xref: /plan9-contrib/sys/src/cmd/gs/src/gsrect.h (revision 593dc095aefb2a85c828727bbfa9da139a49bdf4)

/* Copyright (C) 1997, 1998, 1999 Aladdin Enterprises.  All rights reserved.

  This software is provided AS-IS with no warranty, either express or
  implied.

  This software is distributed under license and may not be copied,
  modified or distributed except as expressly authorized under the terms
  of the license contained in the file LICENSE in this distribution.

  For more information about licensing, please refer to
  http://www.ghostscript.com/licensing/. For information on
  commercial licensing, go to http://www.artifex.com/licensing/ or
  contact Artifex Software, Inc., 101 Lucas Valley Road #110,
  San Rafael, CA  94903, U.S.A., +1(415)492-9861.
*/

/* $Id: gsrect.h,v 1.5 2002/06/16 08:45:42 lpd Exp $ */
/* Rectangle utilities */

#ifndef gsrect_INCLUDED
#  define gsrect_INCLUDED

#include "gxfixed.h"

/* Check whether one rectangle is included entirely within another. */
#define rect_within(inner, outer)\
  ((inner).q.y <= (outer).q.y && (inner).q.x <= (outer).q.x &&\
   (inner).p.y >= (outer).p.y && (inner).p.x >= (outer).p.x)

/*
 * Intersect two rectangles, replacing the first.  The result may be
 * anomalous (q < p) if the intersection is empty.
 */
#define rect_intersect(to, from)\
  BEGIN\
    if ((from).p.x > (to).p.x) (to).p.x = (from).p.x;\
    if ((from).q.x < (to).q.x) (to).q.x = (from).q.x;\
    if ((from).p.y > (to).p.y) (to).p.y = (from).p.y;\
    if ((from).q.y < (to).q.y) (to).q.y = (from).q.y;\
  END

/*
 * Merge two rectangles, replacing the first.  The result may be
 * anomalous (q < p) if the first rectangle was anomalous.
 */
#define rect_merge(to, from)\
  BEGIN\
    if ((from).p.x < (to).p.x) (to).p.x = (from).p.x;\
    if ((from).q.x > (to).q.x) (to).q.x = (from).q.x;\
    if ((from).p.y < (to).p.y) (to).p.y = (from).p.y;\
    if ((from).q.y > (to).q.y) (to).q.y = (from).q.y;\
  END

/*
 * Calculate the difference of two rectangles, a list of up to 4 rectangles.
 * Return the number of rectangles in the list, and set the first rectangle
 * to the intersection.  The resulting first rectangle is guaranteed not to
 * be anomalous (q < p) iff it was not anomalous originally.
 *
 * Note that unlike the macros above, we need different versions of this
 * depending on the data type of the individual values: we'll only implement
 * the variations that we need.
 */
int int_rect_difference(gs_int_rect * outer, const gs_int_rect * inner,
			gs_int_rect * diffs /*[4] */ );

/*
 * Check whether a parallelogram is a rectangle.
 */
#define PARALLELOGRAM_IS_RECT(ax, ay, bx, by)\
  ( ((ax) | (by)) == 0 || ((bx) | (ay)) == 0 )

/*
 * Convert a rectangular parallelogram to a rectangle, carefully following
 * the center-of-pixel rule in all cases.
 */
#define INT_RECT_FROM_PARALLELOGRAM(prect, px, py, ax, ay, bx, by)\
  BEGIN\
    int px_ = fixed2int_pixround(px);\
    int py_ = fixed2int_pixround(py);\
    int qx_ = fixed2int_pixround((px) + (ax) + (bx));  /* only one is non-zero */\
    int qy_ = fixed2int_pixround((py) + (ay) + (by));  /* ditto */\
\
    if (qx_ < px_)\
      (prect)->p.x = qx_, (prect)->q.x = px_;\
    else\
      (prect)->p.x = px_, (prect)->q.x = qx_;\
    if (qy_ < py_)\
      (prect)->p.y = qy_, (prect)->q.y = py_;\
    else\
      (prect)->p.y = py_, (prect)->q.y = qy_;\
  END

#endif /* gsrect_INCLUDED */