabola operation. Consider -the following example: - +Although Karl does not need them for his picture, he is pleased to learn that +there are |parabola| and |sin| and |cos| path operations for adding parabolas +and sine and cosine curves to the current path. For the |parabola| operation, +the current point will lie on the parabola as well as the point given after the +parabola operation. Consider the following example: +% \begin{codeexample}[] \tikz \draw (0,0) rectangle (1,1) (0,0) parabola (1,1); \end{codeexample} It is also possible to place the bend somewhere else: - +% \begin{codeexample}[] \tikz \draw[x=1pt,y=1pt] (0,0) parabola bend (4,16) (6,12); \end{codeexample} The operations |sin| and |cos| add a sine or cosine curve in the interval -$[0,\pi/2]$ such that the previous current point is at the start of -the curve and the curve ends at the given end point. Here are two -examples: +$[0,\pi/2]$ such that the previous current point is at the start of the curve +and the curve ends at the given end point. Here are two examples: \begin{codeexample}[] A sine \tikz \draw[x=1ex,y=1ex] (0,0) sin (1.57,1); curve. \end{codeexample} @@ -646,13 +619,12 @@ A sine \tikz \draw[x=1ex,y=1ex] (0,0) sin (1.57,1); curve. \end{codeexample} - \subsection{Filling and Drawing} -Returning to the picture, Karl now wants the angle to be ``filled'' -with a very light green. For this he uses |\fill| instead of -|\draw|. Here is what Karl does: - +Returning to the picture, Karl now wants the angle to be ``filled'' with a very +light green. For this he uses |\fill| instead of |\draw|. Here is what Karl +does: +% \begin{codeexample}[] \begin{tikzpicture}[scale=3] \clip (-0.1,-0.2) rectangle (1.1,0.75); @@ -665,24 +637,25 @@ with a very light green. For this he uses |\fill| instead of \end{tikzpicture} \end{codeexample} -The color |green!20!white| means 20\% green and 80\% white mixed -together. Such color expression are possible since \tikzname\ uses Uwe -Kern's |xcolor| package, see the documentation of that package for -details on color expressions. +The color |green!20!white| means 20\% green and 80\% white mixed together. Such +color expression are possible since \tikzname\ uses Uwe Kern's |xcolor| +package, see the documentation of that package for details on color +expressions. -What would have happened, if Karl had not ``closed'' the path using -|--(0,0)| at the end? In this case, the path is closed automatically, -so this could have been omitted. Indeed, it would even have been -better to write the following, instead: +What would have happened, if Karl had not ``closed'' the path using |--(0,0)| +at the end? In this case, the path is closed automatically, so this could have +been omitted. Indeed, it would even have been better to write the following, +instead: +% \begin{codeexample}[code only] \fill[green!20!white] (0,0) -- (3mm,0mm) arc [start angle=0, end angle=30, radius=3mm] -- cycle; \end{codeexample} -The |--cycle| causes the current path to be closed (actually the -current part of the current path) by smoothly joining the first and -last point. To appreciate the difference, consider the following -example: - +% +The |--cycle| causes the current path to be closed (actually the current part +of the current path) by smoothly joining the first and last point. To +appreciate the difference, consider the following example: +% \begin{codeexample}[] \begin{tikzpicture}[line width=5pt] \draw (0,0) -- (1,0) -- (1,1) -- (0,0); @@ -691,12 +664,11 @@ example: \end{tikzpicture} \end{codeexample} -You can also fill and draw a path at the same time using the -|\filldraw| command. This will first draw the path, then fill it. This -may not seem too useful, but you can specify different colors to be -used for filling and for stroking. These are specified as optional -arguments like this: - +You can also fill and draw a path at the same time using the |\filldraw| +command. This will first draw the path, then fill it. This may not seem too +useful, but you can specify different colors to be used for filling and for +stroking. These are specified as optional arguments like this: +% \begin{codeexample}[] \begin{tikzpicture}[scale=3] \clip (-0.1,-0.2) rectangle (1.1,0.75); @@ -710,21 +682,20 @@ arguments like this: \end{codeexample} - \subsection{Shading} -Karl briefly considers the possibility of making the angle ``more -fancy'' by \emph{shading} it. Instead of filling the area with a uniform -color, a smooth transition between different colors is used. For this, -|\shade| and |\shadedraw|, for shading and drawing at the same time, -can be used: - +Karl briefly considers the possibility of making the angle ``more fancy'' by +\emph{shading} it. Instead of filling the area with a uniform color, a smooth +transition between different colors is used. For this, |\shade| and +|\shadedraw|, for shading and drawing at the same time, can be used: +% \begin{codeexample}[] \tikz \shade (0,0) rectangle (2,1) (3,0.5) circle (.5cm); \end{codeexample} -The default shading is a smooth transition from gray to white. To -specify different colors, you can use options: - +% +The default shading is a smooth transition from gray to white. To specify +different colors, you can use options: +% \begin{codeexample}[] \begin{tikzpicture}[rounded corners,ultra thick] \shade[top color=yellow,bottom color=black] (0,0) rectangle +(2,1); @@ -735,7 +706,7 @@ specify different colors, you can use options: \end{codeexample} For Karl, the following might be appropriate: - +% \begin{codeexample}[] \begin{tikzpicture}[scale=3] \clip (-0.1,-0.2) rectangle (1.1,0.75); @@ -749,35 +720,34 @@ For Karl, the following might be appropriate: \end{tikzpicture} \end{codeexample} -However, he wisely decides that shadings usually only distract without -adding anything to the picture. +However, he wisely decides that shadings usually only distract without adding +anything to the picture. \subsection{Specifying Coordinates} -Karl now wants to add the sine and cosine lines. He knows already that -he can use the |color=| option to set the lines' colors. So, what is -the best way to specify the coordinates? - -There are different ways of specifying coordinates. The easiest way is -to say something like |(10pt,2cm)|. This means 10pt in $x$-direction -and 2cm in $y$-directions. Alternatively, you can also leave out the -units as in |(1,2)|, which means ``one times the current $x$-vector -plus twice the current $y$-vector.'' These vectors default to 1cm in -the $x$-direction and 1cm in the $y$-direction, respectively. - -In order to specify points in polar coordinates, use the notation -|(30:1cm)|, which means 1cm in direction 30 degree. This is obviously -quite useful to ``get to the point $(\cos 30^\circ,\sin 30^\circ)$ on -the circle.'' - -You can add a single |+| sign in front of a coordinate or two of -them as in |+(0cm,1cm)| or |++(2cm,0cm)|. Such coordinates are interpreted -differently: The first form means ``1cm upwards from the previous -specified position'' and the second means ``2cm to the right of the -previous specified position, making this the new specified position.'' -For example, we can draw the sine line as follows: - +Karl now wants to add the sine and cosine lines. He knows already that he can +use the |color=| option to set the lines' colors. So, what is the best way to +specify the coordinates? + +There are different ways of specifying coordinates. The easiest way is to say +something like |(10pt,2cm)|. This means 10pt in $x$-direction and 2cm in +$y$-directions. Alternatively, you can also leave out the units as in |(1,2)|, +which means ``one times the current $x$-vector plus twice the current +$y$-vector''. These vectors default to 1cm in the $x$-direction and 1cm in the +$y$-direction, respectively. + +In order to specify points in polar coordinates, use the notation |(30:1cm)|, +which means 1cm in direction 30 degree. This is obviously quite useful to ``get +to the point $(\cos 30^\circ,\sin 30^\circ)$ on the circle''. + +You can add a single |+| sign in front of a coordinate or two of them as in +|+(0cm,1cm)| or |++(2cm,0cm)|. Such coordinates are interpreted differently: +The first form means ``1cm upwards from the previous specified position'' and +the second means ``2cm to the right of the previous specified position, making +this the new specified position''. For example, we can draw the sine line as +follows: +% \begin{codeexample}[] \begin{tikzpicture}[scale=3] \clip (-0.1,-0.2) rectangle (1.1,0.75); @@ -791,18 +761,17 @@ For example, we can draw the sine line as follows: \end{tikzpicture} \end{codeexample} -Karl used the fact $\sin 30^\circ = 1/2$. However, he very much -doubts that his students know this, so it would be nice to have a way -of specifying ``the point straight down from |(30:1cm)| that lies on -the $x$-axis.'' This is, indeed, possible using a special syntax: Karl -can write \verb!(30:1cm |- 0,0)!. In general, the meaning of -|(|\meta{p}\verb! |- !\meta{q}|)| is ``the intersection of a vertical -line through $p$ and a horizontal line through $q$.'' +Karl used the fact $\sin 30^\circ = 1/2$. However, he very much doubts that his +students know this, so it would be nice to have a way of specifying ``the point +straight down from |(30:1cm)| that lies on the $x$-axis''. This is, indeed, +possible using a special syntax: Karl can write \verb!(30:1cm |- 0,0)!. In +general, the meaning of |(|\meta{p}\verb! |- !\meta{q}|)| is ``the intersection +of a vertical line through $p$ and a horizontal line through $q$''. Next, let us draw the cosine line. One way would be to say -\verb!(30:1cm |- 0,0) -- (0,0)!. Another way is the following: we -``continue'' from where the sine ends: - +\verb!(30:1cm |- 0,0) -- (0,0)!. Another way is the following: we ``continue'' +from where the sine ends: +% \begin{codeexample}[] \begin{tikzpicture}[scale=3] \clip (-0.1,-0.2) rectangle (1.1,0.75); @@ -817,17 +786,16 @@ Next, let us draw the cosine line. One way would be to say \end{tikzpicture} \end{codeexample} -Note that there is no |--| between |(30:1cm)| and |++(0,-0.5)|. In -detail, this path is interpreted as follows: ``First, the |(30:1cm)| -tells me to move by pen to $(\cos 30^\circ,1/2)$. Next, there comes -another coordinate specification, so I move my pen there without drawing -anything. This new point is half a unit down from the last position, -thus it is at $(\cos 30^\circ,0)$. Finally, I move the pen to the -origin, but this time drawing something (because of the |--|).'' - -To appreciate the difference between |+| and |++| consider the -following example: +Note that there is no |--| between |(30:1cm)| and |++(0,-0.5)|. In detail, this +path is interpreted as follows: ``First, the |(30:1cm)| tells me to move by pen +to $(\cos 30^\circ,1/2)$. Next, there comes another coordinate specification, +so I move my pen there without drawing anything. This new point is half a unit +down from the last position, thus it is at $(\cos 30^\circ,0)$. Finally, I move +the pen to the origin, but this time drawing something (because of the |--|).'' +To appreciate the difference between |+| and |++| consider the following +example: +% \begin{codeexample}[] \begin{tikzpicture} \def\rectanglepath{-- ++(1cm,0cm) -- ++(0cm,1cm) -- ++(-1cm,0cm) -- cycle} @@ -837,7 +805,7 @@ following example: \end{codeexample} By comparison, when using a single |+|, the coordinates are different: - +% \begin{codeexample}[] \begin{tikzpicture} \def\rectanglepath{-- +(1cm,0cm) -- +(1cm,1cm) -- +(0cm,1cm) -- cycle} @@ -849,6 +817,7 @@ By comparison, when using a single |+|, the coordinates are different: Naturally, all of this could have been written more clearly and more economically like this (either with a single of a double |+|): +% \begin{codeexample}[] \tikz \draw (0,0) rectangle +(1,1) (1.5,0) rectangle +(1,1); \end{codeexample} @@ -856,35 +825,33 @@ economically like this (either with a single of a double |+|): \subsection{Intersecting Paths} -Karl is left with the line for $\tan \alpha$, which seems difficult to -specify using transformations and polar coordinates. The first -- and -easiest -- thing he can do is so simply use the coordinate -|(1,{tan(30)})| since \tikzname's math engine knows how to compute -things like |tan(30)|. Note the added braces since, otherwise, -\tikzname's parser would think that the first closing parenthesis ends -the coordinate (in general, you need to add braces around components -of coordinates when these components contain parentheses). - -Karl can, however, also use a more elaborate, but also more -``geometric'' way of computing the length of the orange line: He can -specify intersections of paths as coordinates. The line for $\tan -\alpha$ starts at $(1,0)$ -and goes upward to a point that is at the intersection of a line going -``up'' and a line going from the origin through |(30:1cm)|. Such -computations are made available by the |intersections| library. - -What Karl must do is to create two ``invisible'' paths that intersect -at the position of interest. Creating paths that are not otherwise -seen can be done using the |\path| command without any options like -|draw| or |fill|. Then, Karl can add the |name path| option to the -path for later reference. Once the paths have been constructed, Karl -can use the |name intersections| to assign names to the coordinate for -later reference. - +Karl is left with the line for $\tan \alpha$, which seems difficult to specify +using transformations and polar coordinates. The first -- and easiest -- thing +he can do is so simply use the coordinate |(1,{tan(30)})| since \tikzname's +math engine knows how to compute things like |tan(30)|. Note the added braces +since, otherwise, \tikzname's parser would think that the first closing +parenthesis ends the coordinate (in general, you need to add braces around +components of coordinates when these components contain parentheses). + +Karl can, however, also use a more elaborate, but also more ``geometric'' way +of computing the length of the orange line: He can specify intersections of +paths as coordinates. The line for $\tan \alpha$ starts at $(1,0)$ and goes +upward to a point that is at the intersection of a line going ``up'' and a line +going from the origin through |(30:1cm)|. Such computations are made available +by the |intersections| library. + +What Karl must do is to create two ``invisible'' paths that intersect at the +position of interest. Creating paths that are not otherwise seen can be done +using the |\path| command without any options like |draw| or |fill|. Then, Karl +can add the |name path| option to the path for later reference. Once the paths +have been constructed, Karl can use the |name intersections| to assign names to +the coordinate for later reference. +% \begin{codeexample}[code only] \path [name path=upward line] (1,0) -- (1,1); \path [name path=sloped line] (0,0) -- (30:1.5cm); % a bit longer, so that there is an intersection +% (add `\usetikzlibrary{intersections}' after loading tikz in the preamble) \draw [name intersections={of=upward line and sloped line, by=x}] [very thick,orange] (1,0) -- (x); \end{codeexample} @@ -893,14 +860,14 @@ later reference. \subsection{Adding Arrow Tips} Karl now wants to add the little arrow tips at the end of the axes. He has -noticed that in many plots, even in scientific journals, these arrow tips -seem to be missing, presumably because the generating programs cannot -produce them. Karl thinks arrow tips belong at the end of axes. His -son agrees. His students do not care about arrow tips. - -It turns out that adding arrow tips is pretty easy: Karl adds the option -|->| to the drawing commands for the axes: +noticed that in many plots, even in scientific journals, these arrow tips seem +to be missing, presumably because the generating programs cannot produce them. +Karl thinks arrow tips belong at the end of axes. His son agrees. His students +do not care about arrow tips. +It turns out that adding arrow tips is pretty easy: Karl adds the option |->| +to the drawing commands for the axes: +% \begin{codeexample}[] \begin{tikzpicture}[scale=3] \clip (-0.1,-0.2) rectangle (1.1,1.51); @@ -920,17 +887,16 @@ It turns out that adding arrow tips is pretty easy: Karl adds the option \end{tikzpicture} \end{codeexample} -If Karl had used the option |<-| instead of |->|, arrow tips would -have been put at the beginning of the path. The option |<->| puts -arrow tips at both ends of the path. - -There are certain restrictions to the kind of paths to which arrow tips -can be added. As a rule of thumb, you can add arrow tips only to a -single open ``line.'' For example, you cannot add tips to, -say, a rectangle or a circle. However, you can add arrow -tips to curved paths and to paths that have several segments, as in -the following examples: +If Karl had used the option |<-| instead of |->|, arrow tips would have been +put at the beginning of the path. The option |<->| puts arrow tips at both ends +of the path. +There are certain restrictions to the kind of paths to which arrow tips can be +added. As a rule of thumb, you can add arrow tips only to a single open +``line''. For example, you cannot add tips to, say, a rectangle or a circle. +However, you can add arrow tips to curved paths and to paths that have several +segments, as in the following examples: +% \begin{codeexample}[] \begin{tikzpicture} \draw [<->] (0,0) arc [start angle=180, end angle=30, radius=10pt]; @@ -938,57 +904,55 @@ the following examples: \end{tikzpicture} \end{codeexample} -Karl has a more detailed look at the arrow that \tikzname\ puts at the -end. It looks like this when he zooms it: \tikz[baseline] -\draw[->,line width=1pt] (0pt,.5ex) -- ++(10pt,0pt);. The shape seems -vaguely familiar and, indeed, this is exactly the end of \TeX's -standard arrow used in something like $f\colon A \to B$. - -Karl likes the arrow, especially since it is not ``as thick'' as the -arrows offered by many other packages. However, he expects that, -sometimes, he might need to use some other kinds of arrow. -To do so, Karl can say |>=|\meta{kind of end arrow tip}, where -\meta{kind of end arrow tip} is a special arrow tip specification. For -example, if Karl says |>=Stealth|, then he tells \tikzname\ +Karl has a more detailed look at the arrow that \tikzname\ puts at the end. It +looks like this when he zooms it: \tikz[baseline] \draw[->,line width=1pt] +(0pt,.5ex) -- ++(10pt,0pt);. The shape seems vaguely familiar and, indeed, this +is exactly the end of \TeX's standard arrow used in something like $f\colon A +\to B$. + +Karl likes the arrow, especially since it is not ``as thick'' as the arrows +offered by many other packages. However, he expects that, sometimes, he might +need to use some other kinds of arrow. To do so, Karl can say |>=|\meta{kind of +end arrow tip}, where \meta{kind of end arrow tip} is a special arrow tip +specification. For example, if Karl says |>=Stealth|, then he tells \tikzname\ that he would like ``stealth-fighter-like'' arrow tips: - +\todosp{remaining instance of bug \#473} +% \begin{codeexample}[] \begin{tikzpicture}[>=Stealth] \draw [->] (0,0) arc [start angle=180, end angle=30, radius=10pt]; \draw [<<-,very thick] (1,0) -- (1.5cm,10pt) -- (2cm,0pt) -- (2.5cm,10pt); \end{tikzpicture} -\end{codeexample}%>> +\end{codeexample} Karl wonders whether such a military name for the arrow type is really -necessary. He is not really mollified when his son tells him that -Microsoft's PowerPoint uses the same name. He decides to have his -students discuss this at some point. +necessary. He is not really mollified when his son tells him that Microsoft's +PowerPoint uses the same name. He decides to have his students discuss this at +some point. -In addition to |Stealth| there are several other predefined kinds of -arrow tips Karl can choose from, see Section~\ref{section-arrows}. Furthermore, -he can define arrows types himself, if he needs new ones. +In addition to |Stealth| there are several other predefined kinds of arrow tips +Karl can choose from, see Section~\ref{section-arrows}. Furthermore, he can +define arrows types himself, if he needs new ones. \subsection{Scoping} -Karl saw already that there are numerous graphic options that affect how -paths are rendered. Often, he would like to apply certain options to -a whole set of graphic commands. For example, Karl might wish to draw -three paths using a |thick| pen, but would like everything else to -be drawn ``normally.'' - -If Karl wishes to set a certain graphic option for the whole picture, -he can simply pass this option to the |\tikz| command or to the -|{tikzpicture}| environment (Gerda would pass the options to -|\tikzpicture| and Hans passes them to |\starttikzpicture|). However, -if Karl wants to apply graphic options to a local group, he put these -commands inside a |{scope}| environment (Gerda uses |\scope| and -|\endscope|, Hans uses |\startscope| and |\stopscope|). This -environment takes graphic options as an optional argument and these -options apply to everything inside the scope, but not to anything outside. +Karl saw already that there are numerous graphic options that affect how paths +are rendered. Often, he would like to apply certain options to a whole set of +graphic commands. For example, Karl might wish to draw three paths using a +|thick| pen, but would like everything else to be drawn ``normally''. -Here is an example: +If Karl wishes to set a certain graphic option for the whole picture, he can +simply pass this option to the |\tikz| command or to the |{tikzpicture}| +environment (Gerda would pass the options to |\tikzpicture| and Hans passes +them to |\starttikzpicture|). However, if Karl wants to apply graphic options +to a local group, he put these commands inside a |{scope}| environment (Gerda +uses |\scope| and |\endscope|, Hans uses |\startscope| and |\stopscope|). This +environment takes graphic options as an optional argument and these options +apply to everything inside the scope, but not to anything outside. +Here is an example: +% \begin{codeexample}[] \begin{tikzpicture}[ultra thick] \draw (0,0) -- (0,1); @@ -1000,58 +964,51 @@ Here is an example: \end{tikzpicture} \end{codeexample} -Scoping has another interesting effect: Any changes to the clipping -area are local to the scope. Thus, if you say |\clip| somewhere inside -a scope, the effect of the |\clip| command ends at the end of the -scope. This is useful since there is no other way of ``enlarging'' the -clipping area. - -Karl has also already seen that giving options to commands like -|\draw| apply only to that command. It turns out that the situation is -slightly more complex. First, options to a command like |\draw| are -not really options to the command, but they are ``path options'' and -can be given anywhere on the path. So, instead of -|\draw[thin] (0,0) -- (1,0);| one can also write -|\draw (0,0) [thin] -- (1,0);| or |\draw (0,0) -- (1,0) [thin];|; all -of these have the same effect. This might seem strange since in the -last case, it would appear that the |thin| should take effect only -``after'' the line from $(0,0)$ to $(1,0)$ has been drawn. However, -most graphic options only apply to the whole path. Indeed, if you say -both |thin| and |thick| on the same path, the last option given will -``win.'' - -When reading the above, Karl notices that only ``most'' graphic -options apply to the whole path. Indeed, all transformation options do -\emph{not} apply to the whole path, but only to ``everything following -them on the path.'' We will have a more detailed look at this in a -moment. Nevertheless, all options given during a path construction -apply only to this path. - +Scoping has another interesting effect: Any changes to the clipping area are +local to the scope. Thus, if you say |\clip| somewhere inside a scope, the +effect of the |\clip| command ends at the end of the scope. This is useful +since there is no other way of ``enlarging'' the clipping area. + +Karl has also already seen that giving options to commands like |\draw| apply +only to that command. It turns out that the situation is slightly more complex. +First, options to a command like |\draw| are not really options to the command, +but they are ``path options'' and can be given anywhere on the path. So, +instead of |\draw[thin] (0,0) -- (1,0);| one can also write +|\draw (0,0) [thin] -- (1,0);| or |\draw (0,0) -- (1,0) [thin];|; all of these +have the same effect. This might seem strange since in the last case, it would +appear that the |thin| should take effect only ``after'' the line from $(0,0)$ +to $(1,0)$ has been drawn. However, most graphic options only apply to the +whole path. Indeed, if you say both |thin| and |thick| on the same path, the +last option given will ``win''. + +When reading the above, Karl notices that only ``most'' graphic options apply +to the whole path. Indeed, all transformation options do \emph{not} apply to +the whole path, but only to ``everything following them on the path''. We will +have a more detailed look at this in a moment. Nevertheless, all options given +during a path construction apply only to this path. \subsection{Transformations} -When you specify a coordinate like |(1cm,1cm)|, where is that -coordinate placed on the page? To determine the position, \tikzname, -\TeX, and \textsc{pdf} or PostScript all apply certain transformations -to the given coordinate in order to determine the final position on -the page. +When you specify a coordinate like |(1cm,1cm)|, where is that coordinate +placed on the page? To determine the position, \tikzname, \TeX, and +\textsc{pdf} or PostScript all apply certain transformations to the given +coordinate in order to determine the final position on the page. -\tikzname\ provides numerous options that allow you to transform -coordinates in \tikzname's private coordinate system. For example, the -|xshift| option allows you to shift all subsequent points by a certain -amount: +\tikzname\ provides numerous options that allow you to transform coordinates in +\tikzname's private coordinate system. For example, the |xshift| option allows +you to shift all subsequent points by a certain amount: \begin{codeexample}[] \tikz \draw (0,0) -- (0,0.5) [xshift=2pt] (0,0) -- (0,0.5); \end{codeexample} -It is important to note that you can change transformation ``in the -middle of a path,'' a feature that is not supported by \pdf\ -or PostScript. The reason is that \tikzname\ keeps track of its own -transformation matrix. +It is important to note that you can change transformation ``in the middle of a +path'', a feature that is not supported by \pdf\ or PostScript. The reason is +that \tikzname\ keeps track of its own transformation matrix. Here is a more complicated example: +% \begin{codeexample}[] \begin{tikzpicture}[even odd rule,rounded corners=2pt,x=10pt,y=10pt] \filldraw[fill=yellow!80!black] (0,0) rectangle (1,1) @@ -1060,48 +1017,45 @@ Here is a more complicated example: \end{tikzpicture} \end{codeexample} -The most useful transformations are |xshift| and |yshift| for -shifting, |shift| for shifting to a given point as in |shift={(1,0)}| -or |shift={+(0,0)}| (the braces are necessary so that \TeX\ does not -mistake the comma for separating options), |rotate| for rotating by a -certain angle (there is also a |rotate around| for rotating around a -given point), |scale| for scaling by a certain factor, |xscale| and -|yscale| for scaling only in the $x$- or $y$-direction (|xscale=-1| is -a flip), and |xslant| and |yslant| for slanting. If these -transformation and those that I have not mentioned are not -sufficient, the |cm| option allows you to apply an arbitrary -transformation matrix. Karl's students, by the way, do not know what a -transformation matrix is. - +The most useful transformations are |xshift| and |yshift| for shifting, |shift| +for shifting to a given point as in |shift={(1,0)}| or |shift={+(0,0)}| (the +braces are necessary so that \TeX\ does not mistake the comma for separating +options), |rotate| for rotating by a certain angle (there is also a +|rotate around| for rotating around a given point), |scale| for scaling by a +certain factor, |xscale| and |yscale| for scaling only in the $x$- or +$y$-direction (|xscale=-1| is a flip), and |xslant| and |yslant| for slanting. +If these transformation and those that I have not mentioned are not sufficient, +the |cm| option allows you to apply an arbitrary transformation matrix. Karl's +students, by the way, do not know what a transformation matrix is. \subsection{Repeating Things: For-Loops} -Karl's next aim is to add little ticks on the axes at positions $-1$, -$-1/2$, $1/2$, and $1$. For this, it would be nice to use some kind of -``loop,'' especially since he wishes to do the same thing at each of -these positions. There are different packages for doing this. \LaTeX\ -has its own internal command for this, |pstricks| comes along with the -powerful |\multido| command. All of these can be used together with -\tikzname, so if you are familiar with them, feel free to -use them. \tikzname\ introduces yet another command, called |\foreach|, -which I introduced since I could never remember the syntax of the other -packages. |\foreach| is defined in the package |pgffor| and can be used +Karl's next aim is to add little ticks on the axes at positions $-1$, $-1/2$, +$1/2$, and $1$. For this, it would be nice to use some kind of ``loop'', +especially since he wishes to do the same thing at each of these positions. +There are different packages for doing this. \LaTeX\ has its own internal +command for this, |pstricks| comes along with the powerful |\multido| command. +All of these can be used together with \tikzname, so if you are familiar with +them, feel free to use them. \tikzname\ introduces yet another command, called +|\foreach|, which I introduced since I could never remember the syntax of the +other packages. |\foreach| is defined in the package |pgffor| and can be used independently \tikzname, but \tikzname\ includes it automatically. In its basic form, the |\foreach| command is easy to use: +% \begin{codeexample}[] \foreach \x in {1,2,3} {$x =\x$, } \end{codeexample} -The general syntax is |\foreach| \meta{variable}| in {|\meta{list of - values}|} |\meta{commands}. Inside the \meta{commands}, the -\meta{variable} will be assigned to the different values. If the -\meta{commands} do not start with a brace, everything up to the -next semicolon is used as \meta{commands}. +The general syntax is +|\foreach| \meta{variable}| in {|\meta{list of values}|} |\meta{commands}. +Inside the \meta{commands}, the \meta{variable} will be assigned to the +different values. If the \meta{commands} do not start with a brace, everything +up to the next semicolon is used as \meta{commands}. For Karl and the ticks on the axes, he could use the following code: - +% \begin{codeexample}[] \begin{tikzpicture}[scale=3] \clip (-0.1,-0.2) rectangle (1.1,1.51); @@ -1119,36 +1073,36 @@ For Karl and the ticks on the axes, he could use the following code: \end{tikzpicture} \end{codeexample} -As a matter of fact, there are many different ways of creating the -ticks. For example, Karl could have put the |\draw ...;| inside curly -braces. He could also have used, say, +As a matter of fact, there are many different ways of creating the ticks. For +example, Karl could have put the |\draw ...;| inside curly braces. He could +also have used, say, +% \begin{codeexample}[code only] \foreach \x in {-1,-0.5,1} \draw[xshift=\x cm] (0pt,-1pt) -- (0pt,1pt); \end{codeexample} -Karl is curious what would happen in a more complicated situation -where there are, say, 20 ticks. It seems bothersome to explicitly -mention all these numbers in the set for |\foreach|. Indeed, it is -possible to use |...| inside the |\foreach| statement to iterate over -a large number of values (which must, however, be dimensionless -real numbers) as in the following example: - +Karl is curious what would happen in a more complicated situation where there +are, say, 20 ticks. It seems bothersome to explicitly mention all these numbers +in the set for |\foreach|. Indeed, it is possible to use |...| inside the +|\foreach| statement to iterate over a large number of values (which must, +however, be dimensionless real numbers) as in the following example: +% \begin{codeexample}[] \tikz \foreach \x in {1,...,10} \draw (\x,0) circle (0.4cm); \end{codeexample} -If you provide \emph{two} numbers before the |...|, the |\foreach| -statement will use their difference for the stepping: - +If you provide \emph{two} numbers before the |...|, the |\foreach| statement +will use their difference for the stepping: +% \begin{codeexample}[] \tikz \foreach \x in {-1,-0.5,...,1} \draw (\x cm,-1pt) -- (\x cm,1pt); \end{codeexample} We can also nest loops to create interesting effects: - +% \begin{codeexample}[] \begin{tikzpicture} \foreach \x in {1,2,...,5,7,8,...,12} @@ -1160,31 +1114,28 @@ We can also nest loops to create interesting effects: \end{tikzpicture} \end{codeexample} -The |\foreach| statement can do even trickier stuff, but the above -gives the idea. - - +The |\foreach| statement can do even trickier stuff, but the above gives the +idea. \subsection{Adding Text} -Karl is, by now, quite satisfied with the picture. However, the most -important parts, namely the labels, are still missing! - -\tikzname\ offers an easy-to-use and powerful system for adding text and, -more generally, complex shapes to a picture at specific positions. The -basic idea is the following: When \tikzname\ is constructing a path and -encounters the keyword |node| in the middle of a path, it -reads a \emph{node specification}. The keyword |node| is typically -followed by some options and then some text between curly braces. This -text is put inside a normal \TeX\ box (if the node specification -directly follows a coordinate, which is usually the case, \tikzname\ is -able to perform some magic so that it is even possible to use verbatim -text inside the boxes) and then placed at the current position, that -is, at the last specified position (possibly shifted a bit, according -to the given options). However, all nodes are drawn only after the -path has been completely drawn/filled/shaded/clipped/whatever. - +Karl is, by now, quite satisfied with the picture. However, the most important +parts, namely the labels, are still missing! + +\tikzname\ offers an easy-to-use and powerful system for adding text and, more +generally, complex shapes to a picture at specific positions. The basic idea is +the following: When \tikzname\ is constructing a path and encounters the +keyword |node| in the middle of a path, it reads a \emph{node specification}. +The keyword |node| is typically followed by some options and then some text +between curly braces. This text is put inside a normal \TeX\ box (if the node +specification directly follows a coordinate, which is usually the case, +\tikzname\ is able to perform some magic so that it is even possible to use +verbatim text inside the boxes) and then placed at the current position, that +is, at the last specified position (possibly shifted a bit, according to the +given options). However, all nodes are drawn only after the path has been +completely drawn/filled/shaded/clipped/whatever. +% \begin{codeexample}[] \begin{tikzpicture} \draw (0,0) rectangle (2,2); @@ -1194,17 +1145,16 @@ path has been completely drawn/filled/shaded/clipped/whatever. \end{tikzpicture} \end{codeexample} -Obviously, Karl would not only like to place nodes \emph{on} the last -specified position, but also to the left or the -right of these positions. For this, every node object that you -put in your picture is equipped with several \emph{anchors}. For -example, the |north| anchor is in the middle at the upper end of the shape, -the |south| anchor is at the bottom and the |north east| anchor is in -the upper right corner. When you give the option |anchor=north|, the -text will be placed such that this northern anchor will lie on the -current position and the text is, thus, below the current -position. Karl uses this to draw the ticks as follows: - +Obviously, Karl would not only like to place nodes \emph{on} the last specified +position, but also to the left or the right of these positions. For this, every +node object that you put in your picture is equipped with several +\emph{anchors}. For example, the |north| anchor is in the middle at the upper +end of the shape, the |south| anchor is at the bottom and the |north east| +anchor is in the upper right corner. When you give the option |anchor=north|, +the text will be placed such that this northern anchor will lie on the current +position and the text is, thus, below the current position. Karl uses this to +draw the ticks as follows: +% \begin{codeexample}[] \begin{tikzpicture}[scale=3] \clip (-0.6,-0.2) rectangle (0.6,1.51); @@ -1221,38 +1171,35 @@ position. Karl uses this to draw the ticks as follows: \end{tikzpicture} \end{codeexample} -This is quite nice, already. Using these anchors, Karl can now add -most of the other text elements. However, Karl thinks that, though -``correct,'' it is quite counter-intuitive that in order to place something -\emph{below} a given point, he has to use the \emph{north} anchor. For -this reason, there is an option called |below|, which does the -same as |anchor=north|. Similarly, |above right| does the same as -|anchor=south west|. In addition, |below| takes an optional -dimension argument. If given, the shape will additionally be shifted -downwards by the given amount. So, |below=1pt| can be used to put -a text label below some point and, additionally shift it 1pt -downwards. - -Karl is not quite satisfied with the ticks. He would like to have -$1/2$ or $\frac{1}{2}$ shown instead of $0.5$, partly to show off the -nice capabilities of \TeX\ and \tikzname, partly because for positions -like $1/3$ or $\pi$ it is certainly very much preferable to have the -``mathematical'' tick there instead of just the ``numeric'' tick. -His students, on the other hand, prefer $0.5$ over $1/2$ -since they are not too fond of fractions in general. - -Karl now faces a problem: For the |\foreach| statement, the position -|\x| should still be given as |0.5| since \tikzname\ will not know where -|\frac{1}{2}| is supposed to be. On the other hand, the typeset text -should really be |\frac{1}{2}|. To solve this problem, |\foreach| -offers a special syntax: Instead of having one variable |\x|, Karl can -specify two (or even more) variables separated by a slash as in -|\x / \xtext|. Then, the elements in the set over which |\foreach| -iterates must also be of the form \meta{first}|/|\meta{second}. In -each iteration, |\x| will be set to \meta{first} and |\xtext| will be -set to \meta{second}. If no \meta{second} is given, the \meta{first} -will be used again. So, here is the new code for the ticks: - +This is quite nice, already. Using these anchors, Karl can now add most of the +other text elements. However, Karl thinks that, though ``correct'', it is quite +counter-intuitive that in order to place something \emph{below} a given point, +he has to use the \emph{north} anchor. For this reason, there is an option +called |below|, which does the same as |anchor=north|. Similarly, |above right| +does the same as |anchor=south west|. In addition, |below| takes an optional +dimension argument. If given, the shape will additionally be shifted downwards +by the given amount. So, |below=1pt| can be used to put a text label below some +point and, additionally shift it 1pt downwards. + +Karl is not quite satisfied with the ticks. He would like to have $1/2$ or +$\frac{1}{2}$ shown instead of $0.5$, partly to show off the nice capabilities +of \TeX\ and \tikzname, partly because for positions like $1/3$ or $\pi$ it is +certainly very much preferable to have the ``mathematical'' tick there instead +of just the ``numeric'' tick. His students, on the other hand, prefer $0.5$ +over $1/2$ since they are not too fond of fractions in general. + +Karl now faces a problem: For the |\foreach| statement, the position |\x| +should still be given as |0.5| since \tikzname\ will not know where +|\frac{1}{2}| is supposed to be. On the other hand, the typeset text should +really be |\frac{1}{2}|. To solve this problem, |\foreach| offers a special +syntax: Instead of having one variable |\x|, Karl can specify two (or even +more) variables separated by a slash as in |\x / \xtext|. Then, the elements in +the set over which |\foreach| iterates must also be of the form +\meta{first}|/|\meta{second}. In each iteration, |\x| will be set to +\meta{first} and |\xtext| will be set to \meta{second}. If no \meta{second} is +given, the \meta{first} will be used again. So, here is the new code for the +ticks: +% \begin{codeexample}[] \begin{tikzpicture}[scale=3] \clip (-0.6,-0.2) rectangle (0.6,1.51); @@ -1269,26 +1216,22 @@ will be used again. So, here is the new code for the ticks: \end{tikzpicture} \end{codeexample} -Karl is quite pleased with the result, but his son points out that -this is still not perfectly satisfactory: The grid and the circle -interfere with the numbers and decrease their legibility. Karl is not -very concerned by this (his students do not even notice), but his son -insists that there is an easy solution: Karl can add the -|[fill=white]| option to fill out the background of the text shape -with a white color. - -The next thing Karl wants to do is to add the labels like $\sin -\alpha$. For this, he would like to place a label ``in the middle of -the line.'' To do so, instead of specifying the label -|node {$\sin\alpha$}| directly after one of the endpoints of the line -(which would place -the label at that endpoint), Karl can give the label directly after -the |--|, before the coordinate. By default, this places the label in -the middle of the line, but the |pos=| options can be used to modify -this. Also, options like |near start| and |near end| can be used to -modify this position: - - +Karl is quite pleased with the result, but his son points out that this is +still not perfectly satisfactory: The grid and the circle interfere with the +numbers and decrease their legibility. Karl is not very concerned by this (his +students do not even notice), but his son insists that there is an easy +solution: Karl can add the |[fill=white]| option to fill out the background of +the text shape with a white color. + +The next thing Karl wants to do is to add the labels like $\sin \alpha$. For +this, he would like to place a label ``in the middle of the line''. To do so, +instead of specifying the label |node {$\sin\alpha$}| directly after one of +the endpoints of the line (which would place the label at that endpoint), Karl +can give the label directly after the |--|, before the coordinate. By default, +this places the label in the middle of the line, but the |pos=| options can be +used to modify this. Also, options like |near start| and |near end| can be used +to modify this position: +% \begin{codeexample}[] \begin{tikzpicture}[scale=3] \clip (-2,-0.2) rectangle (2,0.8); @@ -1319,10 +1262,9 @@ modify this position: \end{tikzpicture} \end{codeexample} -You can also position labels on curves and, by adding the |sloped| -option, have them rotated such that they match the line's slope. Here -is an example: - +You can also position labels on curves and, by adding the |sloped| option, have +them rotated such that they match the line's slope. Here is an example: +% \begin{codeexample}[] \begin{tikzpicture} \draw (0,0) .. controls (6,1) and (9,1) .. @@ -1332,12 +1274,11 @@ is an example: \end{tikzpicture} \end{codeexample} -It remains to draw the explanatory text at the right of the -picture. The main difficulty here lies in limiting the width of the -text ``label,'' which is quite long, so that line breaking is -used. Fortunately, Karl can use the option |text width=6cm| to get the -desired effect. So, here is the full code: - +It remains to draw the explanatory text at the right of the picture. The main +difficulty here lies in limiting the width of the text ``label'', which is +quite long, so that line breaking is used. Fortunately, Karl can use the option +|text width=6cm| to get the desired effect. So, here is the full code: +% \begin{codeexample}[code only] \begin{tikzpicture} [scale=3,line cap=round, @@ -1402,35 +1343,32 @@ desired effect. So, here is the full code: \end{codeexample} - \subsection{Pics: The Angle Revisited} -Karl expects that the code of certain parts of the picture he created -might be so useful that he might wish to reuse them in the -future. A natural thing to do is to create \TeX\ macros that store -the code he wishes to reuse. However, \tikzname\ offers another way -that is integrated directly into its parser: pics! - -A ``pic'' is ``not quite a full picture,'' hence the short name. The -idea is that a pic is simply some code that you can add to a picture -at different places using the |pic| command whose syntax is almost -identical to the |node| command. The main difference is that instead -of specifying some text in curly braces that should be shown, you -specify the name of a predefined picture that should be shown. - -Defining new pics is easy enough, see Section~\ref{section-pics}, but -right now we just want to use one such predefined pic: the |angle| -pic. As the name suggests, it is a small drawing of an angle -consisting of a little wedge and an arc together with some text (Karl -needs to load the |angle| library and the |quotes| for the following -examples). What makes this pic useful is the fact that the size of the -wedge will be computed automatically. - -The |angle| pic draws an angle between the two lines $BA$ and $BC$, -where $A$, $B$, and $C$ are three coordinates. In our case, $B$ is the -origin, $A$ is somewhere on the $x$-axis and $C$ is somewhere on a -line at $30^\circ$. - +Karl expects that the code of certain parts of the picture he created might be +so useful that he might wish to reuse them in the future. A natural thing to do +is to create \TeX\ macros that store the code he wishes to reuse. However, +\tikzname\ offers another way that is integrated directly into its parser: +pics! + +A ``pic'' is ``not quite a full picture'', hence the short name. The idea is +that a pic is simply some code that you can add to a picture at different +places using the |pic| command whose syntax is almost identical to the |node| +command. The main difference is that instead of specifying some text in curly +braces that should be shown, you specify the name of a predefined picture that +should be shown. + +Defining new pics is easy enough, see Section~\ref{section-pics}, but right now +we just want to use one such predefined pic: the |angle| pic. As the name +suggests, it is a small drawing of an angle consisting of a little wedge and an +arc together with some text (Karl needs to load the |angles| library and the +|quotes| for the following examples). What makes this pic useful is the fact +that the size of the wedge will be computed automatically. + +The |angle| pic draws an angle between the two lines $BA$ and $BC$, where $A$, +$B$, and $C$ are three coordinates. In our case, $B$ is the origin, $A$ is +somewhere on the $x$-axis and $C$ is somewhere on a line at $30^\circ$. +% \begin{codeexample}[] \begin{tikzpicture}[scale=3] \coordinate (A) at (1,0); @@ -1440,18 +1378,17 @@ line at $30^\circ$. \draw (A) -- (B) -- (C) pic [draw=green!50!black, fill=green!20, angle radius=9mm, "$\alpha$"] {angle = A--B--C}; -\end{tikzpicture} +\end{tikzpicture} \end{codeexample} Let us see, what is happening here. First we have specified three -\emph{coordinates} using the |\coordinate| command. It allows us to -name a specific coordinate in the picture. Then comes something that -starts as a normal |\draw|, but then comes the |pic| command. This -command gets lots of options and, in curly braces, comes the most -important point: We specify that we want to add an |angle| pic and -this angle should be between the points we named |A|, |B|, and |C| (we -could use other names). Note that the text that we want to be shown in -the pic is specified in quotes inside the options of the |pic|, not -inside the curly braces. - -To learn more about pics, please see Section~\ref{section-pics}.
\ No newline at end of file +\emph{coordinates} using the |\coordinate| command. It allows us to name a +specific coordinate in the picture. Then comes something that starts as a +normal |\draw|, but then comes the |pic| command. This command gets lots of +options and, in curly braces, comes the most important point: We specify that +we want to add an |angle| pic and this angle should be between the points we +named |A|, |B|, and |C| (we could use other names). Note that the text that we +want to be shown in the pic is specified in quotes inside the options of the +|pic|, not inside the curly braces. + +To learn more about pics, please see Section~\ref{section-pics}. |