Skip to contents

Layer with Grid or Function

Source: R/geom-draw.R
geom_draw.Rd

Draw ggplot2 layer with a grod or function.

Usage

geom_draw(
  draw = grid::nullGrob(),
  ...,
  mapping = NULL,
  data = NULL,
  stat = "identity",
  position = "identity",
  na.rm = FALSE,
  inherit.aes = TRUE
)

Arguments

draw

Either a grob object or a function (can be purrr-style) which accepts two arguments (data and coords) and returns a grob.

when draw is a function, it is used as the draw_group function in a Geom ggproto object.

...

Additional arguments passed to draw.

mapping

Set of aesthetic mappings created by aes(). If specified and inherit.aes = TRUE (the default), it is combined with the default mapping at the top level of the plot. You must supply mapping if there is no plot mapping.

data

The data to be displayed in this layer. There are three options:

If NULL, the default, the data is inherited from the plot data as specified in the call to ggplot().

A data.frame, or other object, will override the plot data. All objects will be fortified to produce a data frame. See fortify() for which variables will be created.

A function will be called with a single argument, the plot data. The return value must be a data.frame, and will be used as the layer data. A function can be created from a formula (e.g. ~ head(.x, 10)).

stat

The statistical transformation to use on the data for this layer. When using a geom_*() function to construct a layer, the stat argument can be used the override the default coupling between geoms and stats. The stat argument accepts the following:

  • A Stat ggproto subclass, for example StatCount.

  • A string naming the stat. To give the stat as a string, strip the function name of the stat_ prefix. For example, to use stat_count(), give the stat as "count".

  • For more information and other ways to specify the stat, see the layer stat documentation.

position

A position adjustment to use on the data for this layer. This can be used in various ways, including to prevent overplotting and improving the display. The position argument accepts the following:

  • The result of calling a position function, such as position_jitter(). This method allows for passing extra arguments to the position.

  • A string naming the position adjustment. To give the position as a string, strip the function name of the position_ prefix. For example, to use position_jitter(), give the position as "jitter".

  • For more information and other ways to specify the position, see the layer position documentation.

na.rm

If FALSE, the default, missing values are removed with a warning. If TRUE, missing values are silently removed.

inherit.aes

If FALSE, overrides the default aesthetics, rather than combining with them. This is most useful for helper functions that define both data and aesthetics and shouldn't inherit behaviour from the default plot specification, e.g. borders().

Value

A ggplot2 layer.

Details

If you want to combine the functionality of multiple geoms it can usually be achieved by preparing the data for each of the geoms inside the draw_*() call and send it off to the different geoms, collecting the output in a grid::gList (a list of grobs) if the call is draw_group() or a grid::gTree (a grob containing multiple children grobs) if the call is draw_panel().

See also

https://ggplot2.tidyverse.org/reference/ggplot2-ggproto.html

Examples

ggdraw_text <- grid::textGrob(
    "ggdraw",
    x = c(0, 0, 0.5, 1, 1),
    y = c(0, 1, 0.5, 0, 1),
    hjust = c(0, 0, 0.5, 1, 1),
    vjust = c(0, 1, 0.5, 0, 1)
)
ggplot2::ggplot(data.frame(x = 1, y = 2)) +
    geom_draw(ggdraw_text)