geom_tiplab2() is broken with custom coord_polar() settings

[willgearty]

My understanding is that specifying ggtree(..., layout="circular") is essentially the same as this:

library(ggplot2)
library(ggtree)
library(ape)
data("chiroptera")
ggtree(chiroptera) +
    coord_polar(theta = "y", start = -pi/2, direction = -1) +
    scale_y_continuous(limits = c(0, NA), expand = expansion(0, 0.6))

^{Created on 2024-10-24 with reprex v2.1.1}

Based on the code here:

ggtree/R/method-ggplot-add.R

Lines 106 to 114 in 8798543

	} else if (object$layout == 'circular' || object$layout == "inward_circular") {
	## refer to: https://github.com/GuangchuangYu/ggtree/issues/6
	## and also have some space for tree scale (legend)
	obj <- list(coord_polar(theta='y', start=-pi/2, -1, clip = 'off'),
	scale_y_continuous(limits = c(0, NA), expand = expansion(0, 0.6))
	)
	if (object$layout == 'inward_circular') {
	obj[[3]] <- scale_x_reverse(limits = object$xlim)
	}

However, this hardcodes the starting and ending points of the phylogeny, which I would prefer to have on the left. So I've been playing around with changing the start and direction arguments in coord_polar(), which seems to work fine, until you try to add tip labels. For any values other than the defaults, geom_tiplab2() breaks. Here are some interesting examples:

library(ggplot2)
library(ggtree)
library(ape)
data("chiroptera")
ggtree(chiroptera) +
    coord_polar(theta = "y", start = pi/2, direction = -1) +
    scale_y_continuous(limits = c(0, NA), expand = expansion(0, 0.6)) +
    geom_tiplab2(size = 0.8)

^{Created on 2024-10-24 with reprex v2.1.1}

library(ggplot2)
library(ggtree)
library(ape)
data("chiroptera")
ggtree(chiroptera) +
    coord_polar(theta = "y", start = -pi/2, direction = 1) +
    scale_y_continuous(limits = c(0, NA), expand = expansion(0, 0.6)) +
    geom_tiplab2(size = 0.8)

^{Created on 2024-10-24 with reprex v2.1.1}

[willgearty]

Note that I discovered this after an issue was raised for my deeptime package: willgearty/deeptime#72

[xiangpin]

I recommend using rotate_tree since the internal function needs the layout of ggtree.

library(ggplot2)
library(ggtree)
library(ape)
data("chiroptera")
p1 <- ggtree(chiroptera, layout='circular')
p2 <- rotate_tree(p1, 135)
p2 + geom_tiplab(size=1)

[willgearty]

Ah, that's an excellent function to know about, thanks! Any way we could get it to work with coord_radial() with different start and end arguments? I see that you can combine the open_tree() and rotate_tree() functions, but both of those use coordinate systems, making it hard for me to combine them with coord_geo_polar() or coord_geo_radial() from deeptime.

[willgearty]

I've developed a new geom that works with all coordinate systems: https://williamgearty.com/deeptime/dev/reference/geom_text_phylo.html