// Copyright (c) 1997 - 2022 kio@little-bat.de
// BSD-2-Clause license
// https://opensource.org/licenses/BSD-2-Clause


#define SAFE 3
#define LOG	 1

#import "BoxP1P2.h"


#define SETMIN(A, B) \
  if (B < A) A = B
#define SETMAX(A, B) \
  if (B > A) A = B

#define x1 p1.x
#define x2 p2.x
#define y1 p1.y
#define y2 p2.y
#define w  (x2 - x1)
#define h  (y2 - y1)


/* ----	calculate enclosing rectangle of two rectangles ------------------------------
		returns the bounding box of two boxes
		if one of both boxes is empty, the other box is returned
		if both boxes are empty, the first box is returned
*/
Box& Box::operator+=(cBox& q)
{
	if (q.IsNotEmpty())
	{
		if (this->IsNotEmpty())
		{
			SETMIN(x1, q.x1);
			SETMIN(y1, q.y1);
			SETMAX(x2, q.x2);
			SETMAX(y2, q.y2);
		}
		else { *this = q; }
	}
	else
	{
		if (this->IsEmpty()) p2 = p1;
	}

	return *this;
}


/* ----	calculate the intersection of two rectangles ----------------------------------
		P1 is always repositioned to [ max(x1,q.x1), max(y1,,q.y1) ]
			even if the intersection is empty.
		If the intersection is empty, then an empty box with W=H=0 is returned.
*/
Box& Box::operator^=(cBox& q)
{
	SETMAX(x1, q.x1);
	SETMAX(y1, q.y1);
	SETMIN(x2, q.x2);
	SETMIN(y2, q.y2);

	if (this->IsEmpty()) p2 = p1;
	return *this;
}


/* ----	punch rectangle -----------------------------------------------
		box q is subtracted from this box and the bounding box of the result is returned.
		if box q is not high or not wide enough to fully cover the with or height of this box,
		then this box is not modified.
*/
Box& Box::operator-=(cBox& q)
{
	if (q.y1 <= y1 && q.y2 >= y2)
	{
		if (q.x1 <= x1) { SETMAX(x1, q.x2); }
		if (q.x2 >= x2) { SETMIN(x2, q.x1); }
	}

	if (q.x1 <= x1 && q.x2 >= x2)
	{
		if (q.y1 <= y1) { SETMAX(y1, q.y2); }
		if (q.y2 >= y2) { SETMIN(y2, q.y1); }
	}

	if (this->IsEmpty()) p2 = p1;
	return *this;
}