Allow separate expansion values for lower and upper range limits (v2) #1805

huftis · 2016-10-01T09:04:21Z

Fixes issue #1669.

The expand argument for scale_*_continuous() and scale_*_discrete() now accepts separate expansion constants for the lower and upper range limits.

This is useful for creating bar charts where the bottom of the bars are flush with the x axis but the bars still have some (automatically calculated amount of) space above them:

ggplot(mtcars) +
  geom_bar(aes(x = factor(cyl))) +
  scale_y_continuous(expand = c(0, 0, 0.1, 0))

It can also be useful for line charts, e.g. for counts over time, where one wants to have a ’hard’ lower limit of y = 0, but leave the upper limit unspecified (and perhaps differing between panels), but with some extra space above the highest point on the line. (With symmetrical limits, the extra space above the highest point could cause the lower limit to be negative.)

The syntax for the multiplicative and additive expansion constants has been changed from c(m, a) to c(m_lower, a_lower, m_uppper, a_upper). The old syntax will still work, as length 2 vectors c(m, a) are expanded to c(m, a, m, a) and length 3 vectors are expanded from c(m1, a1, m2) to c(m1, a2, m2, a1).

Note that by default, all graphs should exactly look like they do with the current version of ggplot2.

Some examples (only meant to illustrate the functionality – several don’t make much sense from a graphical point of view):

# Continuous scales
p = ggplot(mtcars) +
      geom_bar(aes(x = factor(cyl)))

# No space below but 10% space above bars
p + scale_y_continuous(expand = c(0, 0, 0.10, 0))

# It also works with facets
p + facet_wrap(~cyl) +
    scale_y_continuous(expand = c(0, 0, 0.05))
p + facet_wrap(~cyl, scales="free_y") +
    scale_y_continuous(expand = c(0, 0, 0.05))
# Note that all the bars should
# look identical in this last example

# Coordinate flipping also works
p + scale_y_continuous(expand = c(.5, 0, 0.05, 0)) +
    coord_flip()
p + scale_y_continuous(expand = c(0, 2, 0, 5)) +
    coord_flip()


# Similar examples for discrete scales
d <- ggplot(subset(diamonds, carat > 1), aes(cut, clarity)) +
  geom_jitter()

d + scale_x_discrete(expand = c(.25, 0))
d + scale_x_discrete(expand = c(0, 1))
d + scale_x_discrete(expand = c(0, 1, 0, 5))
d + scale_x_discrete(expand = c(.25, 0, .5, 0))
d + scale_x_discrete(expand = c(.25, 1, .25, 5))
d + scale_x_discrete(expand = c(.25, 1, .25, 5)) + coord_flip()

@huftis

The `expand` argument for `scale_*_continuous()` and `scale_*_discrete()` now accepts separate expansion constants for the lower and upper range limits. This is useful for creating bar charts where the bottom of the bars are flush with the x axis but the bars still have some (automatically calculated amount of) space above them: ```R ggplot(mtcars) + geom_bar(aes(x = factor(cyl))) + scale_y_continuous(expand = c(0, 0, 0.1, 0)) ``` It can also be useful for line charts, e.g. for counts over time, where one wants to have a ’hard’ lower limit of y = 0, but leave the upper limit unspecified (and perhaps differing between panels), but with some extra space above the highest point on the line. (With symmetrical limits, the extra space above the highest point could cause the lower limit to be negative.) The syntax for the multiplicative and additive expansion constants has been changed from `c(m, a)` to `c(m_lower, a_lower, m_uppper, a_upper)`. The old syntax will still work, as length 2 vectors `c(m, a)` are expanded to `c(m, a, m, a)` and length 3 vectors are expanded from `c(m1, a1, m2)` to `c(m1, a2, m2, a1)`. (@huftis, tidyverse#1669)

…etric_expand_argument_v2

hadley · 2016-10-02T14:01:39Z

I think expand = c(0, 0, 0.1, 0) is hard to understand. Can you please add a helper function with named arguments and documentation? I think it might be best to have mult and add arguments that can take a vector of length 1 or 2.

huftis · 2016-10-02T14:18:22Z

@hadley The reason I used expand = c(0, 0, 0.1, 0) is for backwards compatibility, so that all old code would continue to work. But I guess converting the expand argument to a list could also work, expand = list(mult=c(0, .1), add=c(0,0)). Or are you thinking that I should add a helper function that takes a mult and add argument and converts it into the new c(m1, a1, m2, a2) syntax? (BTW, any suggestion for the name of this function, given that expand_range() and expand_limits() are both taken?)

hadley · 2016-10-03T01:30:33Z

Yes, a helper function (possibly returning an S3 object or just a vector). I don't know what to call it either 😞

hadley · 2016-10-04T12:04:56Z

Maybe expand_scale()? Or expansion()?

hadley · 2017-01-25T17:56:28Z

Are you still interested in this PR? I'm going to be working on ggplot2 off and on for a bit.

huftis · 2017-01-26T21:21:19Z

@hadley Yes, I’m still interested; I’ve just been too busy to take a look at it (or, really, it’s been too low on my priority list for too long). I hope to have a new go at it sometime in the next few weeks. When are you planning a test/beta release of the next ggplot2 version? I’ll try to finish it before that, so that it can be properly tested.

vectors. Instead of having to manually specify an `expand` argument using a somewhat confusing syntax (a vector of 2, 3 or 4 numeric values), it’s now possible to use the user-friendly (and documented) `expand_scale()` function. This commit also cleans up the documentation related to the `expand` argument, which was duplicated in several functions.

The documentation for one of the functions had a no-breaking space, (between a number and the word ‘units’), which caused R CMD check to complain about ‘non-ASCII input and no declared encoding’. This adds a character encoding declaration of UTF-8 to the DESCRIPTION file to fix this problem.

huftis · 2017-02-05T15:14:10Z

@hadley, I have now added an expand_scale() function for specifying the expansion values, along with documentation and and couple of examples.

One thing I’m not entirely happy with regarding this patch, is that the defaults for expand_scale() don’t duplicate the defaults of mult = .05, add = 0’ for continuous scales and mult = 0, add = 0.6` for discrete scales. It’s not a problem functionality-wise; the defaults do continue to work as before. But it’s not possible change the ‘Usage’ section of the documentation for the scales from

scale_x_discrete(..., expand = waiver(), position = "bottom")

to the more user-friendly

scale_x_discrete(..., expand = expand_scale(), position = "bottom")

since expand_scale() can’t know if it’s a continuous or discrete scale that is being used (and adjust its defaults based on this). I’m not sure if it is possible to fix this.

hannes101 · 2017-05-18T14:25:33Z

Could this also be implemented for area plots, since especially when using a color scheme with a light color at the bottom it gives the impression of a much bigger area and additionally it kind of wastes space in a publications.
Thanks a lot in advance.
Just a quick'n'dirty example showing the "problem".

 ggplot(melt(dt id.vars = c("Year.and.Quarter"), measure.vars = colnames(dt)[-1])[like(variable,"Gas"),], aes( x = Year.and.Quarter, y = value)) +
        geom_area(aes(fill= variable), position = 'stack') +
        scale_x_yearqtr(format = "%Y-Q%q",n = 8, expand = c(0,0)) +
        theme_bw() +
        scale_fill_brewer(name = "", labels =c(  "Directional"
                                                 , "Horizontal "
                                                 , "Unknown"
                                                 , "Vertical"),direction = -1, palette = my.color.scheme) +
        labs(title = "", x = "Time", y = "Quarterly Gas Production in mmcf ") +
        theme(text=element_text(family="CMU Serif", size=24)
              , strip.text.y = element_text(family="CMU Serif", size=14, colour = "black")
              , legend.position="bottom"
              , plot.margin = unit(c(1,1.5,1,1), "cm"))

hadley

Just a couple of tiny style issues and it'll be ready to merge 😄

hadley · 2017-07-03T17:03:57Z

R/utilities.r

+  stopifnot(is.numeric(mult) && is.numeric(add))
+  stopifnot((length(mult) %in% 1:2) && (length(add) %in% 1:2))
+
+  mult = rep(mult, length.out = 2)


Can you please use <- here

hadley · 2017-07-03T17:04:07Z

R/utilities.r

+
+  mult = rep(mult, length.out = 2)
+  add = rep(add, length.out = 2)
+  expand = c(mult[1], add[1], mult[2], add[2])


No need for expand variable

…etric_expand_argument_v2

huftis · 2017-07-09T16:39:58Z

@hannes101 This feature works with scales in general, so yes, it should work with area plots too.

huftis · 2017-07-09T16:41:47Z

@hadley I’ve now fixed the issues you mentioned and updated the PR to cleanly apply to master.

hadley

One tiny last change and we can merge 😄

hadley · 2017-07-10T16:05:27Z

R/utilities.r

@@ -172,6 +172,76 @@ rescale01 <- function(x) {
  (x - rng[1]) / (rng[2] - rng[1])
 }

+#' Similar to expand_range(), but taking a vector ‘expand’


Let's @noRd this

hadley · 2017-07-10T22:41:55Z

Thanks for all your hard work on this!

@huftis

…tidyverse#1805) * Allow separate expansion values for lower and upper range limits. The `expand` argument for `scale_*_continuous()` and `scale_*_discrete()` now accepts separate expansion constants for the lower and upper range limits. This is useful for creating bar charts where the bottom of the bars are flush with the x axis but the bars still have some (automatically calculated amount of) space above them: ```R ggplot(mtcars) + geom_bar(aes(x = factor(cyl))) + scale_y_continuous(expand = c(0, 0, 0.1, 0)) ``` It can also be useful for line charts, e.g. for counts over time, where one wants to have a ’hard’ lower limit of y = 0, but leave the upper limit unspecified (and perhaps differing between panels), but with some extra space above the highest point on the line. (With symmetrical limits, the extra space above the highest point could cause the lower limit to be negative.) The syntax for the multiplicative and additive expansion constants has been changed from `c(m, a)` to `c(m_lower, a_lower, m_uppper, a_upper)`. The old syntax will still work, as length 2 vectors `c(m, a)` are expanded to `c(m, a, m, a)` and length 3 vectors are expanded from `c(m1, a1, m2)` to `c(m1, a2, m2, a1)`. (@huftis, tidyverse#1669) * Added `expand_scale()` function for easier generation of scale expansion vectors. Instead of having to manually specify an `expand` argument using a somewhat confusing syntax (a vector of 2, 3 or 4 numeric values), it’s now possible to use the user-friendly (and documented) `expand_scale()` function. This commit also cleans up the documentation related to the `expand` argument, which was duplicated in several functions. * Added UTF-8 character encoding declaration to DESCRIPTION. The documentation for one of the functions had a no-breaking space, (between a number and the word ‘units’), which caused R CMD check to complain about ‘non-ASCII input and no declared encoding’. This adds a character encoding declaration of UTF-8 to the DESCRIPTION file to fix this problem. * Fixed some style issues. * Updated and regenerated documentation. * Specify character encoding used for documentation. * Minor grammar improvement in documentation. * Don’t generate documentation for internal function expand_range4().

lock · 2019-01-18T11:29:43Z

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/

huftis added 2 commits October 1, 2016 10:46

Merge branch 'master' of https://github.com/hadley/ggplot2 into asymm…

1e614f7

…etric_expand_argument_v2

huftis added 3 commits February 5, 2017 13:16

Merged with upstream.

09075ff

dhimmel mentioned this pull request May 3, 2017

Add asymmetrical expand argument to continuous and discrete scales #1669

Closed

hadley reviewed Jul 3, 2017

View reviewed changes

huftis added 5 commits July 9, 2017 17:37

Merge branch 'master' of https://github.com/hadley/ggplot2 into asymm…

cdb9439

…etric_expand_argument_v2

Fixed some style issues.

6ba346d

Updated and regenerated documentation.

34b6fd9

Specify character encoding used for documentation.

8589c7c

Minor grammar improvement in documentation.

2b60c61

hadley reviewed Jul 10, 2017

View reviewed changes

Don’t generate documentation for internal function expand_range4().

15ff597

hadley merged commit 4255cd8 into tidyverse:master Jul 10, 2017

AliciaSchep mentioned this pull request Nov 9, 2017

Set origin to zero jonocarroll/ggeasy#1

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Allow separate expansion values for lower and upper range limits (v2) #1805

Allow separate expansion values for lower and upper range limits (v2) #1805

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Allow separate expansion values for lower and upper range limits (v2) #1805

Allow separate expansion values for lower and upper range limits (v2) #1805

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