Double buffer technique improving painting effect of Port Information System

In the object-oriented system, painting images as a simple and direct method is increasingly adopted. In the Port Information System, different sizes of images are drawn according to ships´ types. When one painted image is shown in the window, especially with large number of container rectangles in it, most part of these rectangles are unnecessarily repainted each time refreshing occurs. As a result, the flashing phenomenon appears and even gets serious. This issue focuses on how to use double buffering of DGI+ in C# to solve the serious flash during the process of painting ships´ bay plan and side elevation by computer.