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;
  }
}