summaryrefslogtreecommitdiffstats
path: root/layout/xul/nsSliderFrame.cpp
blob: db2218944287a804393d5440d084d5832642b37b (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
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

//
// Eric Vaughan
// Netscape Communications
//
// See documentation in associated header file
//

#include "nsSliderFrame.h"

#include "gfxPrefs.h"
#include "nsStyleContext.h"
#include "nsPresContext.h"
#include "nsIContent.h"
#include "nsCOMPtr.h"
#include "nsNameSpaceManager.h"
#include "nsGkAtoms.h"
#include "nsHTMLParts.h"
#include "nsIPresShell.h"
#include "nsCSSRendering.h"
#include "nsIDOMEvent.h"
#include "nsIDOMMouseEvent.h"
#include "nsScrollbarButtonFrame.h"
#include "nsISliderListener.h"
#include "nsIScrollableFrame.h"
#include "nsIScrollbarMediator.h"
#include "nsISupportsImpl.h"
#include "nsScrollbarFrame.h"
#include "nsRepeatService.h"
#include "nsBoxLayoutState.h"
#include "nsSprocketLayout.h"
#include "nsIServiceManager.h"
#include "nsContentUtils.h"
#include "nsLayoutUtils.h"
#include "nsDisplayList.h"
#include "mozilla/Assertions.h"         // for MOZ_ASSERT
#include "mozilla/Preferences.h"
#include "mozilla/LookAndFeel.h"
#include "mozilla/MouseEvents.h"
#include "mozilla/Telemetry.h"
#include "mozilla/layers/APZCCallbackHelper.h"
#include "mozilla/layers/AsyncDragMetrics.h"
#include "mozilla/layers/InputAPZContext.h"
#include "mozilla/layers/ScrollInputMethods.h"
#include <algorithm>

using namespace mozilla;
using mozilla::layers::APZCCallbackHelper;
using mozilla::layers::AsyncDragMetrics;
using mozilla::layers::InputAPZContext;
using mozilla::layers::ScrollInputMethod;

bool nsSliderFrame::gMiddlePref = false;
int32_t nsSliderFrame::gSnapMultiplier;

// Turn this on if you want to debug slider frames.
#undef DEBUG_SLIDER

static already_AddRefed<nsIContent>
GetContentOfBox(nsIFrame *aBox)
{
  nsCOMPtr<nsIContent> content = aBox->GetContent();
  return content.forget();
}

nsIFrame*
NS_NewSliderFrame (nsIPresShell* aPresShell, nsStyleContext* aContext)
{
  return new (aPresShell) nsSliderFrame(aContext);
}

NS_IMPL_FRAMEARENA_HELPERS(nsSliderFrame)

NS_QUERYFRAME_HEAD(nsSliderFrame)
  NS_QUERYFRAME_ENTRY(nsSliderFrame)
NS_QUERYFRAME_TAIL_INHERITING(nsBoxFrame)

nsSliderFrame::nsSliderFrame(nsStyleContext* aContext):
  nsBoxFrame(aContext),
  mCurPos(0),
  mChange(0),
  mDragFinished(true),
  mUserChanged(false),
  mScrollingWithAPZ(false),
  mSuppressionActive(false)
{
}

// stop timer
nsSliderFrame::~nsSliderFrame()
{
  if (mSuppressionActive) {
    APZCCallbackHelper::SuppressDisplayport(false, PresContext() ?
                                                   PresContext()->PresShell() :
                                                   nullptr);
  }
}

void
nsSliderFrame::Init(nsIContent*       aContent,
                    nsContainerFrame* aParent,
                    nsIFrame*         aPrevInFlow)
{
  nsBoxFrame::Init(aContent, aParent, aPrevInFlow);

  static bool gotPrefs = false;
  if (!gotPrefs) {
    gotPrefs = true;

    gMiddlePref = Preferences::GetBool("middlemouse.scrollbarPosition");
    gSnapMultiplier = Preferences::GetInt("slider.snapMultiplier");
  }

  mCurPos = GetCurrentPosition(aContent);
}

void
nsSliderFrame::RemoveFrame(ChildListID     aListID,
                           nsIFrame*       aOldFrame)
{
  nsBoxFrame::RemoveFrame(aListID, aOldFrame);
  if (mFrames.IsEmpty())
    RemoveListener();
}

void
nsSliderFrame::InsertFrames(ChildListID     aListID,
                            nsIFrame*       aPrevFrame,
                            nsFrameList&    aFrameList)
{
  bool wasEmpty = mFrames.IsEmpty();
  nsBoxFrame::InsertFrames(aListID, aPrevFrame, aFrameList);
  if (wasEmpty)
    AddListener();
}

void
nsSliderFrame::AppendFrames(ChildListID     aListID,
                            nsFrameList&    aFrameList)
{
  // if we have no children and on was added then make sure we add the
  // listener
  bool wasEmpty = mFrames.IsEmpty();
  nsBoxFrame::AppendFrames(aListID, aFrameList);
  if (wasEmpty)
    AddListener();
}

int32_t
nsSliderFrame::GetCurrentPosition(nsIContent* content)
{
  return GetIntegerAttribute(content, nsGkAtoms::curpos, 0);
}

int32_t
nsSliderFrame::GetMinPosition(nsIContent* content)
{
  return GetIntegerAttribute(content, nsGkAtoms::minpos, 0);
}

int32_t
nsSliderFrame::GetMaxPosition(nsIContent* content)
{
  return GetIntegerAttribute(content, nsGkAtoms::maxpos, 100);
}

int32_t
nsSliderFrame::GetIncrement(nsIContent* content)
{
  return GetIntegerAttribute(content, nsGkAtoms::increment, 1);
}


int32_t
nsSliderFrame::GetPageIncrement(nsIContent* content)
{
  return GetIntegerAttribute(content, nsGkAtoms::pageincrement, 10);
}

int32_t
nsSliderFrame::GetIntegerAttribute(nsIContent* content, nsIAtom* atom, int32_t defaultValue)
{
    nsAutoString value;
    content->GetAttr(kNameSpaceID_None, atom, value);
    if (!value.IsEmpty()) {
      nsresult error;

      // convert it to an integer
      defaultValue = value.ToInteger(&error);
    }

    return defaultValue;
}

class nsValueChangedRunnable : public Runnable
{
public:
  nsValueChangedRunnable(nsISliderListener* aListener,
                         nsIAtom* aWhich,
                         int32_t aValue,
                         bool aUserChanged)
  : mListener(aListener), mWhich(aWhich),
    mValue(aValue), mUserChanged(aUserChanged)
  {}

  NS_IMETHOD Run() override
  {
    return mListener->ValueChanged(nsDependentAtomString(mWhich),
                                   mValue, mUserChanged);
  }

  nsCOMPtr<nsISliderListener> mListener;
  nsCOMPtr<nsIAtom> mWhich;
  int32_t mValue;
  bool mUserChanged;
};

class nsDragStateChangedRunnable : public Runnable
{
public:
  nsDragStateChangedRunnable(nsISliderListener* aListener,
                             bool aDragBeginning)
  : mListener(aListener),
    mDragBeginning(aDragBeginning)
  {}

  NS_IMETHOD Run() override
  {
    return mListener->DragStateChanged(mDragBeginning);
  }

  nsCOMPtr<nsISliderListener> mListener;
  bool mDragBeginning;
};

nsresult
nsSliderFrame::AttributeChanged(int32_t aNameSpaceID,
                                nsIAtom* aAttribute,
                                int32_t aModType)
{
  nsresult rv = nsBoxFrame::AttributeChanged(aNameSpaceID, aAttribute,
                                             aModType);
  // if the current position changes
  if (aAttribute == nsGkAtoms::curpos) {
     CurrentPositionChanged();
  } else if (aAttribute == nsGkAtoms::minpos ||
             aAttribute == nsGkAtoms::maxpos) {
      // bounds check it.

      nsIFrame* scrollbarBox = GetScrollbar();
      nsCOMPtr<nsIContent> scrollbar;
      scrollbar = GetContentOfBox(scrollbarBox);
      int32_t current = GetCurrentPosition(scrollbar);
      int32_t min = GetMinPosition(scrollbar);
      int32_t max = GetMaxPosition(scrollbar);

      // inform the parent <scale> that the minimum or maximum changed
      nsIFrame* parent = GetParent();
      if (parent) {
        nsCOMPtr<nsISliderListener> sliderListener = do_QueryInterface(parent->GetContent());
        if (sliderListener) {
          nsContentUtils::AddScriptRunner(
            new nsValueChangedRunnable(sliderListener, aAttribute,
                                       aAttribute == nsGkAtoms::minpos ? min : max, false));
        }
      }

      if (current < min || current > max)
      {
        int32_t direction = 0;
        if (current < min || max < min) {
          current = min;
          direction = -1;
        } else if (current > max) {
          current = max;
          direction = 1;
        }

        // set the new position and notify observers
        nsScrollbarFrame* scrollbarFrame = do_QueryFrame(scrollbarBox);
        if (scrollbarFrame) {
          nsIScrollbarMediator* mediator = scrollbarFrame->GetScrollbarMediator();
          scrollbarFrame->SetIncrementToWhole(direction);
          if (mediator) {
            mediator->ScrollByWhole(scrollbarFrame, direction,
                                    nsIScrollbarMediator::ENABLE_SNAP);
          }
        }
        // 'this' might be destroyed here

        nsContentUtils::AddScriptRunner(
          new nsSetAttrRunnable(scrollbar, nsGkAtoms::curpos, current));
      }
  }

  if (aAttribute == nsGkAtoms::minpos ||
      aAttribute == nsGkAtoms::maxpos ||
      aAttribute == nsGkAtoms::pageincrement ||
      aAttribute == nsGkAtoms::increment) {

      PresContext()->PresShell()->
        FrameNeedsReflow(this, nsIPresShell::eStyleChange, NS_FRAME_IS_DIRTY);
  }

  return rv;
}

void
nsSliderFrame::BuildDisplayList(nsDisplayListBuilder*   aBuilder,
                                const nsDisplayListSet& aLists)
{
  if (aBuilder->IsForEventDelivery() && isDraggingThumb()) {
    // This is EVIL, we shouldn't be messing with event delivery just to get
    // thumb mouse drag events to arrive at the slider!
    aLists.Outlines()->AppendNewToTop(new (aBuilder)
      nsDisplayEventReceiver(aBuilder, this));
    return;
  }
  
  nsBoxFrame::BuildDisplayList(aBuilder, aLists);
}

void
nsSliderFrame::BuildDisplayListForChildren(nsDisplayListBuilder*   aBuilder,
                                           const nsDisplayListSet& aLists)
{
  // if we are too small to have a thumb don't paint it.
  nsIFrame* thumb = nsBox::GetChildXULBox(this);

  if (thumb) {
    nsRect thumbRect(thumb->GetRect());
    nsMargin m;
    thumb->GetXULMargin(m);
    thumbRect.Inflate(m);

    nsRect crect;
    GetXULClientRect(crect);

    if (crect.width < thumbRect.width || crect.height < thumbRect.height)
      return;

    // If this scrollbar is the scrollbar of an actively scrolled scroll frame,
    // layerize the scrollbar thumb, wrap it in its own ContainerLayer and
    // attach scrolling information to it.
    // We do this here and not in the thumb's nsBoxFrame::BuildDisplayList so
    // that the event region that gets created for the thumb is included in
    // the nsDisplayOwnLayer contents.

    uint32_t flags = 0;
    mozilla::layers::FrameMetrics::ViewID scrollTargetId =
      mozilla::layers::FrameMetrics::NULL_SCROLL_ID;
    aBuilder->GetScrollbarInfo(&scrollTargetId, &flags);
    bool thumbGetsLayer = (scrollTargetId != layers::FrameMetrics::NULL_SCROLL_ID);
    nsLayoutUtils::SetScrollbarThumbLayerization(thumb, thumbGetsLayer);

    if (thumbGetsLayer) {
      nsDisplayListCollection tempLists (aBuilder);
      nsBoxFrame::BuildDisplayListForChildren(aBuilder, tempLists);

      // This is a bit of a hack. Collect up all descendant display items
      // and merge them into a single Content() list.
      nsDisplayList masterList;
      masterList.AppendToTop(tempLists.BorderBackground());
      masterList.AppendToTop(tempLists.BlockBorderBackgrounds());
      masterList.AppendToTop(tempLists.Floats());
      masterList.AppendToTop(tempLists.Content());
      masterList.AppendToTop(tempLists.PositionedDescendants());
      masterList.AppendToTop(tempLists.Outlines());

      // Wrap the list to make it its own layer.
      aLists.Content()->AppendNewToTop(new (aBuilder)
        nsDisplayOwnLayer(aBuilder, this, &masterList, flags, scrollTargetId,
                          GetThumbRatio()));

      return;
    }
  }
  
  nsBoxFrame::BuildDisplayListForChildren(aBuilder, aLists);
}

NS_IMETHODIMP
nsSliderFrame::DoXULLayout(nsBoxLayoutState& aState)
{
  // get the thumb should be our only child
  nsIFrame* thumbBox = nsBox::GetChildXULBox(this);

  if (!thumbBox) {
    SyncLayout(aState);
    return NS_OK;
  }

  EnsureOrient();

#ifdef DEBUG_LAYOUT
  if (mState & NS_STATE_DEBUG_WAS_SET) {
      if (mState & NS_STATE_SET_TO_DEBUG)
          SetXULDebug(aState, true);
      else
          SetXULDebug(aState, false);
  }
#endif

  // get the content area inside our borders
  nsRect clientRect;
  GetXULClientRect(clientRect);

  // get the scrollbar
  nsIFrame* scrollbarBox = GetScrollbar();
  nsCOMPtr<nsIContent> scrollbar;
  scrollbar = GetContentOfBox(scrollbarBox);

  // get the thumb's pref size
  nsSize thumbSize = thumbBox->GetXULPrefSize(aState);

  if (IsXULHorizontal())
    thumbSize.height = clientRect.height;
  else
    thumbSize.width = clientRect.width;

  int32_t curPos = GetCurrentPosition(scrollbar);
  int32_t minPos = GetMinPosition(scrollbar);
  int32_t maxPos = GetMaxPosition(scrollbar);
  int32_t pageIncrement = GetPageIncrement(scrollbar);

  maxPos = std::max(minPos, maxPos);
  curPos = clamped(curPos, minPos, maxPos);

  nscoord& availableLength = IsXULHorizontal() ? clientRect.width : clientRect.height;
  nscoord& thumbLength = IsXULHorizontal() ? thumbSize.width : thumbSize.height;

  if ((pageIncrement + maxPos - minPos) > 0 && thumbBox->GetXULFlex() > 0) {
    float ratio = float(pageIncrement) / float(maxPos - minPos + pageIncrement);
    thumbLength = std::max(thumbLength, NSToCoordRound(availableLength * ratio));
  }

  // Round the thumb's length to device pixels.
  nsPresContext* presContext = PresContext();
  thumbLength = presContext->DevPixelsToAppUnits(
                  presContext->AppUnitsToDevPixels(thumbLength));

  // mRatio translates the thumb position in app units to the value.
  mRatio = (minPos != maxPos) ? float(availableLength - thumbLength) / float(maxPos - minPos) : 1;

  // in reverse mode, curpos is reversed such that lower values are to the
  // right or bottom and increase leftwards or upwards. In this case, use the
  // offset from the end instead of the beginning.
  bool reverse = mContent->AttrValueIs(kNameSpaceID_None, nsGkAtoms::dir,
                                         nsGkAtoms::reverse, eCaseMatters);
  nscoord pos = reverse ? (maxPos - curPos) : (curPos - minPos);

  // set the thumb's coord to be the current pos * the ratio.
  nsRect thumbRect(clientRect.x, clientRect.y, thumbSize.width, thumbSize.height);
  int32_t& thumbPos = (IsXULHorizontal() ? thumbRect.x : thumbRect.y);
  thumbPos += NSToCoordRound(pos * mRatio);

  nsRect oldThumbRect(thumbBox->GetRect());
  LayoutChildAt(aState, thumbBox, thumbRect);

  SyncLayout(aState);

  // Redraw only if thumb changed size.
  if (!oldThumbRect.IsEqualInterior(thumbRect))
    XULRedraw(aState);

  return NS_OK;
}


nsresult
nsSliderFrame::HandleEvent(nsPresContext* aPresContext,
                           WidgetGUIEvent* aEvent,
                           nsEventStatus* aEventStatus)
{
  NS_ENSURE_ARG_POINTER(aEventStatus);

  // If a web page calls event.preventDefault() we still want to
  // scroll when scroll arrow is clicked. See bug 511075.
  if (!mContent->IsInNativeAnonymousSubtree() &&
      nsEventStatus_eConsumeNoDefault == *aEventStatus) {
    return NS_OK;
  }

  if (!mDragFinished && !isDraggingThumb()) {
    StopDrag();
    return NS_OK;
  }

  nsIFrame* scrollbarBox = GetScrollbar();
  nsCOMPtr<nsIContent> scrollbar;
  scrollbar = GetContentOfBox(scrollbarBox);
  bool isHorizontal = IsXULHorizontal();

  if (isDraggingThumb())
  {
    switch (aEvent->mMessage) {
    case eTouchMove:
    case eMouseMove: {
      if (mScrollingWithAPZ) {
        break;
      }
      nsPoint eventPoint;
      if (!GetEventPoint(aEvent, eventPoint)) {
        break;
      }
      if (mChange) {
        // On Linux the destination point is determined by the initial click
        // on the scrollbar track and doesn't change until the mouse button
        // is released.
#ifndef MOZ_WIDGET_GTK
        // On the other platforms we need to update the destination point now.
        mDestinationPoint = eventPoint;
        StopRepeat();
        StartRepeat();
#endif
        break;
      }

      nscoord pos = isHorizontal ? eventPoint.x : eventPoint.y;

      nsIFrame* thumbFrame = mFrames.FirstChild();
      if (!thumbFrame) {
        return NS_OK;
      }

      // take our current position and subtract the start location
      pos -= mDragStart;
      bool isMouseOutsideThumb = false;
      if (gSnapMultiplier) {
        nsSize thumbSize = thumbFrame->GetSize();
        if (isHorizontal) {
          // horizontal scrollbar - check if mouse is above or below thumb
          // XXXbz what about looking at the .y of the thumb's rect?  Is that
          // always zero here?
          if (eventPoint.y < -gSnapMultiplier * thumbSize.height ||
              eventPoint.y > thumbSize.height +
                               gSnapMultiplier * thumbSize.height)
            isMouseOutsideThumb = true;
        }
        else {
          // vertical scrollbar - check if mouse is left or right of thumb
          if (eventPoint.x < -gSnapMultiplier * thumbSize.width ||
              eventPoint.x > thumbSize.width +
                               gSnapMultiplier * thumbSize.width)
            isMouseOutsideThumb = true;
        }
      }
      if (aEvent->mClass == eTouchEventClass) {
        *aEventStatus = nsEventStatus_eConsumeNoDefault;
      }
      if (isMouseOutsideThumb)
      {
        SetCurrentThumbPosition(scrollbar, mThumbStart, false, false);
        return NS_OK;
      }

      // set it
      SetCurrentThumbPosition(scrollbar, pos, false, true); // with snapping
    }
    break;

    case eTouchEnd:
    case eMouseUp:
      if (ShouldScrollForEvent(aEvent)) {
        StopDrag();
        //we MUST call nsFrame HandleEvent for mouse ups to maintain the selection state and capture state.
        return nsFrame::HandleEvent(aPresContext, aEvent, aEventStatus);
      }
      break;

    default:
      break;
    }

    //return nsFrame::HandleEvent(aPresContext, aEvent, aEventStatus);
    return NS_OK;
  } else if (ShouldScrollToClickForEvent(aEvent)) {
    nsPoint eventPoint;
    if (!GetEventPoint(aEvent, eventPoint)) {
      return NS_OK;
    }
    nscoord pos = isHorizontal ? eventPoint.x : eventPoint.y;

    // adjust so that the middle of the thumb is placed under the click
    nsIFrame* thumbFrame = mFrames.FirstChild();
    if (!thumbFrame) {
      return NS_OK;
    }
    nsSize thumbSize = thumbFrame->GetSize();
    nscoord thumbLength = isHorizontal ? thumbSize.width : thumbSize.height;

    // set it
    nsWeakFrame weakFrame(this);
    // should aMaySnap be true here?
    SetCurrentThumbPosition(scrollbar, pos - thumbLength/2, false, false);
    NS_ENSURE_TRUE(weakFrame.IsAlive(), NS_OK);

    DragThumb(true);

#ifdef MOZ_WIDGET_GTK
    nsCOMPtr<nsIContent> thumb = thumbFrame->GetContent();
    thumb->SetAttr(kNameSpaceID_None, nsGkAtoms::active, NS_LITERAL_STRING("true"), true);
#endif

    if (aEvent->mClass == eTouchEventClass) {
      *aEventStatus = nsEventStatus_eConsumeNoDefault;
    }

    if (isHorizontal)
      mThumbStart = thumbFrame->GetPosition().x;
    else
      mThumbStart = thumbFrame->GetPosition().y;

    mDragStart = pos - mThumbStart;
  }
#ifdef MOZ_WIDGET_GTK
  else if (ShouldScrollForEvent(aEvent) &&
           aEvent->mClass == eMouseEventClass &&
           aEvent->AsMouseEvent()->button == WidgetMouseEvent::eRightButton) {
    // HandlePress and HandleRelease are usually called via
    // nsFrame::HandleEvent, but only for the left mouse button.
    if (aEvent->mMessage == eMouseDown) {
      HandlePress(aPresContext, aEvent, aEventStatus);
    } else if (aEvent->mMessage == eMouseUp) {
      HandleRelease(aPresContext, aEvent, aEventStatus);
    }

    return NS_OK;
  }
#endif

  // XXX hack until handle release is actually called in nsframe.
  //  if (aEvent->mMessage == eMouseOut ||
  //      aEvent->mMessage == NS_MOUSE_RIGHT_BUTTON_UP ||
  //      aEvent->mMessage == NS_MOUSE_LEFT_BUTTON_UP) {
  //    HandleRelease(aPresContext, aEvent, aEventStatus);
  //  }

  if (aEvent->mMessage == eMouseOut && mChange)
     HandleRelease(aPresContext, aEvent, aEventStatus);

  return nsFrame::HandleEvent(aPresContext, aEvent, aEventStatus);
}

// Helper function to collect the "scroll to click" metric. Beware of
// caching this, users expect to be able to change the system preference
// and see the browser change its behavior immediately.
bool
nsSliderFrame::GetScrollToClick()
{
  if (GetScrollbar() != this) {
    return LookAndFeel::GetInt(LookAndFeel::eIntID_ScrollToClick, false);
  }

  if (mContent->AttrValueIs(kNameSpaceID_None, nsGkAtoms::movetoclick,
                            nsGkAtoms::_true, eCaseMatters)) {
    return true;
  }
  if (mContent->AttrValueIs(kNameSpaceID_None, nsGkAtoms::movetoclick,
                            nsGkAtoms::_false, eCaseMatters)) {
    return false;
  }

#ifdef XP_MACOSX
  return true;
#else
  return false;
#endif
}

nsIFrame*
nsSliderFrame::GetScrollbar()
{
  // if we are in a scrollbar then return the scrollbar's content node
  // if we are not then return ours.
   nsIFrame* scrollbar;
   nsScrollbarButtonFrame::GetParentWithTag(nsGkAtoms::scrollbar, this, scrollbar);

   if (scrollbar == nullptr)
       return this;

   return scrollbar->IsXULBoxFrame() ? scrollbar : this;
}

void
nsSliderFrame::PageUpDown(nscoord change)
{
  // on a page up or down get our page increment. We get this by getting the scrollbar we are in and
  // asking it for the current position and the page increment. If we are not in a scrollbar we will
  // get the values from our own node.
  nsIFrame* scrollbarBox = GetScrollbar();
  nsCOMPtr<nsIContent> scrollbar;
  scrollbar = GetContentOfBox(scrollbarBox);

  nscoord pageIncrement = GetPageIncrement(scrollbar);
  int32_t curpos = GetCurrentPosition(scrollbar);
  int32_t minpos = GetMinPosition(scrollbar);
  int32_t maxpos = GetMaxPosition(scrollbar);

  // get the new position and make sure it is in bounds
  int32_t newpos = curpos + change * pageIncrement;
  if (newpos < minpos || maxpos < minpos)
    newpos = minpos;
  else if (newpos > maxpos)
    newpos = maxpos;

  SetCurrentPositionInternal(scrollbar, newpos, true);
}

// called when the current position changed and we need to update the thumb's location
void
nsSliderFrame::CurrentPositionChanged()
{
  nsIFrame* scrollbarBox = GetScrollbar();
  nsCOMPtr<nsIContent> scrollbar;
  scrollbar = GetContentOfBox(scrollbarBox);

  // get the current position
  int32_t curPos = GetCurrentPosition(scrollbar);

  // do nothing if the position did not change
  if (mCurPos == curPos)
    return;

  // get our current min and max position from our content node
  int32_t minPos = GetMinPosition(scrollbar);
  int32_t maxPos = GetMaxPosition(scrollbar);

  maxPos = std::max(minPos, maxPos);
  curPos = clamped(curPos, minPos, maxPos);

  // get the thumb's rect
  nsIFrame* thumbFrame = mFrames.FirstChild();
  if (!thumbFrame)
    return; // The thumb may stream in asynchronously via XBL.

  nsRect thumbRect = thumbFrame->GetRect();

  nsRect clientRect;
  GetXULClientRect(clientRect);

  // figure out the new rect
  nsRect newThumbRect(thumbRect);

  bool reverse = mContent->AttrValueIs(kNameSpaceID_None, nsGkAtoms::dir,
                                         nsGkAtoms::reverse, eCaseMatters);
  nscoord pos = reverse ? (maxPos - curPos) : (curPos - minPos);

  if (IsXULHorizontal())
     newThumbRect.x = clientRect.x + NSToCoordRound(pos * mRatio);
  else
     newThumbRect.y = clientRect.y + NSToCoordRound(pos * mRatio);

  // avoid putting the scroll thumb at subpixel positions which cause needless invalidations
  nscoord appUnitsPerPixel = PresContext()->AppUnitsPerDevPixel();
  nsPoint snappedThumbLocation = ToAppUnits(
      newThumbRect.TopLeft().ToNearestPixels(appUnitsPerPixel),
      appUnitsPerPixel);
  if (IsXULHorizontal()) {
    newThumbRect.x = snappedThumbLocation.x;
  } else {
    newThumbRect.y = snappedThumbLocation.y;
  }

  // set the rect
  thumbFrame->SetRect(newThumbRect);

  // Request a repaint of the scrollbar
  nsScrollbarFrame* scrollbarFrame = do_QueryFrame(scrollbarBox);
  nsIScrollbarMediator* mediator = scrollbarFrame
      ? scrollbarFrame->GetScrollbarMediator() : nullptr;
  if (!mediator || !mediator->ShouldSuppressScrollbarRepaints()) {
    SchedulePaint();
  }

  mCurPos = curPos;

  // inform the parent <scale> if it exists that the value changed
  nsIFrame* parent = GetParent();
  if (parent) {
    nsCOMPtr<nsISliderListener> sliderListener = do_QueryInterface(parent->GetContent());
    if (sliderListener) {
      nsContentUtils::AddScriptRunner(
        new nsValueChangedRunnable(sliderListener, nsGkAtoms::curpos, mCurPos, mUserChanged));
    }
  }
}

static void UpdateAttribute(nsIContent* aScrollbar, nscoord aNewPos, bool aNotify, bool aIsSmooth) {
  nsAutoString str;
  str.AppendInt(aNewPos);
  
  if (aIsSmooth) {
    aScrollbar->SetAttr(kNameSpaceID_None, nsGkAtoms::smooth, NS_LITERAL_STRING("true"), false);
  }
  aScrollbar->SetAttr(kNameSpaceID_None, nsGkAtoms::curpos, str, aNotify);
  if (aIsSmooth) {
    aScrollbar->UnsetAttr(kNameSpaceID_None, nsGkAtoms::smooth, false);
  }
}

// Use this function when you want to set the scroll position via the position
// of the scrollbar thumb, e.g. when dragging the slider. This function scrolls
// the content in such a way that thumbRect.x/.y becomes aNewThumbPos.
void
nsSliderFrame::SetCurrentThumbPosition(nsIContent* aScrollbar, nscoord aNewThumbPos,
                                       bool aIsSmooth, bool aMaySnap)
{
  nsRect crect;
  GetXULClientRect(crect);
  nscoord offset = IsXULHorizontal() ? crect.x : crect.y;
  int32_t newPos = NSToIntRound((aNewThumbPos - offset) / mRatio);
  
  if (aMaySnap && mContent->AttrValueIs(kNameSpaceID_None, nsGkAtoms::snap,
                                        nsGkAtoms::_true, eCaseMatters)) {
    // If snap="true", then the slider may only be set to min + (increment * x).
    // Otherwise, the slider may be set to any positive integer.
    int32_t increment = GetIncrement(aScrollbar);
    newPos = NSToIntRound(newPos / float(increment)) * increment;
  }
  
  SetCurrentPosition(aScrollbar, newPos, aIsSmooth);
}

// Use this function when you know the target scroll position of the scrolled content.
// aNewPos should be passed to this function as a position as if the minpos is 0.
// That is, the minpos will be added to the position by this function. In a reverse
// direction slider, the newpos should be the distance from the end.
void
nsSliderFrame::SetCurrentPosition(nsIContent* aScrollbar, int32_t aNewPos,
                                  bool aIsSmooth)
{
   // get min and max position from our content node
  int32_t minpos = GetMinPosition(aScrollbar);
  int32_t maxpos = GetMaxPosition(aScrollbar);

  // in reverse direction sliders, flip the value so that it goes from
  // right to left, or bottom to top.
  if (mContent->AttrValueIs(kNameSpaceID_None, nsGkAtoms::dir,
                            nsGkAtoms::reverse, eCaseMatters))
    aNewPos = maxpos - aNewPos;
  else
    aNewPos += minpos;

  // get the new position and make sure it is in bounds
  if (aNewPos < minpos || maxpos < minpos)
    aNewPos = minpos;
  else if (aNewPos > maxpos)
    aNewPos = maxpos;

  SetCurrentPositionInternal(aScrollbar, aNewPos, aIsSmooth);
}

void
nsSliderFrame::SetCurrentPositionInternal(nsIContent* aScrollbar, int32_t aNewPos,
                                          bool aIsSmooth)
{
  nsCOMPtr<nsIContent> scrollbar = aScrollbar;
  nsIFrame* scrollbarBox = GetScrollbar();
  nsWeakFrame weakFrame(this);

  mUserChanged = true;

  nsScrollbarFrame* scrollbarFrame = do_QueryFrame(scrollbarBox);
  if (scrollbarFrame) {
    // See if we have a mediator.
    nsIScrollbarMediator* mediator = scrollbarFrame->GetScrollbarMediator();
    if (mediator) {
      nscoord oldPos = nsPresContext::CSSPixelsToAppUnits(GetCurrentPosition(scrollbar));
      nscoord newPos = nsPresContext::CSSPixelsToAppUnits(aNewPos);
      mediator->ThumbMoved(scrollbarFrame, oldPos, newPos);
      if (!weakFrame.IsAlive()) {
        return;
      }
      UpdateAttribute(scrollbar, aNewPos, /* aNotify */false, aIsSmooth);
      CurrentPositionChanged();
      mUserChanged = false;
      return;
    }
  }

  UpdateAttribute(scrollbar, aNewPos, true, aIsSmooth);
  if (!weakFrame.IsAlive()) {
    return;
  }
  mUserChanged = false;

#ifdef DEBUG_SLIDER
  printf("Current Pos=%d\n",aNewPos);
#endif

}

nsIAtom*
nsSliderFrame::GetType() const
{
  return nsGkAtoms::sliderFrame;
}

void
nsSliderFrame::SetInitialChildList(ChildListID     aListID,
                                   nsFrameList&    aChildList)
{
  nsBoxFrame::SetInitialChildList(aListID, aChildList);
  if (aListID == kPrincipalList) {
    AddListener();
  }
}

nsresult
nsSliderMediator::HandleEvent(nsIDOMEvent* aEvent)
{
  // Only process the event if the thumb is not being dragged.
  if (mSlider && !mSlider->isDraggingThumb())
    return mSlider->StartDrag(aEvent);

  return NS_OK;
}

bool
nsSliderFrame::StartAPZDrag()
{
  if (!gfxPlatform::GetPlatform()->SupportsApzDragInput()) {
    return false;
  }

  nsContainerFrame* cf = GetScrollbar()->GetParent();
  if (!cf) {
    return false;
  }

  nsIContent* scrollableContent = cf->GetContent();
  if (!scrollableContent) {
    return false;
  }

  mozilla::layers::FrameMetrics::ViewID scrollTargetId;
  bool hasID = nsLayoutUtils::FindIDFor(scrollableContent, &scrollTargetId);
  bool hasAPZView = hasID && (scrollTargetId != layers::FrameMetrics::NULL_SCROLL_ID);

  if (!hasAPZView) {
    return false;
  }

  nsIFrame* scrollbarBox = GetScrollbar();
  nsCOMPtr<nsIContent> scrollbar = GetContentOfBox(scrollbarBox);

  // This rect is the range in which the scroll thumb can slide in.
  nsRect sliderTrack = GetRect() - scrollbarBox->GetPosition();
  CSSIntRect sliderTrackCSS = CSSIntRect::FromAppUnitsRounded(sliderTrack);

  uint64_t inputblockId = InputAPZContext::GetInputBlockId();
  uint32_t presShellId = PresContext()->PresShell()->GetPresShellId();
  AsyncDragMetrics dragMetrics(scrollTargetId, presShellId, inputblockId,
                               NSAppUnitsToIntPixels(mDragStart,
                                 float(AppUnitsPerCSSPixel())),
                               sliderTrackCSS,
                               IsXULHorizontal() ? AsyncDragMetrics::HORIZONTAL :
                                                   AsyncDragMetrics::VERTICAL);

  if (!nsLayoutUtils::HasDisplayPort(scrollableContent)) {
    return false;
  }

  // When we start an APZ drag, we wont get mouse events for the drag.
  // APZ will consume them all and only notify us of the new scroll position.
  this->GetNearestWidget()->StartAsyncScrollbarDrag(dragMetrics);
  return true;
}

nsresult
nsSliderFrame::StartDrag(nsIDOMEvent* aEvent)
{
#ifdef DEBUG_SLIDER
  printf("Begin dragging\n");
#endif
  if (mContent->AttrValueIs(kNameSpaceID_None, nsGkAtoms::disabled,
                            nsGkAtoms::_true, eCaseMatters))
    return NS_OK;

  WidgetGUIEvent* event = aEvent->WidgetEventPtr()->AsGUIEvent();

  if (!ShouldScrollForEvent(event)) {
    return NS_OK;
  }

  nsPoint pt;
  if (!GetEventPoint(event, pt)) {
    return NS_OK;
  }
  bool isHorizontal = IsXULHorizontal();
  nscoord pos = isHorizontal ? pt.x : pt.y;

  // If we should scroll-to-click, first place the middle of the slider thumb
  // under the mouse.
  nsCOMPtr<nsIContent> scrollbar;
  nscoord newpos = pos;
  bool scrollToClick = ShouldScrollToClickForEvent(event);
  if (scrollToClick) {
    // adjust so that the middle of the thumb is placed under the click
    nsIFrame* thumbFrame = mFrames.FirstChild();
    if (!thumbFrame) {
      return NS_OK;
    }
    nsSize thumbSize = thumbFrame->GetSize();
    nscoord thumbLength = isHorizontal ? thumbSize.width : thumbSize.height;

    newpos -= (thumbLength/2);

    nsIFrame* scrollbarBox = GetScrollbar();
    scrollbar = GetContentOfBox(scrollbarBox);
  }

  DragThumb(true);

  if (scrollToClick) {
    // should aMaySnap be true here?
    SetCurrentThumbPosition(scrollbar, newpos, false, false);
  }

  nsIFrame* thumbFrame = mFrames.FirstChild();
  if (!thumbFrame) {
    return NS_OK;
  }

#ifdef MOZ_WIDGET_GTK
  nsCOMPtr<nsIContent> thumb = thumbFrame->GetContent();
  thumb->SetAttr(kNameSpaceID_None, nsGkAtoms::active, NS_LITERAL_STRING("true"), true);
#endif

  if (isHorizontal)
    mThumbStart = thumbFrame->GetPosition().x;
  else
    mThumbStart = thumbFrame->GetPosition().y;

  mDragStart = pos - mThumbStart;

  mScrollingWithAPZ = StartAPZDrag();

#ifdef DEBUG_SLIDER
  printf("Pressed mDragStart=%d\n",mDragStart);
#endif

  if (!mScrollingWithAPZ && !mSuppressionActive) {
    MOZ_ASSERT(PresContext()->PresShell());
    APZCCallbackHelper::SuppressDisplayport(true, PresContext()->PresShell());
    mSuppressionActive = true;
  }

  return NS_OK;
}

nsresult
nsSliderFrame::StopDrag()
{
  AddListener();
  DragThumb(false);

  mScrollingWithAPZ = false;

  if (mSuppressionActive) {
    MOZ_ASSERT(PresContext()->PresShell());
    APZCCallbackHelper::SuppressDisplayport(false, PresContext()->PresShell());
    mSuppressionActive = false;
  }

#ifdef MOZ_WIDGET_GTK
  nsIFrame* thumbFrame = mFrames.FirstChild();
  if (thumbFrame) {
    nsCOMPtr<nsIContent> thumb = thumbFrame->GetContent();
    thumb->UnsetAttr(kNameSpaceID_None, nsGkAtoms::active, true);
  }
#endif

  if (mChange) {
    StopRepeat();
    mChange = 0;
  }
  return NS_OK;
}

void
nsSliderFrame::DragThumb(bool aGrabMouseEvents)
{
  mDragFinished = !aGrabMouseEvents;

  // inform the parent <scale> that a drag is beginning or ending
  nsIFrame* parent = GetParent();
  if (parent) {
    nsCOMPtr<nsISliderListener> sliderListener = do_QueryInterface(parent->GetContent());
    if (sliderListener) {
      nsContentUtils::AddScriptRunner(
        new nsDragStateChangedRunnable(sliderListener, aGrabMouseEvents));
    }
  }

  nsIPresShell::SetCapturingContent(aGrabMouseEvents ? GetContent() : nullptr,
                                    aGrabMouseEvents ? CAPTURE_IGNOREALLOWED : 0);
}

bool
nsSliderFrame::isDraggingThumb()
{
  return (nsIPresShell::GetCapturingContent() == GetContent());
}

void
nsSliderFrame::AddListener()
{
  if (!mMediator) {
    mMediator = new nsSliderMediator(this);
  }

  nsIFrame* thumbFrame = mFrames.FirstChild();
  if (!thumbFrame) {
    return;
  }
  thumbFrame->GetContent()->
    AddSystemEventListener(NS_LITERAL_STRING("mousedown"), mMediator,
                           false, false);
  thumbFrame->GetContent()->
    AddSystemEventListener(NS_LITERAL_STRING("touchstart"), mMediator,
                           false, false);
}

void
nsSliderFrame::RemoveListener()
{
  NS_ASSERTION(mMediator, "No listener was ever added!!");

  nsIFrame* thumbFrame = mFrames.FirstChild();
  if (!thumbFrame)
    return;

  thumbFrame->GetContent()->
    RemoveSystemEventListener(NS_LITERAL_STRING("mousedown"), mMediator, false);
}

bool
nsSliderFrame::ShouldScrollForEvent(WidgetGUIEvent* aEvent)
{
  switch (aEvent->mMessage) {
    case eTouchStart:
    case eTouchEnd:
      return true;
    case eMouseDown:
    case eMouseUp: {
      uint16_t button = aEvent->AsMouseEvent()->button;
#ifdef MOZ_WIDGET_GTK
      return (button == WidgetMouseEvent::eLeftButton) ||
             (button == WidgetMouseEvent::eRightButton && GetScrollToClick()) ||
             (button == WidgetMouseEvent::eMiddleButton && gMiddlePref && !GetScrollToClick());
#else
      return (button == WidgetMouseEvent::eLeftButton) ||
             (button == WidgetMouseEvent::eMiddleButton && gMiddlePref);
#endif
    }
    default:
      return false;
  }
}

bool
nsSliderFrame::ShouldScrollToClickForEvent(WidgetGUIEvent* aEvent)
{
  if (!ShouldScrollForEvent(aEvent)) {
    return false;
  }

  if (aEvent->mMessage == eTouchStart) {
    return GetScrollToClick();
  }

  if (aEvent->mMessage != eMouseDown) {
    return false;
  }

#if defined(XP_MACOSX) || defined(MOZ_WIDGET_GTK)
  // On Mac and Linux, clicking the scrollbar thumb should never scroll to click.
  if (IsEventOverThumb(aEvent)) {
    return false;
  }
#endif

  WidgetMouseEvent* mouseEvent = aEvent->AsMouseEvent();
  if (mouseEvent->button == WidgetMouseEvent::eLeftButton) {
#ifdef XP_MACOSX
    bool invertPref = mouseEvent->IsAlt();
#else
    bool invertPref = mouseEvent->IsShift();
#endif
    return GetScrollToClick() != invertPref;
  }

#ifdef MOZ_WIDGET_GTK
  if (mouseEvent->button == WidgetMouseEvent::eRightButton) {
    return !GetScrollToClick();
  }
#endif

  return true;
}

bool
nsSliderFrame::IsEventOverThumb(WidgetGUIEvent* aEvent)
{
  nsIFrame* thumbFrame = mFrames.FirstChild();
  if (!thumbFrame) {
    return false;
  }

  nsPoint eventPoint;
  if (!GetEventPoint(aEvent, eventPoint)) {
    return false;
  }

  nsRect thumbRect = thumbFrame->GetRect();
#if defined(MOZ_WIDGET_GTK)
  /* Scrollbar track can have padding, so it's better to check that eventPoint
   * is inside of actual thumb, not just its one axis. The part of the scrollbar
   * track adjacent to thumb can actually receive events in GTK3 */
  return eventPoint.x >= thumbRect.x && eventPoint.x < thumbRect.XMost() &&
         eventPoint.y >= thumbRect.y && eventPoint.y < thumbRect.YMost();
#else
  bool isHorizontal = IsXULHorizontal();
  nscoord eventPos = isHorizontal ? eventPoint.x : eventPoint.y;
  nscoord thumbStart = isHorizontal ? thumbRect.x : thumbRect.y;
  nscoord thumbEnd = isHorizontal ? thumbRect.XMost() : thumbRect.YMost();

  return eventPos >= thumbStart && eventPos < thumbEnd;
#endif
}

NS_IMETHODIMP
nsSliderFrame::HandlePress(nsPresContext* aPresContext,
                           WidgetGUIEvent* aEvent,
                           nsEventStatus* aEventStatus)
{
  if (!ShouldScrollForEvent(aEvent) || ShouldScrollToClickForEvent(aEvent)) {
    return NS_OK;
  }

  if (IsEventOverThumb(aEvent)) {
    return NS_OK;
  }

  nsIFrame* thumbFrame = mFrames.FirstChild();
  if (!thumbFrame) // display:none?
    return NS_OK;

  if (mContent->AttrValueIs(kNameSpaceID_None, nsGkAtoms::disabled,
                            nsGkAtoms::_true, eCaseMatters))
    return NS_OK;
  
  nsRect thumbRect = thumbFrame->GetRect();
  
  nscoord change = 1;
  nsPoint eventPoint;
  if (!GetEventPoint(aEvent, eventPoint)) {
    return NS_OK;
  }
  if (IsXULHorizontal() ? eventPoint.x < thumbRect.x 
                        : eventPoint.y < thumbRect.y)
    change = -1;

  mChange = change;
  DragThumb(true);
  // On Linux we want to keep scrolling in the direction indicated by |change|
  // until the mouse is released. On the other platforms we want to stop
  // scrolling as soon as the scrollbar thumb has reached the current mouse
  // position.
#ifdef MOZ_WIDGET_GTK
  nsRect clientRect;
  GetXULClientRect(clientRect);

  // Set the destination point to the very end of the scrollbar so that
  // scrolling doesn't stop halfway through.
  if (change > 0) {
    mDestinationPoint = nsPoint(clientRect.width, clientRect.height);
  }
  else {
    mDestinationPoint = nsPoint(0, 0);
  }
#else
  mDestinationPoint = eventPoint;
#endif
  StartRepeat();
  PageScroll(change);

  return NS_OK;
}

NS_IMETHODIMP
nsSliderFrame::HandleRelease(nsPresContext* aPresContext,
                             WidgetGUIEvent* aEvent,
                             nsEventStatus* aEventStatus)
{
  StopRepeat();

  nsIFrame* scrollbar = GetScrollbar();
  nsScrollbarFrame* sb = do_QueryFrame(scrollbar);
  if (sb) {
    nsIScrollbarMediator* m = sb->GetScrollbarMediator();
    if (m) {
      m->ScrollbarReleased(sb);
    }
  }
  return NS_OK;
}

void
nsSliderFrame::DestroyFrom(nsIFrame* aDestructRoot)
{
  // tell our mediator if we have one we are gone.
  if (mMediator) {
    mMediator->SetSlider(nullptr);
    mMediator = nullptr;
  }
  StopRepeat();

  // call base class Destroy()
  nsBoxFrame::DestroyFrom(aDestructRoot);
}

nsSize
nsSliderFrame::GetXULPrefSize(nsBoxLayoutState& aState)
{
  EnsureOrient();
  return nsBoxFrame::GetXULPrefSize(aState);
}

nsSize
nsSliderFrame::GetXULMinSize(nsBoxLayoutState& aState)
{
  EnsureOrient();

  // our min size is just our borders and padding
  return nsBox::GetXULMinSize(aState);
}

nsSize
nsSliderFrame::GetXULMaxSize(nsBoxLayoutState& aState)
{
  EnsureOrient();
  return nsBoxFrame::GetXULMaxSize(aState);
}

void
nsSliderFrame::EnsureOrient()
{
  nsIFrame* scrollbarBox = GetScrollbar();

  bool isHorizontal = (scrollbarBox->GetStateBits() & NS_STATE_IS_HORIZONTAL) != 0;
  if (isHorizontal)
      mState |= NS_STATE_IS_HORIZONTAL;
  else
      mState &= ~NS_STATE_IS_HORIZONTAL;
}


void
nsSliderFrame::Notify(void)
{
    bool stop = false;

    nsIFrame* thumbFrame = mFrames.FirstChild();
    if (!thumbFrame) {
      StopRepeat();
      return;
    }
    nsRect thumbRect = thumbFrame->GetRect();

    bool isHorizontal = IsXULHorizontal();

    // See if the thumb has moved past our destination point.
    // if it has we want to stop.
    if (isHorizontal) {
        if (mChange < 0) {
            if (thumbRect.x < mDestinationPoint.x)
                stop = true;
        } else {
            if (thumbRect.x + thumbRect.width > mDestinationPoint.x)
                stop = true;
        }
    } else {
         if (mChange < 0) {
            if (thumbRect.y < mDestinationPoint.y)
                stop = true;
        } else {
            if (thumbRect.y + thumbRect.height > mDestinationPoint.y)
                stop = true;
        }
    }


    if (stop) {
      StopRepeat();
    } else {
      PageScroll(mChange);
    }
}

void
nsSliderFrame::PageScroll(nscoord aChange)
{
  if (mContent->AttrValueIs(kNameSpaceID_None, nsGkAtoms::dir,
                            nsGkAtoms::reverse, eCaseMatters)) {
    aChange = -aChange;
  }
  nsIFrame* scrollbar = GetScrollbar();
  nsScrollbarFrame* sb = do_QueryFrame(scrollbar);
  if (sb) {
    nsIScrollbarMediator* m = sb->GetScrollbarMediator();
    sb->SetIncrementToPage(aChange);
    if (m) {
      m->ScrollByPage(sb, aChange, nsIScrollbarMediator::ENABLE_SNAP);
      return;
    }
  }
  PageUpDown(aChange);
}

float
nsSliderFrame::GetThumbRatio() const
{
  // mRatio is in thumb app units per scrolled css pixels. Convert it to a
  // ratio of the thumb's CSS pixels per scrolled CSS pixels. (Note the thumb
  // is in the scrollframe's parent's space whereas the scrolled CSS pixels
  // are in the scrollframe's space).
  return mRatio / mozilla::AppUnitsPerCSSPixel();
}

NS_IMPL_ISUPPORTS(nsSliderMediator,
                  nsIDOMEventListener)