问ggplot2 geom_bar中的条宽

EN

l1<-factor(rep(letters,4))
n1<-abs(rnorm(104))*10000
b1<-rep(c("1","2","3","4","5","6","7","8"),c(2,2,11,24,11,20,33,1))
k1<-rep((rep(c("A","B","C","D"),c(2,3,4,4))),8)
my.df<-data.frame(l1,b1,k1,n1)                            #make a dataframe

names(my.df)<-c("letter","branch","ltrtype","number")     #factor names
library(ggplot2)

branch.list<-unique(my.df$branch)
sayi<-length(branch.list)                                 # list of factor:letters

for (i in 1:sayi) {

branch.iter<-branch.list[i]
my.df.plot<-subset(my.df,my.df$branch==branch.iter,drop=T)

my.df.plot$branch<-factor(my.df.plot$branch)               #So that unused levels don't show up
my.df.plot$letter<-factor(my.df.plot$letter)               #So that unused levels don't show up
my.df.plot$ltrtype<-factor(my.df.plot$ltrtype)             #So that unused levels don't show up
my.df.plot$number<-as.numeric(as.character(my.df.plot$number))
my.df.plot<-data.frame(my.df.plot)

myfilename<-paste(branch.iter,".jpeg",sep="")
jpeg(file=myfilename)

cizim<-ggplot(my.df.plot,aes(letter,number,fill=ltrtype))
cizim<-cizim + geom_bar(width = 1, position = "fill", binwidth = 1) +     facet_grid(ltrtype~.)
cizim<-cizim + opts(title=branch.iter)

print(cizim)
dev.off()

}

 my.df.plot$branch<-factor(my.df.plot$branch)