title: How do I draw an ellipse with arbitrary orientation pixel by pixel?
body: <p>I have to draw an ellipse of arbitrary size and orientation pixel by pixel.  It seems pretty easy to draw an ellipse whose major and minor axes align with the x and y axes, but rotating the ellipse by an arbitrary angle seems trickier.  Initially I though it might work to draw the unrotated ellipse and apply a rotation matrix to each point, but it seems as though that could cause errors do to rounding, and I need rather high precision.</p>
  
  <p>Is my suspicion about this method correct?  How could I accomplish this task more precisely?</p>
  
  <p>I'm programming in C++ (although that shouldn't really matter since this is a more algorithm-oriented question).</p>
  
  <p>Edit: as David pointed out, I guess I may really be wondering how to do pixel interpolation.</p>