title: How to transform image to show the pressure exerted by touch?
body: <p>Lets say I have an android application that shows an image of a pillow. When someone touches the image and presses the screen, I want the image to be transformed to show the effect of the pressure. e.g. If someone presses the image of the pillow, a depression should appear in the image at the point of touch as if it has been pressed in real.</p>
  
  <p>I have searched the web for pointers on how to do that but could not find any. Are there any image transformation algorithms that can simulate something soft being pressed?</p>
  
  <p>Any pointers to code, libraries or research papers would be great.</p>
  
  <p>I don't want it to be absolutely perfect. Any good enough algorithm would be helpful.</p>