Title: Shadow and Glow Geoms for 'ggplot2'
Version: 0.0.5
Description: A collection of Geoms for R's 'ggplot2' library. geom_shadowpath(), geom_shadowline(), geom_shadowstep() and geom_shadowpoint() functions draw a shadow below lines to make busy plots more aesthetically pleasing. geom_glowpath(), geom_glowline(), geom_glowstep() and geom_glowpoint() add a neon glow around lines to get a steampunk style.
Depends: R (≥ 3.4.0)
Imports: stats, ggplot2 (≥ 3.3.0), grid, scales, rlang, glue, vctrs, cli
Suggests: rmarkdown, knitr
VignetteBuilder: knitr
License: GPL-2
Encoding: UTF-8
URL: https://github.com/marcmenem/ggshadow/
BugReports: https://github.com/marcmenem/ggshadow/issues
RoxygenNote: 7.2.1
Collate: 'geom-glowpath.r' 'geom-glowpoint.r' 'geom-shadowpath.r' 'geom-shadowpoint.r' 'internal-doc.r' 'scale-shadow.r'
NeedsCompilation: no
Packaged: 2022-11-20 22:31:36 UTC; marc
Author: Marc Menem [aut, cre]
Maintainer: Marc Menem <marc.menem@m4x.org>
Repository: CRAN
Date/Publication: 2022-11-20 22:50:08 UTC

ggproto classes for ggshadow

Description

Please refer to ggplot2 documentation for more information on the ggproto class system

Connect Observations

Description

Plot a glow beneath the connected lines to make it easier to read a chart with several overlapping observations. 'geom_glowpath()' connects the observations in the order in which they appear in the data. 'geom_glowline()' connects them in order of the variable on the x axis. 'geom_glowstep()' creates a stairstep plot, highlighting exactly when changes occur.

Usage

geom_glowpath(
  mapping = NULL,
  data = NULL,
  stat = "identity",
  position = "identity",
  ...,
  lineend = "butt",
  linejoin = "round",
  linemitre = 10,
  arrow = NULL,
  na.rm = FALSE,
  show.legend = NA,
  inherit.aes = TRUE
)

geom_glowline(
  mapping = NULL,
  data = NULL,
  stat = "identity",
  position = "identity",
  na.rm = FALSE,
  orientation = NA,
  show.legend = NA,
  inherit.aes = TRUE,
  ...
)

geom_glowstep(
  mapping = NULL,
  data = NULL,
  stat = "identity",
  position = "identity",
  direction = "hv",
  na.rm = FALSE,
  show.legend = NA,
  inherit.aes = TRUE,
  ...
)

Arguments

mapping

Set of aesthetic mappings created by [aes()] or [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, as a string.

position

Position adjustment, either as a string, or the result of a call to a position adjustment function.

...

Other arguments passed on to [layer()]. These are often aesthetics, used to set an aesthetic to a fixed value, like 'colour = "red"' or 'size = 3'. They may also be parameters to the paired geom/stat.

lineend

Line end style (round, butt, square).

linejoin

Line join style (round, mitre, bevel).

linemitre

Line mitre limit (number greater than 1).

arrow

Arrow specification, as created by [grid::arrow()].

na.rm

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

show.legend

logical. Should this layer be included in the legends? 'NA', the default, includes if any aesthetics are mapped. 'FALSE' never includes, and 'TRUE' always includes. It can also be a named logical vector to finely select the aesthetics to display.

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()].

orientation

The orientation of the layer. The default ('NA') automatically determines the orientation from the aesthetic mapping. In the rare event that this fails it can be given explicitly by setting 'orientation' to either '"x"' or '"y"'. See the *Orientation* section for more detail.

direction

direction of stairs: 'vh' for vertical then horizontal, 'hv' for horizontal then vertical, or 'mid' for step half-way between adjacent x-values.

Details

The 'group' aesthetic determines which cases are connected together. These functions are designed as a straight replacement to the [geom_path()], [geom_line()] and [geom_step()] functions. To set the order of drawing, make the 'colour' aesthetic a factor, and set the order from bottom to top.

Value

a 'ggplot2' layer to add to a plot.

Functions

Missing value handling

'geom_glowpath()', 'geom_glowline()', and 'geom_glowstep()' handle 'NA' as follows:

* If an 'NA' occurs in the middle of a line, it breaks the line. No warning is shown, regardless of whether 'na.rm' is 'TRUE' or 'FALSE'. * If an 'NA' occurs at the start or the end of the line and 'na.rm' is 'FALSE' (default), the 'NA' is removed with a warning. * If an 'NA' occurs at the start or the end of the line and 'na.rm' is 'TRUE', the 'NA' is removed silently, without warning.

Aesthetics

Adds 3 new aesthetics to [geom_path()]: * shadowcolour defaults to path color, controls the color of the shadow. * shadowsize defaults to size, controls the size of the shadow. * shadowalpha defaults to 0.06 * alpha or 0.06, controls the alpha of the glow.

See Also

[ggplot::geom_path()], [ggplot::geom_line()], [ggplot::geom_step()]: Filled paths (polygons);

Examples

# geom_glowline() is suitable for time series
library(ggplot2)
ggplot(economics_long, aes(date, value01, colour = variable)) + geom_glowline()

Points

Description

The point geom is used to create scatterplots. [geom_glowpoint()] is designed as a drop in replacement for [geom_point()] with an added glow beneath the point to make a busy plot more aesthetically appealing or to make points stand out from the rest of the plot.

Usage

geom_glowpoint(
  mapping = NULL,
  data = NULL,
  stat = "identity",
  position = "identity",
  ...,
  na.rm = FALSE,
  show.legend = NA,
  inherit.aes = TRUE
)

Arguments

mapping

Set of aesthetic mappings created by [aes()] or [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, as a string.

position

Position adjustment, either as a string, or the result of a call to a position adjustment function.

...

Other arguments passed on to [layer()]. These are often aesthetics, used to set an aesthetic to a fixed value, like 'colour = "red"' or 'size = 3'. They may also be parameters to the paired geom/stat.

na.rm

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

show.legend

logical. Should this layer be included in the legends? 'NA', the default, includes if any aesthetics are mapped. 'FALSE' never includes, and 'TRUE' always includes. It can also be a named logical vector to finely select the aesthetics to display.

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 layer to add to a plot.

Aesthetics

Adds 3 new aesthetics to [geom_point()]: * shadowcolour defaults to the same color as the point, controls the color of the glow * shadowsize defaults to size, controls the sie of the shadow. * shadowalpha defaults to 0.06 * alpha or 0.06, controls the alpha of the glow

Examples

library( ggplot2 )
p <- ggplot(mtcars, aes(wt, mpg))
p + geom_shadowpoint()

Connect Observations

Description

Plot a shadow beneath the connected lines to make it easier to read a chart with several overlapping observations. 'geom_shadowpath()' connects the observations in the order in which they appear in the data. 'geom_shadowline()' connects them in order of the variable on the x axis. 'geom_shadowstep()' creates a stairstep plot, highlighting exactly when changes occur.

Usage

geom_shadowpath(
  mapping = NULL,
  data = NULL,
  stat = "identity",
  position = "identity",
  ...,
  lineend = "butt",
  linejoin = "round",
  linemitre = 10,
  arrow = NULL,
  na.rm = FALSE,
  show.legend = NA,
  inherit.aes = TRUE
)

geom_shadowline(
  mapping = NULL,
  data = NULL,
  stat = "identity",
  position = "identity",
  na.rm = FALSE,
  orientation = NA,
  show.legend = NA,
  inherit.aes = TRUE,
  ...
)

geom_shadowstep(
  mapping = NULL,
  data = NULL,
  stat = "identity",
  position = "identity",
  direction = "hv",
  na.rm = FALSE,
  show.legend = NA,
  inherit.aes = TRUE,
  ...
)

Arguments

mapping

Set of aesthetic mappings created by [aes()] or [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, as a string.

position

Position adjustment, either as a string, or the result of a call to a position adjustment function.

...

Other arguments passed on to [layer()]. These are often aesthetics, used to set an aesthetic to a fixed value, like 'colour = "red"' or 'size = 3'. They may also be parameters to the paired geom/stat.

lineend

Line end style (round, butt, square).

linejoin

Line join style (round, mitre, bevel).

linemitre

Line mitre limit (number greater than 1).

arrow

Arrow specification, as created by [grid::arrow()].

na.rm

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

show.legend

logical. Should this layer be included in the legends? 'NA', the default, includes if any aesthetics are mapped. 'FALSE' never includes, and 'TRUE' always includes. It can also be a named logical vector to finely select the aesthetics to display.

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()].

orientation

The orientation of the layer. The default ('NA') automatically determines the orientation from the aesthetic mapping. In the rare event that this fails it can be given explicitly by setting 'orientation' to either '"x"' or '"y"'. See the *Orientation* section for more detail.

direction

direction of stairs: 'vh' for vertical then horizontal, 'hv' for horizontal then vertical, or 'mid' for step half-way between adjacent x-values.

Details

The 'group' aesthetic determines which cases are connected together. These functions are designed as a straight replacement to the [geom_path()], [geom_line()] and [geom_step()] functions. To set the order of drawing, make the 'colour' aesthetic a factor, and set the order from bottom to top.

Value

a layer to add to a plot.

Functions

Missing value handling

'geom_shadowpath()', 'geom_shadowline()', and 'geom_shadowstep()' handle 'NA' as follows:

* If an 'NA' occurs in the middle of a line, it breaks the line. No warning is shown, regardless of whether 'na.rm' is 'TRUE' or 'FALSE'. * If an 'NA' occurs at the start or the end of the line and 'na.rm' is 'FALSE' (default), the 'NA' is removed with a warning. * If an 'NA' occurs at the start or the end of the line and 'na.rm' is 'TRUE', the 'NA' is removed silently, without warning.

Aesthetics

Adds 3 new aesthetics to [geom_path()]: * shadowcolour defaults to white, controls the color of the shadow. * shadowsize defaults to 2.5 * size, controls the size of the shadow. * shadowalpha defaults to 0.25 * alpha or 0.9, controls the alpha of the shadow.

See Also

[ggplot::geom_path()], [ggplot::geom_line()], [ggplot::geom_step()]: Filled paths (polygons);

Examples

# geom_shadowline() is suitable for time series
library(ggplot2)
ggplot(economics_long, aes(date, value01, colour = variable)) + geom_shadowline()

ggplot(economics_long, aes(date, value01, colour = value01,
                           group = variable, alpha=date, shadowalpha=1)) +
          geom_shadowline()

Points

Description

The point geom is used to create scatterplots. [geom_shadowpoint()] is designed as a drop in replacement for [geom_point()] with an added shadow beneath the point to make a busy plot more aesthetically appealing or to make points stand out from the rest of the plot.

Usage

geom_shadowpoint(
  mapping = NULL,
  data = NULL,
  stat = "identity",
  position = "identity",
  ...,
  na.rm = FALSE,
  show.legend = NA,
  inherit.aes = TRUE
)

Arguments

mapping

Set of aesthetic mappings created by [aes()] or [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, as a string.

position

Position adjustment, either as a string, or the result of a call to a position adjustment function.

...

Other arguments passed on to [layer()]. These are often aesthetics, used to set an aesthetic to a fixed value, like 'colour = "red"' or 'size = 3'. They may also be parameters to the paired geom/stat.

na.rm

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

show.legend

logical. Should this layer be included in the legends? 'NA', the default, includes if any aesthetics are mapped. 'FALSE' never includes, and 'TRUE' always includes. It can also be a named logical vector to finely select the aesthetics to display.

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 layer to add to a plot.

Aesthetics

Adds 3 new aesthetics to [geom_point()]: * shadowcolour defaults to white, controls the color of the shadow. * shadowsize defaults to 1.8 * size, controls the sie of the shadow. * shadowalpha defaults to 0.25 * alpha or 0.9, controls the alpha of the shadow.

Examples

library( ggplot2 )
p <- ggplot(mtcars, aes(wt, mpg))
p + geom_shadowpoint()

Default params for geoms

Description

Default params for geoms

Arguments

mapping

Set of aesthetic mappings created by [aes()] or [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, as a string.

position

Position adjustment, either as a string, or the result of a call to a position adjustment function.

show.legend

logical. Should this layer be included in the legends? 'NA', the default, includes if any aesthetics are mapped. 'FALSE' never includes, and 'TRUE' always includes. It can also be a named logical vector to finely select the aesthetics to display.

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 layer object to add to a plot.

Sequential, diverging and qualitative colour scales from colorbrewer.org

Description

The 'brewer' scales provides sequential, diverging and qualitative colour schemes from ColorBrewer. These are particularly well suited to display discrete values on a map. See https://colorbrewer2.org for more information.

Usage

scale_shadowcolour_brewer(
  ...,
  type = "seq",
  palette = 1,
  direction = 1,
  aesthetics = "shadowcolour"
)

scale_shadowcolour_distiller(
  ...,
  type = "seq",
  palette = 1,
  direction = -1,
  values = NULL,
  space = "Lab",
  na.value = "grey50",
  guide = "colourbar",
  aesthetics = "shadowcolour"
)

Arguments

...

Other arguments passed on to [discrete_scale()], [continuous_scale()], or [binned_scale()], for 'brewer', 'distiller', and 'fermenter' variants respectively, to control name, limits, breaks, labels and so forth.

type

One of "seq" (sequential), "div" (diverging) or "qual" (qualitative)

palette

If a string, will use that named palette. If a number, will index into the list of palettes of appropriate 'type'. The list of available palettes can found in the Palettes section.

direction

Sets the order of colours in the scale. If 1, the default, colours are as output by RColorBrewer::brewer.pal(). If -1, the order of colours is reversed.

aesthetics

Character string or vector of character strings listing the name(s) of the aesthetic(s) that this scale works with. This can be useful, for example, to apply colour settings to the colour and fill aesthetics at the same time, via aesthetics = c("colour", "fill").

values

if colours should not be evenly positioned along the gradient this vector gives the position (between 0 and 1) for each colour in the colours vector. See rescale() for a convenience function to map an arbitrary range to between 0 and 1.

space

colour space in which to calculate gradient. Must be "Lab" - other values are deprecated.

na.value

Colour to use for missing values

guide

Type of legend. Use "colourbar" for continuous colour bar, or "legend" for discrete colour legend.

Details

The 'brewer' scales were carefully designed and tested on discrete data. They were not designed to be extended to continuous data, but results often look good. Your mileage may vary.

Value

a scale object to add to a plot.

Palettes

The following palettes are available for use with these scales:

Diverging

BrBG, PiYG, PRGn, PuOr, RdBu, RdGy, RdYlBu, RdYlGn, Spectral

Qualitative

Accent, Dark2, Paired, Pastel1, Pastel2, Set1, Set2, Set3

Sequential

Blues, BuGn, BuPu, GnBu, Greens, Greys, Oranges, OrRd, PuBu, PuBuGn, PuRd, Purples, RdPu, Reds, YlGn, YlGnBu, YlOrBr, YlOrRd

Modify the palette through the 'palette' argument.

Note

The 'distiller' scales extend brewer to continuous scales by smoothly interpolating 7 colours from any palette to a continuous scale. The 'fermenter' scales provide binned versions of the brewer scales.

See Also

Other colour scales: scale_colour_hue, scale_colour_steps, scale_gradient, scale_grey, scale_viridis

Examples

library( ggplot2 )
p <- ggplot(mtcars, aes(wt, mpg, shadowcolor=as.factor(gear)))
p + geom_shadowpoint() + scale_shadowcolour_brewer()

library( ggplot2 )
p <- ggplot(mtcars, aes(wt, mpg, shadowcolor=gear))
p + geom_shadowpoint() + scale_shadowcolour_distiller() + guides(shadowcolor='none')

Evenly spaced colours for discrete data

Description

This is the default colour scale for categorical variables. It maps each level to an evenly spaced hue on the colour wheel. It does not generate colour-blind safe palettes.

Usage

scale_shadowcolour_hue(
  ...,
  h = c(0, 360) + 15,
  c = 100,
  l = 65,
  h.start = 0,
  direction = 1,
  na.value = "grey50",
  aesthetics = "shadowcolour"
)

scale_shadowcolour_discrete(
  ...,
  h = c(0, 360) + 15,
  c = 100,
  l = 65,
  h.start = 0,
  direction = 1,
  na.value = "grey50",
  aesthetics = "shadowcolour"
)

Arguments

...

Arguments passed on to ggplot2::discrete_scale

scale_name

The name of the scale that should be used for error messages associated with this scale.

palette

A palette function that when called with a single integer argument (the number of levels in the scale) returns the values that they should take (e.g., scales::hue_pal()).

name

The name of the scale. Used as the axis or legend title. If waiver(), the default, the name of the scale is taken from the first mapping used for that aesthetic. If NULL, the legend title will be omitted.

breaks

One of:

  • NULL for no breaks

  • waiver() for the default breaks (the scale limits)

  • A character vector of breaks

  • A function that takes the limits as input and returns breaks as output. Also accepts rlang lambda function notation.

labels

One of:

  • NULL for no labels

  • waiver() for the default labels computed by the transformation object

  • A character vector giving labels (must be same length as breaks)

  • A function that takes the breaks as input and returns labels as output. Also accepts rlang lambda function notation.

limits

One of:

  • NULL to use the default scale values

  • A character vector that defines possible values of the scale and their order

  • A function that accepts the existing (automatic) values and returns new ones. Also accepts rlang lambda function notation.

expand

For position scales, a vector of range expansion constants used to add some padding around the data to ensure that they are placed some distance away from the axes. Use the convenience function expansion() to generate the values for the expand argument. The defaults are to expand the scale by 5% on each side for continuous variables, and by 0.6 units on each side for discrete variables.

na.translate

Unlike continuous scales, discrete scales can easily show missing values, and do so by default. If you want to remove missing values from a discrete scale, specify na.translate = FALSE.

drop

Should unused factor levels be omitted from the scale? The default, TRUE, uses the levels that appear in the data; FALSE uses all the levels in the factor.

guide

A function used to create a guide or its name. See guides() for more information.

position

For position scales, The position of the axis. left or right for y axes, top or bottom for x axes.

super

The super class to use for the constructed scale

h

range of hues to use, in [0, 360]

c

chroma (intensity of colour), maximum value varies depending on combination of hue and luminance.

l

luminance (lightness), in [0, 100]

h.start

hue to start at

direction

direction to travel around the colour wheel, 1 = clockwise, -1 = counter-clockwise

na.value

Colour to use for missing values

aesthetics

Character string or vector of character strings listing the name(s) of the aesthetic(s) that this scale works with. This can be useful, for example, to apply colour settings to the 'colour' and 'fill' aesthetics at the same time, via 'aesthetics = c("colour", "fill")'.

Value

a scale object to add to a plot.

See Also

Other colour scales: scale_brewer, scale_colour_steps, scale_gradient, scale_grey, scale_viridis

Examples

library( ggplot2 )
p <- ggplot(mtcars, aes(wt, mpg, shadowcolor=as.factor(gear)))
p + geom_shadowpoint() + scale_shadowcolour_hue()

library( ggplot2 )
p <- ggplot(mtcars, aes(wt, mpg, shadowcolor=as.factor(gear)))
p + geom_shadowpoint() + scale_shadowcolour_discrete()

Binned gradient colour scales

Description

'scale_*_steps' creates a two colour binned gradient (low-high), 'scale_*_steps2' creates a diverging binned colour gradient (low-mid-high), and 'scale_*_stepsn' creates a n-colour binned gradient. These scales are binned variants of the [gradient scale][scale_colour_gradient] family and works in the same way.

Usage

scale_shadowcolour_steps(
  ...,
  low = "#132B43",
  high = "#56B1F7",
  space = "Lab",
  na.value = "grey50",
  guide = "coloursteps",
  aesthetics = "shadowcolour"
)

scale_shadowcolour_steps2(
  ...,
  low = muted("red"),
  mid = "white",
  high = muted("blue"),
  midpoint = 0,
  space = "Lab",
  na.value = "grey50",
  guide = "coloursteps",
  aesthetics = "shadowcolour"
)

scale_shadowcolour_stepsn(
  ...,
  colours,
  values = NULL,
  space = "Lab",
  na.value = "grey50",
  guide = "coloursteps",
  aesthetics = "shadowcolour",
  colors
)

Arguments

...

Arguments passed on to ggplot2::binned_scale

name

The name of the scale. Used as the axis or legend title. If waiver(), the default, the name of the scale is taken from the first mapping used for that aesthetic. If NULL, the legend title will be omitted.

breaks

One of:

  • NULL for no breaks

  • waiver() for the default breaks computed by the transformation object

  • A numeric vector of positions

  • A function that takes the limits as input and returns breaks as output (e.g., a function returned by scales::extended_breaks()). Also accepts rlang lambda function notation.

labels

One of:

  • NULL for no labels

  • waiver() for the default labels computed by the transformation object

  • A character vector giving labels (must be same length as breaks)

  • A function that takes the breaks as input and returns labels as output. Also accepts rlang lambda function notation.

limits

One of:

  • NULL to use the default scale range

  • A numeric vector of length two providing limits of the scale. Use NA to refer to the existing minimum or maximum

  • A function that accepts the existing (automatic) limits and returns new limits. Also accepts rlang lambda function notation. Note that setting limits on positional scales will remove data outside of the limits. If the purpose is to zoom, use the limit argument in the coordinate system (see coord_cartesian()).

oob

One of:

  • Function that handles limits outside of the scale limits (out of bounds). Also accepts rlang lambda function notation.

  • The default (scales::censor()) replaces out of bounds values with NA.

  • scales::squish() for squishing out of bounds values into range.

  • scales::squish_infinite() for squishing infinite values into range.

expand

For position scales, a vector of range expansion constants used to add some padding around the data to ensure that they are placed some distance away from the axes. Use the convenience function expansion() to generate the values for the expand argument. The defaults are to expand the scale by 5% on each side for continuous variables, and by 0.6 units on each side for discrete variables.

n.breaks

The number of break points to create if breaks are not given directly.

nice.breaks

Logical. Should breaks be attempted placed at nice values instead of exactly evenly spaced between the limits. If TRUE (default) the scale will ask the transformation object to create breaks, and this may result in a different number of breaks than requested. Ignored if breaks are given explicitly.

right

Should values on the border between bins be part of the right (upper) bin?

trans

For continuous scales, the name of a transformation object or the object itself. Built-in transformations include "asn", "atanh", "boxcox", "date", "exp", "hms", "identity", "log", "log10", "log1p", "log2", "logit", "modulus", "probability", "probit", "pseudo_log", "reciprocal", "reverse", "sqrt" and "time".

A transformation object bundles together a transform, its inverse, and methods for generating breaks and labels. Transformation objects are defined in the scales package, and are called ⁠<name>_trans⁠ (e.g., scales::boxcox_trans()). You can create your own transformation with scales::trans_new().

show.limits

should the limits of the scale appear as ticks

position

For position scales, The position of the axis. left or right for y axes, top or bottom for x axes.

super

The super class to use for the constructed scale

low, high

Colours for low and high ends of the gradient.

space

colour space in which to calculate gradient. Must be "Lab" - other values are deprecated.

na.value

Colour to use for missing values

guide

Type of legend. Use "colourbar" for continuous colour bar, or "legend" for discrete colour legend.

aesthetics

Character string or vector of character strings listing the name(s) of the aesthetic(s) that this scale works with. This can be useful, for example, to apply colour settings to the colour and fill aesthetics at the same time, via aesthetics = c("colour", "fill").

mid

colour for mid point

midpoint

The midpoint (in data value) of the diverging scale. Defaults to 0.

colours, colors

Vector of colours to use for n-colour gradient.

values

if colours should not be evenly positioned along the gradient this vector gives the position (between 0 and 1) for each colour in the colours vector. See rescale() for a convenience function to map an arbitrary range to between 0 and 1.

Details

Default colours are generated with munsell and 'mnsl(c("2.5PB 2/4", "2.5PB 7/10"))'. Generally, for continuous colour scales you want to keep hue constant, but vary chroma and luminance. The munsell package makes this easy to do using the Munsell colour system.

Value

a scale object to add to a plot.

See Also

[scales::seq_gradient_pal()] for details on underlying palette

Other colour scales: scale_brewer, scale_colour_hue, scale_gradient, scale_grey, scale_viridis

Examples

library( ggplot2 )
p <- ggplot(mtcars, aes(wt, mpg, shadowcolor=gear))
p + geom_shadowpoint() + scale_shadowcolour_steps() + guides(shadowcolour='none')

library( ggplot2 )
p <- ggplot(mtcars, aes(wt, mpg, shadowcolor=gear))
p + geom_shadowpoint() + scale_shadowcolour_steps2() + guides(shadowcolour='none')

library( ggplot2 )
p <- ggplot(mtcars, aes(wt, mpg, shadowcolor=gear))
p <- p + geom_shadowpoint() + scale_shadowcolour_stepsn(colours=c('red', 'yellow'))
p + guides(shadowcolour='none')

Continuous and binned colour scales

Description

Colour scales for continuous data default to the values of the 'ggplot2.continuous.colour' and 'ggplot2.continuous.fill' options. These [options()] default to '"gradient"' (i.e., [scale_colour_gradient()] and [scale_fill_gradient()])

Usage

scale_shadowcolour_continuous(
  ...,
  type = getOption("ggplot2.continuous.colour", default = "gradient")
)

scale_shadowcolour_binned(
  ...,
  type = getOption("ggplot2.binned.colour", default =
    getOption("ggplot2.continuous.colour", default = "gradient"))
)

Arguments

...

Additional parameters passed on to the scale type

type

One of the following: * "gradient" (the default) * "viridis" * A function that returns a continuous colour scale.

Value

a scale object to add to a plot.

Color Blindness

Many color palettes derived from RGB combinations (like the "rainbow" color palette) are not suitable to support all viewers, especially those with color vision deficiencies. Using 'viridis' type, which is perceptually uniform in both colour and black-and-white display is an easy option to ensure good perceptive properties of your visulizations. The colorspace package offers functionalities - to generate color palettes with good perceptive properties, - to analyse a given color palette, like emulating color blindness, - and to modify a given color palette for better perceptivity.

For more information on color vision deficiencies and suitable color choices see the [paper on the colorspace package](https://arxiv.org/abs/1903.06490) and references therein.

See Also

[scale_colour_gradient()], [scale_colour_viridis_c()], [scale_colour_steps()], [scale_colour_viridis_b()], [scale_fill_gradient()], [scale_fill_viridis_c()], [scale_fill_steps()], and [scale_fill_viridis_b()]

Examples

library( ggplot2 )
p <- ggplot(mtcars, aes(wt, mpg, shadowcolor=gear))
p + geom_shadowpoint() + scale_shadowcolour_continuous() + guides(shadowcolour='none')


library( ggplot2 )
p <- ggplot(mtcars, aes(wt, mpg, shadowcolor=gear))
p + geom_shadowpoint() + scale_shadowcolour_binned() + guides(shadowcolour='none')

Gradient colour scales

Description

'scale_*_gradient' creates a two colour gradient (low-high), 'scale_*_gradient2' creates a diverging colour gradient (low-mid-high), 'scale_*_gradientn' creates a n-colour gradient.

Usage

scale_shadowcolour_gradient(
  ...,
  low = "#132B43",
  high = "#56B1F7",
  space = "Lab",
  na.value = "grey50",
  guide = "colourbar",
  aesthetics = "shadowcolour"
)

scale_shadowcolour_gradient2(
  ...,
  low = muted("red"),
  mid = "white",
  high = muted("blue"),
  midpoint = 0,
  space = "Lab",
  na.value = "grey50",
  guide = "colourbar",
  aesthetics = "shadowcolour"
)

scale_shadowcolour_gradientn(
  ...,
  colours,
  values = NULL,
  space = "Lab",
  na.value = "grey50",
  guide = "colourbar",
  aesthetics = "shadowcolour",
  colors
)

scale_shadowcolour_datetime(
  ...,
  low = "#132B43",
  high = "#56B1F7",
  space = "Lab",
  na.value = "grey50",
  guide = "colourbar"
)

scale_shadowcolour_date(
  ...,
  low = "#132B43",
  high = "#56B1F7",
  space = "Lab",
  na.value = "grey50",
  guide = "colourbar"
)

Arguments

...

Arguments passed on to ggplot2::continuous_scale

scale_name

The name of the scale that should be used for error messages associated with this scale.

palette

A palette function that when called with a numeric vector with values between 0 and 1 returns the corresponding output values (e.g., scales::area_pal()).

name

The name of the scale. Used as the axis or legend title. If waiver(), the default, the name of the scale is taken from the first mapping used for that aesthetic. If NULL, the legend title will be omitted.

breaks

One of:

  • NULL for no breaks

  • waiver() for the default breaks computed by the transformation object

  • A numeric vector of positions

  • A function that takes the limits as input and returns breaks as output (e.g., a function returned by scales::extended_breaks()). Also accepts rlang lambda function notation.

minor_breaks

One of:

  • NULL for no minor breaks

  • waiver() for the default breaks (one minor break between each major break)

  • A numeric vector of positions

  • A function that given the limits returns a vector of minor breaks. Also accepts rlang lambda function notation.

n.breaks

An integer guiding the number of major breaks. The algorithm may choose a slightly different number to ensure nice break labels. Will only have an effect if breaks = waiver(). Use NULL to use the default number of breaks given by the transformation.

labels

One of:

  • NULL for no labels

  • waiver() for the default labels computed by the transformation object

  • A character vector giving labels (must be same length as breaks)

  • A function that takes the breaks as input and returns labels as output. Also accepts rlang lambda function notation.

limits

One of:

  • NULL to use the default scale range

  • A numeric vector of length two providing limits of the scale. Use NA to refer to the existing minimum or maximum

  • A function that accepts the existing (automatic) limits and returns new limits. Also accepts rlang lambda function notation. Note that setting limits on positional scales will remove data outside of the limits. If the purpose is to zoom, use the limit argument in the coordinate system (see coord_cartesian()).

rescaler

A function used to scale the input values to the range [0, 1]. This is always scales::rescale(), except for diverging and n colour gradients (i.e., scale_colour_gradient2(), scale_colour_gradientn()). The rescaler is ignored by position scales, which always use scales::rescale(). Also accepts rlang lambda function notation.

oob

One of:

  • Function that handles limits outside of the scale limits (out of bounds). Also accepts rlang lambda function notation.

  • The default (scales::censor()) replaces out of bounds values with NA.

  • scales::squish() for squishing out of bounds values into range.

  • scales::squish_infinite() for squishing infinite values into range.

expand

For position scales, a vector of range expansion constants used to add some padding around the data to ensure that they are placed some distance away from the axes. Use the convenience function expansion() to generate the values for the expand argument. The defaults are to expand the scale by 5% on each side for continuous variables, and by 0.6 units on each side for discrete variables.

trans

For continuous scales, the name of a transformation object or the object itself. Built-in transformations include "asn", "atanh", "boxcox", "date", "exp", "hms", "identity", "log", "log10", "log1p", "log2", "logit", "modulus", "probability", "probit", "pseudo_log", "reciprocal", "reverse", "sqrt" and "time".

A transformation object bundles together a transform, its inverse, and methods for generating breaks and labels. Transformation objects are defined in the scales package, and are called ⁠<name>_trans⁠ (e.g., scales::boxcox_trans()). You can create your own transformation with scales::trans_new().

position

For position scales, The position of the axis. left or right for y axes, top or bottom for x axes.

super

The super class to use for the constructed scale

low, high

Colours for low and high ends of the gradient.

space

colour space in which to calculate gradient. Must be "Lab" - other values are deprecated.

na.value

Colour to use for missing values

guide

Type of legend. Use '"colourbar"' for continuous colour bar, or '"legend"' for discrete colour legend.

aesthetics

Character string or vector of character strings listing the name(s) of the aesthetic(s) that this scale works with. This can be useful, for example, to apply colour settings to the colour and fill aesthetics at the same time, via aesthetics = c("colour", "fill").

mid

colour for mid point

midpoint

The midpoint (in data value) of the diverging scale. Defaults to 0.

colours, colors

Vector of colours to use for n-colour gradient.

values

if colours should not be evenly positioned along the gradient this vector gives the position (between 0 and 1) for each colour in the colours vector. See rescale() for a convenience function to map an arbitrary range to between 0 and 1.

Details

Default colours are generated with munsell and 'mnsl(c("2.5PB 2/4", "2.5PB 7/10"))'. Generally, for continuous colour scales you want to keep hue constant, but vary chroma and luminance. The munsell package makes this easy to do using the Munsell colour system.

Value

a scale object to add to a plot.

See Also

[scales::seq_gradient_pal()] for details on underlying palette

Other colour scales: scale_brewer, scale_colour_hue, scale_colour_steps, scale_grey, scale_viridis

Examples

library( ggplot2 )
p <- ggplot(economics, aes(date, unemploy, shadowcolor=pce))
p + geom_shadowline() + scale_shadowcolour_gradient() + guides(shadowcolour='none')

library( ggplot2 )
p <- ggplot(economics, aes(date, unemploy, shadowcolor=pce))
p + geom_shadowline() + scale_shadowcolour_gradient2() + guides(shadowcolour='none')

library( ggplot2 )
p <- ggplot(economics, aes(date, unemploy, shadowcolor=pce))
p <- p + geom_shadowline() + scale_shadowcolour_gradientn(colours=c('red', 'green'))
p + guides(shadowcolour='none')

library( ggplot2 )
p <- ggplot(economics, aes(uempmed, unemploy, shadowcolor=as.POSIXct(date)))
p + geom_shadowpath() + scale_shadowcolour_datetime() + guides(shadowcolour='none')

library( ggplot2 )
p <- ggplot(economics, aes(uempmed, unemploy, shadowcolor=date))
p + geom_shadowpath() + scale_shadowcolour_date() + guides(shadowcolour='none')

Sequential grey colour scales

Description

Based on [gray.colors()]. This is black and white equivalent of [scale_colour_gradient()].

Usage

scale_shadowcolour_grey(
  ...,
  start = 0.2,
  end = 0.8,
  na.value = "red",
  aesthetics = "shadowcolour"
)

Arguments

...

Arguments passed on to ggplot2::discrete_scale

scale_name

The name of the scale that should be used for error messages associated with this scale.

palette

A palette function that when called with a single integer argument (the number of levels in the scale) returns the values that they should take (e.g., scales::hue_pal()).

name

The name of the scale. Used as the axis or legend title. If waiver(), the default, the name of the scale is taken from the first mapping used for that aesthetic. If NULL, the legend title will be omitted.

breaks

One of:

  • NULL for no breaks

  • waiver() for the default breaks (the scale limits)

  • A character vector of breaks

  • A function that takes the limits as input and returns breaks as output. Also accepts rlang lambda function notation.

labels

One of:

  • NULL for no labels

  • waiver() for the default labels computed by the transformation object

  • A character vector giving labels (must be same length as breaks)

  • A function that takes the breaks as input and returns labels as output. Also accepts rlang lambda function notation.

limits

One of:

  • NULL to use the default scale values

  • A character vector that defines possible values of the scale and their order

  • A function that accepts the existing (automatic) values and returns new ones. Also accepts rlang lambda function notation.

expand

For position scales, a vector of range expansion constants used to add some padding around the data to ensure that they are placed some distance away from the axes. Use the convenience function expansion() to generate the values for the expand argument. The defaults are to expand the scale by 5% on each side for continuous variables, and by 0.6 units on each side for discrete variables.

na.translate

Unlike continuous scales, discrete scales can easily show missing values, and do so by default. If you want to remove missing values from a discrete scale, specify na.translate = FALSE.

drop

Should unused factor levels be omitted from the scale? The default, TRUE, uses the levels that appear in the data; FALSE uses all the levels in the factor.

guide

A function used to create a guide or its name. See guides() for more information.

position

For position scales, The position of the axis. left or right for y axes, top or bottom for x axes.

super

The super class to use for the constructed scale

start

grey value at low end of palette

end

grey value at high end of palette

na.value

Colour to use for missing values

aesthetics

Character string or vector of character strings listing the name(s) of the aesthetic(s) that this scale works with. This can be useful, for example, to apply colour settings to the colour and fill aesthetics at the same time, via aesthetics = c("colour", "fill").

Value

a scale object to add to a plot.

See Also

Other colour scales: scale_brewer, scale_colour_hue, scale_colour_steps, scale_gradient, scale_viridis

Examples

library( ggplot2 )
p <- ggplot(mtcars, aes(wt, mpg, shadowcolour=as.factor(gear)))
p + geom_glowpoint() + scale_shadowcolour_grey() + guides(shadowcolour='none')

Use values without scaling

Description

Use this set of scales when your data has already been scaled, i.e. it already represents aesthetic values that ggplot2 can handle directly. These scales will not produce a legend unless you also supply the 'breaks', 'labels', and type of 'guide' you want.

Usage

scale_shadowcolour_identity(..., guide = "none", aesthetics = "shadowcolour")

Arguments

...

Other arguments passed on to [discrete_scale()] or [continuous_scale()]

guide

Guide to use for this scale. Defaults to '"none"'.

aesthetics

Character string or vector of character strings listing the name(s) of the aesthetic(s) that this scale works with. This can be useful, for example, to apply colour settings to the 'colour' and 'fill' aesthetics at the same time, via 'aesthetics = c("colour", "fill")'.

Details

The functions 'scale_colour_identity()', 'scale_fill_identity()', 'scale_size_identity()', etc. work on the aesthetics specified in the scale name: 'colour', 'fill', 'size', etc. However, the functions 'scale_colour_identity()' and 'scale_fill_identity()' also have an optional 'aesthetics' argument that can be used to define both 'colour' and 'fill' aesthetic mappings via a single function call. The functions 'scale_discrete_identity()' and 'scale_continuous_identity()' are generic scales that can work with any aesthetic or set of aesthetics provided via the 'aesthetics' argument.

Value

a scale object to add to a plot.

Examples

library( ggplot2 )
p <- ggplot(mtcars, aes(wt, mpg, shadowcolor='red'))
p + geom_shadowpoint() + scale_shadowcolour_identity()

Create your own discrete scale

Description

These functions allow you to specify your own set of mappings from levels in the data to aesthetic values.

Usage

scale_shadowcolour_manual(
  ...,
  values,
  aesthetics = "shadowcolour",
  breaks = waiver()
)

Arguments

...

Arguments passed on to ggplot2::discrete_scale

scale_name

The name of the scale that should be used for error messages associated with this scale.

palette

A palette function that when called with a single integer argument (the number of levels in the scale) returns the values that they should take (e.g., scales::hue_pal()).

name

The name of the scale. Used as the axis or legend title. If waiver(), the default, the name of the scale is taken from the first mapping used for that aesthetic. If NULL, the legend title will be omitted.

labels

One of:

  • NULL for no labels

  • waiver() for the default labels computed by the transformation object

  • A character vector giving labels (must be same length as breaks)

  • A function that takes the breaks as input and returns labels as output. Also accepts rlang lambda function notation.

limits

One of:

  • NULL to use the default scale values

  • A character vector that defines possible values of the scale and their order

  • A function that accepts the existing (automatic) values and returns new ones. Also accepts rlang lambda function notation.

na.translate

Unlike continuous scales, discrete scales can easily show missing values, and do so by default. If you want to remove missing values from a discrete scale, specify na.translate = FALSE.

na.value

If na.translate = TRUE, what aesthetic value should the missing values be displayed as? Does not apply to position scales where NA is always placed at the far right.

drop

Should unused factor levels be omitted from the scale? The default, TRUE, uses the levels that appear in the data; FALSE uses all the levels in the factor.

guide

A function used to create a guide or its name. See guides() for more information.

super

The super class to use for the constructed scale

values

a set of aesthetic values to map data values to. The values will be matched in order (usually alphabetical) with the limits of the scale, or with 'breaks' if provided. If this is a named vector, then the values will be matched based on the names instead. Data values that don't match will be given 'na.value'.

aesthetics

Character string or vector of character strings listing the name(s) of the aesthetic(s) that this scale works with. This can be useful, for example, to apply colour settings to the 'colour' and 'fill' aesthetics at the same time, via 'aesthetics = c("colour", "fill")'.

breaks

One of: - 'NULL' for no breaks - 'waiver()' for the default breaks (the scale limits) - A character vector of breaks - A function that takes the limits as input and returns breaks as output

Details

The functions 'scale_colour_manual()', 'scale_fill_manual()', 'scale_size_manual()', etc. work on the aesthetics specified in the scale name: 'colour', 'fill', 'size', etc. However, the functions 'scale_colour_manual()' and 'scale_fill_manual()' also have an optional 'aesthetics' argument that can be used to define both 'colour' and 'fill' aesthetic mappings via a single function call (see examples). The function 'scale_discrete_manual()' is a generic scale that can work with any aesthetic or set of aesthetics provided via the 'aesthetics' argument.

Value

a scale object to add to a plot.

Color Blindness

Many color palettes derived from RGB combinations (like the "rainbow" color palette) are not suitable to support all viewers, especially those with color vision deficiencies. Using 'viridis' type, which is perceptually uniform in both colour and black-and-white display is an easy option to ensure good perceptive properties of your visulizations. The colorspace package offers functionalities - to generate color palettes with good perceptive properties, - to analyse a given color palette, like emulating color blindness, - and to modify a given color palette for better perceptivity.

For more information on color vision deficiencies and suitable color choices see the [paper on the colorspace package](https://arxiv.org/abs/1903.06490) and references therein.

Examples

library( ggplot2 )
p <- ggplot(mtcars, aes(wt, mpg, shadowcolour=as.factor(gear)))
p <- p + geom_glowpoint() + guides(shadowcolour='none')
p + scale_shadowcolour_manual(values=c('red', 'blue', 'green'))

Viridis colour scales from viridisLite

Description

The 'viridis' scales provide colour maps that are perceptually uniform in both colour and black-and-white. They are also designed to be perceived by viewers with common forms of colour blindness. See also <https://bids.github.io/colormap/>.

Usage

scale_shadowcolour_viridis_d(
  ...,
  alpha = 1,
  begin = 0,
  end = 1,
  direction = 1,
  option = "D",
  aesthetics = "shadowcolour"
)

scale_shadowcolour_viridis_c(
  ...,
  alpha = 1,
  begin = 0,
  end = 1,
  direction = 1,
  option = "D",
  values = NULL,
  space = "Lab",
  na.value = "grey50",
  guide = "colourbar",
  aesthetics = "shadowcolour"
)

scale_shadowcolour_viridis_b(
  ...,
  alpha = 1,
  begin = 0,
  end = 1,
  direction = 1,
  option = "D",
  values = NULL,
  space = "Lab",
  na.value = "grey50",
  guide = "coloursteps",
  aesthetics = "shadowcolour"
)

scale_shadowcolour_ordinal(
  ...,
  alpha = 1,
  begin = 0,
  end = 1,
  direction = 1,
  option = "D",
  aesthetics = "shadowcolour"
)

Arguments

...

Other arguments passed on to [discrete_scale()], [continuous_scale()], or [binned_scale] to control name, limits, breaks, labels and so forth.

alpha

The alpha transparency, a number in [0,1], see argument alpha in hsv.

begin, end

The (corrected) hue in ⁠[0,1]⁠ at which the color map begins and ends.

direction

Sets the order of colors in the scale. If 1, the default, colors are ordered from darkest to lightest. If -1, the order of colors is reversed.

option

A character string indicating the color map option to use. Eight options are available:

  • "magma" (or "A")

  • "inferno" (or "B")

  • "plasma" (or "C")

  • "viridis" (or "D")

  • "cividis" (or "E")

  • "rocket" (or "F")

  • "mako" (or "G")

  • "turbo" (or "H")

aesthetics

Character string or vector of character strings listing the name(s) of the aesthetic(s) that this scale works with. This can be useful, for example, to apply colour settings to the 'colour' and 'fill' aesthetics at the same time, via 'aesthetics = c("colour", "fill")'.

values

if colours should not be evenly positioned along the gradient this vector gives the position (between 0 and 1) for each colour in the colours vector. See rescale() for a convenience function to map an arbitrary range to between 0 and 1.

space

colour space in which to calculate gradient. Must be "Lab" - other values are deprecated.

na.value

Missing values will be replaced with this value.

guide

A function used to create a guide or its name. See guides() for more information.

Value

a scale object to add to a plot.

See Also

Other colour scales: scale_brewer, scale_colour_hue, scale_colour_steps, scale_gradient, scale_grey

Examples

library( ggplot2 )
p <- ggplot(mtcars, aes(wt, mpg, shadowcolour=as.factor(gear)))
p + geom_glowpoint() + scale_shadowcolour_viridis_d() + guides(shadowcolour='none')

library( ggplot2 )
p <- ggplot(mtcars, aes(wt, mpg, shadowcolour=gear))
p + geom_glowpoint() + scale_shadowcolour_viridis_c() + guides(shadowcolour='none')

library( ggplot2 )
p <- ggplot(mtcars, aes(wt, mpg, shadowcolour=gear))
p + geom_glowpoint() + scale_shadowcolour_viridis_b() + guides(shadowcolour='none')

library( ggplot2 )
p <- ggplot(mtcars, aes(wt, mpg, shadowcolour=as.factor(gear)))
p + geom_glowpoint() + scale_shadowcolour_ordinal() + guides(shadowcolour='none')