title: process brightness on specific part of image
body: <p>I am creating an application in which i am displaying image view with image and processing brightness on the image using slider. I want that brightness should be done only on the selected part of image and not on the entire image.</p>
  
  <p>I want the brightness should be processed only on the central part of the image without using openGl Image processing.</p>
  
  <p>Please help me to solve this problem. Hey guys Please help me its important for me.</p>