如何从 facet_zoom() 更改缩放区域的位置？
How to change the position of the zoomed area from facet_zoom()?
使用 ggforce 包中的 facet_zoom() 可以创建漂亮的缩放以突出显示绘图的某些区域。不幸的是，当在 y 轴上放大时，原始图总是在右侧。
有没有办法把原图放在左边？
先看主图再看放大区域会感觉更直观。例如，我想交换此图中两个方面的位置：
（没有添加可重现的例子，因为我认为这是一个关于某个功能是否存在的问题。）
我在 GitHub 上为 FacetZoom 调整了 current code 以将水平顺序从 [zoom, original] 切换到 [original, zoom]。这些更改并不复杂，但是它们 分散在 draw_panels() 函数的代码中，因此完整的代码相当长。
结果：
# example 1, with split = FALSE, horizontal = TRUE (i.e. default settings)
p1 <- ggplot(mtcars, aes(x = mpg, y = disp, colour = factor(cyl))) +
geom_point() +
theme_bw()
p1 + ggtitle("Original") + facet_zoom(y = disp > 300)
p1 + ggtitle("Modified") + facet_zoom2(y = disp > 300)
# example 2, with split = TRUE
p2 <- ggplot(iris, aes(Petal.Length, Petal.Width, colour = Species)) +
geom_point() +
theme_bw()
p2 + ggtitle("Original") +
facet_zoom(xy = Species == "versicolor", split = TRUE)
p2 + ggtitle("Modified") +
facet_zoom2(xy = Species == "versicolor", split = TRUE)
使用的代码（我已经注释掉了原始代码，使用修改后的代码，并指出了其他包中函数的包）：
library(ggplot)
library(ggforce)
library(grid)
# define facet_zoom2 function to use FacetZoom2 instead of FacetZoom
# (everything else is the same as facet_zoom)
facet_zoom2 <- function(x, y, xy, zoom.data, xlim = NULL, ylim = NULL,
split = FALSE, horizontal = TRUE, zoom.size = 2,
show.area = TRUE, shrink = TRUE) {
x <- if (missing(x)) if (missing(xy)) NULL else lazyeval::lazy(xy) else lazyeval::lazy(x)
y <- if (missing(y)) if (missing(xy)) NULL else lazyeval::lazy(xy) else lazyeval::lazy(y)
zoom.data <- if (missing(zoom.data)) NULL else lazyeval::lazy(zoom.data)
if (is.null(x) && is.null(y) && is.null(xlim) && is.null(ylim)) {
stop("Either x- or y-zoom must be given", call. = FALSE)
}
if (!is.null(xlim)) x <- NULL
if (!is.null(ylim)) y <- NULL
ggproto(NULL, FacetZoom2,
shrink = shrink,
params = list(
x = x, y = y, xlim = xlim, ylim = ylim, split = split, zoom.data = zoom.data,
zoom.size = zoom.size, show.area = show.area,
horizontal = horizontal
)
)
}
# define FacetZoom as a ggproto object that inherits from FacetZoom,
# with a modified draw_panels function. the compute_layout function references
# the version currently on GH, which is slightly different from the CRAN
# package version.
FacetZoom2 <- ggproto(
"FacetZoom2",
ggforce::FacetZoom,
compute_layout = function(data, params) {
layout <- rbind( # has both x & y dimension
data.frame(name = 'orig', SCALE_X = 1L, SCALE_Y = 1L),
data.frame(name = 'x', SCALE_X = 2L, SCALE_Y = 1L),
data.frame(name = 'y', SCALE_X = 1L, SCALE_Y = 2L),
data.frame(name = 'full', SCALE_X = 2L, SCALE_Y = 2L),
data.frame(name = 'orig_true', SCALE_X = 1L, SCALE_Y = 1L),
data.frame(name = 'zoom_true', SCALE_X = 1L, SCALE_Y = 1L)
)
if (is.null(params$y) && is.null(params$ylim)) { # no y dimension
layout <- layout[c(1,2, 5:6),]
} else if (is.null(params$x) && is.null(params$xlim)) { # no x dimension
layout <- layout[c(1,3, 5:6),]
}
layout$PANEL <- seq_len(nrow(layout))
layout
},
draw_panels = function(panels, layout, x_scales, y_scales, ranges, coord,
data, theme, params) {
if (is.null(params$x) && is.null(params$xlim)) {
params$horizontal <- TRUE
} else if (is.null(params$y) && is.null(params$ylim)) {
params$horizontal <- FALSE
}
if (is.null(theme[['zoom']])) {
theme$zoom <- theme$strip.background
}
if (is.null(theme$zoom.x)) {
theme$zoom.x <- theme$zoom
}
if (is.null(theme$zoom.y)) {
theme$zoom.y <- theme$zoom
}
axes <- render_axes(ranges, ranges, coord, theme, FALSE)
panelGrobs <- ggforce:::create_panels(panels, axes$x, axes$y)
panelGrobs <- panelGrobs[seq_len(length(panelGrobs) - 2)]
if ('full' %in% layout$name && !params$split) {
panelGrobs <- panelGrobs[c(1, 4)]
}
# changed coordinates in indicator / lines to zoom from
# the opposite horizontal direction
if ('y' %in% layout$name) {
if (!inherits(theme$zoom.y, 'element_blank')) {
zoom_prop <- scales::rescale(
y_scales[[2]]$dimension(ggforce:::expansion(y_scales[[2]])),
from = y_scales[[1]]$dimension(ggforce:::expansion(y_scales[[1]])))
indicator <- polygonGrob(
x = c(0, 0, 1, 1), # was x = c(1, 1, 0, 0),
y = c(zoom_prop, 1, 0),
gp = gpar(col = NA, fill = alpha(theme$zoom.y$fill, 0.5)))
lines <- segmentsGrob(
x0 = c(1, 1), x1 = c(0, 0), # was x0 = c(0, 0), x1 = c(1, 1)
y0 = c(0, 1), y1 = zoom_prop,
gp = gpar(col = theme$zoom.y$colour,
lty = theme$zoom.y$linetype,
lwd = theme$zoom.y$size,
lineend = 'round'))
indicator_h <- grobTree(indicator, lines)
} else {
indicator_h <- zeroGrob()
}
}
if ('x' %in% layout$name) {
if (!inherits(theme$zoom.x, 'element_blank')) {
zoom_prop <- scales::rescale(x_scales[[2]]$dimension(ggforce:::expansion(x_scales[[2]])),
from = x_scales[[1]]$dimension(ggforce:::expansion(x_scales[[1]])))
indicator <- polygonGrob(c(zoom_prop, 1, 0), c(1, 1, 0, 0),
gp = gpar(col = NA, fill = alpha(theme$zoom.x$fill, 0.5)))
lines <- segmentsGrob(x0 = c(0, 1), y0 = c(0, 0), x1 = zoom_prop, y1 = c(1, 1),
gp = gpar(col = theme$zoom.x$colour,
lty = theme$zoom.x$linetype,
lwd = theme$zoom.x$size,
lineend = 'round'))
indicator_v <- grobTree(indicator, lines)
} else {
indicator_v <- zeroGrob()
}
}
if ('full' %in% layout$name && params$split) {
space.x <- theme$panel.spacing.x
if (is.null(space.x)) space.x <- theme$panel.spacing
space.x <- unit(5 * as.numeric(convertUnit(space.x, 'cm')), 'cm')
space.y <- theme$panel.spacing.y
if (is.null(space.y)) space.y <- theme$panel.spacing
space.y <- unit(5 * as.numeric(convertUnit(space.y, 'cm')), 'cm')
# change horizontal order of panels from [zoom, original] to [original, zoom]
# final <- gtable::gtable_add_cols(panelGrobs[[3]], space.x)
# final <- cbind(final, panelGrobs[[1]], size = 'first')
# final_tmp <- gtable::gtable_add_cols(panelGrobs[[4]], space.x)
# final_tmp <- cbind(final_tmp, panelGrobs[[2]], size = 'first')
final <- gtable::gtable_add_cols(panelGrobs[[1]], space.x)
final <- cbind(final, panelGrobs[[3]], size = 'first')
final_tmp <- gtable::gtable_add_cols(panelGrobs[[2]], space.x)
final_tmp <- cbind(final_tmp, panelGrobs[[4]], size = 'first')
final <- gtable::gtable_add_rows(final, space.y)
final <- rbind(final, final_tmp, size = 'first')
final <- gtable::gtable_add_grob(final, list(indicator_h, indicator_h),
c(2, 6), 3, c(2, 6), 5,
z = -Inf, name = "zoom-indicator")
final <- gtable::gtable_add_grob(final, list(indicator_v, indicator_v),
3, c(2, 6), 5,
z = -Inf, name = "zoom-indicator")
heights <- unit.c(
unit(max_height(list(axes$x[[1]]$top, axes$x[[3]]$top)), 'cm'),
unit(1, 'null'),
unit(max_height(list(axes$x[[1]]$bottom, axes$x[[3]]$bottom)), 'cm'),
space.y,
unit(max_height(list(axes$x[[2]]$top, axes$x[[4]]$top)), 'cm'),
unit(params$zoom.size, 'null'),
unit(max_height(list(axes$x[[2]]$bottom, axes$x[[4]]$bottom)), 'cm')
)
# swop panel width specifications according to the new horizontal order
widths <- unit.c(
# unit(max_width(list(axes$y[[3]]$left, axes$y[[4]]$left)), 'cm'),
# unit(params$zoom.size, 'null'),
# unit(max_height(list(axes$y[[3]]$right, axes$y[[4]]$right)), 'cm'),
# space.x,
# unit(max_width(list(axes$y[[1]]$left, axes$y[[2]]$left)), 'cm'),
# unit(1, 'null'),
# unit(max_height(list(axes$y[[1]]$right, axes$y[[2]]$right)), 'cm')
unit(max_width(list(axes$y[[1]]$left, axes$y[[2]]$left)), 'cm'),
unit(1, 'null'),
unit(max_height(list(axes$y[[1]]$right, axes$y[[2]]$right)), 'cm'),
space.x,
unit(max_width(list(axes$y[[3]]$left, axes$y[[4]]$left)), 'cm'),
unit(params$zoom.size, 'null'),
unit(max_height(list(axes$y[[3]]$right, axes$y[[4]]$right)), 'cm')
)
final$heights <- heights
final$widths <- widths
} else {
if (params$horizontal) {
space <- theme$panel.spacing.x
if (is.null(space)) space <- theme$panel.spacing
space <- unit(5 * as.numeric(convertUnit(space, 'cm')), 'cm')
heights <- unit.c(
unit(max_height(list(axes$x[[1]]$top, axes$x[[2]]$top)), 'cm'),
unit(1, 'null'),
unit(max_height(list(axes$x[[1]]$bottom, axes$x[[2]]$bottom)), 'cm')
)
# change horizontal order of panels from [zoom, original] to [original, zoom]
# first <- gtable::gtable_add_cols(panelGrobs[[2]], space)
# first <- cbind(final, panelGrobs[[1]], size = 'first')
final <- gtable::gtable_add_cols(panelGrobs[[1]], space)
final <- cbind(final, panelGrobs[[2]], size = "first")
final$heights <- heights
# swop panel width specifications according to the new horizontal order
# unit(c(params$zoom.size, 1), 'null')
final$widths[panel_cols(final)$l] <- unit(c(1, params$zoom.size), 'null')
final <- gtable::gtable_add_grob(final, indicator_h, 2, 3, 2, 5,
z = -Inf, name = "zoom-indicator")
} else {
space <- theme$panel.spacing.y
if (is.null(space)) space <- theme$panel.spacing
space <- unit(5 * as.numeric(convertUnit(space, 'cm')), 'cm')
widths <- unit.c(
unit(max_width(list(axes$y[[1]]$left, axes$y[[2]]$left)), 'cm'),
unit(1, 'null'),
unit(max_height(list(axes$y[[1]]$right, axes$y[[2]]$right)), 'cm')
)
final <- gtable::gtable_add_rows(panelGrobs[[1]], space)
final <- rbind(final, panelGrobs[[2]], size = 'first')
final$widths <- widths
final$heights[panel_rows(final)$t] <- unit(c(1, params$zoom.size), 'null')
final <- gtable::gtable_add_grob(final, indicator_v, 3, 2, 5,
z = -Inf, name = "zoom-indicator")
}
}
final
}
)
注意：create_panels 和 expansion 是 ggforce 包中未导出的函数，因此我用三个冒号引用它们。这对于编写包来说并不可靠，但作为临时解决方法应该足够了。
2019 年 10 月 30 日更新：对那些在尝试按原样使用此解决方案后看到 Invalid 'type' (list) of argument 等错误的人的建议。该问题可能是由于开发此解决方案后对 ggforce 软件包进行的更新所致。要使此解决方案中的代码再次运行，请安装开发该解决方案时可用的 ggforce 版本。这可以通过 devtools 包指向 4008a2e 提交来完成：
devtools::install_github("thomasp85/ggforce", ref = '4008a2e')
使用 ggforce 包中的 facet_zoom() 可以创建漂亮的缩放以突出显示绘图的某些区域。不幸的是，当在 y 轴上放大时，原始图总是在右侧。
有没有办法把原图放在左边？
先看主图再看放大区域会感觉更直观。例如，我想交换此图中两个方面的位置：
（没有添加可重现的例子，因为我认为这是一个关于某个功能是否存在的问题。）
我在 GitHub 上为 FacetZoom 调整了 current code 以将水平顺序从 [zoom, original] 切换到 [original, zoom]。这些更改并不复杂，但是它们 分散在 draw_panels() 函数的代码中，因此完整的代码相当长。
结果：
# example 1, with split = FALSE, horizontal = TRUE (i.e. default settings)
p1 <- ggplot(mtcars, aes(x = mpg, y = disp, colour = factor(cyl))) +
geom_point() +
theme_bw()
p1 + ggtitle("Original") + facet_zoom(y = disp > 300)
p1 + ggtitle("Modified") + facet_zoom2(y = disp > 300)
# example 2, with split = TRUE
p2 <- ggplot(iris, aes(Petal.Length, Petal.Width, colour = Species)) +
geom_point() +
theme_bw()
p2 + ggtitle("Original") +
facet_zoom(xy = Species == "versicolor", split = TRUE)
p2 + ggtitle("Modified") +
facet_zoom2(xy = Species == "versicolor", split = TRUE)
使用的代码（我已经注释掉了原始代码，使用修改后的代码，并指出了其他包中函数的包）：
library(ggplot)
library(ggforce)
library(grid)
# define facet_zoom2 function to use FacetZoom2 instead of FacetZoom
# (everything else is the same as facet_zoom)
facet_zoom2 <- function(x, y, xy, zoom.data, xlim = NULL, ylim = NULL,
split = FALSE, horizontal = TRUE, zoom.size = 2,
show.area = TRUE, shrink = TRUE) {
x <- if (missing(x)) if (missing(xy)) NULL else lazyeval::lazy(xy) else lazyeval::lazy(x)
y <- if (missing(y)) if (missing(xy)) NULL else lazyeval::lazy(xy) else lazyeval::lazy(y)
zoom.data <- if (missing(zoom.data)) NULL else lazyeval::lazy(zoom.data)
if (is.null(x) && is.null(y) && is.null(xlim) && is.null(ylim)) {
stop("Either x- or y-zoom must be given", call. = FALSE)
}
if (!is.null(xlim)) x <- NULL
if (!is.null(ylim)) y <- NULL
ggproto(NULL, FacetZoom2,
shrink = shrink,
params = list(
x = x, y = y, xlim = xlim, ylim = ylim, split = split, zoom.data = zoom.data,
zoom.size = zoom.size, show.area = show.area,
horizontal = horizontal
)
)
}
# define FacetZoom as a ggproto object that inherits from FacetZoom,
# with a modified draw_panels function. the compute_layout function references
# the version currently on GH, which is slightly different from the CRAN
# package version.
FacetZoom2 <- ggproto(
"FacetZoom2",
ggforce::FacetZoom,
compute_layout = function(data, params) {
layout <- rbind( # has both x & y dimension
data.frame(name = 'orig', SCALE_X = 1L, SCALE_Y = 1L),
data.frame(name = 'x', SCALE_X = 2L, SCALE_Y = 1L),
data.frame(name = 'y', SCALE_X = 1L, SCALE_Y = 2L),
data.frame(name = 'full', SCALE_X = 2L, SCALE_Y = 2L),
data.frame(name = 'orig_true', SCALE_X = 1L, SCALE_Y = 1L),
data.frame(name = 'zoom_true', SCALE_X = 1L, SCALE_Y = 1L)
)
if (is.null(params$y) && is.null(params$ylim)) { # no y dimension
layout <- layout[c(1,2, 5:6),]
} else if (is.null(params$x) && is.null(params$xlim)) { # no x dimension
layout <- layout[c(1,3, 5:6),]
}
layout$PANEL <- seq_len(nrow(layout))
layout
},
draw_panels = function(panels, layout, x_scales, y_scales, ranges, coord,
data, theme, params) {
if (is.null(params$x) && is.null(params$xlim)) {
params$horizontal <- TRUE
} else if (is.null(params$y) && is.null(params$ylim)) {
params$horizontal <- FALSE
}
if (is.null(theme[['zoom']])) {
theme$zoom <- theme$strip.background
}
if (is.null(theme$zoom.x)) {
theme$zoom.x <- theme$zoom
}
if (is.null(theme$zoom.y)) {
theme$zoom.y <- theme$zoom
}
axes <- render_axes(ranges, ranges, coord, theme, FALSE)
panelGrobs <- ggforce:::create_panels(panels, axes$x, axes$y)
panelGrobs <- panelGrobs[seq_len(length(panelGrobs) - 2)]
if ('full' %in% layout$name && !params$split) {
panelGrobs <- panelGrobs[c(1, 4)]
}
# changed coordinates in indicator / lines to zoom from
# the opposite horizontal direction
if ('y' %in% layout$name) {
if (!inherits(theme$zoom.y, 'element_blank')) {
zoom_prop <- scales::rescale(
y_scales[[2]]$dimension(ggforce:::expansion(y_scales[[2]])),
from = y_scales[[1]]$dimension(ggforce:::expansion(y_scales[[1]])))
indicator <- polygonGrob(
x = c(0, 0, 1, 1), # was x = c(1, 1, 0, 0),
y = c(zoom_prop, 1, 0),
gp = gpar(col = NA, fill = alpha(theme$zoom.y$fill, 0.5)))
lines <- segmentsGrob(
x0 = c(1, 1), x1 = c(0, 0), # was x0 = c(0, 0), x1 = c(1, 1)
y0 = c(0, 1), y1 = zoom_prop,
gp = gpar(col = theme$zoom.y$colour,
lty = theme$zoom.y$linetype,
lwd = theme$zoom.y$size,
lineend = 'round'))
indicator_h <- grobTree(indicator, lines)
} else {
indicator_h <- zeroGrob()
}
}
if ('x' %in% layout$name) {
if (!inherits(theme$zoom.x, 'element_blank')) {
zoom_prop <- scales::rescale(x_scales[[2]]$dimension(ggforce:::expansion(x_scales[[2]])),
from = x_scales[[1]]$dimension(ggforce:::expansion(x_scales[[1]])))
indicator <- polygonGrob(c(zoom_prop, 1, 0), c(1, 1, 0, 0),
gp = gpar(col = NA, fill = alpha(theme$zoom.x$fill, 0.5)))
lines <- segmentsGrob(x0 = c(0, 1), y0 = c(0, 0), x1 = zoom_prop, y1 = c(1, 1),
gp = gpar(col = theme$zoom.x$colour,
lty = theme$zoom.x$linetype,
lwd = theme$zoom.x$size,
lineend = 'round'))
indicator_v <- grobTree(indicator, lines)
} else {
indicator_v <- zeroGrob()
}
}
if ('full' %in% layout$name && params$split) {
space.x <- theme$panel.spacing.x
if (is.null(space.x)) space.x <- theme$panel.spacing
space.x <- unit(5 * as.numeric(convertUnit(space.x, 'cm')), 'cm')
space.y <- theme$panel.spacing.y
if (is.null(space.y)) space.y <- theme$panel.spacing
space.y <- unit(5 * as.numeric(convertUnit(space.y, 'cm')), 'cm')
# change horizontal order of panels from [zoom, original] to [original, zoom]
# final <- gtable::gtable_add_cols(panelGrobs[[3]], space.x)
# final <- cbind(final, panelGrobs[[1]], size = 'first')
# final_tmp <- gtable::gtable_add_cols(panelGrobs[[4]], space.x)
# final_tmp <- cbind(final_tmp, panelGrobs[[2]], size = 'first')
final <- gtable::gtable_add_cols(panelGrobs[[1]], space.x)
final <- cbind(final, panelGrobs[[3]], size = 'first')
final_tmp <- gtable::gtable_add_cols(panelGrobs[[2]], space.x)
final_tmp <- cbind(final_tmp, panelGrobs[[4]], size = 'first')
final <- gtable::gtable_add_rows(final, space.y)
final <- rbind(final, final_tmp, size = 'first')
final <- gtable::gtable_add_grob(final, list(indicator_h, indicator_h),
c(2, 6), 3, c(2, 6), 5,
z = -Inf, name = "zoom-indicator")
final <- gtable::gtable_add_grob(final, list(indicator_v, indicator_v),
3, c(2, 6), 5,
z = -Inf, name = "zoom-indicator")
heights <- unit.c(
unit(max_height(list(axes$x[[1]]$top, axes$x[[3]]$top)), 'cm'),
unit(1, 'null'),
unit(max_height(list(axes$x[[1]]$bottom, axes$x[[3]]$bottom)), 'cm'),
space.y,
unit(max_height(list(axes$x[[2]]$top, axes$x[[4]]$top)), 'cm'),
unit(params$zoom.size, 'null'),
unit(max_height(list(axes$x[[2]]$bottom, axes$x[[4]]$bottom)), 'cm')
)
# swop panel width specifications according to the new horizontal order
widths <- unit.c(
# unit(max_width(list(axes$y[[3]]$left, axes$y[[4]]$left)), 'cm'),
# unit(params$zoom.size, 'null'),
# unit(max_height(list(axes$y[[3]]$right, axes$y[[4]]$right)), 'cm'),
# space.x,
# unit(max_width(list(axes$y[[1]]$left, axes$y[[2]]$left)), 'cm'),
# unit(1, 'null'),
# unit(max_height(list(axes$y[[1]]$right, axes$y[[2]]$right)), 'cm')
unit(max_width(list(axes$y[[1]]$left, axes$y[[2]]$left)), 'cm'),
unit(1, 'null'),
unit(max_height(list(axes$y[[1]]$right, axes$y[[2]]$right)), 'cm'),
space.x,
unit(max_width(list(axes$y[[3]]$left, axes$y[[4]]$left)), 'cm'),
unit(params$zoom.size, 'null'),
unit(max_height(list(axes$y[[3]]$right, axes$y[[4]]$right)), 'cm')
)
final$heights <- heights
final$widths <- widths
} else {
if (params$horizontal) {
space <- theme$panel.spacing.x
if (is.null(space)) space <- theme$panel.spacing
space <- unit(5 * as.numeric(convertUnit(space, 'cm')), 'cm')
heights <- unit.c(
unit(max_height(list(axes$x[[1]]$top, axes$x[[2]]$top)), 'cm'),
unit(1, 'null'),
unit(max_height(list(axes$x[[1]]$bottom, axes$x[[2]]$bottom)), 'cm')
)
# change horizontal order of panels from [zoom, original] to [original, zoom]
# first <- gtable::gtable_add_cols(panelGrobs[[2]], space)
# first <- cbind(final, panelGrobs[[1]], size = 'first')
final <- gtable::gtable_add_cols(panelGrobs[[1]], space)
final <- cbind(final, panelGrobs[[2]], size = "first")
final$heights <- heights
# swop panel width specifications according to the new horizontal order
# unit(c(params$zoom.size, 1), 'null')
final$widths[panel_cols(final)$l] <- unit(c(1, params$zoom.size), 'null')
final <- gtable::gtable_add_grob(final, indicator_h, 2, 3, 2, 5,
z = -Inf, name = "zoom-indicator")
} else {
space <- theme$panel.spacing.y
if (is.null(space)) space <- theme$panel.spacing
space <- unit(5 * as.numeric(convertUnit(space, 'cm')), 'cm')
widths <- unit.c(
unit(max_width(list(axes$y[[1]]$left, axes$y[[2]]$left)), 'cm'),
unit(1, 'null'),
unit(max_height(list(axes$y[[1]]$right, axes$y[[2]]$right)), 'cm')
)
final <- gtable::gtable_add_rows(panelGrobs[[1]], space)
final <- rbind(final, panelGrobs[[2]], size = 'first')
final$widths <- widths
final$heights[panel_rows(final)$t] <- unit(c(1, params$zoom.size), 'null')
final <- gtable::gtable_add_grob(final, indicator_v, 3, 2, 5,
z = -Inf, name = "zoom-indicator")
}
}
final
}
)
注意：create_panels 和 expansion 是 ggforce 包中未导出的函数，因此我用三个冒号引用它们。这对于编写包来说并不可靠，但作为临时解决方法应该足够了。
2019 年 10 月 30 日更新：对那些在尝试按原样使用此解决方案后看到 Invalid 'type' (list) of argument 等错误的人的建议。该问题可能是由于开发此解决方案后对 ggforce 软件包进行的更新所致。要使此解决方案中的代码再次运行，请安装开发该解决方案时可用的 ggforce 版本。这可以通过 devtools 包指向 4008a2e 提交来完成：
devtools::install_github("thomasp85/ggforce", ref = '4008a2e')