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The pdf of the shape in R has unsightly white lines in it

I am trying to make colorbars as well as raster maps in R, and the output gives unsightly lines in them when exporting to pdf.

Here is the code to create the color bar. It looks great when you run it in R:

color.bar <- function(lut, min, max=-min, nticks=11, ticks=seq(min, max, len=nticks), title='') {
    scale = (length(lut)-1)/(max-min)

    plot(c(0,10), c(min,max), type='n', bty='n', xaxt='n', xlab='', yaxt='n', ylab='', main=title)
    axis(4, ticks, las=1)
    for (i in 1:(length(lut)-1)) {
     y = (i-1)/scale + min
     rect(0,y,10,y+1/scale, col=lut[i], border=NA)
    }
}

par(mfrow=c(2,1))
par(mar=c(3,0,3,2.5))
pal = colorRampPalette(c("red","yellow"))
neg = pal(100)
pal = colorRampPalette(c("yellow","darkgreen"))
pos = pal(50)
color.bar(c(neg,pos),min=-75,max=50,ticks=c(-75,-50,-25,0,25,50))
color.bar(colorRampPalette(c("goldenrod","blue"))(25),min=0,max=1)
par(mar=c(5.1,4.1,4.1,2.1))
    dev.copy2pdf(file = "colorbar_wood.pdf", height = 8, width = 1)
pdf("colorbar_wood.pdf",width=1,height=8)
par(mfrow=c(2,1))
par(mar=c(3,0,3,2.5))
pal = colorRampPalette(c("red","yellow"))
neg = pal(100)
pal = colorRampPalette(c("yellow","darkgreen"))
pos = pal(50)
color.bar(c(neg,pos),min=-75,max=50,ticks=c(-75,-50,-25,0,25,50))
color.bar(colorRampPalette(c("goldenrod","blue"))(25),min=0,max=1)
par(mar=c(5.1,4.1,4.1,2.1))
 dev.off()

And here is what I exit as pdf:

link

I need to bring this to the quality of the publication. Any ideas on how to fix it?

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1 answer

This is always a problem with the software used to render the PDF, not with R, and is due to features such as anti-aliasing and other rendering operations that the PDF viewer does to render the PDF.

This is discussed in ?pdfespecially

Note:

     If you see problems with PDF output, do remember that the problem
     is much more likely to be in your viewer than in R.  Try another
     viewer if possible.  Symptoms for which the viewer has been at
     fault are apparent grids on image plots (turn off graphics
     anti-aliasing in your viewer if you can) and missing or incorrect
     glyphs in text (viewers silently doing font substitution).

     Unfortunately the default viewers on most Linux and Mac OS X
     systems have these problems, and no obvious way to turn off
     graphics anti-aliasing.

     ....

PDF PDF Linux (Evince Okular), , , , Okular -, -. , , -, PDF, R. , .

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