Graph_Window_Display

Figure 5-2. Graph_Window_Display Overview Diagram

Graph_Window_Display Diagram

Motivation

Mechanics

The class Graph_Window_Display creates the Graph Window by getting the data from the Graph_Window_Model. The Graph_Display_Controller handles the events of the Graph Window.

Draw Strategy

The Node_Displays will be drawn on the Node_GC which is a graphic component which includes a pixmap called Draw_Area and if neccessary a second pixmap which is called Back_Area. The Back_Area is used to buffer the old status of the Node_Displays. E.g. the Back_Area is neccessary for drawing the selection scope or the drawing of the moving Node_Displays.

The Edge_Displays will be drawn on the Edge_GC which is a graphic component which also draws on the Draw_Area pixmap but uses different settings.

The Node_Displays which have to be moved to another position will be drawn on the Moving_GC which is also a graphic component but it has its own pixmap.

These GCs will be drawn on the Drawing_Area if they should be displayed in the Graph Window.