allow custom table styles

[JanMarvin]

For custom tablestyles (idea from CHOP-CGTInformatics/REDCapTidieR#148):

• create a custom style in Excel
• export the styled workbook
• import the workbook with openxlsx2
• copy wb$styles_mgr$styles$dxfs and wb$styles_mgr$styles$tableStyles such as below. We might create some better logic, but it is more or less a niche feature
• Should be safe if no other dxf nodes or tableStyles node exist in wb$styles_mgr$styles

library(openxlsx2)
wb <- wb_workbook() %>%
  wb_add_worksheet()

wb$styles_mgr$styles$dxfs <- c(
  "<dxf><fill><patternFill><bgColor theme=\"7\" tint=\"0.79998168889431442\"/></patternFill></fill></dxf>", 
  "<dxf><fill><patternFill><bgColor theme=\"5\" tint=\"0.79998168889431442\"/></patternFill></fill></dxf>", 
  "<dxf><border><left style=\"slantDashDot\"><color auto=\"1\"/></left><right style=\"slantDashDot\"><color auto=\"1\"/></right><top style=\"slantDashDot\"><color auto=\"1\"/></top><bottom style=\"slantDashDot\"><color auto=\"1\"/></bottom><vertical style=\"slantDashDot\"><color auto=\"1\"/></vertical><horizontal style=\"slantDashDot\"><color auto=\"1\"/></horizontal></border></dxf>", 
  "<dxf><fill><patternFill><bgColor rgb=\"FFC00000\"/></patternFill></fill></dxf>"
)
wb$styles_mgr$dxf <- data.frame(
  typ = "dxf",
  id = seq_along(wb$styles_mgr$styles$dxfs) - 1L,
  name = wb$styles_mgr$styles$dxfs
)

wb$styles_mgr$styles$tableStyles <- "<tableStyles count=\"1\" defaultTableStyle=\"TableStyleMedium2\" defaultPivotStyle=\"PivotStyleLight16\"><tableStyle name=\"RedTableStyle\" pivot=\"0\" count=\"4\" xr9:uid=\"{91A57EDA-14C5-4643-B7E3-C78161B6BBA4}\"><tableStyleElement type=\"wholeTable\" dxfId=\"2\"/><tableStyleElement type=\"headerRow\" dxfId=\"3\"/><tableStyleElement type=\"firstRowStripe\" dxfId=\"0\"/><tableStyleElement type=\"secondColumnStripe\" dxfId=\"1\"/></tableStyle></tableStyles>"


wb %>% 
  wb_add_data_table(x = mtcars, tableStyle = "RedTableStyle") %>% 
  wb_open()

[Edit] A little less hackish solution is below:

library(openxlsx2)
wb <- wb_workbook() %>%
  wb_add_worksheet()

tabCol1 <- create_dxfs_style(bgFill = wb_color(theme = 7))
tabCol2 <- create_dxfs_style(bgFill = wb_color(theme = 5))
tabBrd1 <- create_dxfs_style(border = TRUE)
tabCol3 <- create_dxfs_style(bgFill = wb_color(hex = "FFC00000"), font_color = wb_color("white"))

wb$add_style(tabCol1)
wb$add_style(tabCol2)
wb$add_style(tabBrd1)
wb$add_style(tabCol3)


wb$styles_mgr$styles$tableStyles <-
  sprintf(
    "<tableStyles count=\"1\" defaultTableStyle=\"TableStyleMedium2\" defaultPivotStyle=\"PivotStyleLight16\">
     <tableStyle name=\"RedTableStyle\" pivot=\"0\" count=\"%s\" xr9:uid=\"{91A57EDA-14C5-4643-B7E3-C78161B6BBA4}\">
       <tableStyleElement type=\"wholeTable\" dxfId=\"%s\"/>
       <tableStyleElement type=\"headerRow\" dxfId=\"%s\"/>
       <tableStyleElement type=\"firstRowStripe\" dxfId=\"%s\"/>
       <tableStyleElement type=\"secondColumnStripe\" dxfId=\"%s\"/>
     </tableStyle>
  </tableStyles>",
    length(c(tabCol1, tabCol2, tabCol3, tabBrd1)),
    wb$styles_mgr$get_dxf_id("tabBrd1"),
    wb$styles_mgr$get_dxf_id("tabCol3"),
    wb$styles_mgr$get_dxf_id("tabCol1"),
    wb$styles_mgr$get_dxf_id("tabCol2")
  )


wb %>% 
  wb_add_data_table(x = mtcars, tableStyle = "RedTableStyle") %>% 
  wb_open()