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Use axis functions, add tick marks
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@hsonne
hsonne committed Sep 26, 2024
1 parent 31b2f47 commit b4cf7b4
Showing 1 changed file with 107 additions and 73 deletions.
180 changes: 107 additions & 73 deletions R/triangle_of_fractions.R
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Original file line number Diff line number Diff line change
Expand Up @@ -15,92 +15,126 @@ triangle_of_fractions <- function(fractions, cols = c("blue", "red", "green"))
{
stopifnot(sum(fractions) == 1)

point <- function(x, y) data.frame(x = x, y = y)
grad_to_rad <- function(x) x/180 * pi
sin_grad <- function(x) sin(grad_to_rad(x))
cos_grad <- function(x) cos(grad_to_rad(x))
tan_grad <- function(x) tan(grad_to_rad(x))
linear_n <- function(x, y, m) y - m * x

y_fun <- function(m, n) function(x) {m * x + n}
x_fun <- function(m, n) function(y) {stopifnot(m != 0);(y - n) / m}
new_point <- function(x, y) {
data.frame(x = x, y = y)
}

shift_x <- function(dist = 0.04) dist * sin_grad(60)
shift_y <- function(dist = 0.04) dist * cos_grad(60)
new_line <- function(slope, point) {
list(slope = slope, intersept = point$y - slope * point$x)
}

ytop <- 0.5 * sqrt(3)
new_axis <- function(origin, phi) {
function(x) {
# Convert Polar coordinates to Cartesian coordinates
data.frame(x = origin$x + x * cos(phi), y = origin$y + x * sin(phi))
}
}

triangle <- rbind(
point(-0.5, 0),
point( 0, ytop),
point(+0.5, 0),
point(-0.5, 0)
line_crossing <- function(line_1, line_2) {
x <- (line_2$intersept - line_1$intersept) / (line_1$slope - line_2$slope)
new_point(x, line_1$slope * x + line_1$intersept)
}

arrow_path <- function(data, colour = "black") {
ggplot2::geom_path(
data = data,
colour = colour,
linewidth = 1,
arrow = ggplot2::arrow(length = ggplot2::unit(0.3, "cm"))
)
}

tick_path <- function(data, colour = "black") {
ggplot2::geom_path(data = data, colour = colour)
}

rad_60 <- grad_to_rad(60)
rad_150 <- grad_to_rad(150)
rad_180 <- grad_to_rad(180)

axis_1 <- new_axis(new_point(0, 0), phi = rad_60)
axis_2 <- new_axis(axis_1(1), phi = -rad_60)
axis_3 <- new_axis(new_point(1, 0), phi = rad_180)

centre <- line_crossing(
line_1 = new_line(slope = 0, point = axis_1(fractions[1L])),
line_2 = new_line(slope = tan(rad_60), point = axis_2(fractions[2L]))
)

# Share 1 (starting from left leg of triangle)
dx_1 <- fractions[1L] * cos_grad(60)
dy_1 <- fractions[1L] * sin_grad(60)

# Share 2 (starting from right leg of triangle)
dx_2 <- fractions[2L] * sin_grad(30)
dy_2 <- fractions[2L] * cos_grad(30)
slope_2 <- tan_grad(60)
intersept_2 <- linear_n(x = dx_2, y = ytop - dy_2, m = slope_2)
x_fun_2 <- x_fun(slope_2, intersept_2)
y_fun_2 <- y_fun(slope_2, intersept_2)

# Share 3 (starting from bottom leg of triangle)
slope_3 <- -tan_grad(60)
intersept_3 <- linear_n(x = x_fun_2(dy_1), y = dy_1, m = slope_3)
x_fun_3 <- x_fun(slope_3, intersept_3)
centre <- point(x_fun_2(dy_1), dy_1)

my_path <- function(data, colour) ggplot2::geom_path(
data = data,
colour = colour,
linewidth = 1,
arrow = ggplot2::arrow(length = ggplot2::unit(0.3, "cm"))
shift_ortho <- function(points, slope, by) {
if (slope == 0) {
dx <- 0
dy <- by
} else {
ortho_slope <- -1/slope
dx <- by / sqrt(1 + ortho_slope * ortho_slope)
dy <- ortho_slope * dx
}
new_point(points$x + dx, points$y + dy)
}

annotate_axis <- function(points, i, angle = 0, size = 4) {
ggplot2::annotate(
"text",
size = size,
x = points$x,
y = points$y,
label = c("0", names(fractions)[i], "1"),
colour = cols[i],
angle = angle
)
}

tick_pos <- seq(0, 1, 0.1)
tick_begs_1 <- axis_1(tick_pos)
tick_begs_2 <- axis_2(tick_pos)
tick_begs_3 <- axis_3(tick_pos)

by <- -0.02
tick_ends_1 <- shift_ortho(tick_begs_1, tan(rad_60), by)
tick_ends_2 <- shift_ortho(tick_begs_2, -tan(rad_60), -by)
tick_ends_3 <- shift_ortho(tick_begs_3, 0, by)

tick_data <- rbind(
cbind(tick_begs_1, tick_ends_1),
cbind(tick_begs_2, tick_ends_2),
cbind(tick_begs_3, tick_ends_3)
)

names(tick_data) <- c("x", "y", "xend", "yend")

blank <- ggplot2::element_blank()
blank_theme <- ggplot2::theme(
panel.grid.major = blank,
panel.grid.minor = blank,
axis.text = blank,
axis.ticks = blank,
panel.border = blank
)

my_annotate <- function(...) ggplot2::annotate("text", ...)
by <- -0.06
pos <- c(0, 0.5, 1)
label_points_1 <- shift_ortho(axis_1(pos), tan(rad_60), by)
label_points_2 <- shift_ortho(axis_2(pos), -tan(rad_60), -by)
label_points_3 <- shift_ortho(axis_3(pos), 0, by)

ggplot2::ggplot(mapping = ggplot2::aes(x = .data$x, y = .data$y)) +
ggplot2::geom_path(data = triangle) +
my_path(rbind(point(-0.5 + dx_1, dy_1), centre), cols[1L]) +
my_path(rbind(point(dx_2, y_fun_2(dx_2)), centre), cols[2L]) +
my_path(rbind(point(x_fun_3(0), 0), centre), cols[3L]) +
my_annotate(
x = c(-0.5, 0.0, 0.5),
y = -0.05,
label = c("1", names(fractions)[3L], "0"),
colour = cols[3L]
) +
my_annotate(
x = c(-0.5 -shift_x(), -0.3, -shift_x()),
y = c(0 + shift_y(), ytop/2, ytop + shift_y()),
label = c("0", names(fractions)[1L], "1"),
colour = cols[1L],
angle = 60,
hjust = 0.5,
vjust = 0.5
) +
my_annotate(
x = c(0 + shift_x(), 0.3, 0.5 + shift_x()),
y = c(ytop + shift_y(), ytop/2, 0 + shift_y()),
label = c("0", names(fractions)[2L], "1"),
colour = cols[2L],
angle = -60,
hjust = 0.5,
vjust = 0.5
ggplot2::geom_path(
data = rbind(axis_1(1), axis_2(1), axis_3(1), axis_1(1))
) +
arrow_path(rbind(axis_1(fractions[1L]), centre), col = cols[1L]) +
arrow_path(rbind(axis_2(fractions[2L]), centre), col = cols[2L]) +
arrow_path(rbind(axis_3(fractions[3L]), centre), col = cols[3L]) +
ggplot2::coord_fixed() +
ggplot2::labs(x = "", y = "") +
ggplot2::theme_bw() +
ggplot2::theme(
panel.grid.major = ggplot2::element_blank(),
panel.grid.minor = ggplot2::element_blank(),
axis.text = ggplot2::element_blank(),
axis.ticks = ggplot2::element_blank(),
panel.border = ggplot2::element_blank()
)
blank_theme +
ggplot2::geom_segment(data = tick_data, mapping = ggplot2::aes(
x = .data$x, y = .data$y, xend = .data$xend, yend = .data$yend
)) +
annotate_axis(label_points_1, 1, angle = 60) +
annotate_axis(label_points_2, 2, angle = -60) +
annotate_axis(label_points_3, 3)
}

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