ggfla - GGPlot2 Extension for Fixed-Length Axis

This package is initially intended for making scanpy-style short-arrow axis in ggplot2. This package implements what is desired in the most appropriate way--exactly replacing the whole axis line with a fixed-length arrow. Other solutions for scanpy-style axis available at the moment of writing are all workarounds--hide the axis lines and draw arrowed-segment geoms within the plot panel.

This package provides a new theme element element_line_fixlen, which allows everything that the ggplot2 original element_line() can specify, plus the length argument in unit(). Besides, this packagee provides a short cut theme theme_axis_shortArrow() for scanpy-style axis.

Usage

In short, it works as below:

library(ggfla)
ggplot(mtcars, aes(mpg, wt)) +
    geom_point() +
    theme_axis_shortArrow()

Alternatively, the element can be customized within the theme() call:

ggplot(mtcars, aes(mpg, wt)) +
    geom_point() +
    theme(
        axis.ticks = element_blank(),
        axis.text = element_blank(),
        panel.background = element_blank(),
        panel.grid = element_blank(),
        axis.title = element_text(hjust = 0),
        axis.line = element_line_fixlen(
          length = unit(15, "mm"),
          arrow = arrow(type = "closed", angle = 20, length = unit(0.1, "in"))
        )
    )

For more guided usage, please see the package vignette.

Installation

For now, this package can only be installed from source or from GitHub. To remotely install from GitHub, run the following commands in a live R session:

if (!requireNamespace("devtools", quietly = TRUE)) {
    install.packages("devtools")
}
devtools::install_github("mvfki/ggfla", build_vignettes = TRUE)

Open development

This package is under open development. If you have any suggestions or find any bugs, please feel free to open an issue or a pull request.