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 the name specified inlabs
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 bylegend.title
intheme
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. IfFALSE
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 bylegend.text
intheme
or 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 islegend.key.width
orlegend.key.size
intheme
or theme.- keyheight
A numeric or a
unit
object specifying the height of the legend key. Default value islegend.key.height
orlegend.key.size
intheme
or theme.- direction
A character string indicating the direction of the guide. One of "horizontal" or "vertical."
- default.unit
A character string indicating
unit
forkeywidth
andkeyheight
.- 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 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.
- ...
ignored.
Details
Guides can be specified in each scale_*
or in guides
.
guide="legend"
in scale_*
is syntactic sugar for
guide=guide_legend()
(e.g. scale_color_manual(guide = "legend")
).
As for how to specify the guide for each scale in more detail,
see guides
.
See also
Other guides:
guide_colourbar()
,
guides()
Examples
# \donttest{
df <- reshape2::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(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 = 0
)
)
)
# label position
p1 + guides(fill = guide_legend(label.position = "left", label.hjust = 1))
# 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 = 1,
label.theme = element_text(angle = 90)
)
)
# Set aesthetic of legend key
# very low alpha value make it difficult to see legend key
p3 <- ggplot(diamonds, aes(carat, price)) +
geom_point(aes(colour = color), alpha = 1/100)
p3
# override.aes overwrites the alpha
p3 + guides(colour = guide_legend(override.aes = list(alpha = 1)))
# multiple row/col legends
df <- data.frame(x = 1:20, y = 1:20, color = letters[1:20])
p <- ggplot(df, aes(x, y)) +
geom_point(aes(colour = color))
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))
# }