summaryrefslogtreecommitdiff
path: root/src/core/constraints.c
blob: 1b2b70abe168ff6ac5c4fe5416353813e6fc4a91 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */

/* Marco size/position constraints */

/*
 * Copyright (C) 2002, 2003 Red Hat, Inc.
 * Copyright (C) 2003, 2004 Rob Adams
 * Copyright (C) 2005, 2006 Elijah Newren
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 */

#include <config.h>
#include "constraints.h"
#include "workspace.h"
#include "place.h"
#include "prefs.h"

#include <stdlib.h>
#include <math.h>

#if 0
 // This is the short and sweet version of how to hack on this file; see
 // doc/how-constraints-works.txt for the gory details.  The basics of
 // understanding this file can be shown by the steps needed to add a new
 // constraint, which are:
 //   1) Add a new entry in the ConstraintPriority enum; higher values
 //      have higher priority
 //   2) Write a new function following the format of the example below,
 //      "constrain_whatever".
 //   3) Add your function to the all_constraints and all_constraint_names
 //      arrays (the latter of which is for debugging purposes)
 // 
 // An example constraint function, constrain_whatever:
 //
 // /* constrain_whatever does the following:
 //  *   Quits (returning true) if priority is higher than PRIORITY_WHATEVER
 //  *   If check_only is TRUE
 //  *     Returns whether the constraint is satisfied or not
 //  *   otherwise
 //  *     Enforces the constraint
 //  * Note that the value of PRIORITY_WHATEVER is centralized with the
 //  * priorities of other constraints in the definition of ConstrainPriority
 //  * for easier maintenance and shuffling of priorities.
 //  */
 // static gboolean
 // constrain_whatever (MetaWindow         *window,
 //                     ConstraintInfo     *info,
 //                     ConstraintPriority  priority,
 //                     gboolean            check_only)
 // {
 //   if (priority > PRIORITY_WHATEVER)
 //     return TRUE;
 //
 //   /* Determine whether constraint applies; note that if the constraint
 //    * cannot possibly be satisfied, constraint_applies should be set to
 //    * false.  If we don't do this, all constraints with a lesser priority
 //    * will be dropped along with this one, and we'd rather apply as many as
 //    * possible.
 //    */
 //   if (!constraint_applies)
 //     return TRUE;
 //
 //   /* Determine whether constraint is already satisfied; if we're only
 //    * checking the status of whether the constraint is satisfied, we end
 //    * here.
 //    */
 //   if (check_only || constraint_already_satisfied)
 //     return constraint_already_satisfied;
 //
 //   /* Enforce constraints */
 //   return TRUE;  /* Note that we exited early if check_only is FALSE; also,
 //                  * we know we can return TRUE here because we exited early
 //                  * if the constraint could not be satisfied; not that the
 //                  * return value is heeded in this case...
 //                  */
 // }
#endif

typedef enum
{
  PRIORITY_MINIMUM = 0, /* Dummy value used for loop start = min(all priorities) */
  PRIORITY_ASPECT_RATIO = 0,
  PRIORITY_ENTIRELY_VISIBLE_ON_SINGLE_XINERAMA = 0,
  PRIORITY_ENTIRELY_VISIBLE_ON_WORKAREA = 1,
  PRIORITY_SIZE_HINTS_INCREMENTS = 1,
  PRIORITY_MAXIMIZATION = 2,
  PRIORITY_TILING = 2,
  PRIORITY_FULLSCREEN = 2,
  PRIORITY_SIZE_HINTS_LIMITS = 3,
  PRIORITY_TITLEBAR_VISIBLE = 4,
  PRIORITY_PARTIALLY_VISIBLE_ON_WORKAREA = 4,
  PRIORITY_MAXIMUM = 4 /* Dummy value used for loop end = max(all priorities) */
} ConstraintPriority;

typedef enum
{
  ACTION_MOVE,
  ACTION_RESIZE,
  ACTION_MOVE_AND_RESIZE
} ActionType;

typedef struct
{
  MetaRectangle        orig;
  MetaRectangle        current;
  MetaFrameGeometry   *fgeom;
  ActionType           action_type;
  gboolean             is_user_action;

  /* I know that these two things probably look similar at first, but they
   * have much different uses.  See doc/how-constraints-works.txt for for
   * explanation of the differences and similarity between resize_gravity
   * and fixed_directions
   */
  int                  resize_gravity;
  FixedDirections      fixed_directions;

  /* work_area_xinerama - current xinerama region minus struts
   * entire_xinerama    - current xienrama, including strut regions
   */
  MetaRectangle        work_area_xinerama;
  MetaRectangle        entire_xinerama;

  /* Spanning rectangles for the non-covered (by struts) region of the
   * screen and also for just the current xinerama
   */
  GList  *usable_screen_region;
  GList  *usable_xinerama_region;
} ConstraintInfo;

static gboolean constrain_maximization       (MetaWindow         *window,
                                              ConstraintInfo     *info,
                                              ConstraintPriority  priority,
                                              gboolean            check_only);
static gboolean constrain_tiling             (MetaWindow         *window,
                                              ConstraintInfo     *info,
                                              ConstraintPriority  priority,
                                              gboolean            check_only);
static gboolean constrain_fullscreen         (MetaWindow         *window,
                                              ConstraintInfo     *info,
                                              ConstraintPriority  priority,
                                              gboolean            check_only);
static gboolean constrain_size_increments    (MetaWindow         *window,
                                              ConstraintInfo     *info,
                                              ConstraintPriority  priority,
                                              gboolean            check_only);
static gboolean constrain_size_limits        (MetaWindow         *window,
                                              ConstraintInfo     *info,
                                              ConstraintPriority  priority,
                                              gboolean            check_only);
static gboolean constrain_aspect_ratio       (MetaWindow         *window,
                                              ConstraintInfo     *info,
                                              ConstraintPriority  priority,
                                              gboolean            check_only);
static gboolean constrain_to_single_xinerama (MetaWindow         *window,
                                              ConstraintInfo     *info,
                                              ConstraintPriority  priority,
                                              gboolean            check_only);
static gboolean constrain_fully_onscreen     (MetaWindow         *window,
                                              ConstraintInfo     *info,
                                              ConstraintPriority  priority,
                                              gboolean            check_only);
static gboolean constrain_titlebar_visible   (MetaWindow         *window,
                                              ConstraintInfo     *info,
                                              ConstraintPriority  priority,
                                              gboolean            check_only);
static gboolean constrain_partially_onscreen (MetaWindow         *window,
                                              ConstraintInfo     *info,
                                              ConstraintPriority  priority,
                                              gboolean            check_only);

static void setup_constraint_info        (ConstraintInfo      *info,
                                          MetaWindow          *window,
                                          MetaFrameGeometry   *orig_fgeom,
                                          MetaMoveResizeFlags  flags,
                                          int                  resize_gravity,
                                          const MetaRectangle *orig,
                                          MetaRectangle       *new);
static void place_window_if_needed       (MetaWindow     *window,
                                          ConstraintInfo *info);
static void update_onscreen_requirements (MetaWindow     *window,
                                          ConstraintInfo *info);
static void extend_by_frame              (MetaRectangle           *rect,
                                          const MetaFrameGeometry *fgeom);
static void unextend_by_frame            (MetaRectangle           *rect,
                                          const MetaFrameGeometry *fgeom);
static inline void get_size_limits       (const MetaWindow        *window,
                                          const MetaFrameGeometry *fgeom,
                                          gboolean include_frame,
                                          MetaRectangle *min_size,
                                          MetaRectangle *max_size);

typedef gboolean (* ConstraintFunc) (MetaWindow         *window,
                                     ConstraintInfo     *info,
                                     ConstraintPriority  priority,
                                     gboolean            check_only);

typedef struct {
  ConstraintFunc func;
  const char* name;
} Constraint;

static const Constraint all_constraints[] = {
  {constrain_maximization,       "constrain_maximization"},
  {constrain_tiling,             "constrain_tiling"},
  {constrain_fullscreen,         "constrain_fullscreen"},
  {constrain_size_increments,    "constrain_size_increments"},
  {constrain_size_limits,        "constrain_size_limits"},
  {constrain_aspect_ratio,       "constrain_aspect_ratio"},
  {constrain_to_single_xinerama, "constrain_to_single_xinerama"},
  {constrain_fully_onscreen,     "constrain_fully_onscreen"},
  {constrain_titlebar_visible,   "constrain_titlebar_visible"},
  {constrain_partially_onscreen, "constrain_partially_onscreen"},
  {NULL,                         NULL}
};

static gboolean
do_all_constraints (MetaWindow         *window,
                    ConstraintInfo     *info,
                    ConstraintPriority  priority,
                    gboolean            check_only)
{
  const Constraint *constraint;
  gboolean          satisfied;

  constraint = &all_constraints[0];
  satisfied = TRUE;
  while (constraint->func != NULL)
    {
      satisfied = satisfied &&
                  (*constraint->func) (window, info, priority, check_only);

      if (!check_only)
        {
          /* Log how the constraint modified the position */
          meta_topic (META_DEBUG_GEOMETRY,
                      "info->current is %d,%d +%d,%d after %s\n",
                      info->current.x, info->current.y, 
                      info->current.width, info->current.height,
                      constraint->name);
        }
      else if (!satisfied)
        {
          /* Log which constraint was not satisfied */
          meta_topic (META_DEBUG_GEOMETRY,
                      "constraint %s not satisfied.\n",
                      constraint->name);
          return FALSE;
        }
      ++constraint;
    }

  return TRUE;
}

void
meta_window_constrain (MetaWindow          *window,
                       MetaFrameGeometry   *orig_fgeom,
                       MetaMoveResizeFlags  flags,
                       int                  resize_gravity,
                       const MetaRectangle *orig,
                       MetaRectangle       *new)
{
  ConstraintInfo info;
  ConstraintPriority priority = PRIORITY_MINIMUM;
  gboolean satisfied = FALSE;

  /* WARNING: orig and new specify positions and sizes of the inner window,
   * not the outer.  This is a common gotcha since half the constraints
   * deal with inner window position/size and half deal with outer.  See
   * doc/how-constraints-works.txt for more information.
   */
  meta_topic (META_DEBUG_GEOMETRY,
              "Constraining %s in move from %d,%d %dx%d to %d,%d %dx%d\n",
              window->desc,
              orig->x, orig->y, orig->width, orig->height,
              new->x,  new->y,  new->width,  new->height);

  setup_constraint_info (&info,
                         window, 
                         orig_fgeom, 
                         flags,
                         resize_gravity,
                         orig,
                         new);
  place_window_if_needed (window, &info);

  while (!satisfied && priority <= PRIORITY_MAXIMUM) {
    gboolean check_only = TRUE;

    /* Individually enforce all the high-enough priority constraints */
    do_all_constraints (window, &info, priority, !check_only);

    /* Check if all high-enough priority constraints are simultaneously 
     * satisfied
     */
    satisfied = do_all_constraints (window, &info, priority, check_only);

    /* Drop the least important constraints if we can't satisfy them all */
    priority++;
  }

  /* Make sure we use the constrained position */
  *new = info.current;

  /* We may need to update window->require_fully_onscreen,
   * window->require_on_single_xinerama, and perhaps other quantities
   * if this was a user move or user move-and-resize operation.
   */
  update_onscreen_requirements (window, &info);

  /* Ew, what an ugly way to do things.  Destructors (in a real OOP language,
   * not gobject-style--gobject would be more pain than it's worth) or
   * smart pointers would be so much nicer here.  *shrug*
   */
  if (!orig_fgeom)
    g_free (info.fgeom);
}

static void
setup_constraint_info (ConstraintInfo      *info,
                       MetaWindow          *window,
                       MetaFrameGeometry   *orig_fgeom,
                       MetaMoveResizeFlags  flags,
                       int                  resize_gravity,
                       const MetaRectangle *orig,
                       MetaRectangle       *new)
{
  const MetaXineramaScreenInfo *xinerama_info;
  MetaWorkspace *cur_workspace;

  info->orig    = *orig;
  info->current = *new;

  /* Create a fake frame geometry if none really exists */
  if (orig_fgeom && !window->fullscreen)
    info->fgeom = orig_fgeom;
  else
    info->fgeom = g_new0 (MetaFrameGeometry, 1);

  if (flags & META_IS_MOVE_ACTION && flags & META_IS_RESIZE_ACTION)
    info->action_type = ACTION_MOVE_AND_RESIZE;
  else if (flags & META_IS_RESIZE_ACTION)
    info->action_type = ACTION_RESIZE;
  else if (flags & META_IS_MOVE_ACTION)
    info->action_type = ACTION_MOVE;
  else
    g_error ("BAD, BAD developer!  No treat for you!  (Fix your calls to "
             "meta_window_move_resize_internal()).\n");

  info->is_user_action = (flags & META_IS_USER_ACTION);

  info->resize_gravity = resize_gravity;

  /* FIXME: fixed_directions might be more sane if we (a) made it
   * depend on the grab_op type instead of current amount of movement
   * (thus implying that it only has effect when user_action is true,
   * and (b) ignored it for aspect ratio windows -- at least in those
   * cases where both directions do actually change size.
   */
  info->fixed_directions = FIXED_DIRECTION_NONE;
  /* If x directions don't change but either y direction does */
  if ( orig->x == new->x && orig->x + orig->width  == new->x + new->width   &&
      (orig->y != new->y || orig->y + orig->height != new->y + new->height))
    {
      info->fixed_directions = FIXED_DIRECTION_X;
    }
  /* If y directions don't change but either x direction does */
  if ( orig->y == new->y && orig->y + orig->height == new->y + new->height  &&
      (orig->x != new->x || orig->x + orig->width  != new->x + new->width ))
    {
      info->fixed_directions = FIXED_DIRECTION_Y;
    }
  /* The point of fixed directions is just that "move to nearest valid
   * position" is sometimes a poorer choice than "move to nearest
   * valid position but only change this coordinate" for windows the
   * user is explicitly moving.  This isn't ever true for things that
   * aren't explicit user interaction, though, so just clear it out.
   */
  if (!info->is_user_action)
    info->fixed_directions = FIXED_DIRECTION_NONE;

  xinerama_info =
    meta_screen_get_xinerama_for_rect (window->screen, &info->current);
  meta_window_get_work_area_for_xinerama (window,
                                          xinerama_info->number,
                                          &info->work_area_xinerama);

  if (!window->fullscreen || window->fullscreen_monitors[0] == -1)
    {
      info->entire_xinerama = xinerama_info->rect;
    }
  else
    {
      int i = 0;
      long monitor;

      monitor = window->fullscreen_monitors[i];
      info->entire_xinerama =
        window->screen->xinerama_infos[monitor].rect;
      for (i = 1; i <= 3; i++)
        {
          monitor = window->fullscreen_monitors[i];
          meta_rectangle_union (&info->entire_xinerama,
                                &window->screen->xinerama_infos[monitor].rect,
                                &info->entire_xinerama);
        }
    }

  cur_workspace = window->screen->active_workspace;
  info->usable_screen_region   = 
    meta_workspace_get_onscreen_region (cur_workspace);
  info->usable_xinerama_region = 
    meta_workspace_get_onxinerama_region (cur_workspace, 
                                          xinerama_info->number);

  /* Workaround braindead legacy apps that don't know how to
   * fullscreen themselves properly - don't get fooled by
   * windows which hide their titlebar when maximized or which are
   * client decorated; that's not the same as fullscreen, even
   * if there are no struts making the workarea smaller than
   * the monitor.
   */

  if (meta_prefs_get_force_fullscreen() &&
      window->decorated &&
      meta_rectangle_equal (new, &xinerama_info->rect) &&
      window->has_fullscreen_func &&
      !window->fullscreen)
    {
      /*
      meta_topic (META_DEBUG_GEOMETRY,
      */
      meta_warning (
                  "Treating resize request of legacy application %s as a "
                  "fullscreen request\n",
                  window->desc);
      meta_window_make_fullscreen_internal (window);
    }

  /* Log all this information for debugging */
  meta_topic (META_DEBUG_GEOMETRY,
              "Setting up constraint info:\n"
              "  orig: %d,%d +%d,%d\n"
              "  new : %d,%d +%d,%d\n"
              "  fgeom: %d,%d,%d,%d\n"
              "  action_type     : %s\n"
              "  is_user_action  : %s\n"
              "  resize_gravity  : %s\n"
              "  fixed_directions: %s\n"
              "  work_area_xinerama: %d,%d +%d,%d\n"
              "  entire_xinerama   : %d,%d +%d,%d\n",
              info->orig.x, info->orig.y, info->orig.width, info->orig.height,
              info->current.x, info->current.y, 
                info->current.width, info->current.height,
              info->fgeom->left_width, info->fgeom->right_width,
                info->fgeom->top_height, info->fgeom->bottom_height,
              (info->action_type == ACTION_MOVE) ? "Move" :
                (info->action_type == ACTION_RESIZE) ? "Resize" :
                (info->action_type == ACTION_MOVE_AND_RESIZE) ? "Move&Resize" :
                "Freakin' Invalid Stupid",
              (info->is_user_action) ? "true" : "false",
              meta_gravity_to_string (info->resize_gravity),
              (info->fixed_directions == FIXED_DIRECTION_NONE) ? "None" :
                (info->fixed_directions == FIXED_DIRECTION_X) ? "X fixed" :
                (info->fixed_directions == FIXED_DIRECTION_Y) ? "Y fixed" :
                "Freakin' Invalid Stupid",
              info->work_area_xinerama.x, info->work_area_xinerama.y,
                info->work_area_xinerama.width, 
                info->work_area_xinerama.height,
              info->entire_xinerama.x, info->entire_xinerama.y,
                info->entire_xinerama.width, info->entire_xinerama.height);
}

static void
place_window_if_needed(MetaWindow     *window,
                       ConstraintInfo *info)
{
  gboolean did_placement;

  /* Do placement if any, so we go ahead and apply position
   * constraints in a move-only context. Don't place
   * maximized/minimized/fullscreen windows until they are
   * unmaximized, unminimized and unfullscreened.
   */
  did_placement = FALSE;
  if (!window->placed &&
      window->calc_placement &&
      !(window->maximized_horizontally ||
        window->maximized_vertically) &&
      !window->minimized &&
      !window->fullscreen)
    {
      MetaRectangle placed_rect = info->orig;
      MetaWorkspace *cur_workspace;
      const MetaXineramaScreenInfo *xinerama_info;

      meta_window_place (window, info->fgeom, info->orig.x, info->orig.y,
                         &placed_rect.x, &placed_rect.y);
      did_placement = TRUE;

      /* placing the window may have changed the xinerama.  Find the
       * new xinerama and update the ConstraintInfo
       */
      xinerama_info =
        meta_screen_get_xinerama_for_rect (window->screen, &placed_rect);
      info->entire_xinerama = xinerama_info->rect;
      meta_window_get_work_area_for_xinerama (window,
                                              xinerama_info->number,
                                              &info->work_area_xinerama);
      cur_workspace = window->screen->active_workspace;
      info->usable_xinerama_region = 
        meta_workspace_get_onxinerama_region (cur_workspace, 
                                              xinerama_info->number);


      info->current.x = placed_rect.x;
      info->current.y = placed_rect.y;

      /* Since we just barely placed the window, there's no reason to
       * consider any of the directions fixed.
       */
      info->fixed_directions = FIXED_DIRECTION_NONE;
    }

  if (window->placed || did_placement)
    {
      if (window->maximize_horizontally_after_placement ||
          window->maximize_vertically_after_placement   ||
          window->fullscreen_after_placement)
        {
          /* define a sane saved_rect so that the user can unmaximize or
           * make unfullscreen to something reasonable.
           */
          if (info->current.width >= info->work_area_xinerama.width)
            {
              info->current.width = .75 * info->work_area_xinerama.width;
              info->current.x = info->work_area_xinerama.x +
                       .125 * info->work_area_xinerama.width;
            }
          if (info->current.height >= info->work_area_xinerama.height)
            {
              info->current.height = .75 * info->work_area_xinerama.height;
              info->current.y = info->work_area_xinerama.y +
                       .083 * info->work_area_xinerama.height;
            }

          if (window->maximize_horizontally_after_placement ||
              window->maximize_vertically_after_placement)
            meta_window_maximize_internal (window,   
                (window->maximize_horizontally_after_placement ?
                 META_MAXIMIZE_HORIZONTAL : 0 ) |
                (window->maximize_vertically_after_placement ?
                 META_MAXIMIZE_VERTICAL : 0), &info->current);

          /* maximization may have changed frame geometry */
          if (window->frame && !window->fullscreen)
            meta_frame_calc_geometry (window->frame, info->fgeom);

          if (window->fullscreen_after_placement)
            {
              window->saved_rect = info->current;
              window->fullscreen = TRUE;
              window->fullscreen_after_placement = FALSE;
            }

          window->maximize_horizontally_after_placement = FALSE;
          window->maximize_vertically_after_placement = FALSE;
        }
      if (window->minimize_after_placement)
        {
          meta_window_minimize (window);
          window->minimize_after_placement = FALSE;
        }
    }
}

static void
update_onscreen_requirements (MetaWindow     *window,
                              ConstraintInfo *info)
{
  gboolean old;

  /* We only apply the various onscreen requirements to normal windows */
  if (window->type == META_WINDOW_DESKTOP ||
      window->type == META_WINDOW_DOCK)
    return;

  /* We don't want to update the requirements for fullscreen windows;
   * fullscreen windows are specially handled anyway, and it updating
   * the requirements when windows enter fullscreen mode mess up the
   * handling of the window when it leaves that mode (especially when
   * the application sends a bunch of configurerequest events).  See
   * #353699.
   */
  if (window->fullscreen)
    return;

  /* USABILITY NOTE: Naturally, I only want the require_fully_onscreen,
   * require_on_single_xinerama, and require_titlebar_visible flags to
   * *become false* due to user interactions (which is allowed since
   * certain constraints are ignored for user interactions regardless of
   * the setting of these flags).  However, whether to make these flags
   * *become true* due to just an application interaction is a little
   * trickier.  It's possible that users may find not doing that strange
   * since two application interactions that resize in opposite ways don't
   * necessarily end up cancelling--but it may also be strange for the user
   * to have an application resize the window so that it's onscreen, the
   * user forgets about it, and then later the app is able to resize itself
   * off the screen.  Anyway, for now, I think the latter is the more
   * problematic case but this may need to be revisited.
   */

  /* The require onscreen/on-single-xinerama and titlebar_visible
   * stuff is relative to the outer window, not the inner
   */
  extend_by_frame (&info->current, info->fgeom);

  /* Update whether we want future constraint runs to require the
   * window to be on fully onscreen.
   */
  old = window->require_fully_onscreen;
  window->require_fully_onscreen =
    meta_rectangle_contained_in_region (info->usable_screen_region,
                                        &info->current);
  if (old ^ window->require_fully_onscreen)
    meta_topic (META_DEBUG_GEOMETRY,
                "require_fully_onscreen for %s toggled to %s\n",
                window->desc,
                window->require_fully_onscreen ? "TRUE" : "FALSE");

  /* Update whether we want future constraint runs to require the
   * window to be on a single xinerama.
   */
  old = window->require_on_single_xinerama;
  window->require_on_single_xinerama =
    meta_rectangle_contained_in_region (info->usable_xinerama_region,
                                        &info->current);
  if (old ^ window->require_on_single_xinerama)
    meta_topic (META_DEBUG_GEOMETRY,
                "require_on_single_xinerama for %s toggled to %s\n",
                window->desc, 
                window->require_on_single_xinerama ? "TRUE" : "FALSE");

  /* Update whether we want future constraint runs to require the
   * titlebar to be visible.
   */
  if (window->frame && window->decorated)
    {
      MetaRectangle titlebar_rect;

      titlebar_rect = info->current;
      titlebar_rect.height = info->fgeom->top_height;
      old = window->require_titlebar_visible;
      window->require_titlebar_visible =
        meta_rectangle_overlaps_with_region (info->usable_screen_region,
                                             &titlebar_rect);
      if (old ^ window->require_titlebar_visible)
        meta_topic (META_DEBUG_GEOMETRY,
                    "require_titlebar_visible for %s toggled to %s\n",
                    window->desc,
                    window->require_titlebar_visible ? "TRUE" : "FALSE");
    }

  /* Don't forget to restore the position of the window */
  unextend_by_frame (&info->current, info->fgeom);
}

static void
extend_by_frame (MetaRectangle           *rect,
                 const MetaFrameGeometry *fgeom)
{
  rect->x -= fgeom->left_width;
  rect->y -= fgeom->top_height;
  rect->width  += fgeom->left_width + fgeom->right_width;
  rect->height += fgeom->top_height + fgeom->bottom_height;
}

static void
unextend_by_frame (MetaRectangle           *rect,
                   const MetaFrameGeometry *fgeom)
{
  rect->x += fgeom->left_width;
  rect->y += fgeom->top_height;
  rect->width  -= fgeom->left_width + fgeom->right_width;
  rect->height -= fgeom->top_height + fgeom->bottom_height;
}

static inline void
get_size_limits (const MetaWindow        *window,
                 const MetaFrameGeometry *fgeom,
                 gboolean                 include_frame,
                 MetaRectangle *min_size,
                 MetaRectangle *max_size)
{
  /* We pack the results into MetaRectangle structs just for convienience; we
   * don't actually use the position of those rects.
   */
  min_size->width  = window->size_hints.min_width;
  min_size->height = window->size_hints.min_height;
  max_size->width  = window->size_hints.max_width;
  max_size->height = window->size_hints.max_height;

  if (include_frame)
    {
      int fw = fgeom->left_width + fgeom->right_width;
      int fh = fgeom->top_height + fgeom->bottom_height;

      min_size->width  += fw;
      min_size->height += fh;
      max_size->width  += fw;
      max_size->height += fh;
    }
}

static gboolean
constrain_maximization (MetaWindow         *window,
                        ConstraintInfo     *info,
                        ConstraintPriority  priority,
                        gboolean            check_only)
{
  MetaRectangle target_size;
  MetaRectangle min_size, max_size;
  gboolean hminbad, vminbad;
  gboolean horiz_equal, vert_equal;
  gboolean constraint_already_satisfied;

  if (priority > PRIORITY_MAXIMIZATION)
    return TRUE;

  /* Determine whether constraint applies; exit if it doesn't */
  if ((!window->maximized_horizontally && !window->maximized_vertically) ||
      META_WINDOW_TILED (window))
    return TRUE;

  /* Calculate target_size = maximized size of (window + frame) */
  if (window->maximized_horizontally && window->maximized_vertically)
    target_size = info->work_area_xinerama;
  else
    {
      /* Amount of maximization possible in a single direction depends
       * on which struts could occlude the window given its current
       * position.  For example, a vertical partial strut on the right
       * is only relevant for a horizontally maximized window when the
       * window is at a vertical position where it could be occluded
       * by that partial strut.
       */
      MetaDirection  direction;
      GSList        *active_workspace_struts;

      if (window->maximized_horizontally)
        direction = META_DIRECTION_HORIZONTAL;
      else
        direction = META_DIRECTION_VERTICAL;
      active_workspace_struts = window->screen->active_workspace->all_struts;

      target_size = info->current;
      extend_by_frame (&target_size, info->fgeom);
      meta_rectangle_expand_to_avoiding_struts (&target_size,
                                                &info->entire_xinerama,
                                                direction,
                                                active_workspace_struts);
   }
  /* Now make target_size = maximized size of client window */
  unextend_by_frame (&target_size, info->fgeom);

  /* Check min size constraints; max size constraints are ignored for maximized
   * windows, as per bug 327543.
   */
  get_size_limits (window, info->fgeom, FALSE, &min_size, &max_size);
  hminbad = target_size.width < min_size.width && window->maximized_horizontally;
  vminbad = target_size.height < min_size.height && window->maximized_vertically;
  if (hminbad || vminbad)
    return TRUE;

  /* Determine whether constraint is already satisfied; exit if it is */
  horiz_equal = target_size.x      == info->current.x &&
                target_size.width  == info->current.width;
  vert_equal  = target_size.y      == info->current.y &&
                target_size.height == info->current.height;
  constraint_already_satisfied =
    (horiz_equal || !window->maximized_horizontally) &&
    (vert_equal  || !window->maximized_vertically);
  if (check_only || constraint_already_satisfied)
    return constraint_already_satisfied;

  /*** Enforce constraint ***/
  if (window->maximized_horizontally)
    {
      info->current.x      = target_size.x;
      info->current.width  = target_size.width;
    }
  if (window->maximized_vertically)
    {
      info->current.y      = target_size.y;
      info->current.height = target_size.height;
    }
  return TRUE;
}

static gboolean
constrain_tiling (MetaWindow         *window,
                  ConstraintInfo     *info,
                  ConstraintPriority  priority,
                  gboolean            check_only)
{
  MetaRectangle target_size;
  MetaRectangle min_size, max_size;
  gboolean hminbad, vminbad;
  gboolean horiz_equal, vert_equal;
  gboolean constraint_already_satisfied;

  if (priority > PRIORITY_TILING)
    return TRUE;

  /* Determine whether constraint applies; exit if it doesn't */
  if (!META_WINDOW_TILED (window))
    return TRUE;

  /* Calculate target_size - as the tile previews need this as well, we
   * use an external function for the actual calculation
   */
  meta_window_get_current_tile_area (window, &target_size);
  unextend_by_frame (&target_size, info->fgeom);

  /* Check min size constraints; max size constraints are ignored as for
   * maximized windows.
   */
  get_size_limits (window, info->fgeom, FALSE, &min_size, &max_size);
  hminbad = target_size.width < min_size.width;
  vminbad = target_size.height < min_size.height;
  if (hminbad || vminbad)
    return TRUE;

  /* Determine whether constraint is already satisfied; exit if it is */
  horiz_equal = target_size.x      == info->current.x &&
                target_size.width  == info->current.width;
  vert_equal  = target_size.y      == info->current.y &&
                target_size.height == info->current.height;
  constraint_already_satisfied = horiz_equal && vert_equal;
  if (check_only || constraint_already_satisfied)
    return constraint_already_satisfied;

  /*** Enforce constraint ***/
  info->current.x      = target_size.x;
  info->current.width  = target_size.width;
  info->current.y      = target_size.y;
  info->current.height = target_size.height;

  return TRUE;
}

static gboolean
constrain_fullscreen (MetaWindow         *window,
                      ConstraintInfo     *info,
                      ConstraintPriority  priority,
                      gboolean            check_only)
{
  MetaRectangle min_size, max_size, xinerama;
  gboolean too_big, too_small, constraint_already_satisfied;

  if (priority > PRIORITY_FULLSCREEN)
    return TRUE;

  /* Determine whether constraint applies; exit if it doesn't */
  if (!window->fullscreen)
    return TRUE;

  xinerama = info->entire_xinerama;

  get_size_limits (window, info->fgeom, FALSE, &min_size, &max_size);
  too_big =   !meta_rectangle_could_fit_rect (&xinerama, &min_size);
  too_small = !meta_rectangle_could_fit_rect (&max_size, &xinerama);
  if (too_big || too_small)
    return TRUE;

  /* Determine whether constraint is already satisfied; exit if it is */
  constraint_already_satisfied =
    meta_rectangle_equal (&info->current, &xinerama);
  if (check_only || constraint_already_satisfied)
    return constraint_already_satisfied;

  /*** Enforce constraint ***/
  info->current = xinerama;
  return TRUE;
}

static gboolean
constrain_size_increments (MetaWindow         *window,
                           ConstraintInfo     *info,
                           ConstraintPriority  priority,
                           gboolean            check_only)
{
  int bh, hi, bw, wi, extra_height, extra_width;
  int new_width, new_height;
  gboolean constraint_already_satisfied;
  MetaRectangle *start_rect;

  if (priority > PRIORITY_SIZE_HINTS_INCREMENTS)
    return TRUE;

  /* Determine whether constraint applies; exit if it doesn't */
  if (META_WINDOW_MAXIMIZED (window) || window->fullscreen || 
      META_WINDOW_TILED (window) || info->action_type == ACTION_MOVE)
    return TRUE;

  /* Determine whether constraint is already satisfied; exit if it is */
  bh = window->size_hints.base_height;
  hi = window->size_hints.height_inc;
  bw = window->size_hints.base_width;
  wi = window->size_hints.width_inc;
  extra_height = (info->current.height - bh) % hi;
  extra_width  = (info->current.width  - bw) % wi;
  /* ignore size increments for maximized windows */
  if (window->maximized_horizontally)
    extra_width *= 0;
  if (window->maximized_vertically)
    extra_height *= 0;
  /* constraint is satisfied iff there is no extra height or width */
  constraint_already_satisfied = 
    (extra_height == 0 && extra_width == 0);

  if (check_only || constraint_already_satisfied)
    return constraint_already_satisfied;

  /*** Enforce constraint ***/
  new_width  = info->current.width  - extra_width;
  new_height = info->current.height - extra_height;

  /* Adjusting down instead of up (as done in the above two lines) may
   * violate minimum size constraints; fix the adjustment if this
   * happens.
   */
  if (new_width  < window->size_hints.min_width)
    new_width  += ((window->size_hints.min_width  - new_width)/wi  + 1)*wi;
  if (new_height < window->size_hints.min_height)
    new_height += ((window->size_hints.min_height - new_height)/hi + 1)*hi;

  /* Figure out what original rect to pass to meta_rectangle_resize_with_gravity
   * See bug 448183
   */
  if (info->action_type == ACTION_MOVE_AND_RESIZE)
    start_rect = &info->current;
  else
    start_rect = &info->orig;
    
  /* Resize to the new size */
  meta_rectangle_resize_with_gravity (start_rect,
                                      &info->current, 
                                      info->resize_gravity,
                                      new_width,
                                      new_height);
  return TRUE;
}

static gboolean
constrain_size_limits (MetaWindow         *window,
                       ConstraintInfo     *info,
                       ConstraintPriority  priority,
                       gboolean            check_only)
{
  MetaRectangle min_size, max_size;
  gboolean too_big, too_small, constraint_already_satisfied;
  int new_width, new_height;
  MetaRectangle *start_rect;

  if (priority > PRIORITY_SIZE_HINTS_LIMITS)
    return TRUE;

  /* Determine whether constraint applies; exit if it doesn't.
   *
   * Note: The old code didn't apply this constraint for fullscreen or
   * maximized windows--but that seems odd to me.  *shrug*
   */
  if (info->action_type == ACTION_MOVE)
    return TRUE;

  /* Determine whether constraint is already satisfied; exit if it is */
  get_size_limits (window, info->fgeom, FALSE, &min_size, &max_size);
  /* We ignore max-size limits for maximized windows; see #327543 */
  if (window->maximized_horizontally)
    max_size.width = MAX (max_size.width, info->current.width);
  if (window->maximized_vertically)
    max_size.height = MAX (max_size.height, info->current.height);
  too_small = !meta_rectangle_could_fit_rect (&info->current, &min_size);
  too_big   = !meta_rectangle_could_fit_rect (&max_size, &info->current);
  constraint_already_satisfied = !too_big && !too_small;
  if (check_only || constraint_already_satisfied)
    return constraint_already_satisfied;

  /*** Enforce constraint ***/
  new_width  = CLAMP (info->current.width,  min_size.width,  max_size.width);
  new_height = CLAMP (info->current.height, min_size.height, max_size.height);
  
  /* Figure out what original rect to pass to meta_rectangle_resize_with_gravity
   * See bug 448183
   */
  if (info->action_type == ACTION_MOVE_AND_RESIZE)
    start_rect = &info->current;
  else
    start_rect = &info->orig;
  
  meta_rectangle_resize_with_gravity (start_rect,
                                      &info->current, 
                                      info->resize_gravity,
                                      new_width,
                                      new_height);
  return TRUE;
}

static gboolean
constrain_aspect_ratio (MetaWindow         *window,
                        ConstraintInfo     *info,
                        ConstraintPriority  priority,
                        gboolean            check_only)
{
  double minr, maxr;
  gboolean constraints_are_inconsistent, constraint_already_satisfied;
  int fudge, new_width, new_height;
  double best_width, best_height;
  double alt_width, alt_height;
  MetaRectangle *start_rect;

  if (priority > PRIORITY_ASPECT_RATIO)
    return TRUE;

  /* Determine whether constraint applies; exit if it doesn't. */
  minr =         window->size_hints.min_aspect.x /
         (double)window->size_hints.min_aspect.y;
  maxr =         window->size_hints.max_aspect.x /
         (double)window->size_hints.max_aspect.y;
  constraints_are_inconsistent = minr > maxr;
  if (constraints_are_inconsistent ||
      META_WINDOW_MAXIMIZED (window) || window->fullscreen || 
      META_WINDOW_TILED (window) || info->action_type == ACTION_MOVE)
    return TRUE;

  /* Determine whether constraint is already satisfied; exit if it is.  We
   * need the following to hold:
   *
   *                 width
   *         minr <= ------ <= maxr
   *                 height
   *
   * But we need to allow for some slight fudging since width and height
   * are integers instead of floating point numbers (this is particularly
   * important when minr == maxr), so we allow width and height to be off
   * a little bit from strictly satisfying these equations.  For just one
   * sided resizing, we have to make the fudge factor a little bigger
   * because of how meta_rectangle_resize_with_gravity treats those as
   * being a resize increment (FIXME: I should handle real resize
   * increments better here...)
   */
  switch (info->resize_gravity)
    {
    case WestGravity:
    case NorthGravity:
    case SouthGravity:
    case EastGravity:
      fudge = 2;
      break;

    case NorthWestGravity:
    case SouthWestGravity:
    case CenterGravity:
    case NorthEastGravity:
    case SouthEastGravity:
    case StaticGravity:
    default:
      fudge = 1;
      break;
    }
  constraint_already_satisfied = 
    info->current.width - (info->current.height * minr ) > -minr*fudge &&
    info->current.width - (info->current.height * maxr ) <  maxr*fudge;
  if (check_only || constraint_already_satisfied)
    return constraint_already_satisfied;

  /*** Enforce constraint ***/
  new_width = info->current.width;
  new_height = info->current.height;

  switch (info->resize_gravity)
    {
    case WestGravity:
    case EastGravity:
      /* Yeah, I suck for doing implicit rounding -- sue me */
      new_height = CLAMP (new_height, new_width / maxr,  new_width / minr);
      break;

    case NorthGravity:
    case SouthGravity:
      /* Yeah, I suck for doing implicit rounding -- sue me */
      new_width  = CLAMP (new_width,  new_height * minr, new_height * maxr);
      break;

    case NorthWestGravity:
    case SouthWestGravity:
    case CenterGravity:
    case NorthEastGravity:
    case SouthEastGravity:
    case StaticGravity:
    default:
      /* Find what width would correspond to new_height, and what height would
       * correspond to new_width */
      alt_width  = CLAMP (new_width,  new_height * minr, new_height * maxr);
      alt_height = CLAMP (new_height, new_width / maxr,  new_width / minr);

      /* The line connecting the points (alt_width, new_height) and
       * (new_width, alt_height) provide a range of
       * valid-for-the-aspect-ratio-constraint sizes.  We want the
       * size in that range closest to the value requested, i.e. the
       * point on the line which is closest to the point (new_width,
       * new_height)
       */
      meta_rectangle_find_linepoint_closest_to_point (alt_width, new_height,
                                                      new_width, alt_height,
                                                      new_width, new_height,
                                                      &best_width, &best_height);

      /* Yeah, I suck for doing implicit rounding -- sue me */
      new_width  = best_width;
      new_height = best_height;

      break;
    }

  /* Figure out what original rect to pass to meta_rectangle_resize_with_gravity
   * See bug 448183
   */
  if (info->action_type == ACTION_MOVE_AND_RESIZE)
    start_rect = &info->current;
  else
    start_rect = &info->orig;

  meta_rectangle_resize_with_gravity (start_rect,
                                      &info->current, 
                                      info->resize_gravity,
                                      new_width,
                                      new_height);

  return TRUE;
}

static gboolean
do_screen_and_xinerama_relative_constraints (
  MetaWindow     *window,
  GList          *region_spanning_rectangles,
  ConstraintInfo *info,
  gboolean        check_only)
{
  gboolean exit_early = FALSE, constraint_satisfied;
  MetaRectangle how_far_it_can_be_smushed, min_size, max_size;

#ifdef WITH_VERBOSE_MODE
  if (meta_is_verbose ())
    {
      /* First, log some debugging information */
      char spanning_region[1 + 28 * g_list_length (region_spanning_rectangles)];

      meta_topic (META_DEBUG_GEOMETRY,
             "screen/xinerama constraint; region_spanning_rectangles: %s\n",
             meta_rectangle_region_to_string (region_spanning_rectangles, ", ",
                                              spanning_region));
    }
#endif

  /* Determine whether constraint applies; exit if it doesn't */
  how_far_it_can_be_smushed = info->current;
  get_size_limits (window, info->fgeom, TRUE, &min_size, &max_size);
  extend_by_frame (&info->current, info->fgeom);

  if (info->action_type != ACTION_MOVE)
    {
      if (!(info->fixed_directions & FIXED_DIRECTION_X))
        how_far_it_can_be_smushed.width = min_size.width;

      if (!(info->fixed_directions & FIXED_DIRECTION_Y))
        how_far_it_can_be_smushed.height = min_size.height;
    }
  if (!meta_rectangle_could_fit_in_region (region_spanning_rectangles,
                                           &how_far_it_can_be_smushed))
    exit_early = TRUE;

  /* Determine whether constraint is already satisfied; exit if it is */
  constraint_satisfied = 
    meta_rectangle_contained_in_region (region_spanning_rectangles,
                                        &info->current);
  if (exit_early || constraint_satisfied || check_only)
    {
      unextend_by_frame (&info->current, info->fgeom);
      return constraint_satisfied;
    }

  /* Enforce constraint */

  /* Clamp rectangle size for resize or move+resize actions */
  if (info->action_type != ACTION_MOVE)
    meta_rectangle_clamp_to_fit_into_region (region_spanning_rectangles,
                                             info->fixed_directions,
                                             &info->current,
                                             &min_size);

  if (info->is_user_action && info->action_type == ACTION_RESIZE)
    /* For user resize, clip to the relevant region */
    meta_rectangle_clip_to_region (region_spanning_rectangles,
                                   info->fixed_directions,
                                   &info->current);
  else
    /* For everything else, shove the rectangle into the relevant region */
    meta_rectangle_shove_into_region (region_spanning_rectangles,
                                      info->fixed_directions,
                                      &info->current);

  unextend_by_frame (&info->current, info->fgeom);
  return TRUE;
}

static gboolean
constrain_to_single_xinerama (MetaWindow         *window,
                              ConstraintInfo     *info,
                              ConstraintPriority  priority,
                              gboolean            check_only)
{
  if (priority > PRIORITY_ENTIRELY_VISIBLE_ON_SINGLE_XINERAMA)
    return TRUE;

  /* Exit early if we know the constraint won't apply--note that this constraint
   * is only meant for normal windows (e.g. we don't want docks to be shoved 
   * "onscreen" by their own strut) and we can't apply it to frameless windows
   * or else users will be unable to move windows such as XMMS across xineramas.
   */
  if (window->type == META_WINDOW_DESKTOP   ||
      window->type == META_WINDOW_DOCK      ||
      window->screen->n_xinerama_infos == 1 ||
      !window->require_on_single_xinerama   ||
      !window->frame                        ||
      info->is_user_action)
    return TRUE;

  /* Have a helper function handle the constraint for us */
  return do_screen_and_xinerama_relative_constraints (window, 
                                                 info->usable_xinerama_region,
                                                 info,
                                                 check_only);
}

static gboolean
constrain_fully_onscreen (MetaWindow         *window,
                          ConstraintInfo     *info,
                          ConstraintPriority  priority,
                          gboolean            check_only)
{
  if (priority > PRIORITY_ENTIRELY_VISIBLE_ON_WORKAREA)
    return TRUE;

  /* Exit early if we know the constraint won't apply--note that this constraint
   * is only meant for normal windows (e.g. we don't want docks to be shoved 
   * "onscreen" by their own strut).
   */
  if (window->type == META_WINDOW_DESKTOP ||
      window->type == META_WINDOW_DOCK    ||
      window->fullscreen                  ||
      !window->require_fully_onscreen     || 
      info->is_user_action)
    return TRUE;

  /* Have a helper function handle the constraint for us */
  return do_screen_and_xinerama_relative_constraints (window, 
                                                 info->usable_screen_region,
                                                 info,
                                                 check_only);
}

static gboolean
constrain_titlebar_visible (MetaWindow         *window,
                            ConstraintInfo     *info,
                            ConstraintPriority  priority,
                            gboolean            check_only)
{
  gboolean unconstrained_user_action;
  gboolean retval;
  int bottom_amount;
  int horiz_amount_offscreen, vert_amount_offscreen;
  int horiz_amount_onscreen,  vert_amount_onscreen;

  if (priority > PRIORITY_TITLEBAR_VISIBLE)
    return TRUE;

  /* Allow the titlebar beyond the top of the screen only if the user wasn't
   * clicking on the frame to start the move.
   */
  unconstrained_user_action =
    info->is_user_action && !window->display->grab_frame_action;

  /* Exit early if we know the constraint won't apply--note that this constraint
   * is only meant for normal windows (e.g. we don't want docks to be shoved 
   * "onscreen" by their own strut).
   */
  if (window->type == META_WINDOW_DESKTOP ||
      window->type == META_WINDOW_DOCK    ||
      window->fullscreen                  ||
      !window->require_titlebar_visible   ||
      !window->decorated                  ||
      unconstrained_user_action)
    return TRUE;

  /* Determine how much offscreen things are allowed.  We first need to
   * figure out how much must remain on the screen.  For that, we use 25%
   * window width/height but clamp to the range of (10,75) pixels.  This is
   * somewhat of a seat of my pants random guess at what might look good.
   * Then, the amount that is allowed off is just the window size minus
   * this amount (but no less than 0 for tiny windows).
   */
  horiz_amount_onscreen = info->current.width  / 4;
  vert_amount_onscreen  = info->current.height / 4;
  horiz_amount_onscreen = CLAMP (horiz_amount_onscreen, 10, 75);
  vert_amount_onscreen  = CLAMP (vert_amount_onscreen,  10, 75);
  horiz_amount_offscreen = info->current.width - horiz_amount_onscreen;
  vert_amount_offscreen  = info->current.height - vert_amount_onscreen;
  horiz_amount_offscreen = MAX (horiz_amount_offscreen, 0);
  vert_amount_offscreen  = MAX (vert_amount_offscreen,  0);
  /* Allow the titlebar to touch the bottom panel;  If there is no titlebar,
   * require vert_amount to remain on the screen.
   */
  if (window->frame)
    {
      bottom_amount = info->current.height + info->fgeom->bottom_height;
      vert_amount_onscreen = info->fgeom->top_height;
    }
  else
    bottom_amount = vert_amount_offscreen;

  /* Extend the region, have a helper function handle the constraint,
   * then return the region to its original size.
   */
  meta_rectangle_expand_region_conditionally (info->usable_screen_region,
                                              horiz_amount_offscreen,
                                              horiz_amount_offscreen, 
                                              0, /* Don't let titlebar off */
                                              bottom_amount,
                                              horiz_amount_onscreen,
                                              vert_amount_onscreen);
  retval =
    do_screen_and_xinerama_relative_constraints (window, 
                                                 info->usable_screen_region,
                                                 info,
                                                 check_only);
  meta_rectangle_expand_region_conditionally (info->usable_screen_region,
                                              -horiz_amount_offscreen,
                                              -horiz_amount_offscreen,
                                              0, /* Don't let titlebar off */
                                              -bottom_amount,
                                              horiz_amount_onscreen,
                                              vert_amount_onscreen);

  return retval;
}

static gboolean
constrain_partially_onscreen (MetaWindow         *window,
                              ConstraintInfo     *info,
                              ConstraintPriority  priority,
                              gboolean            check_only)
{
  gboolean retval;
  int top_amount, bottom_amount;
  int horiz_amount_offscreen, vert_amount_offscreen;
  int horiz_amount_onscreen,  vert_amount_onscreen;

  if (priority > PRIORITY_PARTIALLY_VISIBLE_ON_WORKAREA)
    return TRUE;

  /* Exit early if we know the constraint won't apply--note that this constraint
   * is only meant for normal windows (e.g. we don't want docks to be shoved 
   * "onscreen" by their own strut).
   */
  if (window->type == META_WINDOW_DESKTOP ||
      window->type == META_WINDOW_DOCK)
    return TRUE;

  /* Determine how much offscreen things are allowed.  We first need to
   * figure out how much must remain on the screen.  For that, we use 25%
   * window width/height but clamp to the range of (10,75) pixels.  This is
   * somewhat of a seat of my pants random guess at what might look good.
   * Then, the amount that is allowed off is just the window size minus
   * this amount (but no less than 0 for tiny windows).
   */
  horiz_amount_onscreen = info->current.width  / 4;
  vert_amount_onscreen  = info->current.height / 4;
  horiz_amount_onscreen = CLAMP (horiz_amount_onscreen, 10, 75);
  vert_amount_onscreen  = CLAMP (vert_amount_onscreen,  10, 75);
  horiz_amount_offscreen = info->current.width - horiz_amount_onscreen;
  vert_amount_offscreen  = info->current.height - vert_amount_onscreen;
  horiz_amount_offscreen = MAX (horiz_amount_offscreen, 0);
  vert_amount_offscreen  = MAX (vert_amount_offscreen,  0);
  top_amount = vert_amount_offscreen;
  /* Allow the titlebar to touch the bottom panel;  If there is no titlebar,
   * require vert_amount to remain on the screen.
   */
  if (window->frame)
    {
      bottom_amount = info->current.height + info->fgeom->bottom_height;
      vert_amount_onscreen = info->fgeom->top_height;
    }
  else
    bottom_amount = vert_amount_offscreen;

  /* Extend the region, have a helper function handle the constraint,
   * then return the region to its original size.
   */
  meta_rectangle_expand_region_conditionally (info->usable_screen_region,
                                              horiz_amount_offscreen,
                                              horiz_amount_offscreen, 
                                              top_amount,
                                              bottom_amount,
                                              horiz_amount_onscreen,
                                              vert_amount_onscreen);
  retval =
    do_screen_and_xinerama_relative_constraints (window, 
                                                 info->usable_screen_region,
                                                 info,
                                                 check_only);
  meta_rectangle_expand_region_conditionally (info->usable_screen_region,
                                              -horiz_amount_offscreen,
                                              -horiz_amount_offscreen,
                                              -top_amount,
                                              -bottom_amount,
                                              horiz_amount_onscreen,
                                              vert_amount_onscreen);

  return retval;
}