ggplot_add_arrow: Add arrows to ggplot

In GJMeijer/soilmech: R functions and plots for Soil Mechanics teaching

Add arrows to ggplot

Description

Add some arrow objects and annotation to an existing ggplot

Usage

ggplot_add_arrow(
  plt,
  x,
  y,
  theta = -pi/2,
  scale = 0.1,
  length = NULL,
  label = NULL,
  label_size = 3.5,
  label_parse = FALSE,
  label_offset = 0.02,
  linewidth = 0.5,
  colour = "black",
  scale_arrow = 0.3,
  scale_arrow_max = 0.1
)

Arguments

plt	existing ggplot object
x, y	x,y positions of arrow tips
theta	orientation of arrows (in rad)
scale	arrow length, in fraction of y-range
length	arrow length in x,y coordinate system. If specified, overrides 'scale' setting
label	labels for each arrow (string). Labels are plotted near the tail of each arrow
label_size	label text size
label_parse	if 'TRUE', parse the label input
label_offset	small offset to create distance between arrow tails. Expressed in fraction of y-range
linewidth	arrow line width
colour	arrow colour
scale_arrow	length of arrow head, as fraction of arrow length
scale_arrow_max	maximum arrow head size, as fraction of y-range

Examples

#generate a plot
plt <- ggplot2::ggplot() +
  ggplot2::geom_rect(ggplot2::aes(xmin = 0, xmax = 2, ymin = 0, ymax = 2), fill = "yellow") +
  ggplot2::coord_fixed(ratio = 1)

#arrow
x = c(1, 1, 1, 1)
y = c(1, 1, 1, 1)
theta = c(-pi/2, 0, pi/2, pi)
label = "test*theta"
ggplot_add_arrow(plt, x, y, theta = theta, label = label, label_parse = TRUE)

GJMeijer/soilmech documentation built on May 22, 2022, 10:39 a.m.