package lotto;

import java.awt.*;
import java.awt.geom.*;
import java.awt.image.*;

public class RoundGradientContext implements PaintContext{
    protected Point2D mPoint;
    protected Point2D mRadius;
    protected Color mC1, mC2;
    
    public RoundGradientContext(Point2D p, Color c1, Point2D r, Color c2){
        mPoint =p;
        mC1 = c1;
        mRadius =r;
        mC2 = c2;
    }
    
    public void dispose(){;}
    
    public ColorModel getColorModel() { return ColorModel.getRGBdefault(); }
    
    public Raster getRaster(int x, int y, int w, int h){
        WritableRaster raster = getColorModel().createCompatibleWritableRaster(w,h);
        int[] data = new int[w*h*4];
        for (int j=0; j < h; j++){
            for (int i =0; i < w; i++){
                double distance = mPoint.distance(x+i, y+j);
                double radius = mRadius.distance(0,0);
                double ratio = distance/radius;
                if  (ratio > 1.0) ratio = 1.0;
                int base = (j*w+i)*4;
                data[base+0] = (int)(mC1.getRed()+ratio*(mC2.getRed()-mC1.getRed()));
                data[base+1] = (int)(mC1.getGreen()+ratio*(mC2.getGreen()-mC1.getGreen()));
                data[base+2] = (int)(mC1.getBlue()+ratio*(mC2.getBlue()-mC1.getBlue()));
                data[base+3] = (int)(mC1.getAlpha()+ratio*(mC2.getAlpha()-mC1.getAlpha()));
            }
        }
        raster.setPixels(0,0,w,h,data);
        
        return raster;
    }
}