likert plot禁用居中视图只有一个方向

Question

下面，我有R代码绘制一个类似的情节。

set.seed(1234)
library(e1071)
probs <- cbind(c(.4,.2/3,.2/3,.2/3,.4),c(.1/4,.1/4,.9,.1/4,.1/4),c(.2,.2,.2,.2,.2))
my.n <- 100
my.len <- ncol(probs)*my.n
raw <- matrix(NA,nrow=my.len,ncol=2)
raw <- NULL
for(i in 1:ncol(probs)){
  raw <- rbind(raw, cbind(i,rdiscrete(my.n,probs=probs[,i],values=1:5)))
}

r <- data.frame( cbind(
  as.numeric( row.names( tapply(raw[,2], raw[,1], mean) ) ),
  tapply(raw[,2], raw[,1], mean),
  tapply(raw[,2], raw[,1], mean) + sqrt( tapply(raw[,2], raw[,1], var)/tapply(raw[,2], raw[,1], length) ) * qnorm(1-.05/2,0,1),
  tapply(raw[,2], raw[,1], mean) - sqrt( tapply(raw[,2], raw[,1], var)/tapply(raw[,2], raw[,1], length) ) * qnorm(1-.05/2,0,1)
))
names(r) <- c("group","mean","ll","ul")

gbar <- tapply(raw[,2], list(raw[,2], raw[,1]), length)

sgbar <- data.frame( cbind(c(1:max(unique(raw[,1]))),t(gbar)) )

sgbar.likert<- sgbar[,2:6]



require(grid)
require(lattice)
require(latticeExtra)
require(HH)
sgbar.likert<- sgbar[,2:6]


yLabels = c(expression(a[1*x]),expression(b[2*x]),expression(c[3*x]))

likert(sgbar.likert,
       scales = list(y = list(labels = yLabels)),
       xlab="Percentage",
       main="Example Diverging Stacked Bar Chart for Likert Scale",
       BrewerPaletteName="Blues",
       sub="Likert Scale")

如下所示。

但是，我不希望绘图居中（如上图所示，绘图以0为中心，然后左右分开）。

我想要的是没有消极和积极的，但只有一个方向，看起来像下面这样：

我试过这个：

likert(sgbar.likert,
       scales = list(y = list(labels = yLabels)),
       xlab="Percentage",
       main="Example Diverging Stacked Bar Chart for Likert Scale",
       BrewerPaletteName="Blues",
       centered = FALSE,
       ordered = FALSE,
       include.center = FALSE,
       sub="Likert Scale")

但是，它没有改变任何东西。那么，如何禁用居中视图？