Theme elements

In conjunction with the theme system, the element_ functions specify the display of how non-data components of the plot are a drawn.

• element_blank: draws nothing, and assigns no space.

• element_rect: borders and backgrounds.

• element_line: lines.

• element_text: text.

rel() is used to specify sizes relative to the parent, margin() is used to specify the margins of elements.

margin(t = 0, r = 0, b = 0, l = 0, unit = "pt")

element_blank()

element_rect(
  fill = NULL,
  colour = NULL,
  size = NULL,
  linetype = NULL,
  color = NULL,
  inherit.blank = FALSE
)

element_line(
  colour = NULL,
  size = NULL,
  linetype = NULL,
  lineend = NULL,
  color = NULL,
  arrow = NULL,
  inherit.blank = FALSE
)

element_text(
  family = NULL,
  face = NULL,
  colour = NULL,
  size = NULL,
  hjust = NULL,
  vjust = NULL,
  angle = NULL,
  lineheight = NULL,
  color = NULL,
  margin = NULL,
  debug = NULL,
  inherit.blank = FALSE
)

rel(x)

Arguments

t, r, b, l	Dimensions of each margin. (To remember order, think trouble).
unit	Default units of dimensions. Defaults to "pt" so it can be most easily scaled with the text.
fill	Fill colour.
colour, color	Line/border colour. Color is an alias for colour.
size	Line/border size in mm; text size in pts.
linetype	Line type. An integer (0:8), a name (blank, solid, dashed, dotted, dotdash, longdash, twodash), or a string with an even number (up to eight) of hexadecimal digits which give the lengths in consecutive positions in the string.
inherit.blank	Should this element inherit the existence of an element_blank among its parents? If TRUE the existence of a blank element among its parents will cause this element to be blank as well. If FALSE any blank parent element will be ignored when calculating final element state.
lineend	Line end Line end style (round, butt, square)
arrow	Arrow specification, as created by grid::arrow()
family	Font family
face	Font face ("plain", "italic", "bold", "bold.italic")
hjust	Horizontal justification (in \([0, 1]\))
vjust	Vertical justification (in \([0, 1]\))
angle	Angle (in \([0, 360]\))
lineheight	Line height
margin	Margins around the text. See margin() for more details. When creating a theme, the margins should be placed on the side of the text facing towards the center of the plot.
debug	If TRUE, aids visual debugging by drawing a solid rectangle behind the complete text area, and a point where each label is anchored.
x	A single number specifying size relative to parent element.

Value

An S3 object of class element, rel, or margin.

Examples

plot <- ggplot(mpg, aes(displ, hwy)) + geom_point()

plot + theme(
  panel.background = element_blank(),
  axis.text = element_blank()
)

plot + theme(
  axis.text = element_text(colour = "red", size = rel(1.5))
)

plot + theme(
  axis.line = element_line(arrow = arrow())
)

plot + theme(
  panel.background = element_rect(fill = "white"),
  plot.margin = margin(2, 2, 2, 2, "cm"),
  plot.background = element_rect(
    fill = "grey90",
    colour = "black",
    size = 1
  )
)