ggpacket {ggpackets}

A container for lazy ggplot layers

Description

ggpackets present a mechanism for easily collecting loose ggplot layers into objects that can be reused across multiple plots, as well as handling of hierarchical argument propegation, as well as data and aesthetic scoping.

Usage

ggpacket(...)

Arguments

...

Arguments passed on to ggpacket_call

data

The data argument to use for all layers within the ggpacket

mapping

The aesthetic mapping to use as a basis for all layers within the ggpacket. Layer-specific mappings will update the value of the mapping, and assigning ..reset.. to any aesthetic field will return the propegated aesthetic mapping to a default, unmapped state for that layer.

.id

an optional identifier tag for the ggpacket, used for filtering arguments and aesthetics that are propegated into the contained ggplot layers.

Details

The ggpacket object behaves like a function, returning an updated ggpacket. As well, it contains a few slots which can be used for programmatically accessing the lazy ggplot calls.

Within ggpacket and subsequent ggplot layer calls, aesthetic mappings can contain references to previously mapped aesthetics using the double-dot keywords (e.g. ..x..). In addition, the keyword ..reset.. can be used to revert aesthetics within the ggpacket or layer to an un-specified state.

Because ggpackets will tolerate a more flexible syntax for layer specifications, it's preferrable to use the ggplot composition operator %+% (instead of +). This allows for duplicate argument names and non-standard aesthetics to be passed, which are both handled internally within the ggpacket call, but will trigger warnings when using a bare +.

Value

A new ggpacket object

Slots

data

A lazy reference to the data parameter of the ggpacket, allowing for scoping the data used by a block of ggplot layers.

mapping

A lazy reference to the mapping parameter of the ggpacket, allowing for scoping of aesthetic mappings over a block of ggplot layers.

dots

Quosures representing arguments to be passed to all of the ggpacket's ggplot layers.

ggcalls

A list containing the layers stored within the ggpacket

Examples

library(ggplot2)

# create a ggpacket directly, setting some fixed argument settings
ggpk_simple <- ggpacket() %+% geom_line(color = "red") %+% geom_point()
ggplot(mtcars, aes(x = wt, y = mpg)) + ggpk_simple()

# any non-fixed arguments can be modified in the ggpacket call
ggplot(mtcars, aes(x = wt, y = mpg)) + ggpk_simple(color = "green")

# arguments can be specified for only specific layers by prefixing them
ggplot(mtcars, aes(x = wt, y = mpg)) + ggpk_simple(point.size = 5)

# allow masking of preset arguments by wrapping the ggpacket in a function
ggpk_func <- function(...) {
  ggpacket() %+%
    geom_line(...) %+%
    geom_point(color = "red", ...)
}

ggplot(mtcars, aes(x = wt, y = mpg)) +
  ggpk_func(color = "purple", size = 2, point.size = 4)