title: pdf device and font family "Arial" / Or: Change font name (not font) in PDF
body: <p>I have a problem with typefaces and PDF-Output in R. On this windows machine there is no <em>Helvetica</em> and the Font used by the device seems to be <em>Arial</em> as you can see below.
  The simple problem is, that Arial is used (as I want it to be) but editing the PDF-File it says <em>Helvetica</em> is used. How can I get R to write the correct Name into the PDF-file. <code>pdf(...,family="Arial")</code> won't work, as this family is not known (grDevices version 2.15.1).</p>
  
  <p>Or can I substitude this font in the PDF afterwards, creating a file with the font I want?</p>
  
  <p>R-PDF-Output
  <img src="https://i.stack.imgur.com/GHv78.png" alt="R Output: Arial Typeface"></p>
  
  <p>Comparision from this Article:<a href="http://ilovetypography.com/2007/10/06/arial-versus-helvetica/" rel="noreferrer">Arial vs. Helvetica</a>
  <img src="https://i.stack.imgur.com/B8JSG.gif" alt="enter image description here"></p>