Newer
Older
piccolo2d.java / examples / edu / umd / cs / piccolo / examples / NodeExample.java
@Jesse Grosjean Jesse Grosjean on 5 Oct 2006 6 KB piccolo java
package edu.umd.cs.piccolo.examples;
import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.geom.Ellipse2D;
import java.awt.geom.Line2D;

import edu.umd.cs.piccolo.PCanvas;
import edu.umd.cs.piccolo.PLayer;
import edu.umd.cs.piccolo.PNode;
import edu.umd.cs.piccolo.event.PBasicInputEventHandler;
import edu.umd.cs.piccolo.event.PDragEventHandler;
import edu.umd.cs.piccolo.event.PInputEvent;
import edu.umd.cs.piccolo.nodes.PImage;
import edu.umd.cs.piccolo.nodes.PPath;
import edu.umd.cs.piccolo.nodes.PText;
import edu.umd.cs.piccolo.util.PBounds;
import edu.umd.cs.piccolo.util.PPaintContext;
import edu.umd.cs.piccolox.PFrame;

/**
 * This example shows how to create and manipulate nodes.
 */
public class NodeExample extends PFrame {

	boolean fIsPressed = false;
		
	public NodeExample() {
		this(null);
	}
	
	public NodeExample(PCanvas aCanvas) {
		super("NodeExample", false, aCanvas);
	}
	
	public void initialize() {
		nodeDemo(); 	
		createNodeUsingExistingClasses();
		subclassExistingClasses();
		composeOtherNodes();
		createCustomNode();
				
		// Last of all lets remove the default pan event handler, and add a 
		// drag event handler instead. This way you will be able to drag the
		// nodes around with the mouse.
		getCanvas().removeInputEventListener(getCanvas().getPanEventHandler());
		getCanvas().addInputEventListener(new PDragEventHandler());
	}
	
	// This method demonstrates the kinds of things that can be done with any node.
	public void nodeDemo() {
		PLayer layer = getCanvas().getLayer();
		PNode aNode = PPath.createRectangle(0, 0, 100, 80);
		
		// A node needs to be a descendent of the root to be displayed on the screen.
		layer.addChild(aNode);
		
		// The default color for a node is blue, but you can change that with 
		// the setPaint method.
		aNode.setPaint(Color.red);
				
		// A node can have children nodes added to it.
		aNode.addChild(PPath.createRectangle(0, 0, 100, 80));
				
		// The base bounds of a node is easy to change. Note that changing the base 
		// bounds of a node will not change it's children.
		aNode.setBounds(-10, -10, 200, 110);
		
		// Each node has a transform that can be used to transform the node, and 
		// all its children on the screen.
		aNode.translate(100, 100);
		aNode.scale(1.5);
		aNode.rotate(45);
		
		// The transparency of any node can be set, this transparency will be 
		// applied to any of the nodes children as well.
		aNode.setTransparency(0.75f);
		
		// Its easy to copy nodes.
		PNode aCopy = (PNode) aNode.clone();

		// Make is so that the copies children are not pickable. For this example
		// that means you will not be able to grab the child and remove it from
		// its parent.
		aNode.setChildrenPickable(false);

		// Change the look of the copy
		aNode.setPaint(Color.GREEN);
		aNode.setTransparency(1.0f);
		
		// Let's add the copy to the root, and translate it so that it does not 
		// cover the original node.
		layer.addChild(aCopy);		
		aCopy.setOffset(0, 0);		
		aCopy.rotate(-45);
	}
		
	// So far we have just been using PNode, but of course PNode has many
	// subclasses that you can try out to.
	public void createNodeUsingExistingClasses() {
		PLayer layer = getCanvas().getLayer();
		layer.addChild(PPath.createEllipse(0, 0, 100, 100));
		layer.addChild(PPath.createRectangle(0, 100, 100, 100));
		layer.addChild(new PText("Hello World"));
		
		// Here we create an image node that displays a thumbnail
		// image of the root node. Note that you can easily get a thumbnail
		// of any node by using PNode.toImage().
		PImage image = new PImage(layer.toImage(300, 300, null));
		layer.addChild(image);
	}
	
	// Another way to create nodes is to customize other nodes that already
	// exist. Here we create an ellipse, except when you press the mouse on
	// this ellipse it turns into a square, when you release the mouse it
	// goes back to being an ellipse.
	public void subclassExistingClasses() {
		final PNode n = new PPath(new Ellipse2D.Float(0, 0, 100, 80)) {
						
			public void paint(PPaintContext aPaintContext) {
				if (fIsPressed) {
					// if mouse is pressed draw self as a square.
					Graphics2D g2 = aPaintContext.getGraphics();
					g2.setPaint(getPaint());
					g2.fill(getBoundsReference());
				} else {
					// if mouse is not pressed draw self normally.
					super.paint(aPaintContext);
				}
			}
		};		
		
		n.addInputEventListener(new PBasicInputEventHandler() {
			public void mousePressed(PInputEvent aEvent) {
				super.mousePressed(aEvent);
				fIsPressed = true;
				n.invalidatePaint(); // this tells the framework that the node needs to be redisplayed.
			}
			
			public void mouseReleased(PInputEvent aEvent) {
				super.mousePressed(aEvent);
				fIsPressed = false;
				n.invalidatePaint(); // this tells the framework that the node needs to be redisplayed.
			}
		});
		
		n.setPaint(Color.ORANGE);
		getCanvas().getLayer().addChild(n);
	}
	
	// Here a new "face" node is created. But instead of drawing the face directly
	// using Graphics2D we compose the face from other nodes.
	public void composeOtherNodes() {
		PNode myCompositeFace = PPath.createRectangle(0, 0, 100, 80);
		
		// create parts for the face.
		PNode eye1 = PPath.createEllipse(0, 0, 20, 20);
		eye1.setPaint(Color.YELLOW);
		PNode eye2 = (PNode) eye1.clone();
		PNode mouth = PPath.createRectangle(0, 0, 40, 20);
		mouth.setPaint(Color.BLACK);
		
		// add the face parts
		myCompositeFace.addChild(eye1);
		myCompositeFace.addChild(eye2);
		myCompositeFace.addChild(mouth);
		
		// don't want anyone grabbing out our eye's.
		myCompositeFace.setChildrenPickable(false);
		
		// position the face parts.
		eye2.translate(25, 0);
		mouth.translate(0, 30);
		
		// set the face bounds so that it neatly contains the face parts.
		PBounds b = myCompositeFace.getUnionOfChildrenBounds(null);
		myCompositeFace.setBounds(b.inset(-5, -5));
		
		// opps it to small, so scale it up.
		myCompositeFace.scale(1.5);
		
		getCanvas().getLayer().addChild(myCompositeFace);
	}
	
	// Here a completely new kind of node, a grid node" is created. We do
	// all the drawing ourselves here instead of passing the work off to 
	// other parts of the framework.
	public void createCustomNode() {
		PNode n = new PNode() {
			public void paint(PPaintContext aPaintContext) {
				double bx = getX();
				double by = getY();
				double rightBorder = bx + getWidth();
				double bottomBorder = by + getHeight();
				
				Line2D line = new Line2D.Double();
				Graphics2D g2 = aPaintContext.getGraphics();
				
				g2.setStroke(new BasicStroke(0));
				g2.setPaint(getPaint());
				
				// draw vertical lines
				for (double x = bx; x < rightBorder; x += 5) {
					line.setLine(x, by, x, bottomBorder);
					g2.draw(line);
				}
				
				for (double y = by; y < bottomBorder; y += 5) {
					line.setLine(bx, y, rightBorder, y);
					g2.draw(line);
				}
			}
		};
		n.setBounds(0, 0, 100, 80);
		n.setPaint(Color.black);
		getCanvas().getLayer().addChild(n);
	}
	
	public static void main(String[] args) {
		new NodeExample();
	}	
}