Convert YAML to an accessible header

Description

Reads an Rmd file, converting the YAML header to a format that is screen reader friendly.

Usage

access_head(
  rmd_path = NULL,
  lan = detect_html_lang(lines),
  inplace = FALSE,
  encoding = "utf-8",
  theme = "default",
  highlight = "null"
)

Arguments

Value

Adjust the Rmd YAML provided to rmd_path, improving its accessibility for screen readers. Only works with html output.

Examples

# create a testfile
rmd <- tempfile("testing", fileext = ".rmd")
# write basic markdown content
writeLines('---
title: "testfile"
author: "Some Author"
date: "`r format(Sys.Date(), "%d %b %Y")`"
output: html_document
---

 ```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)
```

## R Markdown', con = rmd)

# Adjust the document header to improve screen reader accessibility
access_head(rmd, lan = "en")

Produce an accessible image or chart.

Description

Reads in an image and produces the HTML structure expected by web accessibility checkers such as WAVE. Also works as a wrapper around ggplot2 charts.

Usage

access_img(
  img = last_plot(),
  alt = NULL,
  wid = NULL,
  ht = NULL,
  dpi = 300,
  css_class = NULL,
  css_id = NULL
)

Arguments

Value

Inline HTML with the necessary structure for screen reader accessibility.

Examples

# create a ggplot2 chart
ggplot(pressure, aes(temperature, pressure)) +
  geom_point()

# Use 'access_img()' to render the chart with alt text
access_img(alt = "Vapor Pressure of Mercury as a Function of Temperature")

# Create a png.
file.create(tempfile("some_img", fileext = ".png"))

# Read it from disk and include alt text
access_img("some_img.png", alt = "Some meaningful alt text")

Produce an accessible Rmarkdown file template.

Description

Creates an Rmarkdown template with the HTML structure required by screen readers.

Usage

access_rmd(
  filenm = NULL,
  title = NULL,
  subtitle = NULL,
  lan = NULL,
  author = Sys.info()[8],
  date = format(Sys.Date(), "%d %b %Y"),
  toc = FALSE,
  encoding = "utf-8",
  force = FALSE,
  theme = "default",
  highlight = "null"
)

Arguments

Value

An Rmarkdown file with an HTML head, populated with metadata specified within the function parameters.

Examples

# create an accessible rmarkdown document from scratch
access_rmd(
  "some_filenm",
  title = "Title Goes Here", lan = "en", author = "Author here"
)

Assemble HTML header output from text provided.

Description

Returns header structure for use with 'access_head()' and 'access_rmd()'.

Usage

assemble_header(title, subtitle = NULL, auth, doc_date, enc)

Arguments

Value

An assembled html output page containing the required toc code.

Checks if the html doctype is compatible.

Description

Checks to ensure file is not a special flavour of html output, including xaringan, ioslides, flexdashboard or slidy. Output is an error if html doc is a special case.

Usage

check_compat(yaml_txt)

Arguments

Value

Error condition if non-standard html found.

Check an Rmarkdown for broken links.

Description

Check links within an Rmarkdown document for any urls that responds with an error.

Usage

check_urls(rmd_path)

Arguments

Value

Lines of any urls that respond with an error.

Examples

# create a testfile
links <- tempfile("mixed_links", fileext = ".rmd")
file.create(links)
writeLines("[a good link](https://datasciencecampus.ons.gov.uk/)
[a bad link](https://datasciencecampus.ons.gov.uk/broken)",
  con = links
)
# Test the file
check_urls(links)

Searches a file for valid methods of setting HTML lang attribute.

Description

Takes the output of 'readLines()' and looks for lang attribute value, stopping if no valid value is found. Typically used on the output of 'handle_rmd_path()'.

Usage

detect_html_lang(lines = NULL, lang_tags = langs)

Arguments

Value

The lang attribute value if found. Stops if no value found.

Find any markdown or HTML syntax tags within read lines.

Description

Check any lines for images or links and return the line numbers and values.

Usage

find_all_tags(lines = NULL, tag = c("img", "link"))

Arguments

Value

A named vector with line numbers of any found images and their values.

Find alt length limit for specific lang values.

Description

Return language specific alt text length limits. Limits are: eng 100, ger 115, kor 90.

Usage

find_alt_lim(lines = NULL, lan = detect_html_lang(lines))

Arguments

Value

A line limit for alt text.

Searches YAML head for YAML theme parameters, returning the theme if found.

Description

Use on YAML head text only. 'check_compat()' should be used prior to the use of 'find_theme()'. Looks for YAML theme parameter value. Returns the theme if found or 'default' if no theme specified.

Usage

find_theme(yaml = NULL)

Arguments

Value

The theme value as a character string.

Check rmd path & file type.

Description

Checks rmd_path exists and that the file suffix is correct.

Usage

handle_rmd_path(rmd_path = NULL)

Arguments

Value

Reads rmd lines on success. Error if file does not exist or is not an rmd file.

Insert the required code for the specified toc type.

Description

Inserts YAML header for floating toc if toc is TRUE.

Usage

insert_yaml(toc, header, text, lan, theme = "default", highlight = "null")

Arguments

Value

An assembled html output page containing the required toc code.

Find Rmd files within a provided file structure.

Description

Recursively searches file structure for Rmarkdown files. Returns the found Rmd relative paths.

Usage

retrieve_rmds(search_dir = ".", recurse = TRUE, to_txt = FALSE)

Arguments

Value

Relative paths to all found Rmd files.

Examples

# Create a test directory
dir.create("parent")
dir.create("parent/child")

# Create some rmds to find
# An empty vector to collect file names
nm_vec <- character()
# create numbered file names
for (num in 1:6) {
  nm <- paste0(num, "-test.Rmd")
  nm_vec <- append(nm_vec, nm)
}
# Create some files in parent & child directories
file.create(paste0("parent/", nm_vec[1:3]))
file.create(paste0("parent/child/", nm_vec[4:6]))

# Return all Rmd files
retrieve_rmds("parent")

# tidy up environment
unlink(c("parent", "child"), recursive = TRUE)

Return a HTML p tag formatted to resemble a heading tag.

Description

Returns a HTML heading p tag formatted with inline css to appear like of any of the available levels (h1, h2, h3 and so on). This approach is in response to review comments regarding headings that contained no text potentially confusing screen reader users. The class selectors applied will always include "toc-ignore", but an additional selector may be included within the class parameter. If an object of length zero is passed to the txt parameter, NULL is returned, allowing for vectorised usage.

Usage

return_heading(txt, lvl, class, font_weights = c(h1 = 38, h2 = 30, h3 = 24))

Arguments

Value

null if txt is length 0 or p tag styled to appear as required heading level with class attr applied.

Check an R markdown document for suspicious alt text.

Description

Checks if an R markdown contains images alt text is equal to alt attribute placeholder values, including: 'nbsp', 'spacer' and src attribute value (filename).

Usage

sus_alt(rmd_path = NULL, lan = detect_html_lang(lines))

Arguments

Value

Line numbers of images that has alt text equal to placeholder values.

Examples

# create a testfile
rmd <- tempfile("testing", fileext = ".rmd")
# write basic markdown content
writeLines('---
title: "Suspicious Alt Text"
author: "Some Author"
date: "`r format(Sys.Date(), "%d %b %Y")`"
output: html_document
---

 ```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)
```

## R Markdown

![nbsp](some_img)

![another_img](another_img)',
  con = rmd
)

# test the file for suspicious alt text
sus_alt(rmd, lan = "en")

# Adjust the document header to improve screen reader accessibility
access_head(rmd, lan = "en")

"tags" object from "htmltools". License: GPL (>= 2) htmltools GitHub

Description

"tags" object from "htmltools". License: GPL (>= 2) htmltools GitHub

Value

Wraps provided paramaters in HTML tag specified.