Manipulate image with imager

library(imager)

# Ici l'image est en couleur car chaque pixel a 3 valeurs: Red Green Blue (RGB)
a <- array(data = runif(10*10*1*3), dim=c(10, 10, 1, 3))
class(a) <- c("cimg", "imager_array", "numeric")
plot(a)
print.default(a)

# Ici l'image est en niveau de gris car on met la même valeur pour RGB
a <- array(data = rep(runif(10*10*1), 3), dim=c(10, 10, 1, 3))
class(a) <- c("cimg", "imager_array", "numeric")
plot(a)
print.default(a)

# I add a red point
a[5, 5, 1, 1:3] <- c(1, 0, 0)
plot(a, interpolate = FALSE)

# Ici je ne garde qu'une valeur au lieu de 3 pour RGB; c'est donc du niveau de gris
a <- a[, , , 1, drop=FALSE]
plot(a)
print.default(a)

# là je seuille les valeurs
a[, , 1, 1] <- ifelse(a[, , 1, 1]<0.5, 0, 1)
plot(a)
print.default(a)




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