# Research on Visualization Technology of Production Process for Mechanical Manufacturing Workshop
## 4 The Key Technologies of Visualization of Production Process Flow Chart
### Visual Design of Process Flow Chart  
The essential component of the workshop production management system is the visual design of process flow charts, and its interface is shown in Figure 6. At the top of the interface, one can read and present flow charts from databases, copy/paste the process nodes, view the process copy list, save the process flow charts, and close the window. The function menu on the left side of the interface from top to bottom contains the following: drawing process nodes, drawing process lines (straight and broken lines), and delete objects. Figure 5: System interface. A product process flow diagram can be created in one of three ways:  
1. Draw completely by hand. Each process node is dragged and dropped individually; then, they are progressively connected in a straight or broken line based on serial and parallel relationships to create a process flow diagram;
2. Copy or paste some of the current process nodes. One can open the current flow chart, select the process nodes one wants to copy, and then paste them into the desired flow chart if a few of the process nodes in the process flow diagram match those in the existing flow chart. The remaining part is drawn by hand. This technique significantly improves the drawing efficiency;
3. Alter an existing process flow diagram directly. One can call an existing flow chart and edit it if the process flow chart one wants to create is comparable to one already in existence. This approach can effectively reuse the original process flow chart, which will considerably increase work productivity. The following is the exact method by which this module function is implemented:  
1. Go through the flow chart. When entering the module interface, one can read the field content of process flow chart file in the product information table through the data access layer and then use the binary serializer to deserialize the data before obtaining the object set of List <PIaintItem>, which includes all of the process nodes and connecting line segments in the flow chart. After that, one traverses the set and calls the DrawSelf method on each object to draw all of them in the form interface;
2. Draw process nodes. Users can add a process simply by dragging and dropping the process icon from the left toolbar to the appropriate position in the form interface. This function is mainly realized through the DragDrop event of the form. When the user releases the mouse, the node object at the cursor position is established and added to the process flow chart set;  
Figure 6: Flow diagram design module. Set up the process basic information. The MouseDoubleClick event triggers a dialog box when the user double-clicks the process node, allowing the user to enter details such as the process number, the process name, and the assigned team. After setting, the process node can display the process number, process name, and associated colors in accordance with the various allocated teams;
4. Draw connecting line segments between process nodes. The connection relationship is established by drawing a connecting line between process nodes. According to the actual needs, there are two types of connecting lines: straight line and broken line;
5. Move the process node. The operation node be moved. Users can drag the process node to reposition it when editing the process flow chart. The link between process nodes will automatically and instantly change as the user moves;
6. Delete the object. The system will determine which object the user has chosen by comparing the click coordinates with the coordinate range of each object. When the delete function is chosen, the specified object is deleted by invoking the Remove method of the set;
7. Copy/paste process nodes. The ability to copy and paste process nodes is especially useful for process flow chart that contains some same or similar process nodes, which can aid technicians in quickly and effectively drawing the necessary process flow.