Smoothing bumpy text

[AllanCameron]

Thought I'd better make a note somewhere about an attempt I made to add in a smoothing parameter. The idea was to "iron out" small bumps in the text by a simple loess of x co-ordinates and another of y co-ordinates. This produces a very nice effect in some cases. For example, with the trend lines. Compare without any smoothing:

library(geomtextpath)

ggplot(iris, aes(x = Sepal.Length, y = Petal.Length)) +
  geom_point(alpha = 0.1) +
  geom_textpath(aes(label = Species, colour = Species),
                stat = "smooth", method = "loess", formula = y ~ x,
                size = 7, linetype = 3, fontface = 2, linewidth = 1) +
  scale_colour_manual(values = c("forestgreen", "deepskyblue4", "tomato4")) +
  coord_fixed(ratio = 1) +
  theme_bw()

versus with smoothing:

ggplot(iris, aes(x = Sepal.Length, y = Petal.Length)) +
  geom_point(alpha = 0.1) +
  geom_textpath(aes(label = Species, colour = Species),
                stat = "smooth", method = "loess", formula = y ~ x,
                size = 7, linetype = 3, fontface = 2, linewidth = 1,
                smooth = 0.75) +
  scale_colour_manual(values = c("forestgreen", "deepskyblue4", "tomato4")) +
  coord_fixed(ratio = 1) +
  theme_bw()

To my eye this looks a lot nicer and is closer to publication standard. The problem is that it smooths the underlying path itself, so can't be used when the exact path is important (such as density curves), and often distorts the spacing of the text.

We can actually get the same result as the nice one above by simply calling geom_textpath with a span = 1, which, although we don't use as a parameter, gets passed to stat_smooth:

ggplot(iris, aes(x = Sepal.Length, y = Petal.Length)) +
  geom_point(alpha = 0.1) +
  geom_textpath(aes(label = Species, colour = Species),
                stat = "smooth", method = "loess", formula = y ~ x,
                span = 1,
                size = 7, linetype = 3, fontface = 2, linewidth = 1) +
  scale_colour_manual(values = c("forestgreen", "deepskyblue4", "tomato4")) +
  coord_fixed(ratio = 1) +
  theme_bw()

So I'm not convinced that a smoothing feature is required. Perhaps a stat_textspline will be the route to smoothing paths, and this is on the to-do list.

[AllanCameron]

I will close this for now but we can point to this issue in the future if it comes up again.