---
title: "Accessibility"
output: rmarkdown::html_vignette
vignette: >
  %\VignetteIndexEntry{Accessibility}
  %\VignetteEngine{knitr::rmarkdown}
  %\VignetteEncoding{UTF-8}
---

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

pkgdown automates as many accessibility details as possible, so that your package website is readable by as many people as possible. This vignette describes the additional details that can't be automated away and you need to be aware of.

```{r setup}
library(pkgdown)
```

## Theming

* If you adjust any colours from the default theme (including the syntax highlighting theme), you should double check that the contrast between the background and foreground doesn't make any text difficult to read. A good place to start is running a representative page of your site through <https://wave.webaim.org>.

* The default colour of the development version label makes a slightly too low contrast against the pale grey background of the navbar. This colour comes from the bootstrap "danger" colour, so you can fix it by overriding that variable in your `_pkgdown.yml`:

    ```yaml
    template:
      bootstrap: 5
      bslib:
        danger: "#A6081A"
    ```

* If you use custom navbar entries that only display an icon, make sure to also use the `aria-label` field to provide an accessible label that describes the icon.

    ```yaml
    cran:
      icon: fab fa-r-project
      href: https://cloud.r-project.org/package=pkgdown
      aria-label: View on CRAN
    ```

## Images

To make your site fully accessible, the place where you are likely to need to do the most work is adding alternative text to any images that you create. Unfortunately, there's currently no way to do this for plots you generate in examples, but you can and should add alternative text to plots in vignettes using the `fig.alt` chunk option:

````{verbatim}
```{r}
#| fig.alt: >
#|   Histogram of time between eruptions for Old Faithful. 
#|   It is a bimodal distribution with peaks at 50-55 and 
#|   80-90 minutes.
hist(faithful$waiting)
```
````

If you forget to add alt text to your vignettes, pkgdown will automatically remind you.