Displaying an image for zooming and panning

The ZoomScreen class allows you to provide zoom and pan the functionality to an image. When a BlackBerry® device user clicks the trackball or touch screen, the screen displays the center region of the image zoomed in.

When the image is zoomed in, the screen also displays an overlay highlighting the zoomed region. Scrolling the trackball or sliding a finger around the screen pans around the image. When the user stops panning and zooming the overlay disappears from the screen.

On BlackBerry devices with a touch screen, users can define the region of the image to zoom. The user can touch two points on the image to define the diagonally opposite corners of the region. When the region is selected, teh user can move one finger around the image to move the zoom region. To zoom in on the defined region, the user clicks the screen. To zoom out, the user presses the Escape key.


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