Draw binary tree structure

[sachin upatil]

Hello ,

I have created a huffman tree with Node using Comparable interface. working fine.

     public class Node {
	                  char element; // character 
	                  int weight; // weight of tree
              
                          Node left;   // left subtree
	                  Node right; // right subtree
	                  
                          String code = ""; // The code of this node from the root
	      
	                  int x = 0;
	                  int y = 0;
              }

Also i calculated the depth of tree. and i can travel though tree using following method.

                  public void printTree(Node node) {
	  	  if (node != null) {
	  		          
	  		  if(node.left != null){printInOrder(node.left);}  
	  		  	System.out.println(node.element);
	  		  if(node.right!= null){printInOrder(node.right);}  	  		
	  	  }

but now i want to display this tree on Jpanel like binary tree as follow :

A
/ \
/ \
B C

How i can achieve this ???

[Sugantha Jeevankumar]

Have you tried if JTree or swingx.JXTree suits your needs.. or can be customized?

[sachin upatil]

i did it. now i can draw binary tree using following method

/** Display a subtree rooted at position (x, y) */
	     
	      private void displayTree(Graphics g, Node root, int x, int y, int hGap) {
	        // Display the root
	        
	         g.drawOval(x - radius, y - radius, 2 * radius, 2 * radius);
	        
	        if(root.element != 0){
	        	g.drawString(root.weight + "", x - 6, y + 4);
	        	
		g.setColor(Color.red);
	        	g.drawString(root.element + "", x - 6, y + 35);
	        }else{
	    	g.drawString(root.weight + "", x - 6, y + 4);
	    	g.setColor(Color.red);
	        }
	        
	        if (root.left != null) {
	          // Draw a line to the left node
	          g.setColor(Color.black);	
	          leftChild(g, x - hGap, y + vGap, x, y);
	          //Draw the left subtree 
	          displayTree(g, root.left, x - hGap, y + vGap, hGap / 2);
	        }

	        if (root.right != null) {
	          // Draw a line to the right node
	          g.setColor(Color.black);
	          rightChild(g, x + hGap, y + vGap, x, y);
	          // Draw the right subtree recursively
	          displayTree(g, root.right, x + hGap, y + vGap, hGap / 2);  
	        }
	      }

	      /* Draw left child */
	      private void leftChild(Graphics g,  int x1, int y1, int x2, int y2) { 
	        double d = Math.sqrt(vGap * vGap + (x2 - x1) * (x2 - x1));
	        int x11 = (int)(x1 + radius * (x2 - x1) / d);
	        int y11 = (int)(y1 - radius * vGap / d);
	        int x21 = (int)(x2 - radius * (x2 - x1) / d);
	        int y21 = (int)(y2 + radius * vGap / d);	        
	        g.drawLine(x11, y11, x21, y21);
	        
	        g.drawString("0", ((x21+x11)-20)/2, (y21+y11)/2);
	      }

	      /*Draw right child */
	      private void rightChild(Graphics g,  int x1, int y1, int x2, int y2) {
	        double d = Math.sqrt(vGap * vGap + (x2 - x1) * (x2 - x1));
	        int x11 = (int)(x1 - radius * (x1 - x2) / d);
	        int y11 = (int)(y1 - radius * vGap / d);
	        int x21 = (int)(x2 + radius * (x1 - x2) / d);
	        int y21 = (int)(y2 + radius * vGap / d);
	        g.drawLine(x11, y11, x21, y21);
	        
	        g.drawString("1", (x21+x11)/2, (y21+y11)/2);
	      }
	     //------------------------------------------------------------------------- 

But now i want to display this tree node by node using Thread like animation.

[sachin upatil]

I tried it using for loop but it not working. it's showing complete tree.

which is any other option i can try ?