libs/fvwmrect.c

   1 /* -*-c-*- */
   2 /* Copyright (C) 2001  Dominik Vogt */
   3 /* This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation; either version 2 of the License, or
   6  * (at your option) any later version.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program; if not, write to the Free Software
  15  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  16  */
  17
  18 /*
  19 ** fvwmrect.c:
  20 ** This file supplies routines for fvwm internal rectangle handling.
  21 */
  22
  23 /* ---------------------------- included header files ---------------------- */
  24
  25 #include "config.h"
  26 #include <X11/Xlib.h>
  27 #include "fvwmrect.h"
  28
  29 /* ---------------------------- local definitions -------------------------- */
  30
  31 /* ---------------------------- local macros ------------------------------- */
  32
  33 /* ---------------------------- imports ------------------------------------ */
  34
  35 /* ---------------------------- exported variables (globals) --------------- */
  36
  37 /* ---------------------------- local types -------------------------------- */
  38
  39 /* ---------------------------- forward declarations ----------------------- */
  40
  41 /* ---------------------------- local variables ---------------------------- */
  42
  43 /* ---------------------------- local functions ---------------------------- */
  44
  45 static int fvwmrect_do_intervals_intersect(
  46         int x1, int width1, int x2, int width2)
  47 {
  48         return !(x1 + width1 <= x2 || x2 + width2 <= x1);
  49 }
  50
  51 /* ---------------------------- interface functions ------------------------ */
  52
  53 /* Returns 1 if the given rectangles intersect and 0 otherwise */
  54 int fvwmrect_do_rectangles_intersect(rectangle *r, rectangle *s)
  55 {
  56         if (r->x + r->width <= s->x)
  57         {
  58                 return 0;
  59         }
  60         if (s->x + s->width <= r->x)
  61         {
  62                 return 0;
  63         }
  64         if (r->y + r->height <= s->y)
  65         {
  66                 return 0;
  67         }
  68         if (s->y + s->height <= r->y)
  69         {
  70                 return 0;
  71         }
  72
  73         return 1;
  74 }
  75
  76 /* Subtracts the values in s2_ from the ones in s1_g and stores the result in
  77  * diff_g. */
  78 void fvwmrect_subtract_rectangles(
  79         rectangle *rdiff, rectangle *r1, rectangle *r2)
  80 {
  81         rdiff->x = r1->x - r2->x;
  82         rdiff->y = r1->y - r2->y;
  83         rdiff->width = r1->width - r2->width;
  84         rdiff->height = r1->height - r2->height;
  85
  86         return;
  87 }
  88
  89 /* Returns 1 is the rectangles are identical and 0 if not */
  90 int fvwmrect_rectangles_equal(
  91         rectangle *r1, rectangle *r2)
  92 {
  93         if (r1 == r2)
  94         {
  95                 return 1;
  96         }
  97         if (r1 == NULL || r2 == NULL)
  98         {
  99                 return 0;
 100         }
 101         if (r1->x != r2->x || r1->y != r2->y || r1->width != r2->width ||
 102             r1->height != r2->height)
 103         {
 104                 return 1;
 105         }
 106
 107         return 0;
 108 }
 109
 110 int fvwmrect_move_into_rectangle(rectangle *move_rec, rectangle *target_rec)
 111 {
 112         int has_changed = 0;
 113
 114         if (!fvwmrect_do_intervals_intersect(
 115                     move_rec->x, move_rec->width, target_rec->x,
 116                     target_rec->width))
 117         {
 118                 move_rec->x = move_rec->x % (int)target_rec->width;
 119                 if (move_rec->x < 0)
 120                 {
 121                         move_rec->x += target_rec->width;
 122                 }
 123                 move_rec->x += target_rec->x;
 124                 has_changed = 1;
 125         }
 126         if (!fvwmrect_do_intervals_intersect(
 127                     move_rec->y, move_rec->height, target_rec->y,
 128                     target_rec->height))
 129         {
 130                 move_rec->y = move_rec->y % (int)target_rec->height;
 131                 if (move_rec->y < 0)
 132                 {
 133                         move_rec->y += target_rec->height;
 134                 }
 135                 move_rec->y += target_rec->y;
 136                 has_changed = 1;
 137         }
 138
 139         return has_changed;
 140 }
 141
 142 int fvwmrect_intersect_xrectangles(
 143         XRectangle *r1, XRectangle *r2)
 144 {
 145         int x1 = max(r1->x, r2->x);
 146         int y1 = max(r1->y, r2->y);
 147         int x2 = min(r1->x + r1->width, r2->x + r2->width);
 148         int y2 = min(r1->y + r1->height, r2->y + r2->height);
 149
 150         r1->x = x1;
 151         r1->y = y1;
 152         r1->width = x2 - x1;
 153         r1->height = y2 - y1;
 154
 155         if (x2 > x1 && y2 > y1)
 156         {
 157                 return 1;
 158         }
 159         else
 160         {
 161                 return 0;
 162         }
 163 }