<p>As per <a href="https://stats.stackexchange.com/help/on-topic">https://stats.stackexchange.com/help/on-topic</a>, the questions about how to achieve this or that in <code>ggplot2</code> are (now, in 2019) off-topic and should be asked elsewhere:</p>

<blockquote>
  <p><strong>Programming,</strong> ask on Stack Overflow. If the language is statistically oriented (such as R, SAS, Stata, SPSS, etc.), then decide based on the nature of your question: if it needs statistical expertise to understand or answer, ask it here; if it's about the implementation of an algorithm, routine data processing, or details of the language, then please refer to the <a href="https://stats.meta.stackexchange.com/questions/793/internet-support-for-statistics-software">collection of links to resources</a> we maintain.</p>
</blockquote>

<p>A good place to ask questions on <code>ggplot2</code> is StackOverflow that has [ggplot2] tag with 27k+ questions: <a href="https://stackoverflow.com/questions/tagged/ggplot2">https://stackoverflow.com/questions/tagged/ggplot2</a>.</p>
