Adding background image to R Markdown (.rmd) file for PDF document? - r

Question

I have seen this post to include a background image to an R markdown report.
I have created a Shiny app to generate a pdf report:
shinyApp(
ui = fluidPage(
sliderInput("slider", "Slider", 1, 10, 5),
downloadButton("report", "Generate report")
),
server = function(input, output) {
test1 <- reactive({
n = input$slider
df=matrix(1:n^2,n,n)
df = as.data.frame(df)
result <- list(df=df,n=n)
return(result)
})
output$report <- downloadHandler(
# For PDF output, change this to "report.pdf"
filename = "report.pdf",
content = function(file) {
# Copy the report file to a temporary directory before processing it, in
# case we don't have write permissions to the current working dir (which
# can happen when deployed).
tempReport <- file.path(tempdir(), "report.Rmd")
file.copy("report.Rmd", tempReport, overwrite = TRUE)
# Set up parameters to pass to Rmd document
params <- list(n = test1()$n,
df = test1()$df)
# Knit the document, passing in the `params` list, and eval it in a
# child of the global environment (this isolates the code in the document
# from the code in this app).
rmarkdown::render(tempReport, output_file = file,
params = params,
envir = new.env(parent = globalenv())
)
}
)
}
)
And here is my .rmd file :
---
title: "Title"
author: "Name"
date: "`r Sys.Date()`"
output:
pdf_document :
fig_caption: yes
keep_tex: yes
number_sections: yes
header-includes:
\usepackage{booktabs}
\usepackage{longtable}
\usepackage{array}
\usepackage{multirow}
\usepackage{wrapfig}
\usepackage{float}
\usepackage{colortbl}
\usepackage{pdflscape}
\usepackage{tabu}
\usepackage{threeparttable}
\usepackage{threeparttablex}
\usepackage[normalem]{ulem}
\usepackage{makecell}
\usepackage{background}
\backgroundsetup{
scale=1,
color=black,
opacity=0.4,
angle=0,
pages=all,
contents={
\includegraphics[width=\paperwidth,height=\paperheight]{C:/Users/path_to_image/image.jpg}
}
}
params:
n: NA
df: NA
---
```{r}
# The `params` object is available in the document.
params$n
```
A plot of `params$n` random points.
```{r}
plot(rnorm(params$n), rnorm(params$n))
```
```{r}
params$df %>%
mutate_if(is.numeric, function(x) {
cell_spec(x, "latex", bold = T, color = spec_color(x, end = 0.85),
font_size = spec_font_size(x))
}) %>%
kable("latex", escape = F, booktabs = T, linesep = "", align = "c")%>%
kable_styling(latex_options = c("striped", "scale_down"))
```
The error that I'm getting is :
! Undefined control sequence.
l.171 \centering\rowcolors
{2}{gray!6}{white}
Here is how much of TeX's memory you used:
24161 strings out of 492990
415742 string characters out of 6136334
504502 words of memory out of 5000000
27291 multiletter control sequences out of 15000+600000
19644 words of font info for 30 fonts, out of 8000000 for 9000
1141 hyphenation exceptions out of 8191
62i,4n,56p,577b,315s stack positions out of 5000i,500n,10000p,200000b,80000s
[1]: http
Which in tex community they referring to forgetting something like \end{document}. I should mention that if I use the .rmd file alone and replace the last part with :
{r}
library(kableExtra)
library(dplyr)
iris[1:10, ] %>%
mutate_if(is.numeric, function(x) {
cell_spec(x, "latex", bold = T, color = spec_color(x, end = 0.9),
font_size = spec_font_size(x))
}) %>%
mutate(Species = cell_spec(
Species, "latex", color = "white", bold = T,
background = spec_color(1:10, end = 0.9, option = "A", direction = -1)
)) %>%
kable("latex", escape = F, booktabs = T, linesep = "", align = "c")
I will be able to compile it with that background image, the current shiny app is also generating the report if I exclude the part that related to the background image setting.

Answer 1

That's because xcolor must be loaded before background. Do:
---
title: "Title"
author: "Name"
date: "`r Sys.Date()`"
output:
pdf_document :
fig_caption: yes
keep_tex: yes
number_sections: yes
header-includes:
\usepackage{background}
\usepackage{float}
\backgroundsetup{
scale=1,
color=black,
opacity=0.4,
angle=0,
pages=all,
contents={
\includegraphics[width=\paperwidth,height=\paperheight]{C:/Users/path_to_image/image.jpg}
}
}
---
Note that your "header-includes" is useless because all these packages are automatically included.