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diff --git a/Master/texmf-dist/doc/latex/beamer/beamerug-elements.tex b/Master/texmf-dist/doc/latex/beamer/beamerug-elements.tex new file mode 100644 index 00000000000..7a7ca41cc9c --- /dev/null +++ b/Master/texmf-dist/doc/latex/beamer/beamerug-elements.tex @@ -0,0 +1,830 @@ +% $Header: /cvsroot/latex-beamer/latex-beamer/doc/beamerug-elements.tex,v 1.12 2004/12/09 22:31:18 tantau Exp $ + +% Copyright 2003, 2004 by Till Tantau <tantau@users.sourceforge.net>. +% +% This program can be redistributed and/or modified under the terms +% of the GNU Public License, version 2. + + +\section{Inner Themes, Outer Themes, and Templates} + +\label{section-elements} + +This section discusses the inner and outer themes that are +available in \beamer. These themes install certain \emph{templates} +for the different elements of a presentation. The template mechanism is +explained at the end of the section. + +Before we plunge into the details, let us agree on some terminology +for this section. In \beamer, an \emph{element} is part of a +presentation that is potentially typeset in some special way. Examples +of elements are frame titles, the author's name, or the footnote +sign. The appearance of every element is governed by a \emph{template} +for this element. Appropriate templates are installed by inner and +outer themes, where the \emph{inner} themes only install templates for +elements that are typically ``inside the main text,'' while \emph{outer} +themes install templates for elements ``around the main text.'' Thus, +from the templates's point of view, there is no real difference +between inner and outer themes. + + + +\subsection{Inner Themes} + +An inner theme installs templates that dictate how the following +elements are typeset: +\begin{itemize} +\item Title and part pages. +\item Itemize environments. +\item Enumerate environments. +\item Description environments. +\item Block environments. +\item Theorem and proof environments. +\item Figures and tables. +\item Footnotes. +\item Bibliography entries. +\end{itemize} + + +In the following examples, the color themes |seahorse| and |rose| are +used to show where and how background colors are +honoured. Furthermore, background colors have been specified for all +elements that honour them in the default theme. In the default color +theme, all of the large rectangular areas are transparent. + +\begin{innerthemeexample}{default} + The default element theme is quite sober. The only extravagance is + the fact that a little triangle is used in |itemize| environments + instead of the usual dot. + + In some cases the theme will honour background color specifications + for elements. For example, if you set the background color for block + titles to green, block titles will have a green background. The + background specifications are currently honoured for the following + elements: + \begin{itemize} + \item Title, author, institute, and date fields in the title + page. + \item Block environments, both for the title and for the body. + \end{itemize} + This list may increase in the future. +\end{innerthemeexample} + +\begin{innerthemeexample}{circles} + In this theme, |itemize| and |enumerate| items start with a small + circle. Likewise, entries in the table of contents start with + circles. +\end{innerthemeexample} + +\begin{innerthemeexample}{rectangles} + In this theme, |itemize| and |enumerate| items and table of contents + entries start with small rectangles. +\end{innerthemeexample} + +\begin{innerthemeexample}[\oarg{options}]{rounded} + In this theme, |itemize| and |enumerate| items and table of contents + entries start with small balls. If a background is specified for + blocks, then the corners of the background rectangles will be + rounded off. The following \meta{options} may be given: + + \begin{itemize} + \item \declare{|shadow|} adds a shadow to all blocks. + \end{itemize} +\end{innerthemeexample} + +\begin{innerthemeexample}{inmargin} + The idea behind this theme is to have ``structuring'' information on + the left and ``normal'' information on the right. To this end, + blocks are redefined such that the block title is shown on the left + and the block body is shown on the right. + + The code used to place text in the margin is a bit fragile. You may + often need to adjust the spacing ``by hand,'' so use at your own risk. + + Itemize items are redefined such that they appear on the + left. However, only the position is changed by changing some spacing + parameters; the code used to draw the items is not changed + otherwise. Because of this, you can load another inner theme first + and then load this theme afterwards. + + This theme is a ``dirty'' an inner theme since it messes with things + that an inner theme should not mess with. In particular, it changes + the width of the left sidebar to a large value. However, you can + still use it together with most outer themes. + + Using columns inside this theme is problematic. Most of the time, + the result will not be what you expect. +\end{innerthemeexample} + + + + +\subsection{Outer Themes} + +An outer theme dictates (roughly) the overall layout of frames. It +specifies where any navigational elements should go (like a mini table +of contents or navigational mini frames) and what they should look +like. Typically, an outer theme specifies how the following elements +are rendered: +\begin{itemize} +\item The head- and footline. +\item The sidebars. +\item The logo. +\item The frame title. +\end{itemize} + +An outer theme will not specify how things like |itemize| environments +should be rendered---that is the job of an inner theme. + +In the following examples the color theme |seahorse| is +used. Since the default color theme leaves most backgrounds empty, +most of the outer themes look too unstructured with the default +color theme. + + +\begin{outerthemeexample}{default} + The default layout theme is the most sober and minimalistic theme + around. It will flush left the frame title and it will not install + any head- or footlines. However, even this theme honours the + background color specified for the frame title. If a color is + specified, a bar occupying the whole page width is put behind the + frame title. A background color of the frame subtitle is ignored. +\end{outerthemeexample} + +\begin{outerthemeexample}{infolines} + This theme installs a headline showing the current section and the + current subsection. It installs a footline showing the author's + name, the institution, the presentation's title, the current date, + and a frame count. This theme uses only little space. + + The colors used in the headline and footline are drawn from + |palette primary|, |palette secondary|, and |primary tertiary| (see + Section~\ref{section-colors} for details on how to change these). +\end{outerthemeexample} + +\begin{outerthemeexample}[\oarg{options}]{miniframes} + This theme installs a headline in which a horizontal navigational + bar is shown. This bar contains one entry for each section of the + presentation. Below each section entry, small circles are shown that + represent the different frames in the section. The frames are + arranged subsection-wise, that is, there is a line of frames for + each subsection. If the class option |compress| is given, the + frames will instead be arranged in a single row for each + section. The navigation bars draws its color from + |section in head/foot|. + + Below the navigation bar, a line is put showing the title of the + current subsection. The color is drawn from |subsection in head/foot|. + + At the bottom, two lines are put that contain information such as + the author's name, the institution, or the paper's title. What is + shown exactly is influenced by the \meta{options} given. The colors + are drawn from the appropriate \beamer-colors like + |author in head/foot|. + + At the top and bottom of both the head- and footline and between the + navigation bar and the subsection name, separation lines are drawn + \emph{if} the background color of |separation line| is set. This + separation line will have a height of 3pt. You can get even more + fine-grained control over the colors of the separation lines by + setting appropriate colors like |lower separation line head|. + + The following \meta{options} can be given: + \begin{itemize} + \item \declare{|footline=empty|} suppressed the footline (default). + \item \declare{|footline=authorinstitute|} shows the author's name + and the institute in the footline. + \item \declare{|footline=authortitle|} shows the author's name + and the title in the footline. + \item \declare{|footline=institutetitle|} shows the institute + and the title in the footline. + \item \declare{|footline=authorinstitutetitle|} shows the author's + name, the institute, and the title in the footline. + \item \declare{|subsection=|\meta{true or false}} shows or suppresses + line showing the subsection in the headline. It is shown by + default. + \end{itemize} +\end{outerthemeexample} + +\begin{outerthemeexample}[\oarg{options}]{smoothbars} + This theme behaves very much like the |miniframes| theme, at least + with respect to the headline. There, the only difference is the + smooth transitions are installed between the background colors of + the navigation bar, the (optional) bar for the subsection name, and + the background of the frame title. No footline is created. You can + get the footlines of the |miniframes| theme by first loading the + theme and then loading the |smoothbars| theme. + + The following \meta{options} can be given: + \begin{itemize} + \item \declare{|subsection=|\meta{true or false}} shows or suppresses + line showing the subsection in the headline. It is shown by + default. + \end{itemize} +\end{outerthemeexample} + +\begin{outerthemeexample}[\oarg{options}]{sidebar} + In this layout, a sidebar is shown that contains a small table of + contents with the current section, subsection, or subsection hilighted. The + frame title is vertically centered in a rectangular area at the top + that always occupies the same amount of space in all + frames. Finally, the logo is shown in the ``corner'' resulting from + the sidebar and the frame title rectangle. + + There are several ways of modifying the layout using the + \meta{options}. If you set the width of the sidebar to 0pt, it is + not shown, giving you a layout in which the frame title does not + ``wobble'' since it always occupies the same amount of space on all + slides. Conversely, if you set the height of the frame title + rectangle to 0pt, the rectangular area is not used and the frame + title is inserted normally (occupying as much space as needed on + each slide). + + The background color of the sidebar is taken from |sidebar|, the + background color of the frame title from |frametitle|, and the + background color of the logo corner from |logo|. + + The colors of the entries in the table of contents are drawn from + the \beamer-color |section in sidebar| and |section in sidebar current| as well as the + corresponding \beamer-colors for subsections. If an entry does not + fit on a single line it is automatically ``linebroken.'' + + The following \meta{options} may be given: + \begin{itemize} + \item + \declare{|height=|\meta{dimension}} specifies the height of the + frame title rectangle. If it is set to 0pt, no frame title + rectangle is created. Instead, the frame title is inserted + normally into the frame. The default is 2.5 base line heights of + the frame title font. Thus, there is about enough space for a + two-line frame title plus a one-line subtitle. + \item + \declare{|hideothersubsections|} causes all subsections except + those of the current section to be suppressed in the table of + contents. This is useful if you have lots of subsections. + \item + \declare{|hideallsubsections|} causes all subsections to be + suppressed in the table of contents. + \item + \declare{|left|} puts the sidebar on the left side. Note that in a + left-to-right reading culture this is the side people look first. Note + also that this table of contents is usually \emph{not} the most + important part of the frame, so you do not necessarily want people + to look at it first. Nevertheless, it is the default. + \item + \declare{|right|} puts the sidebar of the right side. + \item + \declare{|width=|\meta{dimension}} specifies the width of the + sidebar. If it is set to 0pt, it is completely suppressed. The + default is 2.5 base line heights of the frame title font. + \end{itemize} +\end{outerthemeexample} + +\begin{outerthemeexample}{split} + This theme installs a headline in which, on the left, the sections + of the talk are shown and, on the right, the subsections of the + current section. If the class option |compress| has been given, + the sections and subsections will be put in one line; normally there + is one line per section or subsection. + + The footline shows the author on the left and the talk's title on + the right. + + The colors are taken from |palette primary| and |palette fourth|. +\end{outerthemeexample} + +\begin{outerthemeexample}{shadow} + This layout theme extends the |split| theme by putting a horizontal + shading behind the frame title and adding a little ``shadow'' at the + bottom of the headline. +\end{outerthemeexample} + +\begin{outerthemeexample}[\oarg{options}]{tree} + In this layout, the headline contains three lines that show the + title of the current talk, the current section in this talk, and the + current subsection in the section. The colors are drawn from + |title in head/foot|, |section in head/foot|, and + |subsection in head/foot|. + + In addition, separation lines of height 3pt are shown above and + below the three lines \emph{if} the background of |separation line| + is set. More fine-grained control of the colors of these lines can + be gained by setting |upper separation line head| and + |lower separation line head|. + + The following \meta{options} may be given: + \begin{itemize} + \item + \declare{|hooks|} causes little ``hooks'' to be drawn in front of + the section and subsection entries. These are supposed to increase + the tree-like appearance. + \end{itemize} +\end{outerthemeexample} + +\begin{outerthemeexample}{smoothtree} + This layout is similar to the |tree| layout. The main difference is + that the background colors change smoothly. +\end{outerthemeexample} + + + + + +\subsection{Changing the Templates Used for Different Elements of a Presentation} + +\label{section-templates} + +This section explains how \beamer's template management works. + + + +\subsubsection{Overview of Beamer's Template Management} + +If you only wish to modify the appearance of a single or few elements, +you do not need to create a whole new inner or outer theme. Instead, +you can modify the appropriate template. + +A template specifies how an element of a presentation is typeset. For +example, the |frametitle| template dictates where the frame title is +put, which font is used, and so on. + +As the name suggests, you specify a template by writing the exact +\LaTeX\ code you would also use when typesetting a single frame title +by hand. Only, instead of the actual title, you use the command +|\insertframetitle|. + +\example +Suppose we would like to have the frame title typeset in +red, centered, and boldface. If we were to typeset a single frame +title by hand, it might be done like this: +\begin{verbatim} +\begin{frame} + \begin{centering} + \color{red} + \textbf{The Title of This Frame.} + \par + \end{centering} + + Blah, blah. +\end{frame} +\end{verbatim} + +In order to typeset the frame title in this way on all slides, in the +simplest case we can change the frame title template as follows: +\begin{verbatim} +\setbeamertemplate{frametitle} +{ + \begin{centering} + \color{red} + \textbf{\insertframetitle} + \par + \end{centering} +} +\end{verbatim} + +We can then use the following code to get the desired effect: +\begin{verbatim} +\begin{frame} + \frametitle{The Title of This Frame.} + + Blah, blah. +\end{frame} +\end{verbatim} +When rendering the frame, \beamer\ will use the code of the +frame title template to typeset the frame title and it will replace +every occurrence of |\insertframetitle| by the current frame +title. + +We can take this example a step further. It would be nicer if we did +not have to ``hardwire'' the color of the frametitle, but if this +color could be specified independently of the code for the +template. This way, a color theme could change this color. Since this +a problem that is common to most templates, \beamer\ will +automatically setup the \beamer-color |frametitle| when the template +|frametitle| is used. Thus, we can remove the |\color{red}| command if +we set the \beamer-color |frametitle| to red at some point. +\begin{verbatim} +\setbeamercolor{frametitle}{fg=red} +\setbeamertemplate{frametitle} +{ + \begin{centering} + \textbf{\insertframetitle} + \par + \end{centering} +} +\end{verbatim} +Next, we can also make the font ``themable.'' Just like the color, the +\beamer-font |frametitle| is installed before the |frametitle| +template is typeset. Thus, we should rewrite the code as follows: +\begin{verbatim} +\setbeamercolor{frametitle}{fg=red} +\setbeamerfont{frametitle}{series=\bfseries} +\setbeamertemplate{frametitle} +{ + \begin{centering} + \insertframetitle\par + \end{centering} +} +\end{verbatim} +Users, themes, or whoever can now easily change the color or font of +the frametitle without having to mess with the code used to typeset +it. + +\articlenote +In |article| mode, most of the template mechanism is switched off and +has no effect. However, a few templates are also available. If this is +the case, it is specially indicated. +\smallskip + +Here are a few hints that might be helpful when you wish to set a +template: +\begin{itemize} +\item + Usually, you might wish to copy code from an existing template. The + code often takes care of some things that you may not yet have + thought about. The default inner and outer themes might be useful + starting points. Also, the file |beamerbaseauxtemplates.sty| + contains interesting ``auxilliary'' templates. +\item + When copying code from another template and when inserting this code + in the preamble of your document (not in another style file), you may + have to ``switch on'' the at-character (|@|). To do so, add the + command |\makeatletter| before the |\setbeamertemplate| command and the + command |\makeatother| afterward. +\item + Most templates having to do with the frame components (headlines, + sidebars, etc.)\ can only be changed in the preamble. Other + templates can be changed during the document. +\item + The height of the headline and footline templates is calculated + automatically. This is done by typesetting the templates and then + ``having a look'' at their heights. This recalculation is done right + at the beginning of the document, \emph{after} all packages have + been loaded and even \emph{after} these have executed their + |\AtBeginDocument| initialization. +\item + Getting the boxes right inside any template is often a bit of a + hassle. You may wish to consult the \TeX\ book for the glorious + details on ``Making Boxes.'' If your headline is simple, you might + also try putting everything into a |pgfpicture| environment, which + makes the placement easier. +\end{itemize} + + + + +\subsubsection{Using Beamer's Templates} + +As a user of the \beamer\ class you typically do not ``use'' or +``invoke'' templates yourself, directly. For example, the frame title +template is automatically invoked by \beamer\ somewhere deep inside +the frame typesetting process. The same is true of most other +templates. However, if, for whatever reason, you wish to invoke a +template yourself, you can use the following command. + +\begin{command}{\usebeamertemplate\opt{|***|}\marg{element name}} + If none of the stars is given, the text of the \meta{element name} + is directly inserted at the current position. This text should + previously have been specified using the |\setbeamertemplate| + command. No text is inserted if this command has not been called + before. + \example +\begin{verbatim} +\setbeamertemplate{my template}{correct} +... +Your answer is \usebeamertemplate{my template}. +\end{verbatim} + + If you add one star, three things happen. First, the template is put + inside a \TeX-group, thereby limiting most side effects of commands + used inside the template. Second, inside this group the + \beamer-color named \meta{element name} is used and the foreground + color is selected. Third, the \beamer-font \meta{element name} is + also used. This one-starred version is usually the best version to + use. + + If you add a second star, nearly the same happens as with only one + star. However, in addition, the color is used with the command + |\setbeamercolor*|. This causes the colors to be reset to the normal + text color if no special foreground or background is specified by + the \beamer-color \meta{element name}. Thus, in this twice-starred + version, the color used for the template is guaranteed to be + independent of the color that was currently in use when the template + is used. + + Finally, adding a third star will also cause a star to be added to + the |\setbeamerfont*| command. This causes the font used for the + template also to be reset to normal text, unless the \beamer-font + \meta{element name} specifies things differently. This three-star + version is the ``most protected'' version available. +\end{command} + +\begin{command}{\ifbeamertemplateempty\marg{beamer template + name}\marg{executed if empty}\marg{executed otherwise}} + This command checks whether a template is defined and set to a + non-empty text. If the text is empty or the template is not + defined at all, \meta{executed if empty} is executed. Otherwise, + \meta{executed otherwise} is executed. +\end{command} + +\begin{command}{\expandbeamertemplate\marg{beamer template name}} + This command does the same as |\usebeamertemplate|\marg{beamer + template name}. The difference is that this command performs a + direct expansion and does not scan for a star. This is important + inside, for example, an |\edef|. If you don't know the difference + between |\def| and |\edef|, you won't need this command. +\end{command} + +\subsubsection{Setting Beamer's Templates} + +To set a \beamer-template, you can use the following command: + +\begin{command}{\setbeamertemplate\marg{element name}\oarg{predefined option}\meta{args}} + In the simplest case, if no \meta{predefined option} is given, the + \meta{args} must be a single argument and the text of the template + \meta{element name} is setup to be this text. Upon later invocation + of the template by the command |\usebeamertemplate| this text is + used. + + \example +\begin{verbatim} +\setbeamertemplate{answer}{correct} +... +Your answer is \usebeamertemplate*{answer}. +\end{verbatim} + + If you specify a \meta{predefined option}, this command behaves + slightly differently. In this case, someone has used the command + |\defbeamertemplate| to predefined a template for you. By giving the + name of this predefined template as the optional parameter + \meta{predefined option}, you cause the template \meta{element name} + to be set to this template. + + \example |\setbeamertemplate{bibliography item}[book]| causes the + bibliography items to become little book icons. This command cause a + subsequent call of |\usebeamertemplate{bibliography item}| to insert + the predefined code for inserting a book. + + Some predefined template options take parameters themselves. In such + a case, the parameters are given as \meta{args}. + + \example + The \meta{predefined option} |grid| for the template |background| + takes an optional argument: +\begin{verbatim} +\setbeamertemplate{background}[grid][step=1cm] +\end{verbatim} + In the example, the second argument in square brackets is the + optional argument. + + In the descriptions of elements, if there are possible + \meta{predefined option}, the description shows how the + \meta{predefined option} can be used together with its arguments, + but the |\setbeamertemplate{xxxx}| is omitted. Thus, the above + example would be documented in the description of the |background| + element like this: + \begin{itemize} + \itemoption{grid}{\oarg{step options}} causes a light grid to be + \dots + \end{itemize} +\end{command} + +\begin{command}{\addtobeamertemplate\marg{element + name}\marg{pre-text}\marg{post-text}} + This command adds the \meta{pre-text} before the text that is + currently installed as the template \meta{element name} and the + \meta{post-text} after it. This allows you a limited form of + modification of existing templates. + + \example The following commands have the same effect: +\begin{verbatim} +\setbeamertemplate{my template}{Hello world!} + +\setbeamertemplate{my template}{world} +\addtobeamertemplate{my template}{Hello }{!} +\end{verbatim} + + If a new template is installed, any additions will be deleted. On + the other hand, you can repeatedly use this command to add multiple + things. +\end{command} + +\begin{command}{\defbeamertemplate\sarg{mode specification}\opt{|*|}% + \marg{element name}\marg{predefined option}\\ + \oarg{argument number}\oarg{default optional argument}\marg{predefined + text}\\ + \opt{|[action]|\marg{action command}}} + This command installs a \emph{predefined option} for the template + \meta{element name}. Once this command has been used, users can + access the predefined template using the |\setbeamertemplate| + command. + + \example + |\defbeamertemplate{itemize item}{double arrow}{$\Rightarrow$}| + + After the above command has been invoked, the following two commands + will have the same effect: +\begin{verbatim} +\setbeamertemplate{itemize item}{$\Rightarrow$} +\setbeamertemplate{itemize item}[double arrow] +\end{verbatim} + + Sometimes, a predefined template needs to get an argument when it is + installed. Suppose, for example, we want to define a predefined + template that draws a square as the itemize item and we want to make + this size of this square configurable. In this case, we can specify + the \meta{argument number} of the predefined option the same way one + does for the |\newcommand| command: + +\begin{verbatim} +\defbeamertemplate{itemize item}{square}[1]{\hrule width #1 height #1} + +%% The following have the same effect: +\setbeamertemplate{itemize item}[square]{3pt} +\setbeamertemplate{itemize item}{\hrule width 3pt height 3pt} +\end{verbatim} + + As for the |\newcommand| command, you can also specify a + \meta{default optional argument}: + +\begin{verbatim} +\defbeamertemplate{itemize item}{square}[1][1ex]{\hrule width #1 height #1} + +%% The following have the same effect: +\setbeamertemplate{itemize item}[square][3pt] +\setbeamertemplate{itemize item}{\hrule width 3pt height 3pt} + +%% So do the following: +\setbeamertemplate{itemize item}[square] +\setbeamertemplate{itemize item}{\hrule width 1ex height 1ex} +\end{verbatim} + + The starred version of the command installs the predefined template + option, but then immediately calls |\setbeamertemplate| for this + option. This is useful for the default templates. If there are any + arguments necessary, these are set to |\relax|. + + In certain cases, if a predefined template option is chosen, you do + not only wish the template text to be installed, but certain extra + ``actions'' must also be taken once. For example, a shading must be + defined that should not be redefined every time the shading is used + later on. To implement such ``actions,'' you can use the optional + argument \meta{action} following the keyword |[action]|. Thus, after + the normal use of the |\defbeamertemplate| you add the text + |[action]| and then any commands that should be executed once when + the \meta{predefined option} is selected by the |\setbeamertemplate| + command. + + \example +\begin{verbatim} +\defbeamertemplate{background canvas}{my shading}[2] +{ + \pgfuseshading{myshading}% simple enough +} +[action] +{ + \pgfdeclareverticalshading{myshading}{\the\paperwidth} + {color(0cm)=(#1); color(\the\paperheight)=(#2)} +} +... + +\setbeamertemplate{background canvas}{myshading}{red!10}{blue!10} +%% Defines the shading myshading right here. Subsequent calls to +%% \usebeamertemplate{background canvas} will yield +%% ``\pgfuseshading{myshading}''. +\end{verbatim} + + \articlenote + Normally, this command has no effect in |article| mode. However, if + a \meta{mode specification} is given, this command is applied for + the specified modes. Thus, this command behaves like the |\\| + command, which also gets the implicit mode specification + |<presentation>| if no other specification is given. + + \example |\defbeamertemplate{my template}{default}{something}| has no effect + in |article| mode. + + \example |\defbeamertemplate<article>{my template}{default}{something}| has + no effect in |presentation| modes, but has an effect in |article| + mode. + + \example |\defbeamertemplate<all>{my template}{default}{something}| applies + to all modes. +\end{command} + +It is often useful to have access to the same template option via +different names. For this, you can use the following command to create +aliases: +\begin{command}{\defbeamertemplatealias\marg{element name}\marg{new + predefined option name}\marg{existing predefined option name}} + Causes the two predefined options to have the same effect. +\end{command} + +There is no inheritance relation among templates as there is for +colors and fonts. This is due to the fact the templates for one +element seldom make sense for another. However, sometimes certain +elements ``behave similarly'' and one would like a +|\setbeamertemplate| to apply to a whole set of templates via +inheritance. For example, one might want that +|\setbeamertemplate{items}[circle]| causes all items to use the +|circle| option, though the effects for the |itemize item| as opposed +to the |itemize subsubitem| as opposed to |enumerate item| must be +slightly different. + +The \beamer-template mechanism implements a simple form of inheritance +via \emph{parent templates}. In element descriptions, parent templates +are indicated via a check mark in parentheses. + +\begin{command}{\defbeamertemplateparent\marg{parent template +name}\oarg{predefined option name}\marg{child template +list}\\ +\oarg{argument number}\oarg{default optional +argument}\marg{arguments for children}} + The effect of this command is that whenever someone calls + |\setbeamertemplate{|\meta{parent template name}|}{|\meta{args}|}|, + the command |\setbeamertemplate{|\meta{child template + name}|}{|\meta{args}|}| is called for each \meta{child + template name} in the \meta{child template list}. + + The \meta{arguments for children} come into play if the + |\setbeamertemplate| command is called with a predefined option name + (not necessarily the same as the \meta{predefined option name}, + we'll come to that). If |\setbeamertemplate| is called with some + predefined option name, the children are called with the + \meta{arguments for children} instead. Let's look at two examples: + + \example The following is the typical, simple usage: +\begin{verbatim} +\defbeamertemplateparent{itemize items}{itemize item,itemize subitem,itemize subsubitem} +{} + +%% The following command has the same effect as the three commands below: +\setbeamertemplate{itemize items}[circle] + +\setbeamertemplate{itemite item}[circle] % actually, the ``empty'' argument is added +\setbeamertemplate{itemize subitem}[circle] +\setbeamertemplate{itemize subsubitem}[circle] +\end{verbatim} + + \example In the following case, an argument is passed to the + children: +\begin{verbatim} +\defbeamertemplateparent{sections/subsections in toc shaded} +{section in toc shaded,subsection in toc shaded}[1][20] +{[#1]} + +%% The following command has the same effect as the two commands below: +\setbeamertemplate{sections/subsection in toc shaded}[default][35] + +\setbeamertemplate{section in toc shaded}[default][35] +\setbeamertemplate{subsection in toc shaded}[default][35] + + +%% Again: +\setbeamertemplate{sections/subsection in toc shaded}[default] + +\setbeamertemplate{section in toc shaded}[default][20] +\setbeamertemplate{subsection in toc shaded}[default][20] +\end{verbatim} + + In detail, the following happens: When |\setbeamertemplate| is + encountered for a parent template, \beamer\ first checks whether a + predefined option follows. If not, a single argument is read and + |\setbeamertemplate| is called for all children for this + template. If there is a predefined template option set, \beamer\ + evaluates the \meta{argument for children}. It may contain + parameters like |#1| or |#2|. These parameters are filled with the + arguments that follow the call of |\setbeamertemplate| for the + parent template. The number of arguments must be the number given + as \meta{argument number}. An optional argument can also be + specified in the usual way. Once the \meta{arguments for the + children} have been computed, |\setbeamertemplate| is called for all + children for the predefined template and with the computed + arguments. + + You may wonder what happens when certain predefined options take a + certain number of arguments, but another predefined option takes a + different number of arguments. In this case, the above-described + mechanism cannot differentiate between the predefined options and it + is unclear which or even how many arguments should be contained in + \meta{arguments for children}. For this reason, you can give the + optional argument \meta{predefined option name} when calling + |\defbeamertemplateparent|. If this optional argument is specified, + the parenthood of the template applies only to this particular + \meta{predefined option name}. Thus, if someone calls + |\setbeamertemplate| for this \meta{predefined option name}, the + given \meta{argument for children} is used. For other predefined + option names a possibly different definition is used. You can + imaging that leaving out the optional \meta{predefined option name} + means ``this \meta{argument for children} applies to all predefined + option names that have not been specially defined differently.'' +\end{command} + + + + + +%%% Local Variables: +%%% mode: latex +%%% TeX-master: "beameruserguide" +%%% End: |