public class LowpassMapping extends PixelMapping
{
    int ccx=0,ccy=0;
    boolean startAgain;
    boolean lastPixel = false;
    float radius = 0;
    float amount = 0;
    
    // touchest the inside of a circle at the centre of the picture
     public LowpassMapping(ComplexImage ci, PixelMapping ne){super(ci,ne);}

    public void setOrigin(int x,int y)
    {
        startAgain=true;
        ox = x;
        oy = y;
        if (next!=null) next.setOrigin(ox,oy);      
    }
    public boolean morePixels()
    {
        if (!lastPixel) return true;
        if (next!=null) return next.morePixels();
        return false;
    }
    public PixelDesc nextPixel()
    { 
        if (next == null)
        {
            System.out.println("Should never be called");
        }
        else
        {
            
            if (!startAgain)            
            {
                boolean ex = false;
                ccx++;
                while((!ex) && (ccy<complexImage.h))
                {                    
                    while((!ex) && (ccx<complexImage.w))
                    {
                        float r = (float)Math.sqrt((ccx-complexImage.w/2)*(ccx-complexImage.w/2)+(ccy-complexImage.h/2)*(ccy-complexImage.h/2));
                        if (r>radius) ex=true; else                                                
                            ccx++;
                    }
                    if (!ex) 
                    {
                        ccy++;
                        ccx =  0;
                    }
                }
                if (ex) 
                {
                   // System.out.println("returning : "+ccx+" "+ccy);                    
                    return new PixelDesc(null,ccx,ccy,amount);
                }                
                else 
                if (next.morePixels())
                {
                    System.out.println("asking for another pixel");
                    startAgain=true; 
                }
                else 
                {
                    System.out.println("end of all of it");
                   lastPixel = true;
                   return null;
                }
            }
            
            // fall through
            
            if (startAgain)
            {
                startAgain = false;
                PixelDesc pd = next.nextPixel();
                amount = pd.amount;   
                radius = (float)Math.sqrt((pd.x-complexImage.w/2)*(pd.x-complexImage.w/2)+(pd.y-complexImage.h/2)*(pd.y-complexImage.h/2));
                               
                // now draw an ellipse from the center to that point
                lastPixel = false;
                ccx=0;ccy=0;
                boolean ex = false;
                while((!ex) && (ccy<complexImage.h))
                {
                    ccx =  0;
                    while((!ex) && (ccx<complexImage.w))
                    {
                        float r = (float)Math.sqrt((ccx-complexImage.w/2)*(ccx-complexImage.w/2)+(ccy-complexImage.h/2)*(ccy-complexImage.h/2));
                        if (r>radius) ex=true; else                                                
                            ccx++;
                    }
                    if (!ex) ccy++;
                }
                if (ex) return new PixelDesc(null,ccx,ccy,pd.amount);
                if (ccy==complexImage.h) lastPixel=true;
                return null;
            }
        }
        return(null);
    }
}