title: PHP/GD, how to copy a circle from one image to another?
body: <p>Is there a reasonably straightforward way to copy a circular area from one image resource to another? Something like <a href="http://nl3.php.net/manual/en/function.imagecopymerge.php" rel="noreferrer">imagecopymerge</a> except with circles or ovals etc?<br>
  If possible, I want to avoid having to use pre-created image files (any oval shape should be possible), and if there's transparency colours involved they should naturally leave the rest of the image alone.</p>
  
  <p>Reason I'm asking, I have a few classes that allow to apply image operations inside a "selected area" of an image, which works by first deleting that area from a copy of the image, then overlaying the copy back on the original. But what if you want to select a rectangle, and then inside that deselect a circle, and have the operations only affect the area that's left?</p>