theme {ggplot2} | R Documentation

## Modify components of a theme

### Description

Use `theme()` to modify individual components of a theme, allowing you to control the appearance of all non-data components of the plot. `theme()` only affects a single plot: see `theme_update` if you want modify the active theme, to affect all subsequent plots.

### Usage

    theme(line, rect, text, title, aspect.ratio, axis.title, axis.title.x,
      axis.title.x.top, axis.title.y, axis.title.y.right, axis.text, axis.text.x,
      axis.text.x.top, axis.text.y, axis.text.y.right, axis.ticks, axis.ticks.x,
      axis.ticks.y, axis.ticks.length, axis.line, axis.line.x, axis.line.y,
      legend.background, legend.margin, legend.spacing, legend.spacing.x,
      legend.spacing.y, legend.key, legend.key.size, legend.key.height,
      legend.key.width, legend.text, legend.text.align, legend.title,
      legend.title.align, legend.position, legend.direction, legend.justification,
      legend.box, legend.box.just, legend.box.margin, legend.box.background,
      legend.box.spacing, panel.background, panel.border, panel.spacing,
      panel.spacing.x, panel.spacing.y, panel.grid, panel.grid.major,
      panel.grid.minor, panel.grid.major.x, panel.grid.major.y, panel.grid.minor.x,
      panel.grid.minor.y, panel.ontop, plot.background, plot.title, plot.subtitle,
      plot.caption, plot.margin, strip.background, strip.placement, strip.text,
      strip.text.x, strip.text.y, strip.switch.pad.grid, strip.switch.pad.wrap, ...,
      complete = FALSE, validate = TRUE)

### Arguments

`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.x.top` | x axis label on top axis (`element_text`; inherits from `axis.title.x`)
`axis.title.y` | y axis label (`element_text`; inherits from `axis.title`)
`axis.title.y.right` | y axis label on right axis (`element_text`; inherits from `axis.title.y`)
`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.x.top` | x axis tick labels on top axis (`element_text`; inherits from `axis.text.x`)
`axis.text.y` | y axis tick labels (`element_text`; inherits from `axis.text`)
`axis.text.y.right` | y axis tick labels on right axis (`element_text`; inherits from `axis.text.y`)
`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` | the margin around each legend (`margin`)
`legend.spacing` | the spacing between legends (`unit`)
`legend.spacing.x` | the horizontal spacing between legends (`unit`); inherits from `legend.spacing`
`legend.spacing.y` | the horizontal spacing between legends (`unit`); inherits from `legend.spacing`
`legend.key` | background underneath legend keys (`element_rect`; inherits from `rect`)
`legend.key.size` | size of legend keys (`unit`)
`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) or the justification according to the plot area when positioned outside the plot
`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")
`legend.box.margin` | margins around the full legend area, as specified using `margin`
`legend.box.background` | background of legend area (`element_rect`; inherits from `rect`)
`legend.box.spacing` | The spacing between the plotting area and the legend box (`unit`)
`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.spacing` | spacing between facet panels (`unit`)
`panel.spacing.x` | horizontal spacing between facet panels (`unit`; inherits from `panel.spacing`)
`panel.spacing.y` | vertical spacing between facet panels (`unit`; inherits from `panel.spacing`)
`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`) left-aligned by default
`plot.subtitle` | plot subtitle (text appearance) (`element_text`; inherits from `title`) left-aligned by default
`plot.caption` | caption below the plot (text appearance) (`element_text`; inherits from `title`) right-aligned by default
`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.placement` | placement of strip with respect to axes, either "inside" or "outside". Only important when axes and strips are on the same side of the plot.
`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`)
`...` | additional element specifications not part of base ggplot2. If supplied `validate` needs to be set to `FALSE`.
`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. Also, when setting `complete = TRUE` all elements will be set to inherit from blank elements.
`validate` | `TRUE` to run validate_element, `FALSE` to bypass checks.

### Theme inheritance

Theme elements 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`. This means that you can modify the appearance of multiple elements by setting a single high-level component.

### See Also

`+.gg` and `%+replace%`, `element_blank`, `element_line`, `element_rect`, and `element_text` for details of the specific theme elements.

### Examples

    p1 <- ggplot(mtcars, aes(wt, mpg)) +
      geom_point() +
      labs(title = "Fuel economy declines as weight increases")
    p1

    # Plot ---------------------------------------------------------------------
    p1 + theme(plot.title = element_text(size = rel(2)))
    p1 + theme(plot.background = element_rect(fill = "green"))

    # Panels --------------------------------------------------------------------

    p1 + theme(panel.background = element_rect(fill = "white", colour = "grey50"))
    p1 + theme(panel.border = element_rect(linetype = "dashed", fill = NA))
    p1 + theme(panel.grid.major = element_line(colour = "black"))
    p1 + theme(
      panel.grid.major.y = element_blank(),
      panel.grid.minor.y = element_blank()
    )

    # Put gridlines on top of data
    p1 + theme(
      panel.background = element_rect(fill = NA),
      panel.grid.major = element_line(colour = "grey50"),
      panel.ontop = TRUE
    )

    # Axes ----------------------------------------------------------------------
    p1 + theme(axis.line = element_line(size = 3, colour = "grey80"))
    p1 + theme(axis.text = element_text(colour = "blue"))
    p1 + theme(axis.ticks = element_line(size = 2))
    p1 + theme(axis.ticks.length = unit(.25, "cm"))
    p1 + theme(axis.title.y = element_text(size = rel(1.5), angle = 90))

    # Legend --------------------------------------------------------------------
    p2 <- ggplot(mtcars, aes(wt, mpg)) +
      geom_point(aes(colour = factor(cyl), shape = factor(vs))) +
      labs(
        x = "Weight (1000 lbs)",
        y = "Fuel economy (mpg)",
        colour = "Cylinders",
        shape = "Transmission"
       )
    p2

    # Position
    p2 + theme(legend.position = "none")
    p2 + theme(legend.justification = "top")
    p2 + theme(legend.position = "bottom")

    # Or place inside the plot using relative coordinates between 0 and 1
    # legend.justification sets the corner that the position refers to
    p2 + theme(
      legend.position = c(.95, .95),
      legend.justification = c("right", "top"),
      legend.box.just = "right",
      legend.margin = margin(6, 6, 6, 6)
    )

    # The legend.box properties work similarly for the space around
    # all the legends
    p2 + theme(
      legend.box.background = element_rect(),
      legend.box.margin = margin(6, 6, 6, 6)
    )

    # You can also control the display of the keys
    # and the justifaction related to the plot area can be set
    p2 + theme(legend.key = element_rect(fill = "white", colour = "black"))
    p2 + theme(legend.text = element_text(size = 8, colour = "red"))
    p2 + theme(legend.title = element_text(face = "bold"))

    # Strips --------------------------------------------------------------------

    p3 <- ggplot(mtcars, aes(wt, mpg)) +
      geom_point() +
      facet_wrap(~ cyl)
    p3

    p3 + theme(strip.background = element_rect(colour = "black", fill = "white"))
    p3 + theme(strip.text.x = element_text(colour = "white", face = "bold"))
    p3 + theme(panel.spacing = unit(1, "lines"))

[Package ggplot2 version 2.2.1 Index]