%%	options

copyright owner	=	Dirk Krause
copyright year	=	2012-2014
license		=	bsd


%%	header

#ifdef __cplusplus
extern "C" {
#endif

/**	Bezier curve value calculation.
	@param	x0	Start point value.
	@param	xp	Value in control point near start.
	@param	xm	Value in control point near end.
	@param	x1	End point.
	@param	t	The t parameter.
	@param	ec	Pointer to error code variable, may be NULL.
	@return	Calculation result.
*/
double
dk3bezier_value(
  double x0, double xp, double xm, double x1, double t, int *ec
);

/**	Add Bezier curve segment to bounding box.
	@param	bb	Bounding box to modify.
	@param	x0	Start point x coordinate.
	@param	y0	Start point y coordinate.
	@param	xp	Control point near start x coordinate.
	@param	yp	Control point near start y coordinate.
	@param	xm	Control point near end x coordinate.
	@param	ym	Control point near end y coordinate.
	@param	x1	End point x coordinate.
	@param	y1	End point y coordinate.
	@param	ra	Half line width.
	@param	ec	Pointer to error code variable, may be NULL.
	@return	1 on success, 0 on error.
*/
int
dk3bezier_bb(
  dk3_bb_t	*bb,
  double	 x0,
  double	 y0,
  double	 xp,
  double	 yp,
  double	 xm,
  double	 ym,
  double	 x1,
  double	 y1,
  double	 ra,
  int		*ec
);

#ifdef __cplusplus
}
#endif

%%	module

#include "dk3all.h"
#include "dk3bb.h"
#include "dk3bezcu.h"



$!trace-include



double
dk3bezier_value(
  double x0, double xp, double xm, double x1, double t, int *ec
)
{
  int		mec = 0;
  double	back;
  $? "+ dk3bezier_value %lg %lg %lg %lg %lg", x0, xp, xm, x1, t
  back = dk3ma_d_add_ok(
    x0,
    dk3ma_d_mul_ok(
      t,
      dk3ma_d_add_ok(
        dk3ma_d_sub_ok(
	  dk3ma_d_mul_ok(3.0, xp, &mec),
	  dk3ma_d_mul_ok(3.0, x0, &mec),
	  &mec
	),
	dk3ma_d_mul_ok(
	  t,
	  dk3ma_d_add_ok(
	    dk3ma_d_add_ok(
	      dk3ma_d_sub_ok(
	        dk3ma_d_mul_ok(3.0, xm, &mec),
		dk3ma_d_mul_ok(6.0, xp, &mec),
		&mec
	      ),
	      dk3ma_d_mul_ok(3.0, x0, &mec),
	      &mec
	    ),
	    dk3ma_d_mul_ok(
	      t,
	      dk3ma_d_add_ok(
	        dk3ma_d_sub_ok(
		  dk3ma_d_mul_ok(3.0, xp, &mec),
		  dk3ma_d_mul_ok(3.0, xm, &mec),
		  &mec
		),
		dk3ma_d_sub_ok(x1, x0, &mec),
		&mec
	      ),
	      &mec
	    ),
	    &mec
	  ),
	  &mec
	),
	&mec
      ),
      &mec
    ),
    &mec
  );			$? ". mec = %d", mec
  if(mec) {
    if(ec) { *ec = mec; }
  }
  $? "- dk3bezier_value %lg", back
  return back;
}



/**	Apply one t value to a bounding box.
	@param	bb	Bounding box to modify.
	@param	x0	Start value.
	@param	xp	Control value for start.
	@param	xm	Control value for end.
	@param	x1	End value.
	@param	ra	Point radius (half line width).
	@param	tv	The t value.
	@param	isy	Flag: Y direction.
	@param	ec	Pointer to error code variable, may be NULL.
	@return	1 on success, 0 on error.
*/
static
int
dk3bezier_t_dimension(
  dk3_bb_t	*bb,
  double	 x0,
  double	 xp,
  double	 xm,
  double	 x1,
  double	 ra,
  double	 tv,
  int		 isy,
  int		*ec
)
{
  double	 val;
  int		 back = 1;
  int		 mec = 0;
  $? "+ dk3bezier_t_dimension %lg %lg %lg %lg y=%d", x0, xp, xm, x1, isy
  if(tv > 0.0) {
    if(tv < 1.0) {
      val = dk3bezier_value(x0, xp, xm, x1, tv, &mec); $? ". mec = %d", mec
      if(isy) {
        if(!dk3bb_add_y_width(bb, val, ra)) { back = 0; }
      } else {
        if(!dk3bb_add_x_width(bb, val, ra)) { back = 0; }
      }
    }
  }
  if(mec) {		$? "! mec"
    back = 0;
    if(ec) { *ec = mec; }
  } $? "- dk3bezier_t_dimension %d", back
  return back;
}



#if VERSION_BEFORE_20121218
/**	Apply one dimension to a bounding box.
	@param	bb	Bounding box to modify.
	@param	x0	Start value.
	@param	xp	Control value for start.
	@param	xm	Control value for end.
	@param	x1	End value.
	@param	ra	Point radius (half line width).
	@param	isy	Flag: Y direction.
	@param	ec	Pointer to error code variable, may be NULL.
	@return	1 on success, 0 on error.
*/
static
int
dk3bezier_bb_dimension(
  dk3_bb_t	*bb,
  double	 x0,
  double	 xp,
  double	 xm,
  double	 x1,
  double	 ra,
  int		 isy,
  int		*ec
)
{
  double	 n;
  double	 z1;
  double	 z2;
  double	 t;
  int		 back = 1;
  int		 mec = 0;
  $? "+ dk3bezier_bb_dimension %lg %lg %lg %lg y=%d", x0, xp, xm, x1, isy
  n = dk3ma_d_add_ok(
    dk3ma_d_sub_ok(x1, x0, &mec),
    dk3ma_d_mul_ok(3.0, dk3ma_d_sub_ok(xp, xm, &mec), &mec),
    &mec
  );	$? ". mec = %d", mec
  z1 = dk3ma_d_sub_ok(
    dk3ma_d_sub_ok(dk3ma_d_mul_ok(2.0, xp, &mec), xm, &mec),
    x0,
    &mec
  );	$? ". mec = %d", mec
  z2 = dk3ma_d_add_ok(
    dk3ma_d_sub_ok(
      xm,
      dk3ma_d_mul_ok(2.0, xp, &mec),
      &mec
    ),
    x0,
    &mec
  );	$? ". mec = %d", mec
  z2 = dk3ma_d_mul_ok(z2, z2, &mec);
  z2 = dk3ma_d_sub_ok(
    z2,
    dk3ma_d_mul_ok(
      dk3ma_d_sub_ok(xp, x0, &mec),
      n,
      &mec
    ),
    &mec
  );	$? ". mec = %d", mec
  if(z2 >= 0.0) {
    z2 = sqrt(z2);	$? ". z1 = %lg   z2 = %lg", z1, z2
    t = dk3ma_d_div_ok(
      dk3ma_d_add_ok(z1, z2, &mec),
      n,
      &mec
    );	$? ". mec = %d", mec
    if(!dk3bezier_t_dimension(bb, x0, xp, xm, x1, ra, t, isy, &mec)) {
      back = 0;
    }	$? ". mec = %d", mec
    t = dk3ma_d_div_ok(
      dk3ma_d_sub_ok(z1, z2, &mec),
      n,
      &mec
    );	$? ". mec = %d", mec
    if(!dk3bezier_t_dimension(bb, x0, xp, xm, x1, ra, t, isy, &mec)) {
      back = 0;
    }	$? ". mec = %d", mec
  }
  if(mec) {		$? "! math error"
    back = 0;
    if(ec) { *ec = mec; }
  } $? "- dk3bezier_bb_dimension %d", back
  return back;
}
#else
/**	Apply one dimension to a bounding box.
	@param	bb	Bounding box to modify.
	@param	x0	Start value.
	@param	xp	Control value for start.
	@param	xm	Control value for end.
	@param	x1	End value.
	@param	ra	Point radius (half line width).
	@param	isy	Flag: Y direction.
	@param	ec	Pointer to error code variable, may be NULL.
	@return	1 on success, 0 on error.
*/
static
int
dk3bezier_bb_dimension(
  dk3_bb_t	*bb,
  double	 x0,
  double	 xp,
  double	 xm,
  double	 x1,
  double	 ra,
  int		 isy,
  int		*ec
)
{
  double	 n;
  double	 z1;
  double	 z2;
  double	 t;
  int		 back = 1;
  int		 mec = 0;
  int		 testmec;
  $? "+ dk3bezier_bb_dimension %lg %lg %lg %lg y=%d", x0, xp, xm, x1, isy
  n = dk3ma_d_add_ok(
    dk3ma_d_sub_ok(x1, x0, &mec),
    dk3ma_d_mul_ok(3.0, dk3ma_d_sub_ok(xp, xm, &mec), &mec),
    &mec
  );	$? ". mec = %d", mec
  z1 = dk3ma_d_sub_ok(
    dk3ma_d_sub_ok(dk3ma_d_mul_ok(2.0, xp, &mec), xm, &mec),
    x0,
    &mec
  );	$? ". mec = %d", mec
  z2 = dk3ma_d_add_ok(
    dk3ma_d_sub_ok(
      xm,
      dk3ma_d_mul_ok(2.0, xp, &mec),
      &mec
    ),
    x0,
    &mec
  );	$? ". mec = %d", mec
  z2 = dk3ma_d_mul_ok(z2, z2, &mec);
  z2 = dk3ma_d_sub_ok(
    z2,
    dk3ma_d_mul_ok(
      dk3ma_d_sub_ok(xp, x0, &mec),
      n,
      &mec
    ),
    &mec
  );	$? ". mec = %d", mec
  if(z2 >= 0.0) {
    z2 = sqrt(z2);	$? ". z1 = %lg   z2 = %lg", z1, z2
    testmec = 0;
    t = dk3ma_d_div_ok(
      dk3ma_d_add_ok(z1, z2, &mec),
      n,
      &testmec
    );	$? ". mec = %d", mec
    if(0 == testmec) {
      if(!dk3bezier_t_dimension(bb, x0, xp, xm, x1, ra, t, isy, &mec)) {
        back = 0;
      }	$? ". mec = %d", mec
    }
    testmec = 0;
    t = dk3ma_d_div_ok(
      dk3ma_d_sub_ok(z1, z2, &mec),
      n,
      &testmec
    );	$? ". mec = %d", mec
    if(0 == testmec) {
      if(!dk3bezier_t_dimension(bb, x0, xp, xm, x1, ra, t, isy, &mec)) {
        back = 0;
      }	$? ". mec = %d", mec
    }
  }
  if(mec) {		$? "! math error"
    back = 0;
    if(ec) { *ec = mec; }
  } $? "- dk3bezier_bb_dimension %d", back
  return back;
}
#endif


int
dk3bezier_bb(
  dk3_bb_t	*bb,
  double	 x0,
  double	 y0,
  double	 xp,
  double	 yp,
  double	 xm,
  double	 ym,
  double	 x1,
  double	 y1,
  double	 ra,
  int		*ec
)
{
  int		 back = 0;
  int		 mec = 0;
  $? "+ dk3bezier_bb %lg %lg %lg %lg %lg %lg %lg %lg", x0, y0, xp, yp, xm, ym, x1, y1
  if(bb) {
    back = 1;
    if(!dk3bb_point_width(bb, x0, y0, ra)) {
      back = 0;
    }
    if(!dk3bb_point_width(bb, x1, y1, ra)) {
      back = 0;
    }
    if(!dk3bezier_bb_dimension(bb, x0, xp, xm, x1, ra, 0, &mec)) {
      back = 0;
    }
    if(!dk3bezier_bb_dimension(bb, y0, yp, ym, y1, ra, 1, &mec)) {
      back = 0;
    }
    if(mec) {
      back = 0;
      if(ec) { *ec = mec; }
    }
  } else {
    if(ec) { *ec = DK3_ERROR_INVALID_ARGS; }
  } $? "- dk3bezier_bb %d", back
  return back;
}