add magic kernel filter label

filter/index.html

@@ -1291,6 +1291,7 @@ <h4>Cylindrical Filter Summary</h4>Nicolas Robidoux in the long, and on going, f
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           </table>Nicolas has a lot more to say. So much he has his own section <a href="nicolas/">Resampling by Nicolas Robidoux</a> which is now a separate and extensive page in its own right.
+          <a name="magic-kernel-sharp" id="magic-kernel-sharp"></a>
           <h4>Magic Kernel Sharp 2013 + 2021</h4><a>The Magic Kernel Sharp is an image resizing algorithm developed by John Costella, originally created in 2013 for a project at Facebook. It includes a three-tap sharpening step that enhances image clarity while resizing, making it both fast and efficient. This version has been used by Facebook for server-side image resizing since its development.  In 2021, Costella refined the Magic Kernel Sharp to improve its accuracy, providing at least nine bits of precision and better meeting the sharpening requirements. This updated version continues to be employed by Facebook, Instagram, and other applications like the pica resizing engine and RedKetchup image compressor, ensuring high-quality image resizing with remarkable fidelity.</a>
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