Some embodiments provide a method that provides a display area for displaying an image. Some embodiments provide a tool that when activated generates a deformable tunnel based on a cursor movement through the display area. The tunnel is for differentiating a region of interest of the image from the rest of the image. The method provides a moveable tool for determining a width for the tunnel region. The moveable tool is a slider tool in some embodiments. In some embodiments, the moveable tool is for determining the initial width at which the tunnel is generated. The moveable tool is further for modifying the width of the tunnel after the tunnel is generated in some embodiments.