METHOD FOR ASYNCHRONOUSLY MAINTAINING AN IMAGE ON A DISPLAY DEVICE

摘要

A method for asynchronously maintaining an image on a display device is disclosed which comprises the following steps. First, a drawing request is received from the application program. Then a drawing area of the image is determined in response to the received drawing request and the drawing area is inserted into a list of drawing areas. A screen update request is then received from the application program. In response to this received screen update request, a drawing area is retrieved from the list, and all graphic objects are redrawn if any portion of the graphic object lies within the retrieved drawing area.