Setup
Base Plot
To avoid repetitive code, we set defaults and make a base plot:
#| label: baseplot
my_font <- "Roboto Condensed"
my_font_size <- 20
my_point_size <- 2
my_arrowhead <- arrowheadr::arrow_head_deltoid(2.1)
# my_colors <- viridis::viridis(2, begin = .25, end = .5)
my_colors <- c("#3B528B", "#21908C")
theme_set(
theme_minimal(
base_size = my_font_size,
base_family = my_font) +
theme(axis.title.y = element_text(angle = 0, vjust = 0.5)))
bp <- ggdiagram(
font_family = my_font,
font_size = my_font_size,
point_size = my_point_size,
linewidth = .5,
theme_function = theme_minimal,
axis.title.x = element_text(face = "italic"),
axis.title.y = element_text(
face = "italic",
angle = 0,
hjust = .5,
vjust = .5)) +
scale_x_continuous(labels = signs_centered,
limits = c(-4, 4)) +
scale_y_continuous(labels = signs::signs,
limits = c(-4, 4))
Bézier curves
The ob_bezier
function creates an object that specifies the control points for a bézier curve. A bézier curve is an extremely useful way of making elegantly curved lines between points.
bp +
{control_points <- ob_point(
x = c(-4,4,4),
y = c(4,-4, 0))} +
ob_path(control_points, linetype = "dashed", linewidth = .25) +
ob_bezier(control_points)
I like to make a list of control points setting the start and end points first. Then I find internal control points by offsetting from the end points—adding or subtracting a point at a specified x and y distance (or angle using the polar
function).
The c
function creates a list of all the points, and the bind
function binds the list into a single point object containing all the points.
# start and end of control points
p_start <- ob_point(-4,-2)
p_end <- ob_point(4, 2)
# Offset ob_point from the endpoints
p_offset <- ob_point(5,6)
# Make list of points and bind them into a single ob_point
p <- c(p_start,
p_start + p_offset,
p_end - p_offset,
p_end) |>
bind()
bp +
ob_path(p,
linetype = "dashed",
color = "gray",
linewidth = .25) +
p +
ob_bezier(p,
label = ob_label("Labels can follow the path of the bézier curve."))
Multiple bézier paths
If multiple point objects are supplied as a list (or concatenated with the c
function), a bézier curve will be created for each point object in the list.