ggplot2, change title size

Question

I would like to have my main title and axis title have the same font size as the annotated text in my plot.

i used theme_get() and found that text size is 12, so I did that in my theme statement - this did not work. I also tried to send the relative size to 1, and this did not work

I was hoping someone could please help me.

Code is below

library(ggplot2)
library(gridExtra)  #to set up plot grid
library(stringr)  #string formatting functions
library(plyr)  #rbind.fill function
library(reshape2)  #transformation of tables

dat<-data.frame(
est=c(2.75,2.95,2.86,2.99),
ucl=c(2.92,3.23,3.38,4.91),
lcl=c(2.24,1.67,2.44,1.82),
ord=c(1,2,1,2)
)
dat$varname<-c('Estimate','Predictive','Estimate','Predictive')
dat$grp<-c('Cobalt','Cobalt','Chromium','Chromium')

for (i in unique(dat$grp)) {
  dat <- rbind.fill(dat, data.frame(grp = i, ord=0,
                                    stringsAsFactors = F))
}

dat$grp_combo <- factor(paste(dat$grp, dat$ord, sep = ", "))
dat$grpN <- as.numeric(dat$grp_combo)



rng <- c(0,6)
scale.rng <-1


xstart=-(max(dat$grpN)+2)
xend=4


ThemeMain<-theme(legend.position = "none", plot.margin = unit(c(0,0,0, 0), "npc"), 
                 panel.margin = unit(c(0,0, 0, 0), "npc"), 
                 title =element_text(size=12, face='bold'),
                 axis.text.y = element_blank(), 
                 axis.text.x = element_text(color='black'),
                 axis.ticks.y = element_blank(),
                 axis.title.x = element_text(size=12,color='black',face='bold')
                 )
BlankSettings <- theme(legend.position = "none", 
                       title =element_text(size=12, face='bold'),
                       plot.margin = unit(c(0,0, 0, 0), "npc"), 
                       panel.margin = unit(c(0,0, 0, 0), "npc"),              
                       axis.text.x = element_text(color='white'),                             
                       axis.text.y = element_blank(), 
                       axis.ticks.x = element_line(color = "white"),
                       axis.ticks.y=element_blank(),
                       axis.title.x = element_text(size=12,color='white',face='bold'),
                       panel.grid = element_blank(),panel.grid.major = element_blank(),panel.background = element_blank()
                       )

pd <- position_dodge(width = 0.7)

#######################################################################################################
#MAIN PLOT
#######################################################################################################
mainPart<-
  ggplot(dat, aes(x=-grpN,y=est, ymin=lcl, ymax=ucl, group=1)) +
  scale_y_continuous(name=NULL, breaks=seq(rng[1], rng[2], scale.rng), limits=c(rng[1], rng[2]), expand=c(0,0)) + 
  ylab('Ion Concentration') +
  ggtitle('Mean with 95% HDI')+
  #geom_segment(aes(x=xstart, xend=0, y=0, yend=0), linetype=3, alpha=0.01) +
  geom_linerange(aes(linetype="1"),position=pd) +
  geom_point(aes(shape="1"), fill="white",position=pd) +
  coord_flip() +
  scale_x_continuous(limits=c(xstart,xend), expand=c(0,0))+xlab(NULL)+
  ThemeMain

#######################################################################################################
#varnameS
#######################################################################################################
# ystart & yend are arbitrary. [0, 1] is
# convinient for setting relative coordinates of
# columns
ystart = 0
yend = 1
p1 <- 
  ggplot(dat, aes(x = -varnameN, y = 0)) + 
  coord_flip() + 
  scale_y_continuous(limits = c(ystart, yend)) + 
  BlankSettings+
  scale_x_continuous(limits = c(xstart, xend), expand = c(0, 0)) + 
  xlab(NULL) + 
  ylab('') +
  ggtitle('')

studyList<-
  p1 + 
  with(unique(dat[is.na(dat$varname),c("grpN","grp")]), annotate("text",label=grp, x=-grpN,y=0, fontface='bold', hjust=0)) + #Variable Group varnames
  with(dat[!is.na(dat$var),],annotate("text",label=varname,x=-grpN,y=0.04, hjust=0))  #Variables

#######################################################################################################
#EFFECTS
#######################################################################################################
f<-function(x) round(x,2)
dat$msmt<-paste(f(dat$est),' [',f(dat$lcl),', ',f(dat$ucl),']',sep='')


effectSizes<-p1+
  annotate("text",x=-dat$grpN, y=0.25,label=ifelse(is.na(dat$varname)==T,'',dat$msmt))



grid.arrange(ggplotGrob(studyList), ggplotGrob(mainPart), 
             ggplotGrob(effectSizes), ncol = 3, widths = unit(c(0.19, 
                                                                 0.4, 0.41), "npc"))

Alleras

@TrynnaDoStat was faster than me, so I will add my answer as a comment. I think that you need to use plot.title parameter instead of just title in your theme() call. Should you want to change the font type, you can do that via family parameter (may not work on all platforms, though). – Refrigerator

Answer 1

+ theme(plot.title = element_text(size=22))

Here is the full set of things you can change in element_text:

element_text(family = NULL, face = NULL, colour = NULL, size = NULL,
  hjust = NULL, vjust = NULL, angle = NULL, lineheight = NULL,
  color = NULL)

Heaps

Answer 2

Using the theme with plot.title is the easiest way. But there is another option using ggtext which provides Markdown (element_markdown) and HTML rendering for ggplot2. So you can use HTML tags to change the "font-size" of the title for example. The advantage of this is that you can change parts of title easily, so you can give certain parts of the title a different font-size or colors using HTML tags.

Here is a reproducible example:

library(ggplot2)
library(ggtext)
# font size using html
ggplot(mtcars, aes(x = cyl)) +
  geom_bar() +
  ggtitle("<span style='font-size: 22pt;'>This is bigger text</font>") +
  theme(plot.title = element_markdown())

# Change parts of title font size 
ggplot(mtcars, aes(x = cyl)) +
  geom_bar() +
  ggtitle("<span style='font-size: 22pt;'>This is bigger text,</font>
          <span style='font-size: 10pt;'>This is smaller text.</font>") +
  theme(plot.title = element_markdown())

^{Created on 2022-08-24 with reprex v2.0.2}

As you can see, the title has two different font-sizes. For extra information and examples you can check the link above.

Notarial