Discretized continuous colour guide

A version of ggplot2::guide_colourbar that displays discretized values and, by default, puts labels in between values.

guide_colourstrip(
  title = ggplot2::waiver(),
  title.position = NULL,
  title.theme = NULL,
  title.hjust = NULL,
  title.vjust = NULL,
  label = TRUE,
  label.position = NULL,
  label.theme = NULL,
  label.hjust = NULL,
  label.vjust = NULL,
  barwidth = NULL,
  barheight = NULL,
  ticks = FALSE,
  draw.ulim = TRUE,
  draw.llim = TRUE,
  inside = FALSE,
  direction = NULL,
  default.unit = "line",
  reverse = FALSE,
  order = 0,
  available_aes = c("colour", "color", "fill"),
  ...
)

guide_colorstrip(
  title = ggplot2::waiver(),
  title.position = NULL,
  title.theme = NULL,
  title.hjust = NULL,
  title.vjust = NULL,
  label = TRUE,
  label.position = NULL,
  label.theme = NULL,
  label.hjust = NULL,
  label.vjust = NULL,
  barwidth = NULL,
  barheight = NULL,
  ticks = FALSE,
  draw.ulim = TRUE,
  draw.llim = TRUE,
  inside = FALSE,
  direction = NULL,
  default.unit = "line",
  reverse = FALSE,
  order = 0,
  available_aes = c("colour", "color", "fill"),
  ...
)

Arguments

title

A character string or expression indicating a title of guide. If NULL, the title is not shown. By default (waiver()), the name of the scale object or the name specified in labs() is used for the title.

title.position

A character string indicating the position of a title. One of "top" (default for a vertical guide), "bottom", "left" (default for a horizontal guide), or "right."

title.theme

A theme object for rendering the title text. Usually the object of element_text() is expected. By default, the theme is specified by legend.title in theme() or theme.

title.hjust

A number specifying horizontal justification of the title text.

title.vjust

A number specifying vertical justification of the title text.

label

logical. If TRUE then the labels are drawn. If FALSE then the labels are invisible.

label.position

A character string indicating the position of a label. One of "top", "bottom" (default for horizontal guide), "left", or "right" (default for vertical guide).

label.theme

A theme object for rendering the label text. Usually the object of element_text() is expected. By default, the theme is specified by legend.text in theme().

label.hjust

A numeric specifying horizontal justification of the label text. The default for standard text is 0 (left-aligned) and 1 (right-aligned) for expressions.

label.vjust

A numeric specifying vertical justification of the label text.

barwidth

A numeric or a grid::unit() object specifying the width of the colourbar. Default value is legend.key.width or legend.key.size in theme() or theme.

barheight

A numeric or a grid::unit() object specifying the height of the colourbar. Default value is legend.key.height or legend.key.size in theme() or theme.

ticks

A logical specifying if tick marks on the colourbar should be visible.

draw.ulim

A logical specifying if the upper limit tick marks should be visible.

draw.llim

A logical specifying if the lower limit tick marks should be visible.

inside

logical indicating where to position labels (see examples).

direction

A character string indicating the direction of the guide. One of "horizontal" or "vertical."

default.unit

A character string indicating grid::unit() for barwidth and barheight.

reverse

logical. If TRUE the colourbar is reversed. By default, the highest value is on the top and the lowest value is on the bottom

order

positive integer less than 99 that specifies the order of this guide among multiple guides. This controls the order in which multiple guides are displayed, not the contents of the guide itself. If 0 (default), the order is determined by a secret algorithm.

available_aes

A vector of character strings listing the aesthetics for which a colourbar can be drawn.

...

ignored.

Value

A guide object.

Details

The default behaviour works fell for geom_contour_fill in which the colours represent the value between contour surfaces.

`inside = TRUE`` works better for geom_tile where the colour represents the value of the data and is very similar to ggplot2::guide_legend.

See also

Other ggplot2 helpers: DivideTimeseries(), MakeBreaks(), WrapCircular(), geom_arrow(), geom_contour2(), geom_contour_fill(), geom_label_contour(), geom_relief(), geom_streamline(), map_labels, reverselog_trans(), scale_divergent, scale_longitude, stat_na(), stat_subset()

Examples

# In this example the lowest colour represents an area of the data with values
# between 80 and 100.
library(ggplot2)
binwidth <- 20
data(volcano)
ggplot(reshape2::melt(volcano), aes(Var1, Var2, z = value)) +
    geom_contour_fill(binwidth = binwidth) +
    scale_fill_continuous(guide = guide_colourstrip(),
                         breaks = MakeBreaks(binwidth))


# Difference between guide_legend() and guide_colorbar2(inside = T)
df <- reshape2::melt(outer(1:4, 1:4), varnames = c("X1", "X2"))
g <- ggplot(df, aes(X1, X2)) +
        geom_tile(aes(fill = value)) +
        theme(legend.position = "bottom")

# Tick labels are to the side
g + scale_fill_continuous(guide = guide_legend())

# Tick labels are at the bottom
g + scale_fill_continuous(guide = guide_colourstrip(inside = TRUE))