title: R: how to remove this tiny axis margin in plot
body: <p>I want to get rid the small margin close to zero on X and Y value (red line on pic), and plot ONLY what is showed in red square.</p>
  
  <p>I tried setting <code>par(mar = rep(0, 4)</code> and <code>xlim=c(0, ...)</code>, <code>ylim=c(0, ...)</code> but R still keeps adding this tiny margin. How to get rid of it?</p>
  
  <p><a href="https://i.stack.imgur.com/WJJ5S.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/WJJ5S.png" alt="plot in R with margins"></a></p>
  
  <p>EDIT: 
  another point of view on my problem: 
  after running: </p>
  
  <pre><code>require(plotrix)
  axisRange &lt;- c(0,500)
  plot(NULL, xlim = axisRange, ylim=axisRange)
  draw.circle(0, 0, 200, col = "white", border = "red")
  </code></pre>
  
  <p>I end up with a circle positioned not in "true" 0,0 point: 
  <a href="https://i.stack.imgur.com/61aQJ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/61aQJ.png" alt="Circle should be on 0,0 point"></a></p>
  
  <p>EDIT2: 
  Actually what I want to do, is to plot circles of different radius, and save it as an image. That is why I care about the margins.
  I end up with something like this (spots on the corners are for the reference):</p>
  
  <p><a href="https://i.stack.imgur.com/lGaOg.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/lGaOg.jpg" alt="enter image description here"></a></p>
  
  <p>And should be more like this: 
  <a href="https://i.stack.imgur.com/d6Obc.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/d6Obc.jpg" alt="enter image description here"></a></p>