首页 > Windows开发 > 详细

自绘LISTVIEW的滚动条(Delphi实现)

时间:2017-07-17 09:19:47      阅读:364      评论:0      收藏:0      [点我收藏+]

因项目需要准备对LISTVIEW的滚动条进行自绘。于是在网上搜了一下,问题没解决,却搜出一篇令人不愉快的帖子 。确实,那时候实力是不够的,但现在应该是没问题了,为这个目的才不断磨练自己的。

LISTVIEW控件的滚动条是系统自带的,它不创建窗口。对LISTVIEW窗口本身进行子类化后,要处理一些跟滚动条有关的消息。

首先是要骗过WM_NCPAINT消息。这个十分容易。WM_NCPAINT消息的wParam是一个区域的句柄。当它不为1时,从它里面CLIP 掉滚动条的区域,再传给原窗口过程即可。当它为1时,创建一个包含控件全客户区域的Region,再从中CLIP掉滚动条的区域,传给原窗口过程。

然后是WM_HSCROLL和WM_VSCROLL消息。在调用原窗口过程之前需要去掉窗口的WS_HSCROLL和WS_VSCROLL样式,否 则窗口过程就会在消息中绘制滚动条。调用后需要恢复。同时为避免窗口在WM_STYLECHANGING和WM_STYLECHANGED消息中重绘,也 需要截获这两个消息。

WM_NCCALCSIZE消息也是必须截获的。如果是在处理WM_HSCROLL和WM_VSCROLL消息的过程中响应WM_NCCALCSIZE,则必须去掉WS_HSCROLL和WS_VSCROLL样式。

然后是WM_ERASEBACKGROUND,WM_MOUSEWHELL消息。在这消息后需要重绘滚动条。

最重要的莫过于WM_NCHITTEST消息了。因为是自绘,所以滚动条的按下和拖动都必须在这里处理。

在自己写的滚动条Track函数中,最头疼的莫过于ThumbTrack了。当你计算好滚动到的绝对位置后,用SendMessage(hWnd, WM_XSCROLL, MAKEWPARAM(SB_THUMBTRACK, Pos), 0)发给窗口时,它居然没有反应。这是因为窗口过程不会从消息中取得TrackPos,而是会调用GetScrollInfo的API取得 TrackPos(因为前者只有16位)。但是使用SetScrollInfo是没办法设置TrackPos的。虽然你可以用SIF_POS标志让它同时 设置Pos和TrackPos,但当Pos等于TrackPos时,窗口过程不会做任何响应。从windows源代码中我们可以了解到,TrackPos 并不会为每个窗口保存一份,实际上,在任一时刻最多只有一个滚动条在做ThumbTrack的操作,因此系统只需要用一个全局变量来保存就可以了。

解决这个问题的办法是HookAPI。在GetScrollInfo中返回我们自己的TrackPos。要注意的是要Hook的不是本模块的 API,而是ComCtl32.dll中的GetScrollInfo。因此简单的如往@GetScrollInfo地址写几句跳转的方法是行不通的。必 须遍历ComCtl32.dll的pe头。这种技术在很多文章中都有描述。

不多说了,以下是Delphi代码,要点在前面已有描述,源码中没有做特殊说明。

使用说明:

资源中是一张横条的192*16的位图,从左到右依次是:左箭头、右箭头、上箭头、下箭头、左箭头按下、右箭头按下、上箭头按下、下箭头按下、横Thumb条、纵Thumb条、横背景条、纵背景条。

初始化时,调用GetSkinSB.InitSkinSB(ListView1.Handle);即可。窗口销毁前调用GetSkinSB.UninitSkinSB(ListView1.Handle)。

虽然也可针对EDIT(TMemo)和其它使用系统滚动条的控件使用此模块,但效果各有差异,需要分别做特殊处理。

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
unit SkinSB;
 
interface
 
uses
  SysUtils, Classes, Windows, Messages, Graphics;
 
const
  SKINSB_PROP = ‘{8BC6661E-5880-4353-878D-C3B3784CFC5F}‘;
 
type
 
  TBarPosCode = ( bpcNone,
                  bpcHArrowL, bpcHArrowR, bpcHPageL, bpcHPageR, bpcHThumb,
                  bpcVArrowU, bpcVArrowD, bpcVPageU, bpcVPageD, bpcVThumb,
                  bpcCross );
 
  TWindowProc = function (hWnd: HWND; uMsg: UINT; wParam: WPARAM; lParam: LPARAM): LRESULT; stdcall;
 
  PSkinSBInfo = ^TSkinSBInfo;
  TSkinSBInfo = packed record
    OldWndProc: TWindowProc;
    Prevent: Boolean// prevent style change message
    Scrolling: Boolean;
    Style: Cardinal// real style
    ThumbTrack: Boolean;
    ThumbPos: Integer;
    Tracking: Boolean// tracking: click arrow or track thumb
  end;
 
  TSkinSB = class
  protected
    FBitmap: TBitmap;
    constructor CreateInstance;
  public
    constructor Create;
    destructor Destroy; override;
    procedure InitSkinSB(H: HWND);
    procedure UnInitSkinSB(H: HWND);
    procedure DrawElem(H: HWND; Code: TBarPosCode; R: TRect; Down: Boolean);
  end;
 
function GetSkinSB: TSkinSB;
 
function SkinSBWndProc(hWnd: HWND; uMsg: UINT; wParam: WPARAM; lParam: LPARAM): LRESULT; stdcall;
function GetSkinSBInfo(hWnd: HWND): PSkinSBInfo;
 
implementation
 
uses
  CommCtrl;
 
{$R *.res}
 
var
  l_SkinSB: TSkinSB;
  l_SkinSB_Prop: TATOM;
 
type
  PImageImportDescriptor = ^TImageImportDescriptor;
  TImageImportDescriptor = packed record
    OriginalFirstThunk: DWORD;  // or Characteristics: DWORD
    TimeDateStamp: DWORD;
    ForwarderChain: DWORD;
    Name: DWORD;
    FirstThunk: DWORD;
  end;
  PImageChunkData = ^TImageChunkData;
  TImageChunkData = packed record
    case Integer of
      0: ( ForwarderString: DWORD );
      1: ( Func: DWORD );
      2: ( Ordinal: DWORD );
      3: ( AddressOfData: DWORD );
  end;
  PImageImportByName = ^TImageImportByName;
  TImageImportByName = packed record
    Hint: Word;
    Name: array[0..0of Byte;
  end;
 
type
  PHookRec = ^THookRec;
  THookRec = packed record
    OldFunc: Pointer;
    NewFunc: Pointer;
  end;
 
var
  _HookGetScrollInfo: THookRec;
 
procedure HookApiInMod(ImageBase: Cardinal; ApiName: PChar; PHook: PHookRec);
var
  pidh: PImageDosHeader;
  pinh: PImageNtHeaders;
  pSymbolTable: PIMAGEDATADIRECTORY;
  piid: PIMAGEIMPORTDESCRIPTOR;
  pitd_org, pitd_1st: PImageChunkData;
  piibn: PImageImportByName;
  pAPIFunction: Pointer;
  written, oldAccess: DWORD;
begin
  if ImageBase = 0 then Exit;
  pidh := PImageDosHeader(ImageBase);
  pinh := PImageNtHeaders(DWORD(ImageBase) + Cardinal(pidh^._lfanew));
  pSymbolTable := @pinh^.OptionalHeader.DataDirectory[1];
  piid := PImageImportDescriptor(DWORD(ImageBase) + pSymbolTable^.VirtualAddress);
  repeat
    pitd_org := PImageChunkData(DWORD(ImageBase) + piid^.OriginalFirstThunk);
    pitd_1st := PImageChunkData(DWORD(ImageBase) + piid^.FirstThunk);
    repeat
      piibn := PImageImportByName(DWORD(ImageBase) + LPDWORD(pitd_org)^);
      pAPIFunction := Pointer(pitd_1st^.Func);
      if StrComp(ApiName, @piibn^.Name) = 0 then
      begin
        PHook^.OldFunc := pAPIFunction;
        VirtualProtect(@(pitd_1st^.Func), SizeOf(DWORD), PAGE_WRITECOPY, oldAccess);
        WriteProcessMemory(GetCurrentProcess(), @(pitd_1st^.Func), @PHook^.NewFunc, SizeOf(DWORD), written);
        VirtualProtect(@(pitd_1st^.Func), SizeOf(DWORD), oldAccess, oldAccess);
      end;
      Inc(pitd_org);
      Inc(pitd_1st);
    until pitd_1st^.Func = 0;
    Inc(piid);
  until piid^.FirstThunk + piid^.OriginalFirstThunk + piid^.ForwarderChain + piid^.Name = 0;
end;
 
function GetSkinSBInfo(hWnd: HWND): PSkinSBInfo;
begin
  Result := PSkinSBInfo( GetProp(hWnd, MAKEINTATOM(l_SkinSB_Prop)) );
end;
 
function GetSkinSB: TSkinSB;
begin
  if l_SkinSB = nil then l_SkinSB := TSkinSB.CreateInstance;
  Result := l_SkinSB;
end;
 
function CalcScrollBarRect(H: HWND; nBarCode: Cardinal): TRect;
var
  Style, ExStyle: Cardinal;
begin
  SetRect(Result, 0000);
  Style := GetWindowLong(H, GWL_STYLE);
  ExStyle := GetWindowLong(H, GWL_EXSTYLE);
  if (nBarCode = SB_HORZ) and ((Style and WS_HSCROLL) = 0then Exit;
  if (nBarCode = SB_VERT) and ((Style and WS_VSCROLL) = 0then Exit;
  GetWindowRect(H, Result);
  OffsetRect(Result, -Result.Left, -Result.Top);
  if ((ExStyle and WS_EX_DLGMODALFRAME) <> 0)
    or ((ExStyle and WS_EX_CLIENTEDGE) <> 0then
  begin
    InflateRect(Result, -GetSystemMetrics(SM_CXEDGE), -GetSystemMetrics(SM_CYEDGE));
  end;
  // special: returns the cross
  if nBarCode = SB_BOTH then
  begin
    if ((Style and WS_HSCROLL) = 0or ((Style and WS_VSCROLL) = 0then
    begin
      SetRect(Result, 0000);
      Exit;
    end;
    Result.Top := Result.Bottom - GetSystemMetrics(SM_CYVSCROLL);
    if (ExStyle and WS_EX_LEFTSCROLLBAR) <> 0 then Result.Right := Result.Left + GetSystemMetrics(SM_CXHSCROLL)
    else Result.Left := Result.Right - GetSystemMetrics(SM_CXHSCROLL);
    Exit;
  end;
  if nBarCode = SB_HORZ then
  begin
  //    if (ExStyle and WS_EX_TOPSCROLLBAR) <> 0 then Result.Bottom := Result.Top + GetSystemMetrics(SM_CYVSCROLL)
    Result.Top := Result.Bottom - GetSystemMetrics(SM_CYVSCROLL);
    if ((Style and WS_VSCROLL) <> 0then Dec(Result.Right, GetSystemMetrics(SM_CYVSCROLL));
  end;
  if nBarCode = SB_VERT then
  begin
    if (ExStyle and WS_EX_LEFTSCROLLBAR) <> 0 then Result.Right := Result.Left + GetSystemMetrics(SM_CXHSCROLL)
    else Result.Left := Result.Right - GetSystemMetrics(SM_CXHSCROLL);
    if ((Style and WS_HSCROLL) <> 0then Dec(Result.Bottom, GetSystemMetrics(SM_CXHSCROLL));
  end;
end;
 
type
  TBarElem = (beArrow1, beBG, beThumb, beArrow2);
  TBarElemRects = array[TBarElem] of TRect;
 
function CalcBarElemRects(hWnd: HWND; nBarCode: Integer): TBarElemRects;
var
  R: TRect;
  SI: TScrollInfo;
  ThumbSize: Integer;
  X, L, H, BlockH, BlockV: Integer;
begin
  R := CalcScrollBarRect(hWnd, nBarCode);
  SI.cbSize := SizeOf(SI);
  SI.fMask := SIF_ALL;
  GetScrollInfo(hWnd, nBarCode, SI);
  Result[beArrow1] := R;
  Result[beArrow2] := R;
  Result[beBG] := R;
  Result[beThumb] := R;
  if nBarCode = SB_VERT then
  begin
    BlockV := GetSystemMetrics(SM_CYVSCROLL);
    L := Result[beArrow1].Top + BlockV;
    H := Result[beArrow2].Bottom - BlockV;
    Result[beArrow1].Bottom := L;
    Result[beArrow2].Top := H;
//    Inc(L);
//    Dec(H);
    Result[beBG].Top := L;
    Result[beBG].Bottom := H;
  end
  else
  begin
    BlockH := GetSystemMetrics(SM_CXHSCROLL);
    L := Result[beArrow1].Left + BlockH;
    H := Result[beArrow2].Right - BlockH;
    Result[beArrow1].Right := L;
    Result[beArrow2].Left := H;
//    Inc(L);
//    Dec(H);
    Result[beBG].Left := L;
    Result[beBG].Right := H;
  end;
  if SI.nMax - SI.nMin - Integer(SI.nPage) + 1 <= 0 then
  begin
    // max thumb, no thumb
    if nBarCode = SB_VERT then
    begin
      Result[beThumb].Top := L;
      Result[beThumb].Bottom := H;
    end
    else
    begin
      Result[beThumb].Left := L;
      Result[beThumb].Right := H;
    end;
    Exit;
  end;
  ThumbSize := MulDiv(H - L, SI.nPage, SI.nMax - SI.nMin + 1);
  X := L + MulDiv(SI.nTrackPos, H - ThumbSize - L, SI.nMax - Integer(SI.nPage) - SI.nMin + 1);
  if nBarCode = SB_VERT then
  begin
    Result[beThumb].Top := X;
    Result[beThumb].Bottom := X + ThumbSize;
  end
  else
  begin
    Result[beThumb].Left := X;
    Result[beThumb].Right := X + ThumbSize;
  end;
end;
 
function GetPtBarPos(H: HWND; Pt: TPoint): TBarPosCode;
var
  R: TRect;
  BR: TBarElemRects;
begin
  Result := bpcNone;
  R := CalcScrollBarRect(H, SB_HORZ);
  InflateRect(R, GetSystemMetrics(SM_CXEDGE), GetSystemMetrics(SM_CYEDGE));
  if PtInRect(R, Pt) then
  begin
    BR := CalcBarElemRects(H, SB_HORZ);
    if PtInRect(BR[beArrow1], Pt) then Result := bpcHArrowL
    else if PtInRect(BR[beThumb], Pt) then Result := bpcHThumb
    else if PtInRect(BR[beArrow2], Pt) then Result := bpcHArrowR
    else if Pt.X < BR[beThumb].Left then Result := bpcHPageL
    else Result := bpcHPageR;
    Exit;
  end;
  R := CalcScrollBarRect(H, SB_VERT);
  InflateRect(R, GetSystemMetrics(SM_CXEDGE), GetSystemMetrics(SM_CYEDGE));
  if PtInRect(R, Pt) then
  begin
    BR := CalcBarElemRects(H, SB_VERT);
    if PtInRect(BR[beArrow1], Pt) then Result := bpcVArrowU
    else if PtInRect(BR[beThumb], Pt) then Result := bpcVThumb
    else if PtInRect(BR[beArrow2], Pt) then Result := bpcVArrowD
    else if Pt.Y < BR[beThumb].Top then Result := bpcVPageU
    else Result := bpcVPageD;
    Exit;
  end;
end;
 
type
  TGetScrollInfoFunc = function (H: HWND; Code: Integervar SI: TScrollInfo): Boolean; stdcall;
 
function _SkinSB_GetScrollInfo(H: HWND; Code: Integervar SI: TScrollInfo): Boolean; stdcall;
var
  P: PSkinSBInfo;
begin
  Result := TGetScrollInfoFunc(_HookGetScrollInfo.OldFunc)(H, Code, SI);
  P := GetSkinSBInfo(H);
  if (P <> niland P^.ThumbTrack and ((SI.fMask and SIF_TRACKPOS) <> 0then
  begin
    SI.nTrackPos := P^.ThumbPos;
  end;
end;
 
{ TSkinSB }
 
constructor TSkinSB.Create;
begin
  raise Exception.Create(‘use GetSkinSB.‘);
end;
 
constructor TSkinSB.CreateInstance;
begin
  inherited;
  _HookGetScrollInfo.OldFunc := nil;
  _HookGetScrollInfo.NewFunc := @_SkinSB_GetScrollInfo;
  HookApiInMod( GetModuleHandle(‘comctl32.dll‘), ‘GetScrollInfo‘, @_HookGetScrollInfo );
  FBitmap := TBitmap.Create;
  FBitmap.LoadFromResourceName(hInstance, ‘scrollbar‘);
end;
 
destructor TSkinSB.Destroy;
begin
  FreeAndNil(FBitmap);
  inherited;
end;
 
procedure TSkinSB.DrawElem(H: HWND; Code: TBarPosCode; R: TRect;
  Down: Boolean);
var
  Canvas: TCanvas;
begin
  Canvas := TCanvas.Create;
  try
    Canvas.Handle := GetWindowDC(H);
    try
      case Code of
        bpcHArrowL:
        begin
          if Down then BitBlt(Canvas.Handle, R.Left, R.Top, 1616, FBitmap.Canvas.Handle, 640, SRCCOPY)
          else BitBlt(Canvas.Handle, R.Left, R.Top, 1616, FBitmap.Canvas.Handle, 00, SRCCOPY);
          Exit;
        end;
        bpcHArrowR:
        begin
          if Down then BitBlt(Canvas.Handle, R.Left, R.Top, 1616, FBitmap.Canvas.Handle, 800, SRCCOPY)
          else BitBlt(Canvas.Handle, R.Left, R.Top, 1616, FBitmap.Canvas.Handle, 160, SRCCOPY);
          Exit;
        end;
        bpcHThumb:
        begin
          BitBlt(Canvas.Handle, R.Left, R.Top, 216, FBitmap.Canvas.Handle, 1280, SRCCOPY);
          BitBlt(Canvas.Handle, R.Right - 2, R.Top, 216, FBitmap.Canvas.Handle, 1420, SRCCOPY);
          StretchBlt(Canvas.Handle, R.Left + 2, R.Top, R.Right - R.Left - 416, FBitmap.Canvas.Handle,
            13001216, SRCCOPY);
          Exit;
        end;
        bpcHPageL, bpcHPageR:
        begin
          if R.Right - R.Left < 4 then
          begin
            StretchBlt(Canvas.Handle, R.Left, R.Top, R.Right - R.Left, 16, FBitmap.Canvas.Handle,
              16001616, SRCCOPY);
          end
          else
          begin
            BitBlt(Canvas.Handle, R.Left, R.Top, 216, FBitmap.Canvas.Handle, 1600, SRCCOPY);
            BitBlt(Canvas.Handle, R.Right - 2, R.Top, 216, FBitmap.Canvas.Handle, 1740, SRCCOPY);
            StretchBlt(Canvas.Handle, R.Left + 2, R.Top, R.Right - R.Left - 416, FBitmap.Canvas.Handle,
              16201216, SRCCOPY);
          end;
          Exit;
        end;
        bpcVArrowU:
        begin
          if Down then BitBlt(Canvas.Handle, R.Left, R.Top, 1616, FBitmap.Canvas.Handle, 960, SRCCOPY)
          else BitBlt(Canvas.Handle, R.Left, R.Top, 1616, FBitmap.Canvas.Handle, 320, SRCCOPY);
          Exit;
        end;
        bpcVArrowD:
        begin
          if Down then BitBlt(Canvas.Handle, R.Left, R.Top, 1616, FBitmap.Canvas.Handle, 1120, SRCCOPY)
          else BitBlt(Canvas.Handle, R.Left, R.Top, 1616, FBitmap.Canvas.Handle, 480, SRCCOPY);
          Exit;
        end;
        bpcVThumb:
        begin
          BitBlt(Canvas.Handle, R.Left, R.Top, 162, FBitmap.Canvas.Handle, 1440, SRCCOPY);
          BitBlt(Canvas.Handle, R.Left, R.Bottom - 2162, FBitmap.Canvas.Handle, 14414, SRCCOPY);
          StretchBlt(Canvas.Handle, R.Left, R.Top + 216, R.Bottom - R.Top - 4, FBitmap.Canvas.Handle,
            14421612, SRCCOPY);
          Exit;
        end;
        bpcVPageU, bpcVPageD:
        begin
          if R.Bottom - R.Top < 4 then
          begin
            StretchBlt(Canvas.Handle, R.Left, R.Top, 16, R.Bottom - R.Top, FBitmap.Canvas.Handle,
              17601616, SRCCOPY);
          end
          else
          begin
            BitBlt(Canvas.Handle, R.Left, R.Top, 162, FBitmap.Canvas.Handle, 1760, SRCCOPY);
            BitBlt(Canvas.Handle, R.Left, R.Bottom - 2162, FBitmap.Canvas.Handle, 17614, SRCCOPY);
            StretchBlt(Canvas.Handle, R.Left, R.Top + 216, R.Bottom - R.Top - 4, FBitmap.Canvas.Handle,
              17621612, SRCCOPY);
          end;
          Exit;
        end;
      end;
      Canvas.Pen.Color := clBlack;
      Canvas.Brush.Color := clWhite;
      Canvas.Rectangle(R);
    finally
      ReleaseDC(H, Canvas.Handle);
    end;
  finally
    Canvas.Handle := 0;
    FreeAndNil(Canvas);
  end;
end;
 
procedure TSkinSB.InitSkinSB(H: HWND);
var
  PInfo: PSkinSBInfo;
begin
  PInfo := GetSkinSBInfo(H);
  if PInfo <> nil then Exit; // already inited
  New(PInfo);
  PInfo^.OldWndProc := TWindowProc(GetWindowLong(H, GWL_WNDPROC));
  PInfo^.Style := GetWindowLong(H, GWL_STYLE);
  PInfo^.Prevent := False;
  PInfo^.Scrolling := False;
  PInfo^.ThumbTrack := False;
  SetWindowLong(H, GWL_WNDPROC, Cardinal(@SkinSBWndProc));
  SetProp(H, MAKEINTATOM(l_SkinSB_Prop), Cardinal(PInfo));
end;
 
procedure TSkinSB.UnInitSkinSB(H: HWND);
var
  PInfo: PSkinSBInfo;
begin
  PInfo := GetSkinSBInfo(H);
  if PInfo = nil then Exit; // not inited
  RemoveProp(H, MAKEINTATOM(l_SkinSB_Prop));
  SetWindowLong(H, GWL_WNDPROC, Cardinal(@PInfo^.OldWndProc));
  Dispose(PInfo);
end;
 
const
  WM_REPEAT_CLICK = WM_USER + $6478;
 
procedure OnRepeatClickTimer(hWnd: HWND; uMsg: UINT; idEvent: UINT; dwTime: DWORD); stdcall;
begin
  KillTimer(0, idEvent);
  PostThreadMessage(MainThreadID, WM_REPEAT_CLICK, 00);
end;
 
procedure RedrawScrollBars(hWnd: HWND);
var
  RHBar, RVBar, RCross: TRect;
  BR: TBarElemRects;
begin
  RHBar := CalcScrollBarRect(hWnd, SB_HORZ);
  if not IsRectEmpty(RHBar) then
  begin
    BR := CalcBarElemRects(hWnd, SB_HORZ);
    GetSkinSB.DrawElem(hWnd, bpcHPageL, Rect(BR[beBG].Left, BR[beBG].Top, BR[beThumb].Left, BR[beBG].Bottom), False);
    GetSkinSB.DrawElem(hWnd, bpcHPageR, Rect(BR[beThumb].Right, BR[beBG].Top, BR[beBG].Right, BR[beBG].Bottom), False);
    GetSkinSB.DrawElem(hWnd, bpcHThumb, BR[beThumb], False);
    GetSkinSB.DrawElem(hWnd, bpcHArrowL, BR[beArrow1], False);
    GetSkinSB.DrawElem(hWnd, bpcHArrowR, BR[beArrow2], False);
  end;
  RVBar := CalcScrollBarRect(hWnd, SB_VERT);
  if not IsRectEmpty(RVBar) then
  begin
    BR := CalcBarElemRects(hWnd, SB_VERT);
    GetSkinSB.DrawElem(hWnd, bpcVPageU, Rect(BR[beBG].Left, BR[beBG].Top, BR[beBG].Right, BR[beThumb].Top), False);
    GetSkinSB.DrawElem(hWnd, bpcVPageD, Rect(BR[beBG].Left, BR[beThumb].Bottom, BR[beBG].Right, BR[beBG].Bottom), False);
    GetSkinSB.DrawElem(hWnd, bpcVThumb, BR[beThumb], False);
    GetSkinSB.DrawElem(hWnd, bpcVArrowU, BR[beArrow1], False);
    GetSkinSB.DrawElem(hWnd, bpcVArrowD, BR[beArrow2], False);
  end;
  RCross := CalcScrollBarRect(hWnd, SB_BOTH);
  if not IsRectEmpty(RCross) then
  begin
    GetSkinSB.DrawElem(hWnd, bpcCross, RCross, False);
  end;
end;
 
procedure TrackBar(hWnd: HWND; nBarCode: Integer; PosCode: TBarPosCode; BarElem: TBarElem; MsgCode: Integer);
var
  BR: TBarElemRects;
  Msg: tagMSG;
  Pt: TPoint;
  R: TRect;
  ScrollMsg: Cardinal;
  RepeatClick: Boolean;
  idEvent: UINT;
  SI: TScrollInfo;
 
  procedure RefreshRect;
  begin
    BR := CalcBarElemRects(hWnd, nBarCode);
    R := BR[BarElem];
  end;
 
begin
  RepeatClick := False;
  BR := CalcBarElemRects(hWnd, nBarCode);
  R := BR[BarElem];
  GetScrollInfo(hWnd, nBarCode, SI);
  if nBarCode = SB_HORZ then ScrollMsg := WM_HSCROLL
  else ScrollMsg := WM_VSCROLL;
  if BarElem = beBG then
  begin
    if PosCode = bpcHPageL then R.Right := BR[beThumb].Left
    else if PosCode = bpcHPageR then R.Left := BR[beThumb].Right
    else if PosCode = bpcVPageU then R.Bottom := BR[beThumb].Top
    else if PosCode = bpcVPageD then R.Top := BR[beThumb].Bottom;
  end;
  GetSkinSB.DrawElem(hWnd, PosCode, R, True);
  GetSkinSBInfo(hWnd)^.Tracking := True;
  idEvent := 0;
  try
    SetCapture(hWnd);
    idEvent := SetTimer(001000, @OnRepeatClickTimer);
    while GetCapture = hWnd do
    begin
      if not GetMessage(Msg, 000then Break;
      if (Msg.hwnd = 0and (Msg.message = WM_REPEAT_CLICK) then
      begin
        GetCursorPos(Pt);
        ScreenToClient(hWnd, Pt);
        if PtInRect(R, Pt) then
        begin
          RepeatClick := True;
          SendMessage(hWnd, ScrollMsg, MsgCode, 0);
          SendMessage(hWnd, ScrollMsg, SB_ENDSCROLL, 0);
          RefreshRect;
          GetSkinSB.DrawElem(hWnd, PosCode, R, True);
//          if MsgCode = SB_LINEDOWN then SetScrollPos(hWnd, nBarCode, GetScrollPos(hWnd, nBarCode) + 1, False);
          if MsgCode = SB_PAGEDOWN then SetScrollPos(hWnd, nBarCode, GetScrollPos(hWnd, nBarCode) + Integer(SI.nPage), False);
//          if MsgCode = SB_LINEUP then SetScrollPos(hWnd, nBarCode, GetScrollPos(hWnd, nBarCode) - 1, False);
          if MsgCode = SB_PAGEUP then SetScrollPos(hWnd, nBarCode, GetScrollPos(hWnd, nBarCode) - Integer(SI.nPage), False);
          RedrawScrollBars(hWnd);
          SetTimer(0080, @OnRepeatClickTimer);
        end;
      end
      else if Msg.hwnd = hWnd then
      begin
        case Msg.message of
          WM_LBUTTONUP:
          begin
            if RepeatClick then Break;
            GetCursorPos(Pt);
            ScreenToClient(hWnd, Pt);
            if PtInRect(R, Pt) then
            begin
              SendMessage(hWnd, ScrollMsg, MsgCode, 0);
              SendMessage(hWnd, ScrollMsg, SB_ENDSCROLL, 0);
              RefreshRect;
//              if MsgCode = SB_LINEDOWN then SetScrollPos(hWnd, nBarCode, GetScrollPos(hWnd, nBarCode) + 1, False);
              if MsgCode = SB_PAGEDOWN then SetScrollPos(hWnd, nBarCode, GetScrollPos(hWnd, nBarCode) + Integer(SI.nPage), False);
//              if MsgCode = SB_LINEUP then SetScrollPos(hWnd, nBarCode, GetScrollPos(hWnd, nBarCode) - 1, False);
              if MsgCode = SB_PAGEUP then SetScrollPos(hWnd, nBarCode, GetScrollPos(hWnd, nBarCode) - Integer(SI.nPage), False);
            end;
            Break;
          end;
        end;
      end;
      DispatchMessage(Msg);
    end;
  finally
    if idEvent <> 0 then KillTimer(0, idEvent);
    if IsWindow(hWnd) then
    begin
      if GetCapture = hWnd then ReleaseCapture;
      GetSkinSB.DrawElem(hWnd, PosCode, R, False);
      GetSkinSBInfo(hWnd)^.Tracking := False;
    end;
  end;
end;
 
procedure TrackThumb(hWnd: HWND; nBarCode: Integer; PosCode: TBarPosCode; BarElem: TBarElem);
var
  BR: TBarElemRects;
  Msg: tagMSG;
  Pt: TPoint;
  DragX: Integer;
  R: TRect;
  ScrollMsg: Cardinal;
  SI, SI2: TScrollInfo;
  Pos: Integer;
  H, L, ThumbSize, X: Integer;
  Pushed: Boolean;
 
  function ValidDragArea(ARect: TRect; APt: TPoint): Boolean;
  begin
    if nBarCode = SB_HORZ then Result := Abs((ARect.Bottom + ARect.Top) div 2 - APt.Y) < 150
    else Result := Abs((ARect.Left + ARect.Right) div 2 - APt.X) < 150;
  end;
 
  function CalcPos(ARect: TRect; APt: TPoint; ADragX: Integer): Integer;
  var
    NewX: Integer;
  begin
    if nBarCode = SB_HORZ then NewX := APt.X - ADragX
    else NewX := APt.Y - ADragX;
    Result := SI.nMin + MulDiv(NewX - L, SI.nMax - Integer(SI.nPage) - SI.nMin + 1, H - L - ThumbSize);
    if Result < SI.nMin then Result := SI.nMin;
    if Result > SI.nMax - Integer(SI.nPage) + 1 then
      Result := SI.nMax - Integer(SI.nPage) + 1;
  end;
 
  procedure UpdateDragBar(ADown: Boolean; APos: Integer = -10000);
  var
    W: Integer;
  begin
    BR := CalcBarElemRects(hWnd, nBarCode);
    R := BR[BarElem];
    if nBarCode = SB_HORZ then
    begin
      if APos <> -10000 then
      begin
        W := R.Right - R.Left;
        if APos < BR[beArrow1].Right then APos := BR[beArrow1].Right;
        if APos + W > BR[beArrow2].Left then APos := BR[beArrow2].Left - W;
        R.Left := APos;
        R.Right := APos + W;
      end;
      GetSkinSB.DrawElem(hWnd, bpcHPageL, Rect(BR[beBG].Left, BR[beBG].Top, R.Left, BR[beBG].Bottom), False);
      GetSkinSB.DrawElem(hWnd, bpcHPageR, Rect(R.Right, BR[beBG].Top, BR[beBG].Right, BR[beBG].Bottom), False);
    end
    else
    begin
      if APos <> -10000 then
      begin
        W := R.Bottom - R.Top;
        if APos < BR[beArrow1].Bottom then APos := BR[beArrow1].Bottom;
        if APos + W >= BR[beArrow2].Top then APos := BR[beArrow2].Top - W - 1;
        R.Top := APos;
        R.Bottom := APos + W;
      end;
      GetSkinSB.DrawElem(hWnd, bpcVPageU, Rect(BR[beBG].Left, BR[beBG].Top, BR[beBG].Right, R.Top), False);
      GetSkinSB.DrawElem(hWnd, bpcVPageD, Rect(BR[beBG].Left, R.Bottom, BR[beBG].Right, BR[beBG].Bottom), False);
    end;
    GetSkinSB.DrawElem(hWnd, PosCode, R, ADown);
    OutputDebugString(PChar(Format(‘R=(%d,%d,%d,%d)‘, [R.Left, R.Top, R.Right, R.Bottom])));
  end;
 
begin
  BR := CalcBarElemRects(hWnd, nBarCode);
  R := BR[BarElem];
  if nBarCode = SB_HORZ then ScrollMsg := WM_HSCROLL
  else ScrollMsg := WM_VSCROLL;
  SI.cbSize := SizeOf(SI);
  SI.fMask := SIF_ALL;
  GetScrollInfo(hWnd, nBarCode, SI);
  GetCursorPos(Pt);
  ScreenToClient(hWnd, Pt);
  if nBarCode = SB_HORZ then
  begin
    DragX := Pt.X - BR[beThumb].Left;
    ThumbSize := BR[beThumb].Right - BR[beThumb].Left;
    L := BR[beArrow1].Right;
    H := BR[beArrow2].Left;
  end
  else
  begin
    DragX := Pt.Y - BR[beThumb].Top;
    ThumbSize := BR[beThumb].Bottom - BR[beThumb].Top;
    L := BR[beArrow1].Bottom;
    H := BR[beArrow2].Top;
  end;
{  if nBarCode = SB_HORZ then SendMessage(hWnd, WM_SYSCOMMAND, SC_HSCROLL, MAKELPARAM(Pt.X, Pt.Y))
  else SendMessage(hWnd, WM_SYSCOMMAND, SC_VSCROLL, MAKELPARAM(Pt.X, Pt.Y)); }
  GetSkinSBInfo(hWnd)^.Tracking := True;
  UpdateDragBar(True);
  try
    SetCapture(hWnd);
    while GetCapture = hWnd do
    begin
      if not GetMessage(Msg, 000then Break;
      if Msg.hwnd = hWnd then
      begin
        case Msg.message of
          WM_MOUSEMOVE:
          begin
            Pushed := ValidDragArea(R, Pt);
            GetCursorPos(Pt);
            ScreenToClient(hWnd, Pt);
            if ValidDragArea(R, Pt) then
            begin
              Pos := CalcPos(R, Pt, DragX);
              if nBarCode = SB_HORZ then X := Pt.X - DragX
              else X := Pt.Y - DragX;
            end
            else
            begin
              Pos := SI.nPos;
              X := DragX;
            end;
            GetSkinSBInfo(hWnd)^.ThumbPos := Pos;
            GetSkinSBInfo(hWnd)^.ThumbTrack := True;
            SendMessage(hWnd, ScrollMsg, MAKEWPARAM(SB_THUMBTRACK, Pos), 0);
            GetSkinSBInfo(hWnd)^.ThumbTrack := False;
            UpdateDragBar(Pushed, X);
          end;
          WM_LBUTTONUP:
          begin
            GetCursorPos(Pt);
            ScreenToClient(hWnd, Pt);
            if ValidDragArea(R, Pt) then
            begin
              Pos := CalcPos(R, Pt, DragX);
              SI2.cbSize := SizeOf(SI2);
              SI2.fMask := SIF_ALL;
              GetScrollInfo(hWnd, nBarCode, SI2);
              SI2.nPos := Pos;
              SI2.nTrackPos := Pos;
              SetScrollInfo(hWnd, nBarCode, SI2, False);
              SI2.nTrackPos := 0;
              SI2.nPos := 0;
              GetScrollInfo(hWnd, nBarCode, SI2);
              SendMessage(hWnd, ScrollMsg, MAKEWPARAM(SB_THUMBPOSITION, Pos), 0);
              SendMessage(hWnd, ScrollMsg, SB_ENDSCROLL, 0);
            end;
            Break;
          end;
        end;
      end;
      DispatchMessage(Msg);
    end;
  finally
    if IsWindow(hWnd) then
    begin
      if GetCapture = hWnd then ReleaseCapture;
      GetSkinSBInfo(hWnd)^.Tracking := False;
    end;
    UpdateDragBar(False);
  end;
end;
 
function SkinSBWndProc(hWnd: HWND; uMsg: UINT; wParam: WPARAM; lParam: LPARAM): LRESULT;
var
  PInfo: PSkinSBInfo;
  Style, ExStyle: Cardinal;
  R, RHBar, RVBar, RCross: TRect;
  Pt: TPoint;
  Rgn, Rgn2: HRGN;
  PR: PRect;
  BR: TBarElemRects;
  XBar, YBar: Integer;
begin
  PInfo := GetSkinSBInfo(hWnd);
  if PInfo = nil then Result := DefWindowProc(hWnd, uMsg, wParam, lParam) //// error!!!
  else
  begin
    case uMsg of
      WM_NCHITTEST:
      begin
        GetCursorPos(Pt);
        ScreenToClient(hWnd, Pt);
        case GetPtBarPos(hWnd, Pt) of
          bpcHArrowL:
          begin
            if (GetKeyState(VK_LBUTTON) and $8000) <> 0 then
            begin
              if GetCapture <> hWnd then
                TrackBar(hWnd, SB_HORZ, bpcHArrowL, beArrow1, SB_LINELEFT);
            end;
            Result := HTNOWHERE;
            Exit;
          end;
          bpcHArrowR:
          begin
            if (GetKeyState(VK_LBUTTON) and $8000) <> 0 then
            begin
              if GetCapture <> hWnd then
                TrackBar(hWnd, SB_HORZ, bpcHArrowR, beArrow2, SB_LINERIGHT);
            end;
            Result := HTNOWHERE;
            Exit;
          end;
          bpcHPageL:
          begin
            if (GetKeyState(VK_LBUTTON) and $8000) <> 0 then
            begin
              if GetCapture <> hWnd then
              begin
                TrackBar(hWnd, SB_HORZ, bpcHPageL, beBG, SB_PAGELEFT);
                RedrawScrollBars(hWnd);
              end;
            end;
            Result := HTNOWHERE;
            Exit;
          end;
          bpcHPageR:
          begin
            if (GetKeyState(VK_LBUTTON) and $8000) <> 0 then
            begin
              if GetCapture <> hWnd then
              begin
                TrackBar(hWnd, SB_HORZ, bpcHPageR, beBG, SB_PAGERIGHT);
                RedrawScrollBars(hWnd);
              end;
            end;
            Result := HTNOWHERE;
            Exit;
          end;
          bpcHThumb:
          begin
            if (GetKeyState(VK_LBUTTON) and $8000) <> 0 then
            begin
              if GetCapture <> hWnd then
                TrackThumb(hWnd, SB_HORZ, bpcHThumb, beThumb);
            end;
            Result := HTNOWHERE;
            Exit;
          end;
 
          bpcVArrowU:
          begin
            if (GetKeyState(VK_LBUTTON) and $8000) <> 0 then
            begin
              if GetCapture <> hWnd then
                TrackBar(hWnd, SB_VERT, bpcVArrowU, beArrow1, SB_LINELEFT);
            end;
            Result := HTNOWHERE;
            Exit;
          end;
          bpcVArrowD:
          begin
            if (GetKeyState(VK_LBUTTON) and $8000) <> 0 then
            begin
              if GetCapture <> hWnd then
                TrackBar(hWnd, SB_VERT, bpcVArrowD, beArrow2, SB_LINERIGHT);
            end;
            Result := HTNOWHERE;
            Exit;
          end;
          bpcVPageU:
          begin
            if (GetKeyState(VK_LBUTTON) and $8000) <> 0 then
            begin
              if GetCapture <> hWnd then
              begin
                TrackBar(hWnd, SB_VERT, bpcVPageU, beBG, SB_PAGELEFT);
                RedrawScrollBars(hWnd);
              end;
            end;
            Result := HTNOWHERE;
            Exit;
          end;
          bpcVPageD:
          begin
            if (GetKeyState(VK_LBUTTON) and $8000) <> 0 then
            begin
              if GetCapture <> hWnd then
              begin
                TrackBar(hWnd, SB_VERT, bpcVPageD, beBG, SB_PAGERIGHT);
                RedrawScrollBars(hWnd);
              end;
            end;
            Result := HTNOWHERE;
            Exit;
          end;
          bpcVThumb:
          begin
            if (GetKeyState(VK_LBUTTON) and $8000) <> 0 then
            begin
              if GetCapture <> hWnd then
                TrackThumb(hWnd, SB_VERT, bpcVThumb, beThumb);
            end;
            Result := HTNOWHERE;
            Exit;
          end;
        end;
      end;
      WM_HSCROLL:
      begin
        PInfo^.Scrolling := True;
        Style := GetWindowLong(hWnd, GWL_STYLE);
        PInfo^.Style := Style;
        PInfo^.Prevent := True;
        try
          SetWindowLong(hWnd, GWL_STYLE, Style and (not (WS_VSCROLL or WS_HSCROLL)));
        finally
          PInfo^.Prevent := False;
        end;
        Result := CallWindowProc(@PInfo^.OldWndProc, hWnd, uMsg, wParam, lParam);
        RedrawScrollBars(hWnd);
        PInfo^.Prevent := True;
        try
          SetWindowLong(hWnd, GWL_STYLE, Style);
        finally
          PInfo^.Prevent := False;
        end;
        PInfo^.Scrolling := False;
        Exit;
      end;
 
      WM_VSCROLL:
      begin
        PInfo^.Scrolling := True;
        Style := GetWindowLong(hWnd, GWL_STYLE);
        PInfo^.Style := Style;
        PInfo^.Prevent := True;
        try
          SetWindowLong(hWnd, GWL_STYLE, Style and (not (WS_VSCROLL or WS_HSCROLL)));
        finally
          PInfo^.Prevent := False;
        end;
        Result := CallWindowProc(@PInfo^.OldWndProc, hWnd, uMsg, wParam, lParam);
        PInfo^.Prevent := True;
        try
          SetWindowLong(hWnd, GWL_STYLE, Style);
        finally
          PInfo^.Prevent := False;
        end;
        PInfo^.Scrolling := False;
        Exit;
      end;
      WM_STYLECHANGED:
      begin
        if wParam = GWL_STYLE then
        begin
          if PInfo^.Prevent then
          begin
            Result := 0;
            Exit;
          end
          else
          begin
            PInfo^.Style := GetWindowLong(hWnd, GWL_STYLE);
          end;
        end;
      end;
      WM_NCCALCSIZE:
      begin
        Style := GetWindowLong(hWnd, GWL_STYLE);
        ExStyle := GetWindowLong(hWnd, GWL_EXSTYLE);
        XBar := GetSystemMetrics(SM_CXVSCROLL);
        YBar := GetSystemMetrics(SM_CYHSCROLL);
        if PInfo^.Scrolling then
        begin
          PInfo^.Prevent := True;
          try
            SetWindowLong(hWnd, GWL_STYLE, Style and (not (WS_HSCROLL or WS_VSCROLL)));  // real style
          finally
            PInfo^.Prevent := False;
          end;
        end;
        Result := CallWindowProc(@PInfo^.OldWndProc, hWnd, uMsg, wParam, lParam);
        if PInfo^.Scrolling then
        begin
          PR := PRect(lParam);
          if (PInfo^.Style and WS_VSCROLL) <> 0 then
          begin
            if (ExStyle and WS_EX_LEFTSCROLLBAR) <> 0 then Inc(PR^.Left, XBar)
            else Dec(PR^.Right, XBar);
          end;
          if (PInfo^.Style and WS_HSCROLL) <> 0 then
          begin
            Dec(PR^.Bottom, YBar);
          end;
        end;
        if PInfo^.Scrolling then
        begin
          PInfo^.Prevent := True;
          try
            SetWindowLong(hWnd, GWL_STYLE, Style);  // old style
          finally
            PInfo^.Prevent := False;
          end;
        end;
        Exit;
      end;
      WM_NCPAINT:
      begin
        GetWindowRect(hWnd, R);
        Pt := R.TopLeft;
        if wParam = 1 then
        begin
          Rgn := CreateRectRgn(Pt.X, Pt.Y, Pt.X + R.Right, Pt.Y + R.Bottom);
        end else Rgn := wParam;
        RHBar := CalcScrollBarRect(hWnd, SB_HORZ);
        OffsetRect(RHBar, Pt.X, PT.Y);
        if not IsRectEmpty(RHBar) then
        begin
          BR := CalcBarElemRects(hWnd, SB_HORZ);
          GetSkinSB.DrawElem(hWnd, bpcHPageL, Rect(BR[beBG].Left, BR[beBG].Top, BR[beThumb].Left, BR[beBG].Bottom), False);
          GetSkinSB.DrawElem(hWnd, bpcHPageR, Rect(BR[beThumb].Right, BR[beBG].Top, BR[beBG].Right, BR[beBG].Bottom), False);
          GetSkinSB.DrawElem(hWnd, bpcHThumb, BR[beThumb], False);
          GetSkinSB.DrawElem(hWnd, bpcHArrowL, BR[beArrow1], False);
          GetSkinSB.DrawElem(hWnd, bpcHArrowR, BR[beArrow2], False);
        end;
        Rgn2 := CreateRectRgn(RHBar.Left, RHBar.Top, RHBar.Right, RHBar.Bottom);
        CombineRgn(Rgn, Rgn, Rgn2, RGN_DIFF);
        DeleteObject(Rgn2);
        RVBar := CalcScrollBarRect(hWnd, SB_VERT);
        if not IsRectEmpty(RVBar) then
        begin
          BR := CalcBarElemRects(hWnd, SB_VERT);
          GetSkinSB.DrawElem(hWnd, bpcVPageU, Rect(BR[beBG].Left, BR[beBG].Top, BR[beBG].Right, BR[beThumb].Top), False);
          GetSkinSB.DrawElem(hWnd, bpcVPageD, Rect(BR[beBG].Left, BR[beThumb].Bottom, BR[beBG].Right, BR[beBG].Bottom), False);
          GetSkinSB.DrawElem(hWnd, bpcVThumb, BR[beThumb], False);
          GetSkinSB.DrawElem(hWnd, bpcVArrowU, BR[beArrow1], False);
          GetSkinSB.DrawElem(hWnd, bpcVArrowD, BR[beArrow2], False);
        end;
        OffsetRect(RVBar, Pt.X, PT.Y);
        Rgn2 := CreateRectRgn(RVBar.Left, RVBar.Top, RVBar.Right, RVBar.Bottom);
        CombineRgn(Rgn, Rgn, Rgn2, RGN_DIFF);
        DeleteObject(Rgn2);
        RCross := CalcScrollBarRect(hWnd, SB_BOTH);
        if not IsRectEmpty(RCross) then
        begin
          GetSkinSB.DrawElem(hWnd, bpcCross, RCross, False);
        end;
        OffsetRect(RCross, Pt.X, PT.Y);
        Rgn2 := CreateRectRgn(RCross.Left, RCross.Top, RCross.Right, RCross.Bottom);
        CombineRgn(Rgn, Rgn, Rgn2, RGN_DIFF);
        DeleteObject(Rgn2);
        Result := CallWindowProc(@PInfo^.OldWndProc, hWnd, uMsg, Rgn, lParam);
        if wParam = 1 then DeleteObject(Rgn);
        Exit;
      end;
      WM_ERASEBKGND:
      begin
        Style := GetWindowLong(hWnd, GWL_STYLE);
        PInfo^.Prevent := True;
        try
          SetWindowLong(hWnd, GWL_STYLE, Style and (not (WS_VSCROLL or WS_HSCROLL)));
        finally
          PInfo^.Prevent := False;
        end;
 
        Result := CallWindowProc(@PInfo^.OldWndProc, hWnd, uMsg, wParam, lParam);
        PInfo^.Prevent := True;
        try
          SetWindowLong(hWnd, GWL_STYLE, Style);  // old style
        finally
          PInfo^.Prevent := False;
        end;
        Exit;
      end;
      WM_MOUSEWHEEL, WM_MOUSEMOVE:
      begin
        Result := CallWindowProc(@PInfo^.OldWndProc, hWnd, uMsg, wParam, lParam);
        if PInfo^.Tracking then Exit;
        if (uMsg = WM_MOUSEMOVE) and ((wParam and MK_LBUTTON) = 0then Exit;
        RedrawScrollBars(hWnd);
        Exit;
      end;
    end;
    Result := CallWindowProc(@PInfo^.OldWndProc, hWnd, uMsg, wParam, lParam);
  end;
end;
 
initialization
 
  l_SkinSB := nil;
  l_SkinSB_Prop := GlobalAddAtom(SKINSB_PROP);
 
finalization
 
  if Assigned(l_SkinSB) then FreeAndNil(l_SkinSB);
 
end.

补充:使用此方法后,在调用SetScrollInfo后也必须调用RedrawScrollBars重绘滚动条。Hook本模块的SetScrollInfo API是个好方法。在这里就不给出代码了。

自绘LISTVIEW的滚动条(Delphi实现)

原文:http://www.cnblogs.com/findumars/p/7192622.html

(0)
(0)
   
举报
评论 一句话评论(0
关于我们 - 联系我们 - 留言反馈 - 联系我们:wmxa8@hotmail.com
© 2014 bubuko.com 版权所有
打开技术之扣,分享程序人生!