guide_legend

0th

Percentile

Legend guide.

Legend type guide shows key (i.e., geoms) mapped onto values. Legend guides for various scales are integrated if possible.

Usage
guide_legend(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, keywidth = NULL, keyheight = NULL,
  direction = NULL, default.unit = "line", override.aes = list(),
  nrow = NULL, ncol = NULL, byrow = FALSE, reverse = FALSE, order = 0,
  ...)
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 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.
keywidth
A numeric or a unit object specifying the width of the legend key. Default value is legend.key.width or legend.key.size in theme or theme.
keyheight
A numeric or a unit object specifying the height of the legend key. Default value is legend.key.height or legend.key.size in theme or theme.
direction
A character string indicating the direction of the guide. One of "horizontal" or "vertical."
default.unit
A character string indicating unit for keywidth and keyheight.
override.aes
A list specifying aesthetic parameters of legend key. See details and examples.
nrow
The desired number of rows of legends.
ncol
The desired number of column of legends.
byrow
logical. If FALSE (the default) the legend-matrix is filled by columns, otherwise the legend-matrix is filled by rows.
reverse
logical. If TRUE the order of legends is reversed.
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.
...
ignored.
Details

Guides can be specified in each scale or in guides. guide="legend" in scale is syntactic sugar for guide=guide_legend(). As for how to specify the guide for each scales in more detail, see guides.

Value

  • A guide object

See Also

Other guides: guide_colorbar, guide_colourbar; guides

Aliases
  • guide_legend
Examples
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 = "legend")
p1 + scale_fill_continuous(guide = guide_legend())

# Guide title

p1 + scale_fill_continuous(guide = guide_legend(title = "V")) # title text
p1 + scale_fill_continuous(name = "V") # same
p1 + scale_fill_continuous(guide = guide_legend(title = NULL)) # no title

# Control styles

# key size
p1 + guides(fill = guide_legend(keywidth = 3, keyheight = 1))

# title position
p1 + guides(fill = guide_legend(title = "LEFT", title.position = "left"))

# title text styles via element_text
p1 + guides(fill = guide_legend(
  title.theme = element_text(size=15, face="italic", colour = "red", angle = 45)))

# label position
p1 + guides(fill = guide_legend(label.position = "bottom"))

# label styles
p1 + scale_fill_continuous(breaks = c(5, 10, 15),
  labels = paste("long", c(5, 10, 15)),
  guide = guide_legend(direction = "horizontal", title.position = "top",
    label.position="bottom", label.hjust = 0.5, label.vjust = 0.5,
    label.theme = element_text(angle = 90)))

# Set aesthetic of legend key

# very low alpha value make it difficult to see legend key
p3 <- qplot(carat, price, data = diamonds, colour = color,
  alpha = I(1/100))
p3

# override.aes overwrites the alpha
p3 + guides(colour = guide_legend(override.aes = list(alpha = 1)))

# multiple row/col legends
p <- qplot(1:20, 1:20, colour = letters[1:20])
p + guides(col = guide_legend(nrow = 8))
p + guides(col = guide_legend(ncol = 8))
p + guides(col = guide_legend(nrow = 8, byrow = TRUE))
p + guides(col = guide_legend(ncol = 8, byrow = TRUE))

# reversed order legend
p + guides(col = guide_legend(reverse = TRUE))
Documentation reproduced from package ggplot2, version 1.0.1, License: GPL-2

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