[R] levelplot + cut() for custom color palette

[Alex Reynolds]

I have the following data as input, from which I would like to make a lattice levelplot:

-----------------
     x     y     level
1 m3134 m3134 1.0000000
2 m3134 m416B 0.4189057
3 m416B m3134 0.2696508
4 m3134  mA20 0.3322170
5  mA20 m3134 0.2454191
6 m3134    mB 0.3176792 
...                                                     
-----------------

I transform the levels as follows, so that levels are in the range [0,100]:

-----------------
     x     y level                                                                                                                                                                                                                          
1 m3134 m3134   100
2 m3134 m416B    42
3 m416B m3134    27
4 m3134  mA20    33
5  mA20 m3134    25
6 m3134    mB    32
...
-----------------

I want to create a custom color palette with the following groups, based on the levels in my input data frame mostly being between 10 and 80:

level range -- color
-----------------
[0,10) -- white
[10, 11) -- white
[11, 12) -- a mix of mostly white and a little red
...
[78,79) -- a mix of mostly red and a little white
[79,80) -- red
[80, Inf) -- black

In other words, I want to color any cell with the level of 100 (or greater than 80) with black, and any cell with a level between 0 and 80 with a color between white and red.

Here is my code:
-----------------
#! /foo/bar/bin/Rscript --vanilla
args <- commandArgs(TRUE)
dfFn <- args[1]
pdfFn <- args[2]

df <- read.table(dfFn, col.names=c("x", "y", "level"))                                                                                                                                                                           
df$level <- round(df$level*100, 0)

col.seq <- seq(10, 79, 1)
cuts <- cut(df$level, breaks = c(0, 1, seq(10, 79, 1), 80, Inf))
colors <- colorRampPalette(c('white', 'red'))(length(col.seq)+1)
levels(colors) <- c("white", cuts, "black")

library(lattice)
trellis.device(dev=pdf, file=pdfFn)
fig <- levelplot(level~x*y,
                data=df,
                col.regions=colors
                )
print(fig)
graphics.off();
-----------------

This makes a levelplot, but the coloring is incorrect. The cells in the figure are colored from white to red, for levels between 0 and 100, instead of between levels 10 and 79. The cells containing a level of 100 are painted red, instead of black.

I also get the following warning, which comes from the levels(colors) statement:

-----------------
Warning message:                                                                                                                                                                                                                             
In `levels<-`(`*tmp*`, value = c("white", "63", "24", "9", "15",  :                                                                                                                                                                          
 duplicated levels will not be allowed in factors anymore 
-----------------

What am I doing wrong with the cut() and color palette generation steps (and how can I fix them) in order to make the levelplot with correct cell coloring? Thanks for any constructive advice.

Regards,
Alex