Font Coloring Using xlsx Package in R - r

Question

I am writing an R function to save out pre-formatted data frames. Part of the format template calls for changing the column heading font color. The cell styling returns the correct alignment and bolding, but the text is still black.
The below is a bare version to demonstrate my font coloring problem (just change the file_path variable to a location that exists).
library(xlsx)
file_path <- "C:/Users/.../Desktop/tst.xlsx"
wb <- createWorkbook()
headerStyle <- CellStyle(wb,
font = Font(wb, isBold=TRUE, color = "#ffffff"),
fill = Fill(foregroundColor = "#2db6e8",
pattern = "SOLID_FOREGROUND"),
alignment = Alignment(wrapText = TRUE,
horizontal = "ALIGN_CENTER",
vertical = "VERTICAL_CENTER")
)
x <- mtcars
sheet <- createSheet(wb, "test")
cellBlock <- CellBlock(sheet,
startRow = 1,
startCol = 1,
noRows = nrow(x) + 1,
noColumns = ncol(x) + 1,
create = TRUE)
CB.setRowData(cellBlock = cellBlock,
x = colnames(x),
rowIndex = 1,
colOffset = 1,
rowStyle = headerStyle +
Border(pen = "BORDER_MEDIUM", color = "black",
position = "BOTTOM"))
saveWorkbook(wb, file_path)

Answer 1

I was able to get white text using the color index from the INDEXED_COLORS_ constant which is 9 for white. For your example code it would read:
headerStyle <- CellStyle(wb,
font = Font(wb, isBold=TRUE, color = "9"),
fill = Fill(foregroundColor = "#2db6e8",
pattern = "SOLID_FOREGROUND"),
alignment = Alignment(wrapText = TRUE,
horizontal = "ALIGN_CENTER",
vertical = "VERTICAL_CENTER")
)

Answer 2

It seems to relate uniquely to white text. Try using different colors:
headerStyle <- CellStyle(wb,
font = Font(wb, isBold=TRUE, color = "grey"),
fill = Fill(foregroundColor = "#2db6e8",
pattern = "SOLID_FOREGROUND"),
alignment = Alignment(wrapText = TRUE,
horizontal = "ALIGN_CENTER",
vertical = "VERTICAL_CENTER")
)
It works with orange, grey, blue, but not white. This may be an effort to prevent text from being invisible if the background were the default white, but I can't say for certain. Perhaps the package creator can comment.

Answer 3

The constants used by the xlsx package are define in these groups:
HALIGN_STYLES_
VALIGN_STYLES_
BORDER_STYLES_
FILL_STYLES_
CELL_STYLES_
INDEXED_COLORS_
So, just displaying them in the console for INDEX_COLORS_ you get
BLACK WHITE RED BRIGHT_GREEN BLUE YELLOW
8 9 10 11 12 13
PINK TURQUOISE DARK_RED GREEN DARK_BLUE DARK_YELLOW
14 15 16 17 18 19
VIOLET TEAL GREY_25_PERCENT GREY_50_PERCENT CORNFLOWER_BLUE MAROON
20 21 22 23 24 25
LEMON_CHIFFON ORCHID CORAL ROYAL_BLUE LIGHT_CORNFLOWER_BLUE SKY_BLUE
26 28 29 30 31 40
LIGHT_TURQUOISE LIGHT_GREEN LIGHT_YELLOW PALE_BLUE ROSE LAVENDER
41 42 43 44 45 46
TAN LIGHT_BLUE AQUA LIME GOLD LIGHT_ORANGE
47 48 49 50 51 52
ORANGE BLUE_GREY GREY_40_PERCENT DARK_TEAL SEA_GREEN DARK_GREEN
53 54 55 56 57 58
OLIVE_GREEN BROWN PLUM INDIGO GREY_80_PERCENT AUTOMATIC
59 60 61 62 63 64
You can use numeric or alias style:
cs2 <- CellStyle(wb) +
Font(
wb,
heightInPoints = 12,
isBold = F,
isItalic = F,
name = "Arial",
color="ORANGE"
)
cs2 <- CellStyle(wb) +
Font(
wb,
heightInPoints = 12,
isBold = F,
isItalic = F,
name = "Arial",
color=59
)