title: methods sequence by NSMutableArray/NSMutableDictionary contents (Image multi-effecting)
body: <h2>What I want to do:</h2>
  
  <p>I want to implement ability for user to use CIFilters on image. So I need somehow to fix it's sequence. For example if user opens image, then applies <code>CIGaussianBlur</code>, and then <code>CIColorControls</code> and then <code>CISepia</code>, I need to get result like that:</p>
  
  <pre><code>On user opened image apply CIGaussianBlur -&gt; on CIGaussianBlur output image apply CIColorControls - &gt; on CIColorControls output image apply CISepia.
  </code></pre>
  
  <p>Thats OK. But what if then user turns off CIGaussianBlur? I need then to repeat this effect's sequence just without blur. It would look like this:</p>
  
  <pre><code>On user opened image apply CIColorControls -&gt; on CIColorControls output image apply CISepia.
  </code></pre>
  
  <h2>The question</h2>
  
  <p>Is it possible to do something like this:</p>
  
  <p>After applying any effect, add some string in NSMutableArray or NSMutableDictionary. Then when applying another effect, check NSMutableArray or NSMutableDictionary contents like that:</p>
  
  <p>if object at index 0 is equal to "blur", apply blur on source image, then take blur's output image like current effect's input image</p>
  
  <p>And so on? So that effects would be re-applied every time in their sequence made by user.</p>
  
  <p>If it is possible maybe someone could suggest me any solution? </p>