Cannot set legend.box.background with theme_void()

[clauswilke]

It doesn't seem possible to set the legend.box.background theme setting under theme_void(). Other legend settings work.

Reprex:

library(ggplot2)
df <- data.frame(x = 1:3)
ggplot(df, aes(x, x, color = factor(x))) +
  geom_point() +
  theme_void() +
  theme(legend.background = element_rect(fill = "gray80"))

df <- data.frame(x = 1:3)
ggplot(df, aes(x, x, color = factor(x))) +
  geom_point() +
  theme_void() +
  theme(legend.box.background = element_rect(fill = "gray80"))
#> Warning in if (theme$legend.box == "horizontal") {: the condition has
#> length > 1 and only the first element will be used
#> Warning in if (theme$legend.box == "vertical") {: the condition has length
#> > 1 and only the first element will be used
#> Error in gtable_add_cols(guides, theme$legend.box.margin[4], pos = 0): is.gtable(x) is not TRUE

Created on 2018-06-28 by the reprex package (v0.2.0).

[clauswilke]

Also, this works without theme_void(), of course:

library(ggplot2)
df <- data.frame(x = 1:3)
ggplot(df, aes(x, x, color = factor(x))) +
  geom_point() +
  #theme_void() +
  theme(legend.box.background = element_rect(fill = "gray80"))

Created on 2018-06-28 by the reprex package (v0.2.0).

[ptoche]

works for me:

sessionInfo()
R version 3.5.0 (2018-04-23)
Platform: x86_64-apple-darwin15.6.0 (64-bit)
Running under: macOS High Sierra 10.13.4

Matrix products: default
BLAS: /System/Library/Frameworks/Accelerate.framework/Versions/A/Frameworks/vecLib.framework/Versions/A/libBLAS.dylib
LAPACK: /Library/Frameworks/R.framework/Versions/3.5/Resources/lib/libRlapack.dylib

locale:
[1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8

attached base packages:
[1] stats graphics grDevices utils
[5] datasets methods base

other attached packages:
[1] ggplot2_2.2.1

loaded via a namespace (and not attached):
[1] labeling_0.3 colorspace_1.3-2
[3] scales_0.5.0 compiler_3.5.0
[5] lazyeval_0.2.1 plyr_1.8.4
[7] tools_3.5.0 pillar_1.2.3
[9] gtable_0.2.0 tibble_1.4.2
[11] yaml_2.1.19 Rcpp_0.12.17
[13] grid_3.5.0 digest_0.6.15
[15] rlang_0.2.1 munsell_0.5.0

[batpigandme]

I'm able to reproduce this with the latest dev. build.

Traceback

9: stop(msg, call. = FALSE, domain = NA)
8: stopifnot(is.gtable(x))
7: gtable_add_cols(guides, theme$legend.box.margin[4], pos = 0)
6: guides_build(ggrobs, theme)
5: build_guides(plot$scales, plot$layers, plot$mapping, position, 
       theme, plot$guides, plot$labels)
4: ggplot_gtable.ggplot_built(data)
3: ggplot_gtable(data)
2: print.ggplot(x)
1: function (x, ...) 
   UseMethod("print")(x)

[clauswilke]

It's probably related to the changes in the theme inheritance code in the latest version. Some edge case that wasn't considered.

[clauswilke]

I've figured it out. The immediate cause is a missing legend.box element in the theme:

library(ggplot2)
df <- data.frame(x = 1:3)
ggplot(df, aes(x, x, color = factor(x))) +
  geom_point() +
  theme_void() +
  theme(
    legend.box = "horizontal",
    legend.box.background = element_rect(fill = "gray80")
  )

Created on 2018-06-28 by the reprex package (v0.2.0).

The ulterior reason is this if--else sequence:

ggplot2/R/guides-.r

Lines 251 to 280 in 348b26f

	if (theme$legend.box == "horizontal") {
	# Set justification for each legend
	for (i in seq_along(ggrobs)) {
	ggrobs[[i]] <- editGrob(ggrobs[[i]],
	vp = viewport(x = xjust, y = yjust, just = c(xjust, yjust),
	height = heightDetails(ggrobs[[i]])))
	}
	guides <- gtable_row(name = "guides",
	grobs = ggrobs,
	widths = widths, height = max(heights))
	# add space between the guide-boxes
	guides <- gtable_add_col_space(guides, theme$legend.spacing.x)
	} else if (theme$legend.box == "vertical") {
	# Set justification for each legend
	for (i in seq_along(ggrobs)) {
	ggrobs[[i]] <- editGrob(ggrobs[[i]],
	vp = viewport(x = xjust, y = yjust, just = c(xjust, yjust),
	width = widthDetails(ggrobs[[i]])))
	}
	guides <- gtable_col(name = "guides",
	grobs = ggrobs,
	width = max(widths), heights = heights)
	# add space between the guide-boxes
	guides <- gtable_add_row_space(guides, theme$legend.spacing.y)
	}

It contains no default if legend.box is neither "horizontal" nor "vertical". I think this line:

ggplot2/R/guides-.r

Line 266 in 348b26f

} else if (theme$legend.box == "vertical") {

should be turned into an unconditional else.

[karawoo]

I think the fix should actually occur earlier in this section of build_guides():

ggplot2/R/guides-.r

Lines 102 to 114 in 348b26f

	if (position == "inside") {
	theme$legend.box <- theme$legend.box %||% "vertical"
	theme$legend.direction <- theme$legend.direction %||% "vertical"
	theme$legend.box.just <- theme$legend.box.just %||% c("center", "center")
	} else if (position == "vertical") {
	theme$legend.box <- theme$legend.box %||% "vertical"
	theme$legend.direction <- theme$legend.direction %||% "vertical"
	theme$legend.box.just <- theme$legend.box.just %||% c("left", "top")
	} else if (position == "horizontal") {
	theme$legend.box <- theme$legend.box %||% "horizontal"
	theme$legend.direction <- theme$legend.direction %||% "horizontal"
	theme$legend.box.just <- theme$legend.box.just %||% c("center", "top")
	}

theme$legend.box is NULL but theme$legend.box.background is not, and thus theme$legend.box %||% "vertical" is partially matching on theme$legend.box.background and inserting the element_rect() into theme$legend.box.

[clauswilke]

@karawoo Can you think of a clean and simple fix at line 102?

In any case, I think it's always a good idea to have a default option in an if--else chain, so I would change line 266 regardless. And theme_void() needs to define legend.box.

[karawoo]

The easiest I guess would be to change theme$legend.box %||% "vertical" to theme[["legend.box"]] %||% "vertical". Agreed on the other points though.

[clauswilke]

@karawoo I'm moving that discussion to separate issue #2724.

[lock]

This old issue has been automatically locked. If you believe you have found a related problem, please file a new issue (with reprex) and link to this issue. https://reprex.tidyverse.org/