l_system: L-system
In BastiHz/fractalplotr: Plot Beautiful Fractals with R

Description Usage Arguments Details Value See Also Examples

View source: R/l_system.R

Generate L-systems.

l_system(
  axiom,
  rules,
  n = 1,
  angle,
  initial_angle = pi/2,
  draw_f = NULL,
  return_string = FALSE,
  extra_info = FALSE,
  remove_duplicates = TRUE
)

`axiom`	A string of symbols representing the initial state of the system.
`rules`	A list of named strings forming the rules.
`n`	The number of iterations.
`angle`	The angle in radians which determines the change in direction for every "+" or "-".
`initial_angle`	The initial angle of the first line in radians.
`draw_f`	A character vector of symbols the replace with "F" in the instructions.
`return_string`	Logical. If `TRUE` the function returns the string of instructions after `n` iterations. Otherwise they are converted to line segments.
`extra_info`	Logical. If `TRUE` return additional information for all lines: length, angle, stack depth.
`remove_duplicates`	Logical. If `TRUE` remove duplicated lines from the result. Does not consider the direction of the lines, so a line from (0, 0) to (1, 1) is not a duplicate of a line from (1, 1) to (0, 0).

List of valid instructions:

F: Draw a line in the current direction.
+ or -: Turn by angle.
[ or ]: Save or load current state.
@: Multiply the line length by the following numerical argument.
!: Flip the angle direction.

Depending on the value of return_string either the string of instructions after n iterations or a data frame of class "l_system" with the columns x0, y0, x1, and y1 determining the endpoints of the line segments. Includes additional columns if extra_info is TRUE.

plot.l_system()

# plant:
l_plant <- l_system(
    axiom = "X",
    rules = list(
        X = "F+[[X]-X]-F[-FX]+X",
        F = "FF"
    ),
    n = 7,
    angle = pi * 0.15,
    initial_angle = pi * 0.45
)
plot(l_plant, col = colorRampPalette(c("#008000", "#00FF00"))(100))

# dragon curve:
l_dragon <- l_system(
    axiom = "FX",
    rules = list(
        X = "X+YF+",
        Y = "-FX-Y"
    ),
    n = 12,
    angle = pi / 2,
    initial_angle = 0
)
plot(l_dragon, col = rainbow(nrow(l_dragon)))

# sierpinski triangle:
l_triangle <- l_system(
    axiom = "F-G-G",
    rules = list(
        F = "F-G+F+G-F",
        G = "GG"
    ),
    n = 6,
    angle = radians(120),
    initial_angle = radians(60),
    draw_f = "G"
)
plot(l_triangle)

# changing line length, flipping angle, and using extra_info = TRUE
# to vary color and line thickness:
l_tree <- l_system(
    axiom = "X",
    rules = list(X = "F[+@.7X]F![-@.6X]F"),
    n = 10,
    angle = radians(22.5),
    extra_info = TRUE
)
plot(
    l_tree,
    col = ifelse(l_tree$depth < 6, "sienna", "forestgreen"),
    lwd = l_tree$depth / max(l_tree$depth) * -2 + 3
)