public class Matrix3x3
{
   // PUBLIC ACCESS METHODS

   public void identity() {
      doIdentity(data);
   }

   public void rotate( double theta) {
      doMakeRotation(theta, temp);
      doMultiply(data, temp, temp2);              // postMultiply
      copyData(temp2, data);
   }

   public void makeRotation(double theta) {
      doMakeRotation(theta, data);
   }

   public void scale(double sx, double sy) {
      doMakeScale(sx, sy, temp);
      doMultiply(data, temp, temp2);              // postMultiply
      copyData(temp2, data);
   }

   public void makeScale(double sx, double sy) {
      doMakeScale(sx, sy, data);
   }

   public void translate(double dx, double dy) {
      doMakeTranslation(dx, dy, temp);
      doMultiply(data, temp, temp2);              // postMultiply
      copyData(temp2, data);
   }

   public void makeTranslation(double dx, double dy) {
      doMakeTranslation(dx, dy, data);
   }

   public void postMultiply(Matrix3x3 src) {
      doMultiply(data, src.data, temp);
      copyData(temp, data);
   }

   public void preMultiply(Matrix3x3 src) {
      doMultiply(src.data, data, temp);
      copyData(temp, data);
   }

   public void transform(double x, double y, double dst[]) {
      dst[0] = data[0][0] * x + data[0][1] * y + data[0][2];
      dst[1] = data[1][0] * x + data[1][1] * y + data[1][2];
   }
    
    protected boolean setData(double src[][]){
        if(src.length!=3) return false;
        if(src[1].length!=3) return false;
        for(int i=0; i< 3;i++)
          for(int j = 0; j < 3;j++)
              data[i][j] = src[i][j];
       return true;//only return true if success;
    }
    
    public Matrix3x3 getCopy(){
        Matrix3x3 m = new Matrix3x3();
        m.setData(this.data);
        return m;
    }
    
    public void printData(){
    	for(int i=0; i< 3;i++){
          for(int j = 0; j < 3;j++){
              System.out.print (" "+data[i][j]);
       		}
       		System.out.println();
       	}
    }

   // INTERNAL WORKHORSE METHODS


   protected double data[][] = new double[3][3];


   protected static void doIdentity(double data[][]) {
      for (int i = 0 ; i < 3 ; i++)
      for (int j = 0 ; j < 3 ; j++)
         data[i][j] = i == j ? 1 : 0;
   }

   protected static void doMakeRotation(double theta, double data[][]) {
      doIdentity(data);
      data[0][0] = Math.cos(theta);
      data[0][1] = -Math.sin(theta);
      data[1][0] = Math.sin(theta);
      data[1][1] = Math.cos(theta);
  }
   protected static void doMakeScale(double sx, double sy, double data[][]) {
      doIdentity(data);
      data[0][0] = sx;
      data[1][1] = sy;
   }
   protected static void doMakeTranslation(double dx, double dy, double data[][]) {
      doIdentity(data);
      data[0][2] = dx;
      data[1][2] = dy;
   }

   protected static void doMultiply(double a[][], double b[][], double c[][]) {
      for (int i = 0 ; i < 3 ; i++)
      for (int j = 0 ; j < 3 ; j++)
         c[i][j] = a[i][0] * b[0][j] + a[i][1] * b[1][j] + a[i][2] * b[2][j];
   }

   protected static void copyData(double src[][], double dst[][]) {
      for (int i = 0 ; i < 3 ; i++)
      for (int j = 0 ; j < 3 ; j++)
         dst[i][j] = src[i][j];
   }

   private double temp[][] = new double[3][3];
   private double temp2[][] = new double[3][3];
}