[Thez]

I got two classes which can draw a scene/canvas on which I can paint stuff like circles, triangles etc.
If I draw a shape inside the paintComponent and then fill it, it works fine.

If I try to do the same thing from outside of the paintCompoment, using the same methods, it gives a nullPointerException.

The two classes:

Scene.java

Code:

// Created by Thez
// Created on 04 December 2007, 18:48

package crossfire;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Polygon;
import java.awt.Shape;
import javax.swing.JPanel;

public class Scene extends javax.swing.JPanel {
    
    private Graphics2D theScene;
    
    //this overrides the original method to allow for modification
    public void paintComponent(Graphics renderScene){
      
        super.paintComponent(renderScene);
        theScene = (Graphics2D)renderScene;

        //Shape test = createRectangle(20,20,200,100);
        //fillShape(theShape,new Color(200,120,0));
        
        System.out.println("test");
        
    }      
    
    
    //makes a fully filled drawing of the shape given
    public void fillShape(Shape theShape, Color theColor){

        theScene.setColor(theColor);
        theScene.fill(theShape);
        
    }
    
    //makes an outline drawing of the shape given
    public void drawShape(Shape theShape, Color theColor){
        
        theScene.setColor(theColor);
        theScene.draw(theShape);
        
    }
    
    //this creates a rectangle
    public Shape createRectangle(int offsetX, int offsetY, int shapeWidth, int shapeHeight){
        
        Shape newShape = null;
        
        //set the size and position
        int[] xPoints = {offsetX, offsetX + shapeWidth, offsetX + shapeWidth, offsetX};
        int[] yPoints = {offsetY, offsetY, offsetY + shapeHeight, offsetY + shapeHeight};
        
        //a rectangle always has 4 points/corners
        Polygon theRectangle = new Polygon(xPoints,yPoints,4);
        
        //make a shape out of it
        newShape = theRectangle;
        
        return newShape;
    }
}

Main.java

Code:

//Created on 04-12-2007 18:26
//Created by Thez
package crossfire;

import java.awt.Color;
import java.awt.Shape;
import javax.swing.JFrame;

public class Main {
   
    private Window theWindow;
    private JFrame theFrame;
    private Scene theSceneGenerator;
    
    //load the window, note the dimensions are still needed if made fullscreen, in case the user minimizes
    public Main(){
        
        theWindow = new Window(false,true,800,600,"Test");
        loadSceneIntoFrame();
    }
    
    //startup
    public static void main(String[] args) {
    
        new Main();
        
    }
    
    //this loads the scene class and puts it into the frame
    public void loadSceneIntoFrame(){
        
        //first we get the JFrame
        theFrame = theWindow.getFrame();
        theSceneGenerator = new Scene();
        
        theFrame.getContentPane().add(theSceneGenerator);
        
        Shape test = theSceneGenerator.createRectangle(20,20,200,100);
        theSceneGenerator.fillShape(test,new Color(200,120,0));
    }
    
}

Now I've been at it a few hours but I just can't seem to get it to work.
All I need is to able to draw and remove shapes from the scene/canvas outside the paintComponent.

Any ideas?