pdf417_dec.c

PDF417编码的算法的源程序

          for ( ii = endy; ii < beginy; ii += 1)
	    {
	      for ( jj = 0; jj < width; jj += 1)
                {
                  if (( ii + jj < MAX_Y_PIXEL) && ( beginx < MAX_X_PIXEL))
		    {
		     pixel_array[beginx][ii+jj].greyval = 510;
                    }
                }
            } 
        }
    }


  if (( beginy - endy )  == 0)  // horizontal
    {
      if ( endx > beginx )          
        {
	  for ( ii = beginx; ii < endx; ii += 1)
	    {
	      for ( jj = 0; jj < width; jj += 1)
                {
                  if (( ii + jj < MAX_X_PIXEL) && ( beginy < MAX_Y_PIXEL))
		    {
		      pixel_array[ii + jj ][beginy].greyval = 510;
                    }
                }
            } 
        }
      else
        {
          for ( ii = endx; ii < beginx; ii += 1)
	    {
	      for ( jj = 0; jj < width; jj += 1)
                {
                  if (( ii + jj < MAX_X_PIXEL) && ( beginy < MAX_Y_PIXEL))
		    {
		     pixel_array[ii + jj][beginy].greyval = 510;
                    }
                }
            } 
        }
    }


}

//
//  Search thru all the dark squares found and find the 
//      min and max of the x and y directions to make a box

void find_dark_sq_box()

{
  int ii;
  int debug;

  min_box_x = MAX_X_PIXEL;
  min_box_y = MAX_Y_PIXEL;

  max_box_x = 0;
  max_box_y = 0;

  debug = 0;
  
  for (ii = 0; ii < dark_sqindex; ii += 1)
    {
      if ( dark_squares[ii].xloc > max_box_x)
        {
          max_box_x = dark_squares[ii].xloc;
	}
      if ( dark_squares[ii].yloc > max_box_y)
        {
          max_box_y = dark_squares[ii].yloc;
	}
      if ( dark_squares[ii].xloc < min_box_x)
        {
          min_box_x = dark_squares[ii].xloc;
	}
      if ( dark_squares[ii].yloc < max_box_y)
        {
          min_box_y = dark_squares[ii].yloc;
	}

    }

  min_box_x = min_box_x - box_x_incr;
  min_box_y = min_box_y - box_y_incr;
  max_box_x = max_box_x + box_x_incr;
  max_box_y = max_box_y + box_y_incr;

  if  (debug)
    {
     printf("In find dark square bounding box \n");
     printf(" min x,y = %d %d \n", min_box_x, min_box_y);
     printf(" max x,y = %d %d \n", max_box_x, max_box_y);
    }

  // draw a box around the dark squares and put this in pixel_array
  // then you can dump out the pixel_array and see how good it is

  if ( debug)
    {
     draw_pixel_line( 4, max_box_x, max_box_y, min_box_x, max_box_y );
     draw_pixel_line( 4, max_box_x, max_box_y, max_box_x, min_box_y );
     draw_pixel_line( 4, min_box_x, min_box_y, max_box_x, min_box_y );
     draw_pixel_line( 4, min_box_x, min_box_y, min_box_x, max_box_y );
    }

}  // find dark square box

// expand the box around the symbol by 25 %
//   may not be necessary...

void expand_dark_box25()
{
  int x_length;
  int y_length;
  
  int new_x_len;
  int new_y_len;
  
  int new_min_x;
  int new_min_y;
  int new_max_x;
  int new_max_y;


  x_length = max_box_x - min_box_x;
  
  if ( x_length < ( MAX_X_PIXEL / 50) )
    {
      printf("Symbol too small or missing \n");
    }

  y_length = max_box_y - min_box_y;
  
  if ( y_length < ( MAX_Y_PIXEL / 50) )
    {
      printf("Symbol too small or missing \n");
    }
  
  // expand by 25%

  new_x_len = x_length + (x_length / 4);
  new_y_len = y_length + (y_length / 4);


  new_min_x =  max_box_x - ( x_length / 2 ) - new_x_len;
  new_min_y =  max_box_y - ( y_length / 2 ) - new_y_len;

  if ( new_min_x > 0)
    {
      new_max_x =  new_min_x + new_x_len;
    }

  if ( new_min_y > 0)
    {
      new_max_y =  new_min_y + new_y_len;
    }


  if ( new_min_x < 0)
    {
      // could try to expand by 10 % here
      new_min_x = min_box_x;
    }
  
  if ( new_min_y < 0)
    {
      // could try to expand by 10 % here
      new_min_y = min_box_y;
    }

  if ( new_max_x > MAX_X_PIXEL)
    {
      // could try to expand by 10 % here
      new_max_x = max_box_x;
    }

  
  if ( new_min_y > MAX_Y_PIXEL)
    {
      // could try to expand by 10 % here
      new_max_y = max_box_y;
    }

  b_box_maxx = new_max_x;
  b_box_maxy = new_max_y;  

  b_box_minx = new_min_x;
  b_box_miny = new_min_y;  
  
  b_box_xlen = ( b_box_maxx - b_box_minx);
  b_box_ylen = ( b_box_maxy - b_box_miny);
}

void get_box_len()
{
  int x_length;
  int y_length;
  
  int new_x_len;
  int new_y_len;
  
  int new_min_x;
  int new_min_y;
  int new_max_x;
  int new_max_y;
  int debug;


  debug = 0;

  x_length = max_box_x - min_box_x;
  
  if ( x_length < ( MAX_X_PIXEL / 50) )
    {
      printf("Symbol too small or missing \n");
    }

  y_length = max_box_y - min_box_y;
  
  if ( y_length < ( MAX_Y_PIXEL / 50) )
    {
      printf("Symbol too small or missing \n");
    }
  


  new_x_len = x_length ;
  new_y_len = y_length ;


  new_min_x = min_box_x;
  new_min_y = min_box_y;
  new_max_x = max_box_x;
  new_max_y = max_box_y;

  b_box_maxx = new_max_x;
  b_box_maxy = new_max_y;  

  b_box_minx = new_min_x - (x_length / 20);
  if ( b_box_minx < (min_box_x / 2))
    {
      b_box_minx = (min_box_x / 2);
    }

  b_box_miny = new_min_y;  
  
  b_box_xlen = ( b_box_maxx - b_box_minx);
  b_box_ylen = ( b_box_maxy - b_box_miny);
  if (debug)
    {
      printf("End get_box_length \n");
    }
}

// get 3 points on the left edge of the bounding box
// one at upper left
// one at center
// one at bottom left
// use these as starting points for the line scan
//

void get_scan_points()
{
    
  int debug;
  debug = 0;

  
  scan_upleft_x = b_box_minx;
  scan_upleft_y = b_box_maxy;

  scan_cenleft_x = b_box_minx;
  scan_cenleft_y = b_box_maxy - (b_box_ylen/2);

  scan_lowleft_x = b_box_minx;
  scan_lowleft_y = b_box_miny;

  if (debug) { printf(" In scan points upper left = %d %d \n",
		      scan_upleft_x, scan_upleft_y);
               printf(" In scan points center left = %d %d \n",
		      scan_cenleft_x, scan_cenleft_y);
               printf(" In scan points lower left = %d %d \n",
		      scan_lowleft_x, scan_lowleft_y);
  } 
}


void get_pixel(int inx, int iny)
{
 
  if ( pixel_cnt < MAX_LINE_PIXEL)
    {
     line_data[pixel_cnt] = pixel_array[inx][iny].greyval;
     line_x[pixel_cnt]= inx;
     line_y[pixel_cnt]= iny;

     pixel_cnt += 1;
    }
  else
    {
      printf("Too many pixels in this line \n");
      
    }
}

// get pixel used when taking the normal to the line
//
void get_pixel_norm(int inx, int iny)
{
  int debug;
  
  debug = 0;
 
  if ( pixel_cnt < MAX_LINE_PIXEL)
    {
     norm_line_data[pixel_cnt] = pixel_array[inx][iny].greyval;
  
     normal_x[pixel_cnt] = inx;
     normal_y[pixel_cnt] = iny;
     if (debug)
       {
        if ( pixel_cnt == 0)
         {
	  if (debug ) {
            printf("at 0 normal_x , normal_y = %d %d \n", normal_x[0],
		normal_y[0]);
	  }
         }
       }
     pixel_cnt += 1;
    }
  
}

// get pixel used when taking a line from the pix_out data
//   for final processing
//
void get_pixel_post(int inx, int iny)
{
  int debug;

  debug = 0;

  if ( post_pixel_cnt < MAX_LINE_PIXEL)
    {
      if ( ( inx > 0 ) && ( iny > 0))
	{
          if ( ( inx < pixel_out_xlen ) && ( iny < pixel_out_ylen))
            {
              post_line_data[post_pixel_cnt] = pix_out[inx][iny].greyval;
  
              post_x[post_pixel_cnt] = inx;
              post_y[post_pixel_cnt] = iny;
            }
          else
	    {
              post_line_data[post_pixel_cnt] = 0;
            }
        }
      else
	{
          post_line_data[post_pixel_cnt] = 0;
          post_x[post_pixel_cnt] = -1;
          post_y[post_pixel_cnt] = -1;
        }
     if (debug)
       {
        if ( post_pixel_cnt == 0)
         {
	   printf("at 0 post_x , post_y = %d %d \n", post_x[0],
		post_y[0]);
         }
       }
      post_pixel_cnt += 1;
    }
  
}

void save_line()
{
  int jj;

  if ( save_line_cnt < MAX_LINE_SCANS )
    {
      save_line_data[save_line_cnt].pixelcnt = pixel_cnt;
      save_line_data[save_line_cnt].has_8111 = FALSE;
      save_line_data[save_line_cnt].has_7111 = FALSE;
      save_line_data[save_line_cnt].slope = slope;
      save_line_data[save_line_cnt].dir = dir;
      
      for ( jj= 0; jj < pixel_cnt; jj += 1)
	{
          if ( jj < MAX_LINE_PIXEL )
	    {
	     save_line_data[save_line_cnt].line_vals[jj]= line_data[jj];
	  //   printf("line_data,jj=%d = %d \n",jj,line_data[jj]);
             save_line_data[save_line_cnt].line_x[jj] = line_x[jj];
             save_line_data[save_line_cnt].line_y[jj] = line_y[jj];
            }
        }
      
    }
  else
    {
      printf("Internal error: Too many left probe lines  = %d\n", save_line_cnt);
      printf("Allowed max = %d \n",MAX_LINE_SCANS);
    }

}

void skip_underthress()
{

  while(( line_data[lpixel] < line_threshold ) && ( lpixel < pixel_cnt))
    {
      lpixel += 1;
      barwidth += 1;
    }
}


// called by analyzer module , used to get the bar
//   widths in the module  using the best xlines in
//   the column

int get_mod_xline(int yval, int rowin , int colin)
{
  int good_space;
  int kk;
  int debug;
  int mid_point;
  int bit_int;
  int space_min;
  int space_max;
  int bit[20];
  int this_mod_index;

  debug = 0;
  good_space = TRUE;
  space_min = (best_onewidth * 3 ) / 4;
  space_max = (( int)( best_onewf * 6)) / 4;

  bit[0] = 0;
  for ( kk = 1; kk < vert_line_cnt; kk += 1)
    {
      bit[kk] = 0;
      if ( (pix_col_xline[kk] - pix_col_xline[kk-1]) < space_min)
	{
	  good_space = FALSE;
          if (debug) { printf("Good space failed : too narrow \n"); }
        }
      if ( (pix_col_xline[kk] - pix_col_xline[kk-1]) > space_max)
	{
	  good_space = FALSE;
          if (debug) { printf("Good space failed : too wide\n"); }
        }
      if ( debug)
        {
          printf("kk = %d pix_col_xline[kk] = %d \n", kk, pix_col_xline[kk]);
        }
    }

  xline_mod_index = -1;
  this_mod_index = -1;

  if (( vert_line_cnt > 15) && ( good_space == TRUE))
    {
     for ( kk = 0; kk < vert_line_cnt ; kk += 1)
      {
       if ( kk > 0)
	{
          mid_point = ( pix_col_xline[kk] + pix_col_xline[kk-1] ) / 2;
        }
       else
        {
          mid_point = pix_col_xline[kk] / 2;
        }
        
        bit[kk] = test_black( mid_point, yval ,1);
        if (debug)
	  {
	    printf("mid_point = %d yval = %d  kk = %d \n",
		   mid_point, yval, kk );
          }
      }
     
   
      bit_int = bits_to_symbol( bit );

     if (debug) { printf("xline bit_int = %x \n", bit_int); }

     this_mod_index = find_index(bit_int,2, rowin, colin);

     if ( this_mod_index != -1 )
       {
         if (debug) { printf("This mod index = %d \n", this_mod_index); }

         xline_mod_index = this_mod_index;         
         return(0);
         }
     else
       {
	 return(-1);
       }
    }
  else
    {
      return(-1);
    }

}


// called by analyzer module , used to get the bar
//   widths in the module

void get_mod_bar(int in_row, int in_col )
{

  int mbarwidth;
  int debug;

  debug = 0;
  if ( debug) { printf("In get_mod_bar \n"); }


  mbarwidth = 0;

  if ( mod_bar_cnt < MAX_MOD_BARS)
    {
      mod_bar_array[mod_bar_cnt].beginx = mod_line_x[lpixel];
      mod_bar_array[mod_bar_cnt].lpixel = lpixel;
    }