Feature request: repel from geom_segment #206
Description
Summary
Thanks for the great package!
Currently, the repel works to repel text away from single points. However, it would be great if it could repel text away from segments as well. This would be especially useful for automatically generating nice biplots for multivariate analysis (PCA, RDA, etc.).
Minimal code example
Here is the minimum amount of code needed to demonstrate the issue:
library(ggplot2)
library(ggrepel)
## Example data frame where each species' principal components have been computed.
df = data.frame(
Species = paste("Species",1:5),
PC1 = c(-4, -3.5, 1, 2, 3),
PC2 = c(-1, -1, 0, -0.5, 0.7))
## We plot the two primary principal componenets and add species labels
ggplot(df, aes(x=PC1, y = PC2, label=Species)) +
geom_segment(aes(x=0, y=0, xend=PC1, yend=PC2),
arrow = arrow(length = unit(0.1, "inches"))) +
geom_text_repel() +
xlim(-5, 5) +
ylim(-2, 2) +
# Stadard settings for displaying biplots
geom_hline(aes(yintercept = 0), size=.2) +
geom_vline(aes(xintercept = 0), size=.2) +
coord_fixed()Here is an image of the output produced by the code:
Suggestions
The text should be repelled in the direction of the arrow with which it is associated. If the geom_text_repel() function could take as input the aesthetics xend and yend. If these aesthetics are supplied, the text is placed at coordinates yend and xend and some invisible points along the segment are added to the plot in order to repel the text away from the line. An additional option force_line would also be useful to determine the force with which the lines repel the text.
Version information
Here is the output from sessionInfo() in my R session:
R version 3.6.3 (2020-02-29)
Platform: i386-w64-mingw32/i386 (32-bit)
Running under: Windows 10 x64 (build 19041)
Matrix products: default
locale:
[1] LC_COLLATE=English_Canada.1252 LC_CTYPE=English_Canada.1252
[3] LC_MONETARY=English_Canada.1252 LC_NUMERIC=C
[5] LC_TIME=English_Canada.1252
attached base packages:
[1] stats graphics grDevices utils datasets methods base
other attached packages:
[1] ggrepel_0.8.2 ggplot2_3.3.0.9000
loaded via a namespace (and not attached):
[1] vctrs_0.3.1 fansi_0.4.1 digest_0.6.25 htmltools_0.5.1.1
[5] R6_2.4.1 scales_1.1.0 assertthat_0.2.1 tinytex_0.21
[9] grid_3.6.3 knitr_1.31.5 cli_2.0.2 tidyselect_1.1.0
[13] generics_0.0.2 munsell_0.5.0 pillar_1.4.3 pander_0.6.4
[17] compiler_3.6.3 tibble_3.0.0 pkgconfig_2.0.3 labeling_0.3
[21] purrr_0.3.3 rstudioapi_0.11 glue_1.4.0 xfun_0.20
[25] magrittr_1.5 farver_2.0.3 rmarkdown_2.6 evaluate_0.14
[29] gtable_0.3.0 rlang_0.4.10 colorspace_1.4-1 yaml_2.2.1
[33] tools_3.6.3 lifecycle_0.2.0 ellipsis_0.3.0 dplyr_1.0.0
[37] withr_2.1.2 crayon_1.3.4 Rcpp_1.0.4.6 ```