excel - R, XLConnect: Setting color with RGB code -

i have come across following problem. lot of data written excel file. within written excel table, want set cell color non-predefined value (which function of number written cell). e.g.: higher number in given cell, greener cell.

i know solutions exist package xlsx (see here , here). use xlconnect throughout entire project , not want convert of code have far.

currently, use following code set cell color:

# create excel workbook wb <- loadworkbook("filename.xls", create=true)`  # create cellstyle yellow solid foreground cellcolor <- createcellstyle(wb) setfillpattern(cellcolor, fill = xlc$"fill.solid_foreground") setfillforegroundcolor(cellcolor, color = xlc$"color.yellow")  # apply cellstyle given cell, here: (10,10) setcellstyle(wb, sheet=sheetname, row=10, col=10, cellstyle=cellcolor)  # save workbook saveworkbook(wb) 

obviously, problematic part

color = xlc$"color.yellow" 

because not let me set rgb code of color like. attempts like

color = rgb(0.2,0.4,0.8) 

fail.

the xlconnect documentation on page 91 tell

the color specified via corresponding color constant xlc object.

there no explanation on how use rgb code.