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      1 /**************************************************************************
      2  *
      3  * Copyright 2008 VMware, Inc.
      4  * All Rights Reserved.
      5  *
      6  * Permission is hereby granted, free of charge, to any person obtaining a
      7  * copy of this software and associated documentation files (the
      8  * "Software"), to deal in the Software without restriction, including
      9  * without limitation the rights to use, copy, modify, merge, publish,
     10  * distribute, sub license, and/or sell copies of the Software, and to
     11  * permit persons to whom the Software is furnished to do so, subject to
     12  * the following conditions:
     13  *
     14  * The above copyright notice and this permission notice (including the
     15  * next paragraph) shall be included in all copies or substantial portions
     16  * of the Software.
     17  *
     18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
     19  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
     20  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
     21  * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
     22  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
     23  * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
     24  * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
     25  *
     26  **************************************************************************/
     27 
     28 
     29 #ifndef U_RECT_H
     30 #define U_RECT_H
     31 
     32 #include "pipe/p_compiler.h"
     33 #include "util/u_math.h"
     34 
     35 #ifdef __cplusplus
     36 extern "C" {
     37 #endif
     38 
     39 struct u_rect {
     40    int x0, x1;
     41    int y0, y1;
     42 };
     43 
     44 /* Do two rectangles intersect?
     45  * Note: empty rectangles are valid as inputs (and never intersect).
     46  */
     47 static inline boolean
     48 u_rect_test_intersection(const struct u_rect *a,
     49                          const struct u_rect *b)
     50 {
     51    return (!(a->x1 < b->x0 ||
     52              b->x1 < a->x0 ||
     53              a->y1 < b->y0 ||
     54              b->y1 < a->y0 ||
     55              a->x1 < a->x0 ||
     56              a->y1 < a->y0 ||
     57              b->x1 < b->x0 ||
     58              b->y1 < b->y0));
     59 }
     60 
     61 /* Find the intersection of two rectangles known to intersect.
     62  */
     63 static inline void
     64 u_rect_find_intersection(const struct u_rect *a,
     65                          struct u_rect *b)
     66 {
     67    /* Caller should verify intersection exists before calling.
     68     */
     69    if (b->x0 < a->x0) b->x0 = a->x0;
     70    if (b->x1 > a->x1) b->x1 = a->x1;
     71    if (b->y0 < a->y0) b->y0 = a->y0;
     72    if (b->y1 > a->y1) b->y1 = a->y1;
     73 }
     74 
     75 
     76 static inline int
     77 u_rect_area(const struct u_rect *r)
     78 {
     79    return (r->x1 - r->x0) * (r->y1 - r->y0);
     80 }
     81 
     82 static inline void
     83 u_rect_possible_intersection(const struct u_rect *a,
     84                              struct u_rect *b)
     85 {
     86    if (u_rect_test_intersection(a,b)) {
     87       u_rect_find_intersection(a,b);
     88    }
     89    else {
     90       /*
     91        * Note the u_rect_xx tests deal with inclusive coordinates
     92        * hence all-zero would not be an empty box.
     93        */
     94       b->x0 = b->y0 = 0;
     95       b->x1 = b->y1 = -1;
     96    }
     97 }
     98 
     99 /* Set @d to a rectangle that covers both @a and @b.
    100  */
    101 static inline void
    102 u_rect_union(struct u_rect *d, const struct u_rect *a, const struct u_rect *b)
    103 {
    104    d->x0 = MIN2(a->x0, b->x0);
    105    d->y0 = MIN2(a->y0, b->y0);
    106    d->x1 = MAX2(a->x1, b->x1);
    107    d->y1 = MAX2(a->y1, b->y1);
    108 }
    109 
    110 #ifdef __cplusplus
    111 }
    112 #endif
    113 
    114 #endif /* U_RECT_H */
    115