代码从命令行启动：图形设备空白

Question

I have a code that has to work from command-line. If I run it piece by piece from RStudio it works properly. When I run it from command-line, it does open the graphic device, but it remain blank.

require(ggplot2)
#ds <- head(SOM_dist_tot)
num <- 6
ds <- c(1.00566799, 0.81354614, 0.36507594, 0.15541231, 0.13957369, 0.06986632)

vett <- as.data.frame(ds)
pdf("ggplot_test.pdf")
  gioele <-ggplot(vett, aes(x= as.numeric(rownames(vett)), y =vett$ds))+
           geom_point(size=2) + xlab("X") + ylab("Y")+
           ggtitle("...")+
           theme(axis.text.x = element_text(angle=-45, hjust=0, vjust=1), 
                 plot.margin = unit(c(1, 1, 1, 1), "cm"), 
                 plot.title = element_text(size = 20, face = "bold", colour = "black", vjust = -1))
  #print(gioele)
  plot(gioele)
dev.off()

print(gioele)

inputFromUser <- as.numeric(readLines(file("stdin"),1))

dev.off()

I want to show the graph "gioele", such to give informations to the user. Then the user choose a command to insert ( inputFromUser ), and then the window has to close. Do you have any ideas?

Answer 1

After a lot of pain I have understood the problem: it is a conflict between readLines() and the graphic device. Inother words, it correctly open the device plotting the graph, but then the readLines(...) make the graphic device blank (I don't know how it is technically possible).

I have found the solution removing the readLines() and using a more correct readline() .

require(ggplot2)
#ds <- head(SOM_dist_tot)
num <- 6
ds <- c(1.00566799, 0.81354614, 0.36507594, 0.15541231, 0.13957369, 0.06986632)


pdf("plot_test.pdf")
  plot(ds[1:num], type="p", xlab="X", ylab="Y", col="red")
  title(main="...", sub = "...", line=-1.2, cex.sub = 0.75, font.sub = 3, col.sub = "red")
dev.off()
#cat("Faccio il plot")
# plot(ds[1:num], type="p", xlab="X", ylab="Y", col="red")
# title(main="...", sub = "...", line=-1.2, cex.sub = 0.75, font.sub = 3, col.sub = "red")


vett <- as.data.frame(ds)
pdf("ggplot_test.pdf")
  gg2 <-ggplot(vett, aes(x= as.numeric(rownames(vett)), y =vett$ds))+
    geom_point(size=2) + xlab("X") + ylab("Y")+
    ggtitle("...")+
    theme(axis.text.x = element_text(angle=-45, hjust=0, vjust=1), 
          plot.margin = unit(c(1, 1, 1, 1), "cm"), 
          plot.title = element_text(size = 20, face = "bold", colour = "black", vjust = -1))
  #print(gg2)
  plot(gg2)
dev.off()

print(gg2)

#inputFromUser <- as.numeric(readLines(file("stdin"),1))
inputFromUser <- as.numeric(readline())

dev.off()