---
title: "Basic Usage of cpp11qpdf"
output: rmarkdown::html_vignette
vignette: >
  %\VignetteIndexEntry{Basic Usage of cpp11qpdf}
  %\VignetteEngine{knitr::rmarkdown}
  %\VignetteEncoding{UTF-8}
---

```{r, include = FALSE}
knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>"
)
```

# Load the package and example file

Load the `cpp11qpdf` package and set the path to an example PDF file included with R for demonstration purposes.

```{r load}
library(cpp11qpdf)
input_pdf <- system.file("examples", "sufganiyot.pdf", package = "cpp11qpdf")
```

# Compressing a PDF

To compress a PDF file, use the `pdf_compress` function. This function takes an input PDF file and an output file path.

```{r compress}
output_pdf <- tempfile(fileext = ".pdf")
pdf_compress(input_pdf, output_pdf, password = "")
file.exists(output_pdf)
```

# Rotating Pages in a PDF

To rotate pages in a PDF, use the `pdf_rotate_pages` function. This function takes an input PDF file, the pages to rotate, the angle of rotation, and the output file path.

```{r rotate}
output_pdf <- tempfile(fileext = ".pdf")
pdf_rotate_pages(input_pdf, pages = 1, angle = 90, output = output_pdf,
  password = "")
file.exists(output_pdf)
```

# Splitting a PDF

To split a PDF into individual pages, use the `pdf_split` function. This function takes an input PDF file and an output file prefix.

```{r split}
output_prefix <- tempfile()
output_files <- pdf_split(input_pdf, output_prefix, password = "")
output_files
```

# Combining Multiple PDFs

To combine multiple PDF files into a single PDF, use the `pdf_combine` function. This function takes a vector of input PDF files and an output file path.

```{r combine}
# using the output files from the previous example
output_pdf <- tempfile(fileext = ".pdf")
pdf_combine(output_files, output_pdf, password = "")
file.exists(output_pdf)
```

# Extracting Pages from a PDF

To extract specific pages from a PDF, use the `pdf_subset` function. This function takes an input PDF file, the pages to extract, and the output file path.

```{r subset}
output_pdf <- tempfile(fileext = ".pdf")
pdf_subset(input_pdf, 1, output_pdf, password = "")
file.exists(output_pdf)
```

# Overlaying a Stamp on a PDF

To overlay a stamp on each page of a PDF, use the `pdf_overlay_stamp` function. This function takes an input PDF file, a stamp PDF file, and the output file path.

```{r overlay}
stamp_pdf <- system.file("examples", "header.pdf", package = "cpp11qpdf")
output_pdf <- tempfile(fileext = ".pdf")
pdf_overlay_stamp(input_pdf, stamp_pdf, output_pdf, password = "")
file.exists(output_pdf)
```

Now the pages have a header that is not a part of the original PDF.

```{r preview, echo = FALSE}
knitr::include_graphics("added-header.png")
```
