package PEU.P.image;
import java.io.IOException;
//作者,著作权人： 罗瑶光，浏阳
public class Sobel {
  public int[][] P( int[][] g,int choice) throws IOException {     
    int[][] refG =  new Reflection().PadImage(g, 3, 3);  
    int[]size = {g.length,g[0].length};
    double[][] Gx = new double [size[0]][size[1]];
    double[][] Gy = new double [size[0]][size[1]];
    int[][] gxk = new int[][]{{-1, 0, 1},{-2, 0, 2},{-1, 0, 1}};;
    int[][] gyk = new int[][]{{-1,-2,-1},{ 0, 0, 0},{ 1, 2, 1}};
    //GROUP OPERATION
    Gx= new Group_O().GO(gxk, refG, size);
    Gy= new Group_O().GO(gyk, refG, size);
    //MAG operation
    int[][] outmag = mag(Gx,Gy,size);
    //DIR operation
    int[][] outdir = dir(Gx,Gy,size);     
    switch (choice){
      case 1:  return outmag;
      case 2:  return outdir;
      default: return null;
    }        
  }
  
  private int[][] mag(double[][] gx,double[][] gy
  ,int[]size ) throws IOException{
    double[][] mag = new double[size[0]][size[1]];
    int[][] outmag = new int[size[0]][size[1]];
    for(int i = 0;i<size[0];i++){
      for(int j = 0;j<size[1];j++){
        mag[i][j] = Math.sqrt(Math.pow(gx[i][j], 2)
        +Math.pow(gy[i][j], 2));
        outmag[i][j] = (int)(mag[i][j]/(1020*Math.sqrt(2))*255);
      }
    }
    return  new CheckRange().P(outmag); 
  }
  
  private int[][] dir(double[][] gx,double[][] gy
  ,int[]size) throws IOException{  
    double[][] dir = new double[size[0]][size[1]];
    int[][] outdir = new int[size[0]][size[1]];
    for(int i = 0;i<size[0];i++){
      for(int j = 0;j<size[1];j++){
        dir[i][j] = Math.atan2(gy[i][j], gx[i][j]);
        outdir[i][j] = (int)((dir[i][j]+Math.PI)/(2*Math.PI)*32)*8;
        if(outdir[i][j]>255){
          outdir[i][j]=255;
        }
      }
    }
    return  new CheckRange().P(outdir); 
  }

  public int[][] P_WithMask(int[][]  g, int choice
  , int mask) throws IOException {
    int[][] refG =  new Reflection().PadImage(g, 3, 3);  
    int[]size = {g.length,g[0].length};
    double[][] Gx = new double [size[0]][size[1]];
    double[][] Gy = new double [size[0]][size[1]];
    int[][] gxk = new int[][]{{-1, 0, 1},{-2, 0, 2},{-1, 0, 1}};;
    int[][] gyk = new int[][]{{-1,-2,-1},{ 0, 0, 0},{ 1, 2, 1}};
    //GROUP OPERATION
    Gx= new Group_O().GO(gxk, refG, size);
    Gy= new Group_O().GO(gyk, refG, size);
    //MAG operation
    int[][] outmag = mag(Gx,Gy,size,mask);
    //DIR operation
    int[][] outdir = dir(Gx,Gy,size);     
    switch (choice){
      case 1:  return outmag;
      case 2:  return outdir;
      default: return null;
    }        
  }

  private int[][] mag(double[][] gx, double[][] gy
  , int[] size, int mask) throws IOException {
    double[][] mag = new double[size[0]][size[1]];
    int[][] outmag = new int[size[0]][size[1]];
    for(int i = 0;i<size[0];i++){
      for(int j = 0;j<size[1];j++){
        mag[i][j] = Math.sqrt(Math.pow(gx[i][j], 2)
        +Math.pow(gy[i][j], 2));
        outmag[i][j] = (int)(mag[i][j]
        /(1020*Math.sqrt(2))*255);
        if(outmag[i][j] >20) {
          outmag[i][j]=255;
        }else {
          outmag[i][j]=0;
        }
      }
    }
    return  new CheckRange().P(outmag); 
  }
}