图像像素加减乘除操作

主要代码如下：
package chapter5;

import chapter4.*;

import java.awt.image.BufferedImage;
import java.util.Random;

/**

• Created by LENOVO on 18-1-30.
  */
  public class PMMDFilter extends AbstractBufferedImageOp {
  public static final int PLUS = 1;
  public static final int MINUS = 2;
  public static final int MULTIPLE = 4;

  private Random rnd;
  private double range;
  private int type;

  public PMMDFilter(){
  type = MINUS;
  rnd = new Random();
  range =25.0;
  }
  public BufferedImage filter(BufferedImage src,BufferedImage dest){
  int width = src.getWidth();
  int height = src.getHeight();
  if(dest == null){
  dest = creatCompatibleDestImage(src,null);
  }
  int[] inPixels = new int[widthheight];
  int[] outPixels = new int[widthheight];
  getRGB(src,0,0,width,height,inPixels);
  int index = 0;
  int centerX = width/2;
  int centerY = height/2;
  double maxDistance = Math.sqrt(centerXcenterX+centerYcenterY);
  for(int row=0;row<height;row++){
  int ta = 0,tr = 0,tg = 0,tb = 0;
  for(int col=0;col<width;col++){
  index = row*width+col;
  ta = (inPixels[index] >> 24) & 0xff;
  tr = (inPixels[index] >> 16) & 0xff;
  tg = (inPixels[index] >> 8) & 0xff;
  tb = (inPixels[index]) & 0xff;

           int[] rgb = new int[]{tr,tg,tb};
           if(type == PLUS){
               rgb = plus(rgb);
           }
           if(type == MINUS){
               int pcol = col-1;//当前像素之前一个像素
               if(pcol < 0 || pcol >= width){
                    pcol = 0;
               }
               int index2 = row*width +pcol;
               rgb = minus(rgb,inPixels[index2]);
           }
           if(type == MULTIPLE){
               rgb = multiple(rgb,maxDistance,centerX,centerY,row,col);
           }
           tr = rgb[0];
           tg = rgb[1];
           tb = rgb[2];
           outPixels[index] = (ta <<24 ) | (clamp(tr) <<16) | (clamp(tg) << 8) | clamp(tb);
       }
   }
   setRGB(dest,0,0,width,height,outPixels);
   return  dest;
  

  }
  //像素相加操作
  private int[] plus(int[] rgb){
  rgb[0] = addNoise(rgb[0]);
  rgb[1] = addNoise(rgb[1]);
  rgb[2] = addNoise(rgb[2]);
  return rgb;
  }
  //图像加噪
  private int addNoise(int p){
  boolean valid = false;
  do{
  int ran = (int) Math.round(rnd.nextGaussian()*range);//符合标准正态分布
  int v = p+ran;
  valid = v>=0 && v<=255;//判断像素值是否有效
  if (valid) p=v;
  }while(!valid);
  return p;
  }
  //像素相减操作
  private int[] minus (int[] rgb,int p){
  int tr = (p >> 16) & 0xff;
  int tg = (p >> 8) & 0xff;
  int tb =p & 0xff;
  rgb[0] = clamp(rgb[0]-tr);
  rgb[1] = clamp(rgb[1] -tr);
  rgb[2] = clamp(rgb[2]-tb);
  return rgb;
  }

  //像素相乘操作
  private int[] multiple(int[] rgb,double maxDistance,int cx,int cy,int row,int col){
  double scale = 1.0-getDistance(cx,cy,row,col)/maxDistance;
  scale = scalescale;
  rgb[0] = (int) (scalergb[0]);
  rgb[1] = (int) (scalergb[1]);
  rgb[2] = (int) (scalergb[2]);
  return rgb;

  }
  //获取像素与中心点之间的距离
  private double getDistance(int cx,int cy,int px, int py){
  double xx = (cx-px)(cx-px);
  double yy = (cy-py)(cy-py);
  return (int)Math.sqrt(xx+yy);
  }
  }
  测试代码同上。