067-graphics-options.Rnw

\documentclass{article}
\usepackage{float}    % for fig.pos='H'
\usepackage{rotfloat} % for sidewaysfigure
%\usepackage{subfig}   % for subfigure
\usepackage{subcaption}  % an alternative package for sub figures
\newcommand{\subfloat}[2][need a sub-caption]{\subcaptionbox{#1}{#2}}

\title{Graphics Options in knitr}
\author{Yihui Xie}
\begin{document}
\maketitle

<<setup, include=FALSE>>=
library(knitr)
opts_chunk$set(fig.width=4, fig.height=3, par=TRUE, out.width='2in', fig.pos='H')
knit_hooks$set(par = function(before, options, envir) {
  if (before) par(mar = c(4, 4, .1, .1))
})
set.seed(123)
@

These options are vectorized for multiple plots per chunk: \Sexpr{knitr:::.recyle.opts}.
When the plot hook is called, the i-th elements of these options will be
applied to the i-th plot.

Figure captions. Look at Figure \ref{fig:fig-cap-1} and \ref{fig:fig-cap-2}.

<<fig-cap, fig.cap=c('One plot.', 'Another plot.')>>=
par(bg=rgb(runif(1), runif(1), runif(1)))
plot(1:10)
plot(rnorm(10), pch=19)
@

Different out.width and out.height.

<<fig-out, ref.label='fig-cap', out.width=c('1in', '.4\\linewidth')>>=
@

Different out.extra (rotate by different degrees).

<<fig-extra, ref.label='fig-cap', out.extra=sprintf('angle=%d', c(30,120))>>=
@

Short options will be recycled: out.width below is of length 1 but there are
two plots.

<<fig-width, ref.label='fig-cap', out.width='1in'>>=
@

Use subfigures for each plot. Look at Figure \ref{fig:fig-sub-1} and \ref
{fig:fig-sub-2}. By default, knitr uses the \textbf{subfig} package, but it
has a few shortcomings, so some people prefer the \textbf{subcaption}
package. In that case, we can simply redefine the \verb|\subfloat| command;
see the preamble of this document for an example. We are actually using the
\textbf{subcaption} package in this document.

<<fig-sub, ref.label='fig-cap', fig.cap='two plots', fig.subcap=c('one plot', 'the other one'), out.width='.49\\linewidth'>>=
@

The second figure uses sidewaysfigure (i.e. Figure \ref{fig:fig-margin-2}).

<<fig-margin, ref.label='fig-cap', fig.cap=c('ordinary figure', 'sideways figure'), fig.env=c('figure', 'sidewaysfigure')>>=
@

\end{document}