Package 'cowplot'

Description

This function can add an arbitrary label or mathematical expression underneath the plot, similar to the sub parameter in base R. It is mostly superseded now by the caption argument to ggplot2::labs(), and it is recommended to use caption instead of add_sub() whenever possible.

Usage

add_sub(
  plot,
  label,
  x = 0.5,
  y = 0.5,
  hjust = 0.5,
  vjust = 0.5,
  vpadding = grid::unit(1, "lines"),
  fontfamily = "",
  fontface = "plain",
  color = "black",
  size = 14,
  angle = 0,
  lineheight = 0.9,
  colour
)

Arguments

Details

The exact location where the label is placed is controlled by the parameters x, y, hjust, and vjust. By default, all these parameters are set to 0.5, which places the label centered underneath the plot panel. A value of x = 0 indicates the left boundary of the plot panel and a value of x = 1 indicates the right boundary. The parameter hjust works just as elsewhere in ggplot2. Thus, x = 0, hjust = 0 places the label left-justified at the left boundary of the plot panel, x = 0.5, hjust = 0.5 places the label centered underneath the plot panel, and x = 1, hjust = 1 places it right-justified at the right boundary of the plot panel. x-values below 0 or above 1 are allowed, and they move the label beyond the limits of the plot panel.

The y coordinates are relative to the added vertical space that is introduced underneath the x-axis label to place the annotation. A value of y=0 indicates the bottom-most edge of that space and a value of y=1 indicates the top-most edge of that space. The total height of the added space is given by the height needed to draw the label plus the value of vpadding. Thus, if y=0, vjust=0 then the extra padding is added entirely above the label, if y=1, vjust=1 then the extra padding is added entirely below the label, and if y=0.5, vjust=0.5 (the default) then the extra padding is added equally above and below the label. As is the case with x, y-values outside the range 0-1 are allowed. In particular, for sufficiently large values of y, the label will eventually be located inside the plot panel.

Value

A gtable object holding the modified plot.

Examples

library(ggplot2)
theme_set(theme_half_open())
p1 <- ggplot(mtcars, aes(mpg, disp)) + geom_line(colour = "blue") + background_grid(minor='none')
ggdraw(add_sub(p1, "This is an annotation.\nAnnotations can span multiple lines."))

# You can also do this repeatedly.
p2 <- add_sub(p1, "This formula has no relevance here:", y  = 0, vjust = 0)
p3 <- add_sub(p2, expression(paste(a^2+b^2, " = ", c^2)))
ggdraw(p3)

#This code also works with faceted plots:
plot.iris <- ggplot(iris, aes(Sepal.Length, Sepal.Width)) +
  geom_point() + facet_grid(. ~ Species) + stat_smooth(method = "lm") +
  background_grid(major = 'y', minor = "none") + # add thin horizontal lines
  panel_border() # and a border around each panel
p2 <- add_sub(plot.iris, "Annotation underneath a faceted plot, left justified.", x = 0, hjust = 0)
ggdraw(p2)

# Finally, it is possible to move the annotation inside of the plot if desired.
ggdraw(add_sub(p1, "Annotation inside plot", vpadding=grid::unit(0, "lines"),
       y = 6, x = 0.03, hjust = 0))

Description

Align the plot area of multiple plots. Inputs are a list of plots plus alignment parameters. Horizontal or vertical alignment or both are possible. In the simplest case the function will align all elements of each plot, but it can handle more complex cases as long as the axis parameter is defined. In this case, alignment is done through a call to align_margin(). The function align_plots is called by the plot_grid() function and is usually not called directly, though direct calling of the function is useful if plots with multiple y-axes are desired (see example).

Usage

align_plots(
  ...,
  plotlist = NULL,
  align = c("none", "h", "v", "hv"),
  axis = c("none", "l", "r", "t", "b", "lr", "tb", "tblr"),
  greedy = TRUE
)

Arguments

Examples

library(ggplot2)

p1 <- ggplot(mpg, aes(manufacturer, hwy)) + stat_summary(fun.y="median", geom = "bar") +
  theme_half_open() +
  theme(axis.text.x = element_text(angle = 45, hjust = 1, vjust= 1))
p2 <- ggplot(mpg, aes(manufacturer, displ)) + geom_point(color="red") +
  scale_y_continuous(position = "right") +
  theme_half_open() + theme(axis.text.x = element_blank())

# manually align and plot on top of each other
aligned_plots <- align_plots(p1, p2, align="hv", axis="tblr")

# Note: In most cases two y-axes should not be used, but this example
# illustrates how one could accomplish it.
ggdraw(aligned_plots[[1]]) + draw_plot(aligned_plots[[2]])

Description

This function does its best attempt to take whatever you provide it and turn it into a grob. It is primarily meant to convert ggplot plots into grobs, but it will also take any grid object (grob), a recorded base R plot, a formula specifying a base R plot, a function that generates a base R plot, or a trellis object.

Usage

as_grob(plot, device = NULL)

Arguments

Examples

library(grid)
x <- 1:10
y <- (1:10)^2

p <- ~plot(x, y)
grid.newpage()
grid.draw(as_grob(p))

Description

This function does its best attempt to take whatever you provide it and turn it into a gtable. It is primarily meant to convert ggplot plots into gtables, but it will also take any grid object (grob), a recorded R base plot, or a function that generates an R base plot.

Usage

as_gtable(plot)

plot_to_gtable(plot)

Arguments

Details

To convert ggplot plots, the function needs to use a null graphics device. This can be set with set_null_device().

Description

This function takes an existing ggplot2 plot and copies one or both of the axis into a new plot. The main idea is to use this in conjunction with insert_xaxis_grob() or insert_yaxis_grob() to draw custom axis-like objects or margin annotations. Importantly, while this function works for both continuous and discrete scales, notice that discrete scales are converted into continuous scales in the returned axis canvas. The levels of the discrete scale are placed at continuous values of 1, 2, 3, etc. See Examples for an example of how to convert a discrete scale into a continuous scale.

Usage

axis_canvas(
  plot,
  axis = "y",
  data = NULL,
  mapping = aes(),
  xlim = NULL,
  ylim = NULL,
  coord_flip = FALSE
)

Arguments

Examples

# annotate line graphs with labels on the right
library(dplyr)
library(tidyr)
library(ggplot2)
theme_set(theme_half_open())
x <- seq(0, 10, .1)
d <- data.frame(x,
                linear = x,
                squared = x*x/5,
                cubed = x*x*x/25) %>%
  gather(fun, y, -x)

pmain <- ggplot(d, aes(x, y, group = fun)) + geom_line()  +
  scale_x_continuous(expand = c(0, 0))

paxis <- axis_canvas(pmain, axis = "y") +
  geom_text(data = filter(d, x == max(x)), aes(y = y, label = paste0(" ", fun)),
            x = 0, hjust = 0, vjust = 0.5)
ggdraw(insert_yaxis_grob(pmain, paxis, grid::unit(.25, "null")))

# discrete scale with integrated color legend
pmain <- ggplot(iris, aes(x = Species, y = Sepal.Length, fill = Species)) +
  geom_violin(trim = FALSE) + guides(fill = "none") +
  scale_x_discrete(labels = NULL) +
  theme_minimal()

label_data <- data.frame(x = 1:nlevels(iris$Species),
                         Species = levels(iris$Species))
paxis <- axis_canvas(pmain, axis = "x", data = label_data, mapping = aes(x = x)) +
  geom_tile(aes(fill = Species, y = 0.5), width = 0.9, height = 0.3) +
  geom_text(aes(label = Species, y = 0.5), hjust = 0.5, vjust = 0.5, size = 11/.pt)
ggdraw(insert_xaxis_grob(pmain, paxis, grid::unit(.07, "null"),
                         position = "bottom"))

# add marginal density distributions to plot
pmain <- ggplot(iris, aes(x=Sepal.Length, y=Sepal.Width, color=Species)) + geom_point()

xdens <- axis_canvas(pmain, axis = "x") +
  geom_density(data=iris, aes(x=Sepal.Length, fill=Species), alpha=0.7, size=.2)

# need to set `coord_flip = TRUE` if you plan to use `coord_flip()`
ydens <- axis_canvas(pmain, axis = "y", coord_flip = TRUE) +
  geom_density(data=iris, aes(x=Sepal.Width, fill=Species), alpha=0.7, size=.2) +
  coord_flip()

p1 <- insert_xaxis_grob(pmain, xdens, grid::unit(.2, "null"), position = "top")
p2 <- insert_yaxis_grob(p1, ydens, grid::unit(.2, "null"), position = "right")
ggdraw(p2)

Description

This function provides a simple way to set the background grid in ggplot2. It doesn't do anything that can't be done just the same with theme(). However, it simplifies creation of the most commonly needed variations.

Usage

background_grid(
  major = c("xy", "x", "y", "only_minor", "none"),
  minor = c("none", "xy", "x", "y"),
  size.major = 0.5,
  size.minor = 0.2,
  color.major = "grey85",
  color.minor = "grey85",
  colour.major,
  colour.minor
)

Arguments

Details

Note: This function completely overwrites all background grid settings of the current theme. If that is not what you want, you may be better off using theme() directly.

Examples

library(ggplot2)

ggplot(iris, aes(Sepal.Length, Sepal.Width)) +
 geom_point() +
 theme_half_open() +
 background_grid()

Description

The main purpose of this function is to add labels specifying extra information about the figure, such as "Figure 1", or "A" - often useful in cowplots with more than one pane. The function is similar to draw_plot_label.

Usage

draw_figure_label(
  label,
  position = c("top.left", "top", "top.right", "bottom.left", "bottom", "bottom.right"),
  size,
  fontface,
  ...
)

Arguments

Author(s)

Ulrik Stervbo (ulrik.stervbo @ gmail.com)

See Also

draw_plot_label

Examples

library(ggplot2)
df <- data.frame(
  x = 1:10, y1 = 1:10, y2 = (1:10)^2, y3 = (1:10)^3, y4 = (1:10)^4
)

p1 <- ggplot(df, aes(x, y1)) + geom_point()
p2 <- ggplot(df, aes(x, y2)) + geom_point()
p3 <- ggplot(df, aes(x, y3)) + geom_point()
p4 <- ggplot(df, aes(x, y4)) + geom_point()

# Create a simple grid
p <- plot_grid(p1, p2, p3, p4, align = 'hv')

# Default font size and position
p + draw_figure_label(label = "Figure 1")

# Different position and font size
p + draw_figure_label(label = "Figure 1", position = "bottom.right", size = 10)

# Using bold font face
p + draw_figure_label(label = "Figure 1", fontface = "bold")

# Making the label red and slanted
p + draw_figure_label(label = "Figure 1", angle = -45, colour = "red")

# Labeling an individual plot
ggdraw(p2) + draw_figure_label(label = "Figure 1", position = "bottom.right", size = 10)

Description

Places an arbitrary grob somewhere onto the drawing canvas. By default, coordinates run from 0 to 1, and the point (0, 0) is in the lower left corner of the canvas.

Usage

draw_grob(
  grob,
  x = 0,
  y = 0,
  width = 1,
  height = 1,
  scale = 1,
  clip = "inherit",
  hjust = 0,
  vjust = 0,
  halign = 0.5,
  valign = 0.5
)

Arguments

Examples

# A grid grob (here a blue circle)
g <- grid::circleGrob(gp = grid::gpar(fill = "blue"))
# place into the middle of the plotting area, at a scale of 50%
ggdraw() + draw_grob(g, scale = 0.5)

Description

Places an image somewhere onto the drawing canvas. By default, coordinates run from 0 to 1, and the point (0, 0) is in the lower left corner of the canvas. Requires the magick package to work, and fails gracefully if that package is not installed.

Usage

draw_image(
  image,
  x = 0,
  y = 0,
  width = 1,
  height = 1,
  scale = 1,
  clip = "inherit",
  interpolate = TRUE,
  hjust = 0,
  vjust = 0,
  halign = 0.5,
  valign = 0.5
)

Arguments

Examples

library(ggplot2)

# Use image as plot background
p <- ggplot(iris, aes(x = Sepal.Length, fill = Species)) +
  geom_density(alpha = 0.7) +
  scale_y_continuous(expand = expansion(mult = c(0, 0.05))) +
  theme_half_open(12)

logo_file <- system.file("extdata", "logo.png", package = "cowplot")
ggdraw() +
  draw_image(
    logo_file, scale = .7
  ) +
  draw_plot(p)

# Place in lower right corner
ggdraw() +
  draw_image(
    logo_file, scale = .3, x = 1,
    hjust = 1, halign = 1, valign = 0
  ) +
  draw_plot(p)

## Not run: 

# Make grid with plot and image
cow_file <- system.file("extdata", "cow.jpg", package = "cowplot")
p2 <- ggdraw() + draw_image(cow_file, scale = 0.9)
plot_grid(
  p + theme(legend.position = c(1, 1), legend.justification = c(1, 1)),
  p2,
  labels = "AUTO"
)

# Manipulate images and draw in plot coordinates
if (requireNamespace("magick", quietly = TRUE)){
  img <- magick::image_transparent(
    magick::image_read(logo_file),
    color = "white"
  )
  img2 <- magick::image_negate(img)
  ggplot(data.frame(x = 1:3, y = 1:3), aes(x, y)) +
    geom_point(size = 3) +
    geom_abline(slope = 1, intercept = 0, linetype = 2, color = "blue") +
    draw_image(img , x = 1, y = 1, scale = .9) +
    draw_image(img2, x = 2, y = 2, scale = .9)
}

## End(Not run)

Description

This function can draw either a character string or mathematical expression at the given coordinates. It works both on top of ggdraw and directly with ggplot, depending on which coordinate system is desired (see examples).

Usage

draw_label(
  label,
  x = 0.5,
  y = 0.5,
  hjust = 0.5,
  vjust = 0.5,
  fontfamily = "",
  fontface = "plain",
  color = "black",
  size = 14,
  angle = 0,
  lineheight = 0.9,
  alpha = 1,
  colour
)

Arguments

Details

By default, the x and y coordinates specify the center of the text box. Set hjust = 0, vjust = 0 to specify the lower left corner, and other values of hjust and vjust for any other relative location you want to specify.

See Also

ggdraw

Examples

library(ggplot2)

# setup plot and a label (regression description)
p <- ggplot(mtcars, aes(disp, mpg)) +
  geom_line(color = "blue") +
  theme_half_open() +
  background_grid(minor = 'none')
out <- cor.test(mtcars$disp, mtcars$mpg, method = 'sp', exact = FALSE)
label <- substitute(
  paste("Spearman ", rho, " = ", estimate, ", P = ", pvalue),
  list(estimate = signif(out$estimate, 2), pvalue = signif(out$p.value, 2))
)

# Add label to plot, centered on {x,y} (in data coordinates)
p + draw_label(label, x = 300, y = 32)
# Add label to plot in data coordinates, flush-left at x, baseline at y.
p + draw_label(label, x = 100, y = 30, hjust = 0, vjust = 0)

# Add labels via ggdraw. Uses ggdraw coordinates.
# ggdraw coordinates default to xlim = c(0, 1), ylim = c(0, 1).
ggdraw(p) +
  draw_label("centered on 70% of x range,\n90% of y range", x = 0.7, y = 0.9)

ggdraw(p) +
  draw_label("bottom left at (0, 0)", x = 0, y = 0, hjust = 0, vjust = 0) +
  draw_label("top right at (1, 1)", x = 1, y = 1, hjust = 1, vjust = 1) +
  draw_label("centered on (0.5, 0.5)", x = 0.5, y = 0.5, hjust = 0.5, vjust = 0.5)

Description

Provide a sequence of x values and accompanying y values to draw a line on a plot.

Usage

draw_line(x, y, ...)

Arguments

Details

This is a convenience function, providing a wrapper around ggplot2's geom_path.

See Also

geom_path, ggdraw

Examples

ggdraw() +
  draw_line(
    x = c(0.2, 0.7, 0.7, 0.3),
    y = c(0.1, 0.3, 0.9, 0.8),
    color = "blue", size = 2
  )

Description

Places a plot somewhere onto the drawing canvas. By default, coordinates run from 0 to 1, and the point (0, 0) is in the lower left corner of the canvas.

Usage

draw_plot(
  plot,
  x = 0,
  y = 0,
  width = 1,
  height = 1,
  scale = 1,
  hjust = 0,
  vjust = 0,
  halign = 0.5,
  valign = 0.5
)

Arguments

Examples

library(ggplot2)

# make a plot
p <- ggplot(data.frame(x = 1:3, y = 1:3), aes(x, y)) +
    geom_point()
# draw into the top-right corner of a larger plot area
ggdraw() + draw_plot(p, .6, .6, .4, .4)

Description

This function adds a plot label to the upper left corner of a graph (or an arbitrarily specified position). It takes all the same parameters as draw_text, but has defaults that make it convenient to label graphs with letters A, B, C, etc. Just like draw_text(), it can handle vectors of labels with associated coordinates.

Usage

draw_plot_label(
  label,
  x = 0,
  y = 1,
  hjust = -0.5,
  vjust = 1.5,
  size = 16,
  fontface = "bold",
  family = NULL,
  color = NULL,
  colour,
  ...
)

Arguments

Description

This is a convenience function to plot multiple pieces of text at the same time. It cannot handle mathematical expressions, though. For those, use draw_label.

Usage

draw_text(text, x = 0.5, y = 0.5, size = 14, hjust = 0.5, vjust = 0.5, ...)

Arguments

Details

Note that font sizes are scaled by a factor of 2.85, so sizes agree with those of the theme. This is different from geom_text in ggplot2.

By default, the x and y coordinates specify the center of the text box. Set hjust = 0, vjust = 0 to specify the lower left corner, and other values of hjust and vjust for any other relative location you want to specify.

For a full list of ... options, see geom_label.

See Also

draw_label

Examples

# Draw onto a 1*1 drawing surface
ggdraw() + draw_text("Hello World!", x = 0.5, y = 0.5)
#
# Adorn a plot from the Anscombe data set of "identical" data.
library(ggplot2)

p <- ggplot(anscombe, aes(x1, y1)) + geom_point() + geom_smooth()
three_strings <- c("Hello World!", "to be or not to be", "over and out")
p + draw_text(three_strings, x = 8:10, y = 5:7, hjust = 0)

Description

This function extracts just the legend from a ggplot

Usage

get_legend(plot)

Arguments

Value

A gtable object holding just the legend or NULL if there is no legend.

Examples

library(ggplot2)
theme_set(theme_half_open())

p1 <- ggplot(mtcars, aes(mpg, disp)) + geom_line()
plot.mpg <- ggplot(mpg, aes(x = cty, y = hwy, colour = factor(cyl))) + geom_point(size=2.5)
# Note that these cannot be aligned vertically due to the legend in the plot.mpg
ggdraw(plot_grid(p1, plot.mpg, ncol=1, align='v'))

legend <- get_legend(plot.mpg)
plot.mpg <- plot.mpg + theme(legend.position='none')
# Now plots are aligned vertically with the legend to the right
ggdraw(plot_grid(plot_grid(p1, plot.mpg, ncol=1, align='v'),
                 plot_grid(NULL, legend, ncol=1),
                 rel_widths=c(1, 0.2)))

Description

get_panel() extracts just the main panel from a ggplot or a specified panel in a faceted plot. get_panel_component() extracts components from the panel, such as geoms.

Usage

get_panel(plot, panel = NULL, return_all = FALSE)

get_panel_component(panel, pattern)

Arguments

Value

A gtable object holding the panel(s) or a grob of the component

Examples

library(ggplot2)

p <- ggplot(mpg, aes(displ, cty)) + geom_point()
plot_panel <- get_panel(p)
ggdraw(plot_panel)

ggdraw(get_panel_component(plot_panel, "geom_point"))

Description

Extract plot components from a ggplot or gtable. get_plot_component() extracts grobs or a list of grobs. plot_component_names() provides the names of the components in the plot. plot_components() returns all components as a list.

Usage

get_plot_component(plot, pattern, return_all = FALSE)

plot_component_names(plot)

plot_components(plot)

Arguments

Value

A grob or list of grobs (get_plot_component(), plot_components()) or a character vector (plot_component_names())

Examples

library(ggplot2)

p <- ggplot(mpg, aes(displ, cty)) + geom_point()
ggdraw(get_plot_component(p, "ylab-l"))

Description

These functions extract just the titles from a ggplot. get_title() pulls the title, while get_subtitle() pulls the subtitle.

Usage

get_title(plot)

get_subtitle(plot)

Arguments

Examples

library(ggplot2)

p <- ggplot(mpg, aes(displ, cty)) +
  geom_point() +
  labs(
    title = "Plot title",
    subtitle = "Plot subtitle"
  )
ggdraw(get_title(p))
ggdraw(get_subtitle(p))

Description

These functions extract just the axes from a ggplot. get_y_axis() pulls the y-axis, while get_x_axis() pulls the x-axis.

Usage

get_y_axis(plot, position = c("left", "right"))

get_x_axis(plot, position = c("bottom", "top"))

Arguments

Examples

library(ggplot2)

p <- ggplot(mpg, aes(displ, cty)) +
  geom_point()

ggdraw(get_y_axis(p))
p <- p + scale_x_continuous(position = "top")
ggdraw(get_x_axis(p, position = "top"))

Description

Set up a drawing layer on top of a ggplot.

Usage

ggdraw(plot = NULL, xlim = c(0, 1), ylim = c(0, 1), clip = "off")

Arguments

Examples

library(ggplot2)

p <- ggplot(mpg, aes(displ, cty)) +
  geom_point() +
  theme_minimal_grid()
ggdraw(p) + draw_label("Draft", colour = "#80404080", size = 120, angle = 45)

Description

This function behaves just like ggsave() from ggplot2. The main difference is that by default it doesn't use the Dingbats font for pdf output. The Dingbats font causes problems with some pdf readers.

Usage

ggsave2(
  filename,
  plot = ggplot2::last_plot(),
  device = NULL,
  path = NULL,
  scale = 1,
  width = NA,
  height = NA,
  units = c("in", "cm", "mm"),
  dpi = 300,
  limitsize = TRUE,
  ...
)

Arguments

Description

Remove named elements from gtable

Usage

gtable_remove_grobs(table, names, ...)

Arguments

Description

Set the width of given columns to 0.

Usage

gtable_squash_cols(table, cols)

Arguments

Description

Set the height of given rows to 0.

Usage

gtable_squash_rows(table, rows)

Arguments

Insert an axis-like grob on either side of a plot panel in a ggplot2 plot.

Description

The function insert_xaxis_grob() inserts a grob at the top or bottom of the plot panel in a ggplot2 plot.

Usage

insert_xaxis_grob(
  plot,
  grob,
  height = grid::unit(0.2, "null"),
  position = c("top", "bottom"),
  clip = "on"
)

insert_yaxis_grob(
  plot,
  grob,
  width = grid::unit(0.2, "null"),
  position = c("right", "left"),
  clip = "on"
)

Arguments

Details

For usage examples, see axis_canvas().

Description

This function provides a simple way to modify the panel border in ggplot2. It doesn't do anything that can't be done just the same with theme(). However, it saves some typing.

Usage

panel_border(color = "grey85", size = 1, linetype = 1, remove = FALSE, colour)

Arguments

Description

Arrange multiple plots into a grid.

Usage

plot_grid(
  ...,
  plotlist = NULL,
  align = c("none", "h", "v", "hv"),
  axis = c("none", "l", "r", "t", "b", "lr", "tb", "tblr"),
  nrow = NULL,
  ncol = NULL,
  rel_widths = 1,
  rel_heights = 1,
  labels = NULL,
  label_size = 14,
  label_fontfamily = NULL,
  label_fontface = "bold",
  label_colour = NULL,
  label_x = 0,
  label_y = 1,
  hjust = -0.5,
  vjust = 1.5,
  scale = 1,
  greedy = TRUE,
  byrow = TRUE,
  cols = NULL,
  rows = NULL
)

Arguments

Examples

library(ggplot2)

df <- data.frame(
  x = 1:10, y1 = 1:10, y2 = (1:10)^2, y3 = (1:10)^3, y4 = (1:10)^4
)

p1 <- ggplot(df, aes(x, y1)) + geom_point()
p2 <- ggplot(df, aes(x, y2)) + geom_point()
p3 <- ggplot(df, aes(x, y3)) + geom_point()
p4 <- ggplot(df, aes(x, y4)) + geom_point()
p5 <- ggplot(mpg, aes(as.factor(year), hwy)) +
        geom_boxplot() +
        facet_wrap(~class, scales = "free_y")
# simple grid
plot_grid(p1, p2, p3, p4)

# simple grid with labels and aligned plots
plot_grid(
  p1, p2, p3, p4,
  labels = c('A', 'B', 'C', 'D'),
  align="hv"
)

# manually setting the number of rows, auto-generate upper-case labels
plot_grid(p1, p2, p3,
  nrow = 3,
  labels = "AUTO",
  label_size = 12,
  align = "v"
)

# making rows and columns of different widths/heights
plot_grid(
  p1, p2, p3, p4,
  align = 'hv',
  rel_heights = c(2,1),
  rel_widths = c(1,2)
)

# aligning complex plots in a grid
plot_grid(
  p1, p5,
  align = "h", axis = "b", nrow = 1, rel_widths = c(1, 2)
)

# more examples

#' # missing plots in some grid locations, auto-generate lower-case labels
plot_grid(
  p1, NULL, NULL, p2, p3, NULL,
  ncol = 2,
  labels = "auto",
  label_size = 12,
  align = "v"
)

# can arrange plots on the grid by column as well as by row.
plot_grid(
  p1, NULL, p2, NULL, p3,
  ncol = 2,
  byrow = TRUE
)

# can align top of plotting area as well as bottom
plot_grid(
  p1, p5,
  align = "h", axis = "tb",
  nrow = 1, rel_widths = c(1, 2)
)

# other types of plots not generated with ggplot
p6 <- ~{
  par(
    mar = c(3, 3, 1, 1),
    mgp = c(2, 1, 0)
  )
  plot(sqrt)
}

p7 <- function() {
  par(
    mar = c(2, 2, 1, 1),
    mgp = c(2, 1, 0)
  )
  image(volcano)
}
p8 <- grid::circleGrob()

plot_grid(p1, p6, p7, p8, labels = "AUTO", scale = c(1, .9, .9, .7))

Description

Null devices to be used when rendering graphics in the background. See set_null_device() for details.

Usage

png_null_device(width, height)

pdf_null_device(width, height)

cairo_null_device(width, height)

agg_null_device(width, height)

Arguments

Description

These functions create customizable legend key glyphs, such as filled rectangles or circles.

Usage

rectangle_key_glyph(
  colour = NA,
  fill = fill,
  alpha = alpha,
  size = size,
  linetype = linetype,
  padding = unit(c(0, 0, 0, 0), "pt"),
  color
)

circle_key_glyph(
  colour = NA,
  fill = fill,
  alpha = alpha,
  size = size,
  linetype = linetype,
  padding = unit(c(0, 0, 0, 0), "pt"),
  color
)

Arguments

Examples

library(ggplot2)

set.seed(1233)
df <- data.frame(
  x = sample(letters[1:2], 10, TRUE),
  y = rnorm(10)
)

ggplot(df, aes(x, y, color = x)) +
  geom_boxplot(
    key_glyph = rectangle_key_glyph(fill = color, padding = margin(3, 3, 3, 3))
  )

ggplot(df, aes(x, y, color = x)) +
  geom_boxplot(
    key_glyph = circle_key_glyph(
      fill = color,
      color = "black", linetype = 3, size = 0.3,
      padding = margin(2, 2, 2, 2)
    )
  )

Description

This function replaces the standard ggsave() function for saving a plot into a file. It has several advantages over ggsave(). First, it uses default sizes that work well with the cowplot theme, so that frequently a plot size does not have to be explicitly specified. Second, it acknowledges that one often first develops individual plots and then combines them into multi-plot figures, and it makes it easy—in combination with plot_grid()—to carry out this workflow. Finally, it makes it easy to adjust the aspect ratio of the figure, which is frequently necessary to accommodate plots with or without figure legend.

Usage

save_plot(
  filename,
  plot,
  ncol = 1,
  nrow = 1,
  base_height = 3.71,
  base_asp = 1.618,
  base_width = NULL,
  ...,
  cols,
  rows,
  base_aspect_ratio,
  width,
  height
)

Arguments

Details

The key idea for this function is that plots are often grids, with sup-plots at the individual grid locations. Therefore, for this function we specify a base width and aspect ratio that apply to one sup-plot, and we then specify how many rows and columns of subplots we have. This means that if we have code that can save a single figure, it is trivial to adapt this code to save a combination of multiple comparable figures. See examples for details.

Examples

library(ggplot2)

# save a single plot with a legend
p1 <- ggplot(mpg, aes(x = cty, y = hwy, color = factor(cyl))) +
  geom_point(size = 2) +
  theme_half_open()

file1 <- tempfile("file1", fileext = ".png")
file2 <- tempfile("file2", fileext = ".png")
save_plot(file1, p1)
# same as file1 but determine base_width given base_height
save_plot(file2, p1, base_height = NULL, base_width = 6)

# save a single plot without legend, adjust aspect ratio
x <- (1:100)/10
p3 <- ggplot(data.frame(x = x, y = x*sin(x)), aes(x, y)) +
 geom_line() +
 theme_minimal_hgrid()
file3 <- tempfile("file3", fileext = ".pdf")
save_plot(file3, p3, base_asp = 1.1)

# now combine with a second plot and save
p3b <- ggplot(data.frame(x = x, y = cos(x)+x), aes(x, y)) +
 geom_line() +
 theme_minimal_hgrid()
p4 <- plot_grid(p3, p3b, labels = "AUTO")
file4 <- tempfile("file4", fileext = ".pdf")
save_plot(file4, p4, ncol = 2, base_asp = 1.1)

Description

The function as_grob() needs to open a graphics device to render ggplot objects into grid graphics objects. Unfortunately, there is no universally reliable graphics device available in R that always works. Therefore, this function allows you to switch out the null device.

Usage

set_null_device(null_device)

Arguments

Details

You need to be aware that some graphics devices cause side effects when used as null devices. If you use an interactive device as null device, you may see an empty plot window pop up. Similarly, if you use a graphics device that writes a file, then you may find temporary files associated with the device. The default null device, pdf(NULL), does not cause these side effects. However, it has has other limitations. For example, on OS X, it cannot use all the fonts that are available on the system. The ragg device can use all fonts, but it will create temporary files.

See Also

Available null devices are: pdf_null_device(), png_null_device(), cairo_null_device(), agg_null_device()

Examples

set_null_device("png") # set the png null device

# create a jpeg null device
jpeg_null_device <- function(width, height) {
  jpeg(
    filename = tempfile(pattern = "jpeg_null_plot", fileext = ".jpg"),
    width = width, height = height, units = "in", res = 96
   )
  dev.control("enable")
}
set_null_device(jpeg_null_device)

Description

Stamp plots with a label, such as good, bad, or ugly.

Usage

stamp(
  p,
  label,
  color = "black",
  alpha = 1,
  vjust = 1.1,
  hjust = 1,
  size = 14,
  family = "",
  fontface = "bold",
  clip = "on",
  colour
)

stamp_good(p, ...)

stamp_bad(p, ...)

stamp_wrong(p, ...)

stamp_ugly(p, ...)

Arguments

Examples

library(ggplot2)

p <- ggplot(iris, aes(x = Sepal.Length, y = Sepal.Width)) +
  geom_point(aes(color = factor(Petal.Width)))

stamp_bad(p + guides(color = "none"))
stamp_ugly(p)

Description

The default cowplot theme, with a simple half-open frame and no grid. This theme used to be set by default after loading the cowplot package, but this is no longer the case.

Usage

theme_cowplot(
  font_size = 14,
  font_family = "",
  line_size = 0.5,
  rel_small = 12/14,
  rel_tiny = 11/14,
  rel_large = 16/14
)

theme_half_open(
  font_size = 14,
  font_family = "",
  line_size = 0.5,
  rel_small = 12/14,
  rel_tiny = 11/14,
  rel_large = 16/14
)

Arguments

Details

Both theme_cowplot() and theme_half_open() provide exactly the same styling.

Value

The theme.

Examples

library(ggplot2)

ggplot(mtcars, aes(disp, mpg)) +
  geom_point() +
  theme_cowplot(font_size = 12)

Description

The theme created by this function is useful for plotting maps with cowplot default sizing.

Usage

theme_map(
  font_size = 14,
  font_family = "",
  line_size = 0.5,
  rel_small = 12/14,
  rel_tiny = 11/14,
  rel_large = 16/14
)

Arguments

Value

The theme.

Examples

library(ggplot2)
library(maps)

usa_data = map_data("usa")
ggplot(usa_data, aes(long, lat, fill = region)) +
  geom_polygon() + theme_map()
ggplot(usa_data, aes(long, lat, fill = region)) +
  facet_wrap(~region, scales = "free") +
  geom_polygon() + theme_map()

Description

Three minimalistic themes that provide either a full grid, a horizontal grid, or a vertical grid. Similar to theme_minimal(), but with some stylistic differences. Most importantly, these themes do not draw minor grid lines. Also, font sizes are coordinated with theme_half_open() and with the defaults in the save_plot() function.

Usage

theme_minimal_grid(
  font_size = 14,
  font_family = "",
  line_size = 0.5,
  rel_small = 12/14,
  rel_tiny = 11/14,
  rel_large = 16/14,
  color = "grey85",
  colour
)

theme_minimal_vgrid(
  font_size = 14,
  font_family = "",
  line_size = 0.5,
  rel_small = 12/14,
  rel_tiny = 11/14,
  rel_large = 16/14,
  color = "grey85",
  colour
)

theme_minimal_hgrid(
  font_size = 14,
  font_family = "",
  line_size = 0.5,
  rel_small = 12/14,
  rel_tiny = 11/14,
  rel_large = 16/14,
  color = "grey85",
  colour
)

Arguments

Details

theme_minimal_grid() provides a minimal grid theme. theme_minimal_hgrid() strips down this theme even further and draws only horizontal lines, and theme_minimal_vgrid() does the same for vertical lines.

Examples

library(ggplot2)

# theme_minimal_grid()
ggplot(iris, aes(x = Sepal.Length, y = Sepal.Width, color = Species)) +
  geom_point() + theme_minimal_grid()

# theme_minimal_hgrid()
ggplot(mtcars, aes(x = carb)) +
  geom_bar(fill = "lightblue") +
  scale_y_continuous(limits = c(0, 11.5), expand = c(0, 0)) +
  theme_minimal_hgrid()

# theme_minimal_vgrid()
ggplot(mtcars, aes(x = carb)) +
  geom_bar(fill = "lightblue") +
  scale_y_continuous(limits = c(0, 11.5), expand = c(0, 0)) +
  coord_flip() +
  theme_minimal_vgrid()

Description

The theme created by this function shows nothing but the plot panel.

Usage

theme_nothing(font_size = 14, font_family = "", rel_small = 12/14)

Arguments

Value

The theme.

Examples

library(ggplot2)

ggplot(mtcars, aes(disp, mpg, color = cyl)) +
  geom_point() +
  theme_nothing()