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draw borders of bars inside of the rectangles in a barplot

4 messages · Martin Batholdy, Bert Gunter, Richard M. Heiberger +1 more

Martin Batholdy
# 
Dear R-users,

I want to draw a barplot with beside=TRUE.
One halve of the bars are drawn with a border, while the other halve are drawn without a border (i.e. filled bars vs. non-filled bars next to each other).

Because borders are drawn around the bars, doing this leads to one halve of the bars being wider than the other halve, expanding across the 0-point of the y-axis.
This problem emerges especially with small figures and rather large border width.

Now my question:
Is there a way to draw the border inside of the bars instead of surrounding the bars? (similar to border-drawing options in graphics software, like photoshop or inkscape).


Here some example code:

x <- matrix(c(1:10), 2,5)
par(lwd = 5) 
barplot(x, beside=T, border=rep(c(NA, 'black'),5), space=c(0.08,1), col=rep(c('black', 'white'),5))



Thank you!
Bert Gunter
# 
As I read ?barplot, the answer is no. I suspect the same is true in ggplot
and lattice, but you would have to check. If correct, this means you would
explicitly have to use the "width" argument to narrow or widen the bars
appropriately. Or maybe try something like:

barplot(x, beside=T, border= "black", space=c(0.08,1), col=rep(c('gray50',
'white'),5))

instead.

Cheers,
Bert



Bert Gunter

"The trouble with having an open mind is that people keep coming along and
sticking things into it."
-- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )

On Mon, May 21, 2018 at 7:59 AM, Martin Batholdy via R-help <
r-help at r-project.org> wrote:

            

      
      
      
    

        

      
      
    

        

  
  


  


      

    

    

      
      

        


  

        

      Richard M. Heiberger
    

    

      
      #
    

  


  

      
I recommend instead of no border, that you use a border with the same
color as the fill.
I do this in the likert functions in the HH package.

Rich


On Mon, May 21, 2018 at 10:59 AM, Martin Batholdy via R-help

        
<r-help at r-project.org> wrote:

            

      
      
      
    

        

      
      
    

  
  


  


      

    

    
1 day later

    

      
      

        


  

        

      Paul Murrell
    

    

      
      #
    

  


  

      
Hi

In addition to Richard's suggestion to add borders to the "only filled" 
bars, you could add "mitred" corners, like this ...


par(ljoin="mitre")
barplot(x, beside=T, border=rep(c('black', 'black'),5),
         space=c(0.08,1), col=rep(c('black', 'white'),5))


It may be overkill, but if the "bleeding" below y=0 is still a bother, 
here's one way you could then clip the bar bottoms ...


par(lwd=5, ljoin="mitre")
barplot(x, beside=T, border=rep(c('black', 'black'),5),
         space=c(0.08,1), col=rep(c('black', 'white'),5))
## Convert to 'grid'
library(gridGraphics)
grid.echo()
## Which grob is the bars?
barpath <- grid.grep("rect", grep=TRUE, viewports=TRUE)
## Which viewport are the bars drawn within?
barvp <- attr(barpath, "vp")
## Get copy of the bars
bars <- grid.get(barpath)
## Remove the bars
grid.remove(barpath)
## Go to the bars viewport
downViewport(barvp)
## Set up a clipping rect
grid.clip(y=unit(0, "native"),
           height=unit(11, "native"),
           just="bottom",
           name="clip")
## Draw the bars again (now clipped)
grid.draw(bars)


You could take it even further and clip each individual bar (so the 
border is only visible "inside" the bar) ...


par(lwd=5, ljoin="mitre")
barplot(x, beside=T, border=rep(c('black', 'black'),5),
         space=c(0.08,1), col=rep(c('black', 'white'),5))
library(gridGraphics)
grid.echo()
barpath <- grid.grep("rect", grep=TRUE, viewports=TRUE)
barvp <- attr(barpath, "vp")
bars <- grid.get(barpath)
grid.remove(barpath)
downViewport(barvp)
## Filled bars
for (i in 1:5) {
     odd <- i*2 - 1
     grid.rect(bars$x[odd], bars$y[1], bars$width[odd], bars$height[odd],
               just=c("left", "bottom"), gp=gpar(fill="black"))
}
## Border bars (clipped)
for (i in 1:5) {
     even <- i*2
     grid.clip(bars$x[even], bars$y[1],
               bars$width[even], bars$height[even],
               just=c("left", "bottom"))
     grid.rect(bars$x[even], bars$y[2],
               bars$width[even], bars$height[even],
               just=c("left", "bottom"), gp=gpar(lwd=5))
}


And, since you mentioned Photoshop/Inkscape, another option to draw 
borders only "inside" the bars is a "variable-width line" from the 
'vwline' package ...


par(lwd=5, ljoin="mitre")
barplot(x, beside=T, border=rep(c('black', 'black'),5),
         space=c(0.08,1), col=rep(c('black', 'white'),5))
library(gridGraphics)
grid.echo()
barpath <- grid.grep("rect", grep=TRUE, viewports=TRUE)
barvp <- attr(barpath, "vp")
bars <- grid.get(barpath)
grid.remove(barpath)
downViewport(barvp)
## Filled bars
for (i in 1:5) {
     odd <- i*2 - 1
     grid.rect(bars$x[odd], bars$y[1], bars$width[odd], bars$height[odd],
               just=c("left", "bottom"), gp=gpar(fill="black"))
}
## Draw vwline with width only "inside"
library(vwline)
for (i in 1:5) {
     even <- i*2
     left <- bars$x[even]
     right <- bars$x[even] +
         convertUnit(bars$width[even], "in",
                     "x", "dimension", "x", "location")
     bottom <- bars$y[2]
     top <- bars$y[2] +
         convertUnit(bars$height[even], "in",
                     "y", "dimension", "y", "location")
     grid.vwline(unit.c(left, left, right, right),
                 unit.c(bottom, top, top, bottom),
                 w=widthSpec(list(left=rep(0, 4),
                                  right=unit(rep(1, 4), "mm"))),
                 open=FALSE)
}


Paul

        
On 22/05/18 04:05, Richard M. Heiberger wrote: