Connect all points using lines and write text above it using R - r

Question

I'm trying to connect every point in my array with all other points in this array using line segment and write some text slightly above this lines. So, I want to achieve next:
I already tried to use segments() and lines() functions, but I don't know how can I do exactly what I described.
And as I said, now I have only array of coordinates and array of strings which I want to write.
How can I achieve this(It will be good if I will need to use only standard R libraries)?
UPD:
dataset.csv:
,A,B,C
A,0,1,2
B,1,0,3
C,2,3,0
script.r:
myDataset <- read.csv("dataset.csv")
row.names(myDataset) <- myDataset[, 1]
myDataset <- myDataset[, -1]
d <- dist(myDataset)
fit <- cmdscale(d,eig=TRUE, k=2)
x <- fit$points[,1]
y <- fit$points[,2]

Answer 1

Here's an example that uses combn to generate combinations of two points and then draw lines between them and to compute distances and write them in the middle too.
#DATA
set.seed(42)
df = data.frame(x = rnorm(4), y = rnorm(4))
#DRAW POINTS
plot(df)
#DRAW LINES
combn(1:NROW(df), 2, function(x)
lines(df[x,]), simplify = FALSE)
#WRITE TEXT
combn(1:NROW(df), 2, function(x)
text(x = mean(df[x,1]), #calculate center point x-value in the line
y = mean(df[x,2]), #calculate center point y-value in the line
labels = round(dist(df[x,]), 2), #calculate distance to write
srt = 180 * atan(diff(df[x, 2])/diff(df[x,1]))/pi, #calculate rotation angle of text
pos = 3, #place text slightly above given x and y
font = 2), #bold text
simplify = FALSE)
UPDATE
myDataset <- read.csv(strip.white = TRUE, stringsAsFactors = FALSE, header = TRUE, text = ",A,B,C
A,0,1,2
B,1,0,3
C,2,3,0")
row.names(myDataset) <- myDataset[, 1]
myDataset <- myDataset[, -1]
d <- dist(myDataset)
fit <- cmdscale(d,eig=TRUE, k=2)
x <- fit$points[,1]
y <- fit$points[,2]
df = data.frame(x, y)
#DRAW POINTS
plot(df, asp = 1)
text(x = df[,1], y = df[,2], labels = rownames(df), pos = 1)
#Create a list of combination of indices
temp = combn(1:NROW(df), 2, simplify = FALSE)
#DRAW LINES
sapply(temp, function(i) lines(df[i,]))
#WRITE TEXT
sapply(temp, function(x)
text(x = mean(df[x,1]), #calculate center point x-value in the line
y = mean(df[x,2]), #calculate center point y-value in the line
labels = myDataset[cbind(which(row.names(myDataset) == row.names(df)[x[1]]),
which(colnames(myDataset) == row.names(df)[x[2]]))],
srt = 180 * atan(diff(df[x, 2])/diff(df[x,1]))/pi, #calculate rotation angle of text
pos = 3, #place text slightly above given x and y
font = 2), #bold text
simplify = FALSE)

Answer 2

Trying to achieve this with graphics primitives (such as lines) is bound to be a pain.
Use a dedicated library for graph plotting instead, e.g. ggraph. The “Edges” vignette has an example with edge labels:
ggraph(simple, layout = 'graphopt') +
geom_edge_link(aes(label = type),
angle_calc = 'along',
label_dodge = unit(2.5, 'mm'),
arrow = arrow(length = unit(4, 'mm')),
end_cap = circle(3, 'mm')) +
geom_node_point(size = 5)
The one drawback: ggraph doesn’t allow you to explicitly set the node positions; however, you can manipulate them manually.