src/generic/splitter.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        src/generic/splitter.cpp
   3 // Purpose:     wxSplitterWindow implementation
   4 // Author:      Julian Smart
   5 // Modified by:
   6 // Created:     01/02/97
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) Julian Smart
   9 // Licence:     wxWindows licence
  10 /////////////////////////////////////////////////////////////////////////////
  11
  12 #if defined(__GNUG__) && !defined(NO_GCC_PRAGMA)
  13     #pragma implementation "splitter.h"
  14 #endif
  15
  16 // For compilers that support precompilation, includes "wx.h".
  17 #include "wx/wxprec.h"
  18
  19 #if wxUSE_SPLITTER
  20
  21 #ifdef __BORLANDC__
  22     #pragma hdrstop
  23 #endif
  24
  25 #ifndef WX_PRECOMP
  26     #include "wx/string.h"
  27     #include "wx/utils.h"
  28     #include "wx/log.h"
  29
  30     #include "wx/dcscreen.h"
  31
  32     #include "wx/window.h"
  33     #include "wx/dialog.h"
  34     #include "wx/frame.h"
  35
  36     #include "wx/settings.h"
  37 #endif
  38
  39 #ifdef __WXMAC__
  40     #include "wx/mac/private.h"
  41 #endif
  42
  43 #include "wx/renderer.h"
  44
  45 #include "wx/splitter.h"
  46
  47 #include <stdlib.h>
  48
  49 DEFINE_EVENT_TYPE(wxEVT_COMMAND_SPLITTER_SASH_POS_CHANGED)
  50 DEFINE_EVENT_TYPE(wxEVT_COMMAND_SPLITTER_SASH_POS_CHANGING)
  51 DEFINE_EVENT_TYPE(wxEVT_COMMAND_SPLITTER_DOUBLECLICKED)
  52 DEFINE_EVENT_TYPE(wxEVT_COMMAND_SPLITTER_UNSPLIT)
  53
  54 IMPLEMENT_DYNAMIC_CLASS(wxSplitterWindow, wxWindow)
  55
  56 /*
  57     TODO PROPERTIES
  58         style wxSP_3D
  59         sashpos (long , 0 )
  60         minsize (long -1 )
  61         object, object_ref
  62         orientation
  63 */
  64
  65 IMPLEMENT_DYNAMIC_CLASS(wxSplitterEvent, wxNotifyEvent)
  66
  67 BEGIN_EVENT_TABLE(wxSplitterWindow, wxWindow)
  68     EVT_PAINT(wxSplitterWindow::OnPaint)
  69     EVT_SIZE(wxSplitterWindow::OnSize)
  70     EVT_MOUSE_EVENTS(wxSplitterWindow::OnMouseEvent)
  71
  72 #if defined( __WXMSW__ ) || defined( __WXMAC__)
  73     EVT_SET_CURSOR(wxSplitterWindow::OnSetCursor)
  74 #endif // wxMSW
  75
  76     WX_EVENT_TABLE_CONTROL_CONTAINER(wxSplitterWindow)
  77 END_EVENT_TABLE()
  78
  79 WX_DELEGATE_TO_CONTROL_CONTAINER(wxSplitterWindow);
  80
  81 bool wxSplitterWindow::Create(wxWindow *parent, wxWindowID id,
  82                                    const wxPoint& pos,
  83                                    const wxSize& size,
  84                                    long style,
  85                                    const wxString& name)
  86 {
  87     // allow TABbing from one window to the other
  88     style |= wxTAB_TRAVERSAL;
  89
  90     // we draw our border ourselves to blend the sash with it
  91     style &= ~wxBORDER_MASK;
  92     style |= wxBORDER_NONE;
  93
  94     if ( !wxWindow::Create(parent, id, pos, size, style, name) )
  95         return false;
  96
  97     m_permitUnsplitAlways = (style & wxSP_PERMIT_UNSPLIT) != 0;
  98
  99     return true;
 100 }
 101
 102 void wxSplitterWindow::Init()
 103 {
 104     m_container.SetContainerWindow(this);
 105
 106     m_splitMode = wxSPLIT_VERTICAL;
 107     m_permitUnsplitAlways = true;
 108     m_windowOne = (wxWindow *) NULL;
 109     m_windowTwo = (wxWindow *) NULL;
 110     m_dragMode = wxSPLIT_DRAG_NONE;
 111     m_oldX = 0;
 112     m_oldY = 0;
 113     m_firstX = 0;
 114     m_firstY = 0;
 115     m_sashPosition = m_requestedSashPosition = 0;
 116     m_checkRequestedSashPosition = false;
 117     m_minimumPaneSize = 0;
 118     m_sashCursorWE = wxCursor(wxCURSOR_SIZEWE);
 119     m_sashCursorNS = wxCursor(wxCURSOR_SIZENS);
 120     m_sashTrackerPen = new wxPen(*wxBLACK, 2, wxSOLID);
 121
 122     m_needUpdating = false;
 123     m_isHot = false;
 124 }
 125
 126 wxSplitterWindow::~wxSplitterWindow()
 127 {
 128     delete m_sashTrackerPen;
 129 }
 130
 131 // ----------------------------------------------------------------------------
 132 // entering/leaving sash
 133 // ----------------------------------------------------------------------------
 134
 135 void wxSplitterWindow::RedrawIfHotSensitive(bool isHot)
 136 {
 137     if ( wxRendererNative::Get().GetSplitterParams(this).isHotSensitive )
 138     {
 139         m_isHot = isHot;
 140
 141         wxClientDC dc(this);
 142         DrawSash(dc);
 143     }
 144     //else: we don't change our appearance, don't redraw to avoid flicker
 145 }
 146
 147 void wxSplitterWindow::OnEnterSash()
 148 {
 149     SetResizeCursor();
 150
 151     RedrawIfHotSensitive(true);
 152 }
 153
 154 void wxSplitterWindow::OnLeaveSash()
 155 {
 156     SetCursor(*wxSTANDARD_CURSOR);
 157
 158     RedrawIfHotSensitive(false);
 159 }
 160
 161 void wxSplitterWindow::SetResizeCursor()
 162 {
 163     SetCursor(m_splitMode == wxSPLIT_VERTICAL ? m_sashCursorWE
 164                                               : m_sashCursorNS);
 165 }
 166
 167 // ----------------------------------------------------------------------------
 168 // other event handlers
 169 // ----------------------------------------------------------------------------
 170
 171 void wxSplitterWindow::OnPaint(wxPaintEvent& WXUNUSED(event))
 172 {
 173     wxPaintDC dc(this);
 174
 175     DrawSash(dc);
 176 }
 177
 178 void wxSplitterWindow::OnInternalIdle()
 179 {
 180     wxWindow::OnInternalIdle();
 181
 182     // if this is the first idle time after a sash position has potentially
 183     // been set, allow SizeWindows to check for a requested size.
 184     if (!m_checkRequestedSashPosition)
 185     {
 186         m_checkRequestedSashPosition = true;
 187         SizeWindows();
 188         return; // it won't needUpdating in this case
 189     }
 190
 191     if (m_needUpdating)
 192         SizeWindows();
 193 }
 194
 195 void wxSplitterWindow::OnMouseEvent(wxMouseEvent& event)
 196 {
 197     int x = (int)event.GetX(),
 198         y = (int)event.GetY();
 199
 200     if (GetWindowStyle() & wxSP_NOSASH)
 201         return;
 202
 203     // with wxSP_LIVE_UPDATE style the splitter windows are always resized
 204     // following the mouse movement while it drags the sash, without it we only
 205     // draw the sash at the new position but only resize the windows when the
 206     // dragging is finished
 207 #if defined( __WXMAC__ ) && TARGET_API_MAC_OSX == 1
 208     bool isLive = true ;
 209 #else
 210     bool isLive = (GetWindowStyleFlag() & wxSP_LIVE_UPDATE) != 0;
 211 #endif
 212     if (event.LeftDown())
 213     {
 214         if ( SashHitTest(x, y) )
 215         {
 216             // Start the drag now
 217             m_dragMode = wxSPLIT_DRAG_DRAGGING;
 218
 219             // Capture mouse and set the cursor
 220             CaptureMouse();
 221             SetResizeCursor();
 222
 223             if ( !isLive )
 224             {
 225                 // remember the initial sash position and draw the initial
 226                 // shadow sash
 227                 m_sashPositionCurrent = m_sashPosition;
 228
 229                 DrawSashTracker(x, y);
 230             }
 231
 232             m_oldX = x;
 233             m_oldY = y;
 234
 235             SetResizeCursor();
 236             return;
 237         }
 238     }
 239     else if (event.LeftUp() && m_dragMode == wxSPLIT_DRAG_DRAGGING)
 240     {
 241         // We can stop dragging now and see what we've got.
 242         m_dragMode = wxSPLIT_DRAG_NONE;
 243
 244         // Release mouse and unset the cursor
 245         ReleaseMouse();
 246         SetCursor(* wxSTANDARD_CURSOR);
 247
 248         // exit if unsplit after doubleclick
 249         if ( !IsSplit() )
 250         {
 251             return;
 252         }
 253
 254         // Erase old tracker
 255         if ( !isLive )
 256         {
 257             DrawSashTracker(m_oldX, m_oldY);
 258         }
 259
 260         // the position of the click doesn't exactly correspond to
 261         // m_sashPosition, rather it changes it by the distance by which the
 262         // mouse has moved
 263         int diff = m_splitMode == wxSPLIT_VERTICAL ? x - m_oldX : y - m_oldY;
 264
 265         int posSashOld = isLive ? m_sashPosition : m_sashPositionCurrent;
 266         int posSashNew = OnSashPositionChanging(posSashOld + diff);
 267         if ( posSashNew == -1 )
 268         {
 269             // change not allowed
 270             return;
 271         }
 272
 273         if ( m_permitUnsplitAlways || m_minimumPaneSize == 0 )
 274         {
 275             // Deal with possible unsplit scenarios
 276             if ( posSashNew == 0 )
 277             {
 278                 // We remove the first window from the view
 279                 wxWindow *removedWindow = m_windowOne;
 280                 m_windowOne = m_windowTwo;
 281                 m_windowTwo = (wxWindow *) NULL;
 282                 OnUnsplit(removedWindow);
 283                 wxSplitterEvent event(wxEVT_COMMAND_SPLITTER_UNSPLIT, this);
 284                 event.m_data.win = removedWindow;
 285                 (void)DoSendEvent(event);
 286                 SetSashPositionAndNotify(0);
 287             }
 288             else if ( posSashNew == GetWindowSize() )
 289             {
 290                 // We remove the second window from the view
 291                 wxWindow *removedWindow = m_windowTwo;
 292                 m_windowTwo = (wxWindow *) NULL;
 293                 OnUnsplit(removedWindow);
 294                 wxSplitterEvent event(wxEVT_COMMAND_SPLITTER_UNSPLIT, this);
 295                 event.m_data.win = removedWindow;
 296                 (void)DoSendEvent(event);
 297                 SetSashPositionAndNotify(0);
 298             }
 299             else
 300             {
 301                 SetSashPositionAndNotify(posSashNew);
 302             }
 303         }
 304         else
 305         {
 306             SetSashPositionAndNotify(posSashNew);
 307         }
 308
 309         SizeWindows();
 310     }  // left up && dragging
 311     else if ((event.Moving() || event.Leaving() || event.Entering()) && (m_dragMode == wxSPLIT_DRAG_NONE))
 312     {
 313         if ( event.Leaving() || !SashHitTest(x, y) )
 314             OnLeaveSash();
 315         else
 316             OnEnterSash();
 317     }
 318     else if (event.Dragging() && (m_dragMode == wxSPLIT_DRAG_DRAGGING))
 319     {
 320         int diff = m_splitMode == wxSPLIT_VERTICAL ? x - m_oldX : y - m_oldY;
 321         if ( !diff )
 322         {
 323             // nothing to do, mouse didn't really move far enough
 324             return;
 325         }
 326
 327         int posSashOld = isLive ? m_sashPosition : m_sashPositionCurrent;
 328         int posSashNew = OnSashPositionChanging(posSashOld + diff);
 329         if ( posSashNew == -1 )
 330         {
 331             // change not allowed
 332             return;
 333         }
 334
 335         if ( posSashNew == m_sashPosition )
 336             return;
 337
 338         // Erase old tracker
 339         if ( !isLive )
 340         {
 341             DrawSashTracker(m_oldX, m_oldY);
 342         }
 343
 344         if (m_splitMode == wxSPLIT_VERTICAL)
 345             x = posSashNew;
 346         else
 347             y = posSashNew;
 348
 349         // Remember old positions
 350         m_oldX = x;
 351         m_oldY = y;
 352
 353 #ifdef __WXMSW__
 354         // As we captured the mouse, we may get the mouse events from outside
 355         // our window - for example, negative values in x, y. This has a weird
 356         // consequence under MSW where we use unsigned values sometimes and
 357         // signed ones other times: the coordinates turn as big positive
 358         // numbers and so the sash is drawn on the *right* side of the window
 359         // instead of the left (or bottom instead of top). Correct this.
 360         if ( (short)m_oldX < 0 )
 361             m_oldX = 0;
 362         if ( (short)m_oldY < 0 )
 363             m_oldY = 0;
 364 #endif // __WXMSW__
 365
 366         // Draw new one
 367         if ( !isLive )
 368         {
 369             m_sashPositionCurrent = posSashNew;
 370
 371             DrawSashTracker(m_oldX, m_oldY);
 372         }
 373         else
 374         {
 375             SetSashPositionAndNotify(posSashNew);
 376             m_needUpdating = true;
 377         }
 378     }
 379     else if ( event.LeftDClick() && m_windowTwo )
 380     {
 381         OnDoubleClickSash(x, y);
 382     }
 383 }
 384
 385 void wxSplitterWindow::OnSize(wxSizeEvent& event)
 386 {
 387     // only process this message if we're not iconized - otherwise iconizing
 388     // and restoring a window containing the splitter has a funny side effect
 389     // of changing the splitter position!
 390     wxWindow *parent = wxGetTopLevelParent(this);
 391     bool iconized;
 392
 393     wxTopLevelWindow *winTop = wxDynamicCast(parent, wxTopLevelWindow);
 394     if ( winTop )
 395     {
 396         iconized = winTop->IsIconized();
 397     }
 398     else
 399     {
 400         wxFAIL_MSG(wxT("should have a top level parent!"));
 401
 402         iconized = false;
 403     }
 404
 405     if ( iconized )
 406     {
 407         event.Skip();
 408
 409         return;
 410     }
 411
 412     if ( m_windowTwo )
 413     {
 414         int w, h;
 415         GetClientSize(&w, &h);
 416
 417         int size = m_splitMode == wxSPLIT_VERTICAL ? w : h;
 418         if ( m_sashPosition >= size - 5 )
 419             SetSashPositionAndNotify(wxMax(10, size - 40));
 420     }
 421
 422     SizeWindows();
 423 }
 424
 425 bool wxSplitterWindow::SashHitTest(int x, int y, int tolerance)
 426 {
 427     if ( m_windowTwo == NULL || m_sashPosition == 0)
 428         return false; // No sash
 429
 430     int z = m_splitMode == wxSPLIT_VERTICAL ? x : y;
 431     int hitMin = m_sashPosition - tolerance;
 432     int hitMax = m_sashPosition + GetSashSize() + tolerance;
 433
 434     return z >=  hitMin && z <= hitMax;
 435 }
 436
 437 int wxSplitterWindow::GetSashSize() const
 438 {
 439     return wxRendererNative::Get().GetSplitterParams(this).widthSash;
 440 }
 441
 442 int wxSplitterWindow::GetBorderSize() const
 443 {
 444     return wxRendererNative::Get().GetSplitterParams(this).border;
 445 }
 446
 447 // Draw the sash
 448 void wxSplitterWindow::DrawSash(wxDC& dc)
 449 {
 450     if (HasFlag(wxSP_3DBORDER))
 451         wxRendererNative::Get().DrawSplitterBorder
 452                             (
 453                                 this,
 454                                 dc,
 455                                 GetClientRect()
 456                             );
 457
 458     // don't draw sash if we're not split
 459     if ( m_sashPosition == 0 || !m_windowTwo )
 460         return;
 461
 462     // nor if we're configured to not show it
 463     if ( HasFlag(wxSP_NOSASH) )
 464         return;
 465
 466     wxRendererNative::Get().DrawSplitterSash
 467                             (
 468                                 this,
 469                                 dc,
 470                                 GetClientSize(),
 471                                 m_sashPosition,
 472                                 m_splitMode == wxSPLIT_VERTICAL ? wxVERTICAL
 473                                                                 : wxHORIZONTAL,
 474                                 m_isHot ? wxCONTROL_CURRENT : 0
 475                             );
 476 }
 477
 478 // Draw the sash tracker (for whilst moving the sash)
 479 void wxSplitterWindow::DrawSashTracker(int x, int y)
 480 {
 481     int w, h;
 482     GetClientSize(&w, &h);
 483
 484     wxScreenDC screenDC;
 485     int x1, y1;
 486     int x2, y2;
 487
 488     if ( m_splitMode == wxSPLIT_VERTICAL )
 489     {
 490         x1 = x; y1 = 2;
 491         x2 = x; y2 = h-2;
 492
 493         if ( x1 > w )
 494         {
 495             x1 = w; x2 = w;
 496         }
 497         else if ( x1 < 0 )
 498         {
 499             x1 = 0; x2 = 0;
 500         }
 501     }
 502     else
 503     {
 504         x1 = 2; y1 = y;
 505         x2 = w-2; y2 = y;
 506
 507         if ( y1 > h )
 508         {
 509             y1 = h;
 510             y2 = h;
 511         }
 512         else if ( y1 < 0 )
 513         {
 514             y1 = 0;
 515             y2 = 0;
 516         }
 517     }
 518
 519     ClientToScreen(&x1, &y1);
 520     ClientToScreen(&x2, &y2);
 521
 522     screenDC.SetLogicalFunction(wxINVERT);
 523     screenDC.SetPen(*m_sashTrackerPen);
 524     screenDC.SetBrush(*wxTRANSPARENT_BRUSH);
 525
 526     screenDC.DrawLine(x1, y1, x2, y2);
 527
 528     screenDC.SetLogicalFunction(wxCOPY);
 529 }
 530
 531 int wxSplitterWindow::GetWindowSize() const
 532 {
 533     wxSize size = GetClientSize();
 534
 535     return m_splitMode == wxSPLIT_VERTICAL ? size.x : size.y;
 536 }
 537
 538 int wxSplitterWindow::AdjustSashPosition(int sashPos) const
 539 {
 540     int window_size = GetWindowSize();
 541
 542     wxWindow *win;
 543
 544     win = GetWindow1();
 545     if ( win )
 546     {
 547         // the window shouldn't be smaller than its own minimal size nor
 548         // smaller than the minimual pane size specified for this splitter
 549         int minSize = m_splitMode == wxSPLIT_VERTICAL ? win->GetMinWidth()
 550                                                       : win->GetMinHeight();
 551
 552         if ( minSize == -1 || m_minimumPaneSize > minSize )
 553             minSize = m_minimumPaneSize;
 554
 555         minSize += GetBorderSize();
 556
 557         if ( sashPos < minSize )
 558             sashPos = minSize;
 559     }
 560
 561     win = GetWindow2();
 562     if ( win )
 563     {
 564         int minSize = m_splitMode == wxSPLIT_VERTICAL ? win->GetMinWidth()
 565                                                       : win->GetMinHeight();
 566
 567         if ( minSize == -1 || m_minimumPaneSize > minSize )
 568             minSize = m_minimumPaneSize;
 569
 570         int maxSize = window_size - minSize - GetBorderSize() - GetSashSize();
 571         if ( sashPos > maxSize )
 572             sashPos = maxSize;
 573     }
 574
 575     return sashPos;
 576 }
 577
 578 bool wxSplitterWindow::DoSetSashPosition(int sashPos)
 579 {
 580     int newSashPosition = AdjustSashPosition(sashPos);
 581
 582     if ( newSashPosition == m_sashPosition )
 583         return false;
 584
 585     m_sashPosition = newSashPosition;
 586
 587     return true;
 588 }
 589
 590 void wxSplitterWindow::SetSashPositionAndNotify(int sashPos)
 591 {
 592     // we must reset the request here, otherwise the sash would be stuck at
 593     // old position if the user attempted to move the sash after invalid
 594     // (e.g. smaller than minsize) sash position was requested using
 595     // SetSashPosition():
 596     m_requestedSashPosition = INT_MAX;
 597
 598     if ( DoSetSashPosition(sashPos) )
 599     {
 600         wxSplitterEvent event(wxEVT_COMMAND_SPLITTER_SASH_POS_CHANGED, this);
 601         event.m_data.pos = m_sashPosition;
 602
 603         (void)DoSendEvent(event);
 604     }
 605 }
 606
 607 // Position and size subwindows.
 608 // Note that the border size applies to each subwindow, not
 609 // including the edges next to the sash.
 610 void wxSplitterWindow::SizeWindows()
 611 {
 612     // check if we have delayed setting the real sash position
 613     if ( m_checkRequestedSashPosition && m_requestedSashPosition != INT_MAX )
 614     {
 615         int newSashPosition = ConvertSashPosition(m_requestedSashPosition);
 616         if ( newSashPosition != m_sashPosition )
 617         {
 618             DoSetSashPosition(newSashPosition);
 619         }
 620
 621         if ( newSashPosition <= m_sashPosition
 622             && newSashPosition >= m_sashPosition - GetBorderSize() )
 623         {
 624             // don't update it any more
 625             m_requestedSashPosition = INT_MAX;
 626         }
 627     }
 628
 629     int w, h;
 630     GetClientSize(&w, &h);
 631
 632     if ( GetWindow1() && !GetWindow2() )
 633     {
 634         GetWindow1()->SetSize(GetBorderSize(), GetBorderSize(),
 635                               w - 2*GetBorderSize(), h - 2*GetBorderSize());
 636     }
 637     else if ( GetWindow1() && GetWindow2() )
 638     {
 639         const int border = GetBorderSize(),
 640                   sash = GetSashSize();
 641
 642         int size1 = GetSashPosition() - border,
 643             size2 = GetSashPosition() + sash;
 644
 645         int x2, y2, w1, h1, w2, h2;
 646         if ( GetSplitMode() == wxSPLIT_VERTICAL )
 647         {
 648             w1 = size1;
 649             w2 = w - 2*border - sash - w1;
 650             h1 =
 651             h2 = h - 2*border;
 652             x2 = size2;
 653             y2 = border;
 654         }
 655         else // horz splitter
 656         {
 657             w1 =
 658             w2 = w - 2*border;
 659             h1 = size1;
 660             h2 = h - 2*border - sash - h1;
 661             x2 = border;
 662             y2 = size2;
 663         }
 664
 665         GetWindow1()->SetSize(border, border, w1, h1);
 666         GetWindow2()->SetSize(x2, y2, w2, h2);
 667     }
 668
 669     wxClientDC dc(this);
 670     DrawSash(dc);
 671
 672     SetNeedUpdating(false);
 673 }
 674
 675 // Set pane for unsplit window
 676 void wxSplitterWindow::Initialize(wxWindow *window)
 677 {
 678     wxASSERT_MSG( (!window || (window && window->GetParent() == this)),
 679                   _T("windows in the splitter should have it as parent!") );
 680
 681     m_windowOne = window;
 682     m_windowTwo = (wxWindow *) NULL;
 683     DoSetSashPosition(0);
 684 }
 685
 686 // Associates the given window with window 2, drawing the appropriate sash
 687 // and changing the split mode.
 688 // Does nothing and returns false if the window is already split.
 689 bool wxSplitterWindow::DoSplit(wxSplitMode mode,
 690                                wxWindow *window1, wxWindow *window2,
 691                                int sashPosition)
 692 {
 693     if ( IsSplit() )
 694         return false;
 695
 696     wxCHECK_MSG( window1 && window2, false,
 697                  _T("can not split with NULL window(s)") );
 698
 699     wxCHECK_MSG( window1->GetParent() == this && window2->GetParent() == this, false,
 700                   _T("windows in the splitter should have it as parent!") );
 701
 702     m_splitMode = mode;
 703     m_windowOne = window1;
 704     m_windowTwo = window2;
 705
 706     // remember the sash position we want to set for later if we can't set it
 707     // right now (e.g. because the window is too small)
 708     m_requestedSashPosition = sashPosition;
 709     m_checkRequestedSashPosition = false;
 710
 711     DoSetSashPosition(ConvertSashPosition(sashPosition));
 712
 713     SizeWindows();
 714
 715     return true;
 716 }
 717
 718 int wxSplitterWindow::ConvertSashPosition(int sashPosition) const
 719 {
 720     if ( sashPosition > 0 )
 721     {
 722         return sashPosition;
 723     }
 724     else if ( sashPosition < 0 )
 725     {
 726         // It's negative so adding is subtracting
 727         return GetWindowSize() + sashPosition;
 728     }
 729     else // sashPosition == 0
 730     {
 731         // default, put it in the centre
 732         return GetWindowSize() / 2;
 733     }
 734 }
 735
 736 // Remove the specified (or second) window from the view
 737 // Doesn't actually delete the window.
 738 bool wxSplitterWindow::Unsplit(wxWindow *toRemove)
 739 {
 740     if ( ! IsSplit() )
 741         return false;
 742
 743     wxWindow *win;
 744     if ( toRemove == NULL || toRemove == m_windowTwo)
 745     {
 746         win = m_windowTwo ;
 747         m_windowTwo = (wxWindow *) NULL;
 748     }
 749     else if ( toRemove == m_windowOne )
 750     {
 751         win = m_windowOne ;
 752         m_windowOne = m_windowTwo;
 753         m_windowTwo = (wxWindow *) NULL;
 754     }
 755     else
 756     {
 757         wxFAIL_MSG(wxT("splitter: attempt to remove a non-existent window"));
 758
 759         return false;
 760     }
 761
 762     OnUnsplit(win);
 763     DoSetSashPosition(0);
 764     SizeWindows();
 765
 766     return true;
 767 }
 768
 769 // Replace a window with another one
 770 bool wxSplitterWindow::ReplaceWindow(wxWindow *winOld, wxWindow *winNew)
 771 {
 772     wxCHECK_MSG( winOld, false, wxT("use one of Split() functions instead") );
 773     wxCHECK_MSG( winNew, false, wxT("use Unsplit() functions instead") );
 774
 775     if ( winOld == m_windowTwo )
 776     {
 777         m_windowTwo = winNew;
 778     }
 779     else if ( winOld == m_windowOne )
 780     {
 781         m_windowOne = winNew;
 782     }
 783     else
 784     {
 785         wxFAIL_MSG(wxT("splitter: attempt to replace a non-existent window"));
 786
 787         return false;
 788     }
 789
 790     SizeWindows();
 791
 792     return true;
 793 }
 794
 795 void wxSplitterWindow::SetMinimumPaneSize(int min)
 796 {
 797     m_minimumPaneSize = min;
 798     int pos = m_requestedSashPosition != INT_MAX ? m_requestedSashPosition : m_sashPosition;
 799     SetSashPosition(pos); // re-check limits
 800 }
 801
 802 void wxSplitterWindow::SetSashPosition(int position, bool redraw)
 803 {
 804     // remember the sash position we want to set for later if we can't set it
 805     // right now (e.g. because the window is too small)
 806     m_requestedSashPosition = position;
 807     m_checkRequestedSashPosition = false;
 808
 809     DoSetSashPosition(ConvertSashPosition(position));
 810
 811     if ( redraw )
 812     {
 813         SizeWindows();
 814     }
 815 }
 816
 817 // Make sure the child window sizes are updated. This is useful
 818 // for reducing flicker by updating the sizes before a
 819 // window is shown, if you know the overall size is correct.
 820 void wxSplitterWindow::UpdateSize()
 821 {
 822     m_checkRequestedSashPosition = true;
 823     SizeWindows();
 824     m_checkRequestedSashPosition = false;
 825 }
 826
 827 bool wxSplitterWindow::DoSendEvent(wxSplitterEvent& event)
 828 {
 829     return !GetEventHandler()->ProcessEvent(event) || event.IsAllowed();
 830 }
 831
 832 // ---------------------------------------------------------------------------
 833 // wxSplitterWindow virtual functions: they now just generate the events
 834 // ---------------------------------------------------------------------------
 835
 836 bool wxSplitterWindow::OnSashPositionChange(int WXUNUSED(newSashPosition))
 837 {
 838     // always allow by default
 839     return true;
 840 }
 841
 842 int wxSplitterWindow::OnSashPositionChanging(int newSashPosition)
 843 {
 844     // If within UNSPLIT_THRESHOLD from edge, set to edge to cause closure.
 845     const int UNSPLIT_THRESHOLD = 4;
 846
 847     // first of all, check if OnSashPositionChange() doesn't forbid this change
 848     if ( !OnSashPositionChange(newSashPosition) )
 849     {
 850         // it does
 851         return -1;
 852     }
 853
 854     // Obtain relevant window dimension for bottom / right threshold check
 855     int window_size = GetWindowSize();
 856
 857     bool unsplit_scenario = false;
 858     if ( m_permitUnsplitAlways || m_minimumPaneSize == 0 )
 859     {
 860         // Do edge detection if unsplit premitted
 861         if ( newSashPosition <= UNSPLIT_THRESHOLD )
 862         {
 863             // threshold top / left check
 864             newSashPosition = 0;
 865             unsplit_scenario = true;
 866         }
 867         if ( newSashPosition >= window_size - UNSPLIT_THRESHOLD )
 868         {
 869             // threshold bottom/right check
 870             newSashPosition = window_size;
 871             unsplit_scenario = true;
 872         }
 873     }
 874
 875     if ( !unsplit_scenario )
 876     {
 877         // If resultant pane would be too small, enlarge it
 878         newSashPosition = AdjustSashPosition(newSashPosition);
 879     }
 880
 881     // If the result is out of bounds it means minimum size is too big,
 882     // so split window in half as best compromise.
 883     if ( newSashPosition < 0 || newSashPosition > window_size )
 884         newSashPosition = window_size / 2;
 885
 886     // now let the event handler have it
 887     //
 888     // FIXME: shouldn't we do it before the adjustments above so as to ensure
 889     //        that the sash position is always reasonable?
 890     wxSplitterEvent event(wxEVT_COMMAND_SPLITTER_SASH_POS_CHANGING, this);
 891     event.m_data.pos = newSashPosition;
 892
 893     if ( !DoSendEvent(event) )
 894     {
 895         // the event handler vetoed the change
 896         newSashPosition = -1;
 897     }
 898     else
 899     {
 900         // it could have been changed by it
 901         newSashPosition = event.GetSashPosition();
 902     }
 903
 904     return newSashPosition;
 905 }
 906
 907 // Called when the sash is double-clicked. The default behaviour is to remove
 908 // the sash if the minimum pane size is zero.
 909 void wxSplitterWindow::OnDoubleClickSash(int x, int y)
 910 {
 911     wxCHECK_RET(m_windowTwo, wxT("splitter: no window to remove"));
 912
 913     // new code should handle events instead of using the virtual functions
 914     wxSplitterEvent event(wxEVT_COMMAND_SPLITTER_DOUBLECLICKED, this);
 915     event.m_data.pt.x = x;
 916     event.m_data.pt.y = y;
 917     if ( DoSendEvent(event) )
 918     {
 919         if ( GetMinimumPaneSize() == 0 || m_permitUnsplitAlways )
 920         {
 921             wxWindow* win = m_windowTwo;
 922             if ( Unsplit(win) )
 923             {
 924                 wxSplitterEvent unsplitEvent(wxEVT_COMMAND_SPLITTER_UNSPLIT, this);
 925                 unsplitEvent.m_data.win = win;
 926                 (void)DoSendEvent(unsplitEvent);
 927             }
 928         }
 929     }
 930     //else: blocked by user
 931 }
 932
 933 void wxSplitterWindow::OnUnsplit(wxWindow *winRemoved)
 934 {
 935     // call this before calling the event handler which may delete the window
 936     winRemoved->Show(false);
 937 }
 938
 939 #if defined( __WXMSW__ ) || defined( __WXMAC__)
 940
 941 // this is currently called (and needed) under MSW only...
 942 void wxSplitterWindow::OnSetCursor(wxSetCursorEvent& event)
 943 {
 944     // if we don't do it, the resizing cursor might be set for child window:
 945     // and like this we explicitly say that our cursor should not be used for
 946     // children windows which overlap us
 947
 948     if ( SashHitTest(event.GetX(), event.GetY(), 0) )
 949     {
 950         // default processing is ok
 951         event.Skip();
 952     }
 953     //else: do nothing, in particular, don't call Skip()
 954 }
 955
 956 #endif // wxMSW || wxMac
 957
 958 #endif // wxUSE_SPLITTER
 959