[wb_comment] modify the background color. closes #869

[JanMarvin]

wb <- wb_workbook()
wb$add_worksheet("Sheet 1")

# write comment without author
c1 <- wb_comment(text = "this is a comment", author = "", visible = TRUE)
wb$add_comment(dims = "B10", comment = c1)

# Write another comment with author information
c2 <- wb_comment(text = "this is another comment", author = "Marco Polo")
wb$add_comment(sheet = 1, dims = "C10", comment = c2)

# write a styled comment with system author
s1 <- create_font(b = "true", color = wb_color(hex = "FFFF0000"), sz = "12")
s2 <- create_font(color = wb_color(hex = "FF000000"), sz = "9")
c3 <- wb_comment(text = c("This Part Bold red\n\n", "This part black"), style = c(s1, s2))

wb$add_comment(sheet = 1, dims = wb_dims(3, 6), comment = c3, color = wb_color("green"))
if (interactive()) wb$open()

[JanMarvin]

Add background image to comment

library(openxlsx2)
wb <- wb_workbook()
wb$add_worksheet("Sheet 1")

# file extension must be png or jpeg, not jpg?
tmp <- tempfile(fileext = ".png")
png(file = tmp, bg = "transparent")
plot(1:10)
rect(1, 5, 3, 7, col = "white")
dev.off()
#> quartz_off_screen 
#>                 2

# write comment without author
c1 <- wb_comment(text = "this is a comment", author = "", visible = TRUE)
wb$add_comment(dims = "B12", comment = c1, file = tmp)

if (interactive()) wb$open()