Knitr, ggplot and consistent fonts

-----Original Message-----
From: daniel.haugstvedt at gmail.com
Sent: Sun, 22 Dec 2013 12:42:50 +0100
To: r-help at r-project.org
Subject: [R] Knitr, ggplot and consistent fonts

Dear R-help

I am using Knitr and ggplot to draft an article and have now started 
to improve on the layout and graphics. So far I have not been able to 
maintain the same font size for labels in all my figures.

My goal is to be able to change the width of the figures while 
maintaining the same font. This works for the height parameter 
(example not included).

In the true document I also use tikz, but the problem can be 
reproduced without it.

I know the question is very specific, but my understanding is that 
this combination of packages  is common. (They are really great. Keep 
up the good work.)  There has to be others facing the same problem and 
someone must have found a nice solution.

Additional attempts from my side which failed are not included in the 
example. I have tested the Google results i could find without any luck.

Cheers
Daniel

PS. I know the example plots could have been smaller, but they just 
became too ugly for me


\documentclass{article}
\begin{document}

<<setup, include=FALSE, cache=FALSE>>=
library(knitr)
library(ggplot2)
@

\title{Knitr and ggplot2}
\author{Daniel Haugstvedt}

\maketitle

There are four plots in this article. Figure \ref{fig:plot-figHeight} 
uses the argument fig.height=2.5 while Figures \ref{fig:plot-figWidth} 
used both fig.height=2.5 and fig.width=3. The later option makes the 
font too big.

An alternative approach is used in Figures  
\ref{fig:plot-figOutWidthBig} and  \ref{fig:plot-figOutWidthSmall}. 
There the argument out.width is set to
 12 and 8 cm respectively. This stops the problem of excessively large 
fonts  for figures with smaller width, but there is still no 
consistency  across plots in terms of font size.

<<plot-figHeight, echo=FALSE, fig.height=2.5, fig.cap="Density plot 
with no fig.width argument", fig.pos='ht'>>= df = data.frame(x = 
rnorm(100), y = 1:100) ggplot(df, aes(x = x)) +
  geom_histogram(aes(y = ..density..),
                 binwidth = 1, colour = "black", fill = "white") +
  xlab("Improvement, %") +
  ylab("Density") +
  theme_classic()
@

<<plot-figWidth, echo=FALSE, fig.height=2.5, fig.width = 3, 
fig.cap="Density plot with fig.width=3", fig.pos='ht'>>= ggplot(df, 
aes(x = x)) +
  geom_histogram(aes(y = ..density..),
                 binwidth = 1, colour = "black", fill = "white") +
  xlab("Improvement, %") +
  ylab("Density") +
  theme_classic()
@

<<plot-figOutWidthBig, echo=FALSE, fig.height=2.5, out.width = "12cm", 
fig.cap="Density plot with out.width=12cm", fig.pos='ht'>>= ggplot(df, 
aes(x = x)) +
  geom_histogram(aes(y = ..density..),
                 binwidth = 1, colour = "black", fill = "white") +
  xlab("Improvement, %") +
  ylab("Density") +
  theme_classic()
@

<<plot-figOutWidthSmall, echo=FALSE, fig.height=2.5, out.width = 
"8cm", fig.cap="Density plot with out.width=8cm", fig.pos='ht'>>= 
ggplot(df, aes(x = x)) +
  geom_histogram(aes(y = ..density..),
                 binwidth = 1, colour = "black", fill = "white") +
  xlab("Improvement, %") +
  ylab("Density") +
  theme_classic()
@

\end{document}

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