/*			*/
/*	画像フィルタ	*/
/*			*/

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include "vision.h"

/*	リニアスケーリング	*/
void imageLinearScaling(int width, int height,
			int swidth, int sheight,
			double *input, double *output)
{
  int		i, j;
  double	v, inf, sup, p;
  static double	eps = 1e-10;
  
  inf = ELEMENT(input,swidth,sheight,0,0);
  sup = ELEMENT(input,swidth,sheight,0,0);
  
  for (i=0; i<width; i++) {
    for (j=0; j<height; j++) {
      v = ELEMENT(input,swidth,sheight,i,j);
      if (v < inf) {
	inf = v;
      } else if (sup < v) {
	sup = v;
      }
    }
  }
  
#if DEBUG
  printf("inf = %lf   sup = %lf\n", inf, sup);
#endif

  if (fabs(sup - inf) > eps) {
    p = (PIXELMAXVALUE - PIXELMINVALUE)/(sup - inf);
    for (i=0; i<width; i++) {
      for (j=0; j<height; j++) {
	ELEMENT(output,swidth,sheight,i,j) =
	  p*( ELEMENT(input,swidth,sheight,i,j) - inf ) + PIXELMINVALUE;
      }
    }
  } else { 
    for (i=0; i<width; i++) {
      for (j=0; j<height; j++) {
	ELEMENT(output,swidth,sheight,i,j) = PIXELMINVALUE;
      }
    }
  }
}

/*
	3×3 フィルタ
*/

#define LINEARCOM3(coef,input,swidth,sheight,i,j)	\
	coef[0][0] * ELEMENT(input,swidth,sheight,i-1,j-1) + \
	coef[0][1] * ELEMENT(input,swidth,sheight,i-1,j  ) + \
	coef[0][2] * ELEMENT(input,swidth,sheight,i-1,j+1) + \
	coef[1][0] * ELEMENT(input,swidth,sheight,i,  j-1) + \
	coef[1][1] * ELEMENT(input,swidth,sheight,i,  j  ) + \
	coef[1][2] * ELEMENT(input,swidth,sheight,i,  j+1) + \
	coef[2][0] * ELEMENT(input,swidth,sheight,i+1,j-1) + \
	coef[2][1] * ELEMENT(input,swidth,sheight,i+1,j  ) + \
	coef[2][2] * ELEMENT(input,swidth,sheight,i+1,j+1)

/*	3×3 平均化フィルタ	*/

static double average[3][3] = {{1.00/9, 1.00/9, 1.00/9},
			       {1.00/9, 1.00/9, 1.00/9},
			       {1.00/9, 1.00/9, 1.00/9}};

void imageAverageFilter3(int width, int height,
			 int swidth, int sheight,
			 double *input, double *output)
{
  int	i, j;
  
  for (i=1; i<width-1; i++) {
    for (j=1; j<height-1; j++) {
      ELEMENT(output,swidth,sheight,i,j) =
	LINEARCOM3(average,input,swidth,sheight,i,j);
    }
  }
  
  /* 左端と右端の処理 */
  for (j=0; j<height; j++) {
    ELEMENT(output,swidth,sheight,      0,j) = ELEMENT(input,swidth,sheight,      0,j);
    ELEMENT(output,swidth,sheight,width-1,j) = ELEMENT(input,swidth,sheight,width-1,j);
  }
  /* 下端と上端の処理 */
  for (i=0; i<width; i++) {
    ELEMENT(output,swidth,sheight,i,       0) = ELEMENT(input,swidth,sheight,i,       0);
    ELEMENT(output,swidth,sheight,i,height-1) = ELEMENT(input,swidth,sheight,i,height-1);
  }
}

/*	3×3 ラプラシアンフィルタ	*/

static double laplacian[3][3] = {{ 0.00, -1.00,  0.00},
			       {-1.00,  4.00, -1.00},
			       { 0.00, -1.00,  0.00}};

void imageLaplacianFilter3(int width, int height,
			   int swidth, int sheight,
			   double *input, double *output)
{
  int	i, j;
  
  for (i=1; i<width-1; i++) {
    for (j=1; j<height-1; j++) {
      ELEMENT(output,swidth,sheight,i,j) =
	LINEARCOM3(laplacian,input,swidth,sheight,i,j);
    }
  }

  /* 左端と右端の処理 */
  for (j=0; j<height; j++) {
    ELEMENT(output,swidth,sheight,      0,j) = 0;
    ELEMENT(output,swidth,sheight,width-1,j) = 0;
  }
  /* 下端と上端の処理 */
  for (i=0; i<width; i++) {
    ELEMENT(output,swidth,sheight,i,       0) = 0;
    ELEMENT(output,swidth,sheight,i,height-1) = 0;
  }
}

/*	3×3 ソーベルフィルタ	*/

static double sobelx[3][3] = {{-1.00, 0.00, 1.00},
			      {-2.00, 0.00, 2.00},
			      {-1.00, 0.00, 1.00}};
static double sobely[3][3] = {{-1.00, -2.00, -1.00},
			      { 0.00,  0.00,  0.00},
			      { 1.00,  2.00,  1.00}};

void imageSobelFilter3(int width, int height,
		       int swidth, int sheight,
		       double *input, double *output)
{
  int		i, j;
  double	diffx, diffy;
  
  for (i=1; i<width-1; i++) {
    for (j=1; j<height-1; j++) {
      diffx = LINEARCOM3(sobelx, input, swidth, sheight, i, j);
      diffy = LINEARCOM3(sobely, input, swidth, sheight, i, j);
      ELEMENT(output,swidth,sheight,i,j) = sqrt(diffx*diffx + diffy*diffy);
    }
  }
  
  /* 左端と右端の処理 */
  for (j=0; j<height; j++) {
    ELEMENT(output,swidth,sheight,      0,j) = 0;
    ELEMENT(output,swidth,sheight,width-1,j) = 0;
  }
  /* 下端と上端の処理 */
  for (i=0; i<width; i++) {
    ELEMENT(output,swidth,sheight,i,       0) = 0;
    ELEMENT(output,swidth,sheight,i,height-1) = 0;
  }
}