title: Cubic bezier curves - get Y for given X
body: <p>I have a cubic bezier curve where the first and last points are given (namely P0(0,0) and P3(1,1)).
  The other two points are defined like this: cubic-bezier(0.25, 0.1, 0.25, 1.0) (X1, Y1, X2, Y2, also those values must not be smaller or larger than 0 or 1, respectively)<br>
  Now what would I have to do to get the Y coordinate for a given X, assuming there's only one? (I know that under certain circumstances there can be multiple values, but let's just put them aside. I'm not doing rocket science over here, I just want to be able to get Y multiple times per second to do transitions)  </p>
  
  <p>I managed to dig up this: <a href="https://stackoverflow.com/questions/7348009/y-coordinate-for-a-given-x-cubic-bezier">y coordinate for a given x cubic bezier</a>, but I don't understand what xTarget stands for.<br>
  Oh, also this is no homework whatsoever, I'm just a bit annoyed at the fact that there's no comprehensible stuff about cubic bezier curves on the internet.</p>