Setting breaks outside of axis ranges fails

[jiho]

library("ggplot2")

d <- data.frame(x=1:10)

ggplot(d) + geom_point(aes(x=x, y=x))

ggplot(d) + geom_point(aes(x=x, y=x)) + scale_y_continuous(breaks=c(1,5), labels=c("foo", "bar"))
# OK

ggplot(d) + geom_point(aes(x=x, y=x)) + scale_y_continuous(breaks=c(-1,5), labels=c("foo", "bar"))
ggplot(d) + geom_point(aes(x=x, y=x)) + scale_y_continuous(breaks=c(1,11), labels=c("foo", "bar"))
# Fails

ggplot(d) + geom_point(aes(x=x, y=x)) + scale_y_continuous(breaks=c(-1,5), labels=c("foo", "bar"), limits=c(-1,10))
ggplot(d) + geom_point(aes(x=x, y=x)) + scale_y_continuous(breaks=c(1,11), labels=c("foo", "bar"), limits=c(1, 11))
# OK, because the scales are expanded

What should happen is :

• when limits are not explicitly set, setting breaks outside of the data range expands the limits to those breaks
• when limits are explicitly set, breaks and labels outside of the limit range are dropped

[kohske]

good point. thanks.

[wch]

This was broken by 19da6a8.

Bisect script here: https://gist.github.com/2697594

[kohske]

Thanks @wch, I figured out what is problem.

The limits of coord (not limits of scale) will be determined by some ways.

(1) coord limits
(2) scale limits
(3) scale breaks
(4) default (i.e., the range of data)

So the rule is:

a) If (1) coord limits is explicitly set, use it and ignore the others including the oob breaks.
b) If (2) scale limits is explicitly set, use it and ignore the oob breaks.
c) if (3) scale breaks is explicitly set and it spans out of data range, expand the range to the scale breaks.
d) if all of 1-3 are absent, or if (3) is set but it spans inside the data range, use data range.

I'm not sure if (b) and (c) is ok.
Do you have any ideas?

Here is a pseudo code:

range <- data_limits
if (!is.null(coord_limits)) { 
  range <- coord_lim 
  drop_oob_breaks(range)
}
else if(!is.null(scale_limits))  {
  range <- coord
  drop_oob_breaks(range)
}
else if(!is.null(scale_breaks)) {
  range[1] <- min(range[1], scale_breaks[1])
  range[2] <- max(range[2], scale_breaks[2])
}

[kohske]

The problemis if oob breaks expand the existing limits.

Probably three ways:

(1) oob breaks doesn't affect the scale/coord limits and simply will be dropped (@wch's suggestion and compatible with 0.9).
(2) oob breaks expands the scale/coord limits if they are not explicitly set (my tentative implementation).
(3) Parameters to scales such as respect.breaks = T/F to choose (1) or (2). I don't like this way.

I like the @wch's suggestion, because we can set limits explicitly if necessary.