在Java中使用Draw2D和SWT绘图

 
 private ArrayList dataGenerator() { 
  double series1[] = new double[5];  
      for(int i=0; i<series1.length; i++) 
       series1[i] = (i*10) + 10; // a linear  
       series containing 10,20,30,40,50 
       
      double series2[] = new double[9];  
      series2[0] = 20; series2[1] = 150; series2[2] = 5; 
      series2[3] = 90; series2[4] = 35;  series2[5] = 20; 
                            series2[6] = 150; series2[7] = 5; series2[8] = 45; 
       
      double series3[] = new double[7];  
      for(int i=0; i<series3.length; i++) 
       series3[i] = (i*20) + 15; 
      
      seriesData.add(series1); 
      seriesData.add(series2); 
      seriesData.add(series3);  
                 return seriesData; 
 } 

FigureCanvas

Draw2D 中的 FigureCanvas 是 SWT Canvas 的一个扩展。FigureCanvas 可以包含 Draw2D 图形。

Panel

Panel 是 Draw2D 中的一个通用容器图形，它可以包含子图形。您可以向一个 Panel 图形中添加许多图形，然后将这个 Panel 图形提供给 FigureCanvas。

DirectedGraph

DirectedGraph 是一个 2-D 图形，拥有有限数量的 Node，每个 Node 都位于一些 Point 中，相邻的 Node 是通过 Edges 彼此连接在一起的。

 
private int[] getXCoordinates(ArrayList seriesData){ 
 int xSpan = (int)GraFixConstants.xSpan; 
           int longestSeries = Utilities.getLongestSeries(seriesData); 
           int numSegments =  
           ((double[])seriesData.get(longestSeries)).length;         
           int sectionWidth =  
           (int)xSpan / numSegments; //want to divide span of xAxis 
         
           int xPositions[] =  
           new int[numSegments]; // will contain X-coordinate of all dots. 
 for(int i=0; i<numSegments; i++){ 
  xPositions[i]=  
  (i+1)*sectionWidth;//dots spaced at distance of sectionWidth    
 } 
 return xPositions; 
} 

 
line 1---> 2048 / 1024 equals 2. 
line 2---> 100 - 0 equals 100.  
line 3---> 100 / 2 equals 50, which is the desired scaled value. 

 
public class MainGraFixView extends ViewPart{ 
 public void createPartControl(Composite parent) { 
   
  //create or get data in an arraylist 
  ArrayList seriesData = dataGenerator(); 

  //instantiate a plotter, and provide data to it. 
  DirectedGraphXYPlotter dgXYGraph = new DirectedGraphXYPlotter(parent); 
  dgXYGraph.setData(seriesData); 
  dgXYGraph.plot(); //ask it to plot    

 } 
 public void setFocus() {  
 } 
} 

 
1. public void plot(){ 
2.     //if no place to plot, or no data to plot, return. 
3.     if(null==_parent || null==_seriesData) 
4.         return; 
5. 
6.     Composite composite = new Composite(_parent, SWT.BORDER); 
7.     composite.setLayout(new FillLayout()); 
8.     FigureCanvas canvas = new FigureCanvas(composite); 
9.      
10.     Panel contents = new Panel();//A Panel is a general purpose container figure 
11.     contents.setLayoutManager(new XYLayout()); 
12.     initializeSpan(contents.getClientArea()); 
13.      
14.     populateNodesAndEdges();      
15.      
16.     drawAxis(contents); 
17.     for(int i=0; i<_numSeries; i++){ 
18.      drawDotsAndConnections(contents,getDirectedGraph(i)); //  
draw points & connecting wires 
19.     } 
20.     canvas.setContents(contents); 
21. } 

 

//This is a sample, you will need to add actual Node(s) to this NodeList. 
NodeList nodes = new NodeList(); //create a list of nodes. 
//This is a sample, you will need to add actual Edge(s) to this EdgeList. 
EdgeList edges = new EdgeList(); //create a list of edges.  
DirectedGraph graph = new DirectedGraph(); 
graph.nodes = nodes; 
graph.edges = edges; 
new BreakCycles().visit(graph);//ask BreakCycles to visit the graph. 
//now our "graph" is ready to be used.