Arrange ggplots together in custom ratios and spacing

I am trying to combine n number of barplots with one common label plot at the bottom. My problem is that grid.arrange combines the two plots in 50%-50%. I am looking for something like the layout matrix where you can specify 4 slots and first 3 to be taken up by first plot and last slot by second plot. And customise similarly depending on number of plots. I have a sample code here from what I am trying: ``` #load libraries require(ggplot2) require(reshape) require(grid) require(gridExtra) #data creation #DATA temp<-data.frame(var1=sample(0:100,100,replace=T)) temp$var2<-100-temp$var1 temp$type<-factor(c(rep("S1",50),rep("S2",50))) temp$label<-factor(rep(1:50,2)) temp1<-melt(temp,id.var=c("type","label")) #LABELS labs1<-data.frame(pos=c(1,8,22,45,50)) labs2<-data.frame(pos1=round((diff(labs1$pos)/2)+labs1$pos[1:length(labs1$pos)-1],1), lab=c("A","B","D","E")) #plots plot1<-ggplot(data=temp1)+ geom_bar(aes(x=label,y=value,fill=variable),stat="identity",space=0,width=1)+ facet_grid(type~.)+theme_bw()+labs(x=NULL,y=NULL)+ scale_y_continuous(expand=c(0,0))+ theme(legend.position="none",axis.text=element_blank(),axis.ticks=element_blank()) plot2<-ggplot()+ geom_line(data=labs1,aes(x=pos,y=-0.05),size=0.6)+ geom_point(data=labs1,aes(x=pos,y=-0.05))+labs(x=NULL,y=NULL)+ geom_text(data=labs2,aes(x=pos1,y=-0.1,label=lab))+ theme_bw()+scale_x_continuous(expand=c(0,0))+scale_y_continuous(limit=c(-0.5,0))+ theme(legend.position="none",axis.text=element_blank(),axis.ticks=element_blank()) plot3<-grid.arrange(plot1, plot2) #here perhaps there is a way to say plot1 to take up 1/3 of the plot area. ``` The two plots don't align quite perfectly. But that's another issue. And this was useful How can I arrange an arbitrary number of ggplots using grid.arrange? I could plot each one by one, but I would like to have the facet labels.