Understanding ggtext and element_markdown() in R: A Deep Dive into Horizontal Spacing Issues

In this article, we will delve into the world of ggtext and element_markdown() in R, exploring a common issue related to horizontal spacing when using these functions. We’ll take a step-by-step approach to understand the underlying mechanisms and possible solutions.

Introduction to ggtext and element_markdown()

ggtext is a package for text processing in ggplot2 that provides a set of tools for working with text elements within plots. It allows us to create custom text elements, such as titles, subtitles, and annotations, with various formatting options.

element_markdown() is a function within ggtext that enables the use of Markdown syntax for text elements. It converts plain text into HTML, allowing us to style our text using CSS selectors or inline styles.

What causes horizontal spacing issues?

When using element_markdown() to modify text in a plot, we often notice strange horizontal spacing issues. The culprit behind this issue is likely due to the way ggtext handles Markdown formatting.

By default, element_markdown() uses the markdown package under the hood to convert Markdown text into HTML. This process involves parsing the Markdown syntax and converting it into CSS selectors for styling.

However, there seems to be an overlap between these CSS selectors and the margins defined in the plot’s theme. When we use element_markdown() to style our text, it can result in unintended horizontal spacing issues due to this overlap.

Troubleshooting: A Step-by-Step Approach

Let’s go through a step-by-step approach to troubleshoot the issue:

1. Verify ggtext and markdown package versions

Ensure that you’re using the latest versions of both packages. You can check the current version of a package using the packageVersion() function in R:

packageVersion("ggtext")
packageVersion("markdown")

If you find an update, install it using install.packages().

2. Check for CSS selector conflicts

element_markdown() uses CSS selectors to style your text. To identify potential conflicts, inspect the HTML structure of your plot’s annotations or titles using the browser developer tools (e.g., Chrome DevTools).

Look for any duplicate CSS selectors or conflicting styles. You can use online tools like css-validator to validate your CSS code and detect potential issues.

3. Adjust margins in the plot’s theme

Examine the plot’s theme to ensure that there are no unwanted margin settings:

p1 + p1 +
  plot_layout(nrow = 2, heights = c(4, 1.8)) +
  plot_annotation(
    title = "The Rise of Electric Charging",
    subtitle = "Examining the increase in <span style='color:#668F82;'>electric charging</span> stations over time."
  ) +
  theme(plot.title = element_text(color = "White", size = 30, family = "Comfortaa", face = "bold"),
        plot.subtitle = element_markdown(color = "White", size = 15, family = "Comfortaa", face = "bold"))

Check the margin settings in both the plot.title and plot.subtitle elements. If you find any unwanted margins, try adjusting them to see if it resolves the issue.

4. Use Ragg for graphical rendering

As mentioned in the original question, some users have successfully resolved the issue by switching R’s (and RStudio) graphical rendering to Ragg:

# Enable Ragg for graphical rendering
options("Ragg")

p1 + p1 +
  plot_layout(nrow = 2, heights = c(4, 1.8)) +
  plot_annotation(
    title = "The Rise of Electric Charging",
    subtitle = "Examining the increase in <span style='color:#668F82;'>electric charging</span> stations over time."
  ) +
  theme(plot.title = element_text(color = "White", size = 30, family = "Comfortaa", face = "bold"),
        plot.subtitle = element_markdown(color = "White", size = 15, family = "Comfortaa", face = "bold"))

Keep in mind that this is a temporary workaround and may not be suitable for all use cases.

5. Explore alternative text styling options

If you’re still experiencing issues after trying the above steps, consider exploring other text styling options available in ggtext and other R packages. Some alternatives include:

• Using element_text() with custom CSS styles
• Employing latex2exp to create LaTeX-formatted text
• Leveraging the fontfamily argument in theme() for custom font settings

By experimenting with these alternative approaches, you can find a solution that suits your specific needs.

Conclusion

In this article, we’ve delved into the world of ggtext and element_markdown() in R, exploring a common issue related to horizontal spacing. We’ve taken a step-by-step approach to troubleshoot the problem, covering verification of package versions, CSS selector conflicts, margin adjustments, using Ragg for graphical rendering, and alternative text styling options.

By understanding the underlying mechanisms behind these functions and their potential interactions, you’ll be better equipped to resolve similar issues in your own R projects.

Last modified on 2023-11-18