Set theme elements

Usage

theme(..., complete = FALSE, validate = TRUE)

Arguments

...
a list of element name, element pairings that modify the existing theme.
complete
set this to TRUE if this is a complete theme, such as the one returned by theme_grey(). Complete themes behave differently when added to a ggplot object.
validate
TRUE to run validate_element, FALSE to bypass checks.

Description

Use this function to modify theme settings.

Details

Theme elements can inherit properties from other theme elements. For example, axis.title.x inherits from axis.title, which in turn inherits from text. All text elements inherit directly or indirectly from text; all lines inherit from line, and all rectangular objects inherit from rect.

For more examples of modifying properties using inheritance, see +.gg and %+replace%.

To see a graphical representation of the inheritance tree, see the last example below.

Theme elements

The individual theme elements are:

line
all line elements (element_line)
rect
all rectangular elements (element_rect)
text
all text elements (element_text)
title
all title elements: plot, axes, legends (element_text; inherits from text)
aspect.ratio
aspect ratio of the panel

axis.title

label of axes (element_text; inherits from text)
axis.title.x
x axis label (element_text; inherits from axis.title)
axis.title.y
y axis label (element_text; inherits from axis.title)
axis.text
tick labels along axes (element_text; inherits from text)
axis.text.x
x axis tick labels (element_text; inherits from axis.text)
axis.text.y
y axis tick labels (element_text; inherits from axis.text)
axis.ticks
tick marks along axes (element_line; inherits from line)
axis.ticks.x
x axis tick marks (element_line; inherits from axis.ticks)
axis.ticks.y
y axis tick marks (element_line; inherits from axis.ticks)
axis.ticks.length
length of tick marks (unit)
axis.line
lines along axes (element_line; inherits from line)
axis.line.x
line along x axis (element_line; inherits from axis.line)
axis.line.y
line along y axis (element_line; inherits from axis.line)

legend.background

background of legend (element_rect; inherits from rect)
legend.margin
extra space added around legend (unit)
legend.key
background underneath legend keys (element_rect; inherits from rect)
legend.key.size
size of legend keys (unit; inherits from legend.key.size)
legend.key.height
key background height (unit; inherits from legend.key.size)
legend.key.width
key background width (unit; inherits from legend.key.size)
legend.text
legend item labels (element_text; inherits from text)
legend.text.align
alignment of legend labels (number from 0 (left) to 1 (right))
legend.title
title of legend (element_text; inherits from title)
legend.title.align
alignment of legend title (number from 0 (left) to 1 (right))
legend.position
the position of legends ("none", "left", "right", "bottom", "top", or two-element numeric vector)
legend.direction
layout of items in legends ("horizontal" or "vertical")
legend.justification
anchor point for positioning legend inside plot ("center" or two-element numeric vector)
legend.box
arrangement of multiple legends ("horizontal" or "vertical")
legend.box.just
justification of each legend within the overall bounding box, when there are multiple legends ("top", "bottom", "left", or "right")

panel.background

background of plotting area, drawn underneath plot (element_rect; inherits from rect)
panel.border
border around plotting area, drawn on top of plot so that it covers tick marks and grid lines. This should be used with fill=NA (element_rect; inherits from rect)
panel.margin
margin around facet panels (unit)
panel.margin.x
horizontal margin around facet panels (unit; inherits from panel.margin)
panel.margin.y
vertical margin around facet panels (unit; inherits from panel.margin)
panel.grid
grid lines (element_line; inherits from line)
panel.grid.major
major grid lines (element_line; inherits from panel.grid)
panel.grid.minor
minor grid lines (element_line; inherits from panel.grid)
panel.grid.major.x
vertical major grid lines (element_line; inherits from panel.grid.major)
panel.grid.major.y
horizontal major grid lines (element_line; inherits from panel.grid.major)
panel.grid.minor.x
vertical minor grid lines (element_line; inherits from panel.grid.minor)
panel.grid.minor.y
horizontal minor grid lines (element_line; inherits from panel.grid.minor)
panel.ontop
option to place the panel (background, gridlines) over the data layers. Usually used with a transparent or blank panel.background. (logical)

plot.background

background of the entire plot (element_rect; inherits from rect)
plot.title
plot title (text appearance) (element_text; inherits from title)
plot.margin
margin around entire plot (unit with the sizes of the top, right, bottom, and left margins)

strip.background

background of facet labels (element_rect; inherits from rect)
strip.text
facet labels (element_text; inherits from text)
strip.text.x
facet labels along horizontal direction (element_text; inherits from strip.text)
strip.text.y
facet labels along vertical direction (element_text; inherits from strip.text)
strip.switch.pad.grid
space between strips and axes when strips are switched (unit)
strip.switch.pad.wrap
space between strips and axes when strips are switched (unit)

Examples

p <- ggplot(mtcars, aes(mpg, wt)) + geom_point() p

p + theme(panel.background = element_rect(colour = "pink"))

p + theme_bw()

# Scatter plot of gas mileage by vehicle weight p <- ggplot(mtcars, aes(wt, mpg)) + geom_point() # Calculate slope and intercept of line of best fit coef(lm(mpg ~ wt, data = mtcars))
(Intercept) wt 37.285126 -5.344472
p + geom_abline(intercept = 37, slope = -5)

# Calculate correlation coefficient with(mtcars, cor(wt, mpg, use = "everything", method = "pearson"))
[1] -0.8676594
#annotate the plot p + geom_abline(intercept = 37, slope = -5) + geom_text(data = data.frame(), aes(4.5, 30, label = "Pearson-R = -.87"))

# Change the axis labels # Original plot p

p + labs(x = "Vehicle Weight", y = "Miles per Gallon")

# Or p + labs(x = "Vehicle Weight", y = "Miles per Gallon")

# Change title appearance p <- p + labs(title = "Vehicle Weight-Gas Mileage Relationship") # Set title to twice the base font size p + theme(plot.title = element_text(size = rel(2)))

p + theme(plot.title = element_text(size = rel(2), colour = "blue"))

# Changing plot look with themes DF <- data.frame(x = rnorm(400)) m <- ggplot(DF, aes(x = x)) + geom_histogram() # Default is theme_grey() m
`stat_bin()` using `bins = 30`. Pick better value with `binwidth`.

# Compare with m + theme_bw()
`stat_bin()` using `bins = 30`. Pick better value with `binwidth`.

# Manipulate Axis Attributes m + theme(axis.line = element_line(size = 3, colour = "red", linetype = "dotted"))
`stat_bin()` using `bins = 30`. Pick better value with `binwidth`.

m + theme(axis.text = element_text(colour = "blue"))
`stat_bin()` using `bins = 30`. Pick better value with `binwidth`.

m + theme(axis.text.y = element_blank())
`stat_bin()` using `bins = 30`. Pick better value with `binwidth`.

m + theme(axis.ticks = element_line(size = 2))
`stat_bin()` using `bins = 30`. Pick better value with `binwidth`.

m + theme(axis.title.y = element_text(size = rel(1.5), angle = 90))
`stat_bin()` using `bins = 30`. Pick better value with `binwidth`.

m + theme(axis.title.x = element_blank())
`stat_bin()` using `bins = 30`. Pick better value with `binwidth`.

m + theme(axis.ticks.length = unit(.85, "cm"))
`stat_bin()` using `bins = 30`. Pick better value with `binwidth`.

# Legend Attributes z <- ggplot(mtcars, aes(wt, mpg)) + geom_point(aes(colour = factor(cyl))) z

z + theme(legend.position = "none")

z + theme(legend.position = "bottom")

# Or use relative coordinates between 0 and 1 z + theme(legend.position = c(.5, .5))

# Add a border to the whole legend z + theme(legend.background = element_rect(colour = "black"))

# Legend margin controls extra space around outside of legend: z + theme(legend.background = element_rect(), legend.margin = unit(1, "cm"))

z + theme(legend.background = element_rect(), legend.margin = unit(0, "cm"))

# Or to just the keys z + theme(legend.key = element_rect(colour = "black"))

z + theme(legend.key = element_rect(fill = "yellow"))

z + theme(legend.key.size = unit(2.5, "cm"))

z + theme(legend.text = element_text(size = 20, colour = "red", angle = 45))

z + theme(legend.title = element_text(face = "italic"))

# To change the title of the legend use the name argument # in one of the scale options z + scale_colour_brewer(name = "My Legend")

z + scale_colour_grey(name = "Number of \nCylinders")

# Panel and Plot Attributes z + theme(panel.background = element_rect(fill = "black"))

z + theme(panel.border = element_rect(linetype = "dashed", colour = "black"))

z + theme(panel.grid.major = element_line(colour = "blue"))

z + theme(panel.grid.minor = element_line(colour = "red", linetype = "dotted"))

z + theme(panel.grid.major = element_line(size = 2))

z + theme(panel.grid.major.y = element_blank(), panel.grid.minor.y = element_blank())

z + theme(plot.background = element_rect())

z + theme(plot.background = element_rect(fill = "green"))

# Faceting Attributes set.seed(4940) dsmall <- diamonds[sample(nrow(diamonds), 1000), ] k <- ggplot(dsmall, aes(carat, ..density..)) + geom_histogram(binwidth = 0.2) + facet_grid(. ~ cut) k + theme(strip.background = element_rect(colour = "purple", fill = "pink", size = 3, linetype = "dashed"))

k + theme(strip.text.x = element_text(colour = "red", angle = 45, size = 10, hjust = 0.5, vjust = 0.5))

k + theme(panel.margin = unit(5, "lines"))

k + theme(panel.margin.y = unit(0, "lines"))

# Put gridlines on top meanprice <- tapply(diamonds$price, diamonds$cut, mean) cut <- factor(levels(diamonds$cut), levels = levels(diamonds$cut)) df <- data.frame(meanprice, cut) g <- ggplot(df, aes(cut, meanprice)) + geom_bar(stat = "identity") g + geom_bar(stat = "identity") + theme(panel.background = element_blank(), panel.grid.major.x = element_blank(), panel.grid.minor.x = element_blank(), panel.grid.minor.y = element_blank(), panel.ontop = TRUE)

# Modify a theme and save it mytheme <- theme_grey() + theme(plot.title = element_text(colour = "red")) p + mytheme

## Not run: # ## Run this to generate a graph of the element inheritance tree # build_element_graph <- function(tree) { # require(igraph) # require(plyr) # # inheritdf <- function(name, item) { # if (length(item$inherit) == 0) # data.frame() # else # data.frame(child = name, parent = item$inherit) # } # # edges <- plyr::rbind.fill(mapply(inheritdf, names(tree), tree)) # # # Explicitly add vertices (since not all are in edge list) # vertices <- data.frame(name = names(tree)) # graph.data.frame(edges, vertices = vertices) # } # # g <- build_element_graph(ggplot2:::.element_tree) # V(g)$label <- V(g)$name # # set.seed(324) # par(mar=c(0,0,0,0)) # Remove unnecessary margins # plot(g, layout=layout.fruchterman.reingold, vertex.size=4, vertex.label.dist=.25) # # ## End(Not run)