title: Calculating a quad curve between two xy points
body: <p>I have two (x,y) points start and end. I want to animate from start to end but instead of going a linear way I want to create a curved path.</p>
  
  <p>I am quite sure I'm not looking for an easing because I don't want to affect the animation speed, I just want to calculate a curved path.</p>
  
  <p>I figured out I needed some sort of control point, like shown in this image:</p>
  
  <p><img src="https://i.stack.imgur.com/K5jXT.jpg" alt="enter image description here"></p>
  
  <p>But I have no idea how to implement it. I would love to create a function that took the following parameters</p>
  
  <pre><code>function calculateXY(start, end, controlpoint, percentage);
  </code></pre>
  
  <p>Where percentage would be a number from 0 - 100% and where 0 would return the start position and 100% the end position.</p>
  
  <p>The solution doesn't need to be in Objective-C, it could be in any programming language. I just can't get my head around the math :) </p>