title: compare two pixels in a single uiimage ios
body: <p>I am trying to <code>erase</code> which has same <code>colour pixel</code> from particular <code>coordinates</code> and want to erase that pixel.I used <code>floodfill algorithm</code> but it not working properly.I looking for a tool like magicwand tool.</p>
  
  <p>So I am trying to implement on my own so can anyone please help me <strong>how to compare two pixel in an image?</strong></p>
  
  <p>please help me with the code or sample example.</p>