Bar graph in ggplot2 with width as a variable and even spacing between bars

Question

So I am trying to make a stacked bar graph with bar width mapped to a variable; but I want the spacing between my bars to be constant.

Does anyone know how to make the spacing constant between the bars?

Right now I've got this:

p<-ggplot(dd, aes(variable, value.y, fill=Date, width=value.x / 15))+ coord_flip() + opts(ylab="") 

p1<-p+ geom_bar(stat="identity") + scale_fill_brewer(palette="Dark2") + scale_fill_hue(l=55,c=55)

p2<-p1 + opts(axis.title.x = theme_blank(), axis.title.y = theme_blank())

p2

Thanks in advance.

Here's my data by the way (sorry for the long, bulky dput):

> dput(dd)
structure(list(variable = structure(c(1L, 1L, 1L, 1L, 1L, 3L, 
3L, 3L, 3L, 3L, 4L, 4L, 4L, 4L, 4L, 7L, 7L, 7L, 7L, 7L, 2L, 2L, 
2L, 2L, 2L, 6L, 6L, 6L, 6L, 6L, 5L, 5L, 5L, 5L, 5L, 9L, 9L, 9L, 
9L, 9L, 8L, 8L, 8L, 8L, 8L), .Label = c("Alcohol and Tobacco", 
"Health and Personal Care", "Clothing", "Energy", "Recreation and Education", 
"Household", "Food", "Transportation", "Shelter"), class = "factor", scores = structure(c(2.91, 
5.31, 10.08, 15.99, 4.95, 11.55, 11.2, 27.49, 20.6), .Dim = 9L, .Dimnames = list(
    c("Alcohol and Tobacco", "Clothing", "Energy", "Food", "Health and Personal Care", 
    "Household", "Recreation and Education", "Shelter", "Transportation"
    )))), value.x = c(2.91, 2.91, 2.91, 2.91, 2.91, 5.31, 5.31, 
5.31, 5.31, 5.31, 10.08, 10.08, 10.08, 10.08, 10.08, 15.99, 15.99, 
15.99, 15.99, 15.99, 4.95, 4.95, 4.95, 4.95, 4.95, 11.55, 11.55, 
11.55, 11.55, 11.55, 11.2, 11.2, 11.2, 11.2, 11.2, 27.49, 27.49, 
27.49, 27.49, 27.49, 20.6, 20.6, 20.6, 20.6, 20.6), Date = structure(c(5L, 
4L, 3L, 2L, 1L, 5L, 4L, 3L, 2L, 1L, 5L, 4L, 3L, 2L, 1L, 5L, 4L, 
3L, 2L, 1L, 5L, 4L, 3L, 2L, 1L, 5L, 4L, 3L, 2L, 1L, 5L, 4L, 3L, 
2L, 1L, 5L, 4L, 3L, 2L, 1L, 5L, 4L, 3L, 2L, 1L), .Label = c("1993-2001", 
"2001-2006", "2007-2010", "2010-2011", "2012 Jan - May"), class = "factor"), 
    value.y = c(2.1, 2.5, 7.6, 21.7, 2.8, 1.5, 0.3, -4.1, -4.2, 
    4.7, 3, 16.9, 1.9, 32.8, 23.9, 3.2, 4.6, 11.3, 8.9, 12.9, 
    1.7, 2, 7.8, 5.9, 10, 1.9, 2.1, 5.6, 2.2, 9.9, 1.4, 1.3, 
    2.2, 0.6, 17.3, 1.1, 2.3, 6.4, 13.1, 10, 4.3, 7.6, 0.9, 15.2, 
    20.5)), .Names = c("variable", "value.x", "Date", "value.y"
), row.names = c(NA, -45L), class = "data.frame")

Answer 1

Attempt # 2.

I'm tricking ggplot2 into writing a continuous scale as categorical.

# The numbers for tmp I calculated by hand. Not sure how to program 
# this part but the math is 
# last + half(previous_width) + half(current_width)
# Change the 1st number in cumsum to adjust the between category width

tmp <- c(2.91,7.02,14.715,27.75,38.22,46.47,57.845,77.19,101.235) + cumsum(rep(5,9))

dd$x.pos1 <- rep(tmp,each=5)
ggplot(dd,aes(x=x.pos1,y=value.y,fill=Date)) +
geom_bar(aes(width=value.x),stat="identity",position="stack") + 
scale_x_continuous(breaks=tmp,labels=levels(dd$variable)) + 
coord_flip()

For good measure you're probably going to want to adjust the text size. That's done with ... + opts(axis.text.y=theme_text(size=12))