guide_colourbar: Continuous colour bar guide.

Description

Colour bar guide shows continuous color scales mapped onto values. Colour bar is available with scale_fill and scale_colour. For more information, see the inspiration for this function: http://www.mathworks.com/help/techdoc/ref/colorbar.html{Matlab's colorbar function}.

Usage

guide_colourbar(title = 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, nbin = 20, raster = TRUE, ticks = TRUE,
  draw.ulim = TRUE, draw.llim = TRUE, direction = NULL,
  default.unit = "line", reverse = FALSE, order = 0, ...)
guide_colorbar(title = 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, nbin = 20, raster = TRUE, ticks = TRUE,
  draw.ulim = TRUE, draw.llim = TRUE, direction = NULL,
  default.unit = "line", reverse = FALSE, order = 0, ...)

Arguments

barwidth

A numeric or a unit object specifying the width of the colorbar. Default value is legend.key.width or legend.key.size in theme or theme.

barheight

A numeric or a unit object specifying the height of the colorbar. Default value is legend.key.height or legend.key.size in theme or theme.

nbin

A numeric specifying the number of bins for drawing colorbar. A smoother colorbar for a larger value.

raster

A logical. If TRUE then the colorbar is rendered as a raster object. If FALSE then the colorbar is rendered as a set of rectangles. Note that not all graphics devices are capable of rendering raster image.

ticks

A logical specifying if tick marks on colorbar 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.

direction

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

default.unit

A character string indicating unit for barwidth

reverse

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

...

ignored.

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 tha name specified in

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

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 gudie).

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.

label.vjust

A numeric specifying vertical justification of the label text.

order

positive integer less that 99 that specify the order of this guide in the multiple guides. If 0 (default), the order is determined by a secret algorithm.

Value

A guide object

Details

Guides can be specified in each scale or in guides. guide="legend" in scale is syntax sugar for guide=guide_legend() - but the second form allows you to specify more options. As for how to specify the guide for each scales, see guides.

Examples

Run this code

library(reshape2) # for melt
df <- melt(outer(1:4, 1:4), varnames = c("X1", "X2"))

p1 <- ggplot(df, aes(X1, X2)) + geom_tile(aes(fill = value))
p2 <- p1 + geom_point(aes(size = value))

# Basic form
p1 + scale_fill_continuous(guide = "colorbar")
p1 + scale_fill_continuous(guide = guide_colorbar())
p1 + guides(fill = guide_colorbar())

# Control styles

# bar size
p1 + guides(fill = guide_colorbar(barwidth = 0.5, barheight = 10))

# no label
p1 + guides(fill = guide_colorbar(label = FALSE))

# no tick marks
p1 + guides(fill = guide_colorbar(ticks = FALSE))

# label position
p1 + guides(fill = guide_colorbar(label.position = "left"))

# label theme
p1 + guides(fill = guide_colorbar(label.theme = element_text(colour = "blue", angle = 0)))

# small number of bins
p1 + guides(fill = guide_colorbar(nbin = 3))

# large number of bins
p1 + guides(fill = guide_colorbar(nbin = 100))

# make top- and bottom-most ticks invisible
p1 + scale_fill_continuous(limits = c(0,20), breaks=c(0, 5, 10, 15, 20),
 guide = guide_colorbar(nbin=100, draw.ulim = FALSE, draw.llim = FALSE))

# guides can be controlled independently
p2 +
  scale_fill_continuous(guide = "colorbar") +
  scale_size(guide = "legend")
p2 + guides(fill = "colorbar", size = "legend")

p2 +
  scale_fill_continuous(guide = guide_colorbar(direction = "horizontal")) +
  scale_size(guide = guide_legend(direction = "vertical"))