src/gallium/auxiliary/util/u_rect.h

   1 /**************************************************************************
   2  *
   3  * Copyright 2008 VMware, Inc.
   4  * All Rights Reserved.
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   7  * copy of this software and associated documentation files (the
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  11  * permit persons to whom the Software is furnished to do so, subject to
  12  * the following conditions:
  13  *
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  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
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  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 */