Theme elements — margin • ggplot2

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

element_blank(): draws nothing, and assigns no space.
element_rect(): borders and backgrounds.
element_line(): lines.
element_text(): text.
element_polygon(): polygons.
element_point(): points.
element_geom(): defaults for drawing layers.

rel() is used to specify sizes relative to the parent, margin(), margin_part() and margin_auto() are all used to specify the margins of elements.

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

margin_part(t = NA, r = NA, b = NA, l = NA, unit = "pt")

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

element()

element_blank()

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

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

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,
  ...
)

element_polygon(
  fill = NULL,
  colour = NULL,
  linewidth = NULL,
  linetype = NULL,
  color = NULL,
  linejoin = NULL,
  inherit.blank = FALSE,
  ...
)

element_point(
  colour = NULL,
  shape = NULL,
  size = NULL,
  fill = NULL,
  stroke = NULL,
  color = NULL,
  inherit.blank = FALSE,
  ...
)

element_geom(
  ink = NULL,
  paper = NULL,
  accent = NULL,
  linewidth = NULL,
  borderwidth = NULL,
  linetype = NULL,
  bordertype = NULL,
  family = NULL,
  fontsize = NULL,
  pointsize = NULL,
  pointshape = NULL,
  colour = NULL,
  color = NULL,
  fill = NULL,
  ...
)

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.
...: Reserved for future expansion.
fill: Fill colour. fill_alpha() can be used to set the transparency of the fill.
colour, color: Line/border colour. Color is an alias for colour. alpha() can be used to set the transparency of the colour.
linewidth, borderwidth, stroke: Line/border size in mm.
linetype, bordertype: Line type for lines and borders respectively. 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.
linejoin: Line join style, one of "round", "mitre" or "bevel".
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.
size, fontsize, pointsize: text size in pts, point size in mm.
lineend: Line end style, one of "round", "butt" or "square".
arrow: Arrow specification, as created by grid::arrow()
arrow.fill: Fill colour for arrows.
family: The typeface to use. The validity of this value will depend on the graphics device being used for rendering the plot. See the systemfonts vignette for guidance on the best way to access fonts installed on your computer. The values "sans", "serif", and "mono" should always be valid and will select the default typeface for the respective styles. However, what is considered default is dependant on the graphics device and the operating system.
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.
shape, pointshape: Shape for points (1-25).
ink: Foreground colour.
paper: Background colour.
accent: Accent colour.
x: A single number specifying size relative to parent element.

Value

An object of class element, rel, or margin.

Details

The element_polygon() and element_point() functions are not rendered in standard plots and just serve as extension points.

Examples

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

# Turning off theme elements by setting them to blank
plot + theme(
  panel.background = element_blank(),
  axis.text = element_blank()
)


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


# Turning on the axis line with an arrow
plot + theme(
  axis.line = element_line(arrow = arrow())
)


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


ggplot(mpg, aes(displ, hwy)) +
  geom_point() +
  geom_smooth(formula = y ~ x, method = "lm") +
  theme(geom = element_geom(
    ink = "red", accent = "black",
    pointsize = 1, linewidth = 2
  ))