图像处理之边缘褪化效果

package com.process.blur.study;
 
import java.awt.Color;
import java.awt.image.BufferedImage;
 
/**
 * @author gloomy fish
 * Vignette - a photograph whose edges shade off gradually
 * 
 */
public class VignetteFilter extends AbstractBufferedImageOp {
    
  private int vignetteWidth;
  private int fade;
  private Color vignetteColor;
  
  public VignetteFilter() {
    vignetteWidth = 50;
    fade = 35;
    vignetteColor = Color.BLACK;
  }
  
  @Override
  public BufferedImage filter(BufferedImage src, BufferedImage dest) {
    int width = src.getWidth();
        int height = src.getHeight();
 
        if ( dest == null )
          dest = createCompatibleDestImage( src, null );
 
        int[] inPixels = new int[width*height];
        int[] outPixels = new int[width*height];
        getRGB( src, 0, 0, width, height, inPixels );
        int index = 0;
        for(int row=0; row<height; row++) {
          int ta = 0, tr = 0, tg = 0, tb = 0;
          for(int col=0; col<width; col++) {
              
                int dX = Math.min(col, width - col);
                int dY = Math.min(row, height - row);
                index = row * width + col;
            ta = (inPixels[index] >> 24) & 0xff;
                tr = (inPixels[index] >> 16) & 0xff;
                tg = (inPixels[index] >> 8) & 0xff;
                tb = inPixels[index] & 0xff;
                if ((dY <= vignetteWidth) & (dX <= vignetteWidth))
                {
                    double k = 1 - (double)(Math.min(dY, dX) - vignetteWidth + fade) / (double)fade;
                    outPixels[index] = superpositionColor(ta, tr, tg, tb, k);
                    continue;
                }
 
                if ((dX < (vignetteWidth - fade)) | (dY < (vignetteWidth - fade)))
                {
                  outPixels[index] = (ta << 24) | (vignetteColor.getRed() << 16) | (vignetteColor.getGreen() << 8) | vignetteColor.getBlue();
                }
                else
                {
                    if ((dX < vignetteWidth)&(dY>vignetteWidth))
                    {
                        double k = 1 - (double)(dX - vignetteWidth + fade) / (double)fade;
                        outPixels[index] = superpositionColor(ta, tr, tg, tb, k);
                    }
                    else
                    {
                        if ((dY < vignetteWidth)&(dX > vignetteWidth))
                        {
                            double k = 1 - (double)(dY - vignetteWidth + fade) / (double)fade;
                            outPixels[index] = superpositionColor(ta, tr, tg, tb, k);
                        }
                        else
                        {
                          outPixels[index] = (ta << 24) | (tr << 16) | (tg << 8) | tb;
                        }
                    }
                }
            }
        }
        
        setRGB( dest, 0, 0, width, height, outPixels );
        return dest;
  }
  
  public int superpositionColor(int ta, int red, int green, int blue, double k) {
    red = (int)(vignetteColor.getRed() * k + red *(1.0-k));
    green = (int)(vignetteColor.getGreen() * k + green *(1.0-k));
    blue = (int)(vignetteColor.getBlue() * k + blue *(1.0-k));
    int color = (ta << 24) | (clamp(red) << 16) | (clamp(green) << 8) | clamp(blue);
    return color;
  }
  
  public int clamp(int value) {
    return value > 255 ? 255 :((value < 0) ? 0 : value);
  }
  
  public int getVignetteWidth() {
    return vignetteWidth;
  }
 
  public void setVignetteWidth(int vignetteWidth) {
    this.vignetteWidth = vignetteWidth;
  }
 
  public int getFade() {
    return fade;
  }
 
  public void setFade(int fade) {
    this.fade = fade;
  }
  
  public Color getVignetteColor() {
    return vignetteColor;
  }
 
  public void setVignetteColor(Color vignetteColor) {
    this.vignetteColor = vignetteColor;
  }
  
}