GraphPanel.java

import java.util.List;

import javax.swing.JPanel;

import java.awt.Graphics;
import java.awt.Dimension;
import java.awt.Color;

@SuppressWarnings({ "unused", "serial" })
public class GraphPanel extends JPanel {

    // graph layout parameters
    static final int VERTEX_RADIUS = 10;
    static final int SPACE = 3;

    static final int MARGIN_X = 50;
    static final int MARGIN_Y = 50;

    // scale factors
    float xFactor, yFactor;
    
    Graph graph; 

    public GraphPanel(Graph graph) {
        this.graph = graph;
    }

    public void paintComponent(Graphics g) {
        // scale the graph
        int minX = 0;
        int maxX = 1;
        int minY = 0;
        int maxY = 1;
        for (Vertex v : graph.getVertices()) {
            if (v.posX < minX) minX = v.posX;
            if (v.posX > maxX) maxX = v.posX;
            if (v.posY < minY) minY = v.posY;
            if (v.posY > maxY) maxY = v.posY;
        }
        xFactor = (this.getBounds().width - 2 * MARGIN_X) / (float) (maxX - minX);
        yFactor = (this.getBounds().height -2 * MARGIN_Y) / (float) (maxY - minY);
        super.paintComponent(g); // paint the panel
        paintGraph(g); // paint the graph 
    }

    public void paintGraph(Graphics g) {
       for (Vertex v : graph.getVertices()) {
            for (Edge e : v.getEdges()) {
                paintEdge(g, e.sourceVertex, e.targetVertex);
            }
       }
       for (Vertex v : graph.getVertices()) 
            paintVertex(g, v); 
    }

    public void paintVertex(Graphics g, Vertex v) {
        int x = Math.round(xFactor * (float) v.posX + (float) MARGIN_X);
        int y = Math.round(yFactor * (float) v.posY + (float) MARGIN_Y);
        g.setColor(Color.BLACK);
        g.drawOval(x - VERTEX_RADIUS, y - VERTEX_RADIUS, 2 * VERTEX_RADIUS, 2 * VERTEX_RADIUS);
        g.setColor(Color.WHITE);
        g.fillOval(x - VERTEX_RADIUS, y - VERTEX_RADIUS, 2 * VERTEX_RADIUS, 2 * VERTEX_RADIUS);
        g.setColor(Color.BLACK);
        g.drawString(v.name, x - v.name.length() * 8 / 2 , y + VERTEX_RADIUS/2);
    }

    public void paintEdge(Graphics g, Vertex u, Vertex v) {
        int x1 = Math.round(xFactor * (float)u.posX + (float)MARGIN_X);
        int y1 = Math.round(yFactor * (float)u.posY + (float)MARGIN_Y);
        int x2 = Math.round(xFactor * (float)v.posX + (float)MARGIN_X);
        int y2 = Math.round(yFactor * (float)v.posY + (float)MARGIN_Y);
        g.drawLine(x1, y1, x2, y2);
    }


}