src/generic/scrolwin.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        generic/scrolwin.cpp
   3 // Purpose:     wxScrolledWindow implementation
   4 // Author:      Julian Smart
   5 // Modified by:
   6 // Created:     01/02/97
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) Julian Smart and Markus Holzem
   9 // Licence:     wxWindows license
  10 /////////////////////////////////////////////////////////////////////////////
  11
  12 // ============================================================================
  13 // declarations
  14 // ============================================================================
  15
  16 // ----------------------------------------------------------------------------
  17 // headers
  18 // ----------------------------------------------------------------------------
  19
  20 #ifdef __GNUG__
  21     #pragma implementation "scrolwin.h"
  22 #endif
  23
  24 // For compilers that support precompilation, includes "wx.h".
  25 #include "wx/wxprec.h"
  26
  27 #ifdef __BORLANDC__
  28     #pragma hdrstop
  29 #endif
  30
  31 #include "wx/utils.h"
  32 #include "wx/dcclient.h"
  33
  34 #include "wx/generic/scrolwin.h"
  35 #include "wx/panel.h"
  36
  37 #ifdef __WXMSW__
  38     #include "windows.h"
  39 #endif
  40
  41 #ifdef __WXMOTIF__
  42 // For wxRETAINED implementation
  43 #ifdef __VMS__ //VMS's Xm.h is not (yet) compatible with C++
  44                //This code switches off the compiler warnings
  45 # pragma message disable nosimpint
  46 #endif
  47 #include <Xm/Xm.h>
  48 #ifdef __VMS__
  49 # pragma message enable nosimpint
  50 #endif
  51 #endif
  52
  53 // ----------------------------------------------------------------------------
  54 // event tables
  55 // ----------------------------------------------------------------------------
  56
  57 BEGIN_EVENT_TABLE(wxScrolledWindow, wxPanel)
  58     EVT_SCROLLWIN(wxScrolledWindow::OnScroll)
  59     EVT_SIZE(wxScrolledWindow::OnSize)
  60     EVT_PAINT(wxScrolledWindow::OnPaint)
  61     EVT_CHAR(wxScrolledWindow::OnChar)
  62 END_EVENT_TABLE()
  63
  64 IMPLEMENT_DYNAMIC_CLASS(wxScrolledWindow, wxPanel)
  65
  66 // ============================================================================
  67 // implementation
  68 // ============================================================================
  69
  70 // ----------------------------------------------------------------------------
  71 // wxScrolledWindow creation
  72 // ----------------------------------------------------------------------------
  73
  74 wxScrolledWindow::wxScrolledWindow()
  75 {
  76     m_xScrollPixelsPerLine = 0;
  77     m_yScrollPixelsPerLine = 0;
  78     m_xScrollingEnabled = TRUE;
  79     m_yScrollingEnabled = TRUE;
  80     m_xScrollPosition = 0;
  81     m_yScrollPosition = 0;
  82     m_xScrollLines = 0;
  83     m_yScrollLines = 0;
  84     m_xScrollLinesPerPage = 0;
  85     m_yScrollLinesPerPage = 0;
  86     m_scaleX = 1.0;
  87     m_scaleY = 1.0;
  88     m_targetWindow = (wxWindow*) NULL;
  89 }
  90
  91 bool wxScrolledWindow::Create(wxWindow *parent,
  92                               wxWindowID id,
  93                               const wxPoint& pos,
  94                               const wxSize& size,
  95                               long style,
  96                               const wxString& name)
  97 {
  98     m_xScrollPixelsPerLine = 0;
  99     m_yScrollPixelsPerLine = 0;
 100     m_xScrollingEnabled = TRUE;
 101     m_yScrollingEnabled = TRUE;
 102     m_xScrollPosition = 0;
 103     m_yScrollPosition = 0;
 104     m_xScrollLines = 0;
 105     m_yScrollLines = 0;
 106     m_xScrollLinesPerPage = 0;
 107     m_yScrollLinesPerPage = 0;
 108     m_scaleX = 1.0;
 109     m_scaleY = 1.0;
 110
 111     m_targetWindow = this;
 112
 113     bool ok = wxPanel::Create(parent, id, pos, size, style, name);
 114
 115 #ifdef __WXMSW__
 116     // we need to process arrows ourselves for scrolling
 117     m_lDlgCode |= DLGC_WANTARROWS;
 118 #endif // __WXMSW__
 119
 120     return ok;
 121 }
 122
 123 wxScrolledWindow::~wxScrolledWindow()
 124 {
 125 }
 126
 127 // ----------------------------------------------------------------------------
 128 // setting scrolling parameters
 129 // ----------------------------------------------------------------------------
 130
 131 /*
 132  * pixelsPerUnitX/pixelsPerUnitY: number of pixels per unit (e.g. pixels per text line)
 133  * noUnitsX/noUnitsY:        : no. units per scrollbar
 134  */
 135 void wxScrolledWindow::SetScrollbars (int pixelsPerUnitX, int pixelsPerUnitY,
 136                int noUnitsX, int noUnitsY,
 137                int xPos, int yPos, bool noRefresh )
 138 {
 139     int xpos, ypos;
 140
 141     CalcUnscrolledPosition(xPos, yPos, &xpos, &ypos);
 142     bool do_refresh =
 143     (
 144       (noUnitsX != 0 && m_xScrollLines == 0) ||
 145       (noUnitsX < m_xScrollLines && xpos > pixelsPerUnitX*noUnitsX) ||
 146
 147       (noUnitsY != 0 && m_yScrollLines == 0) ||
 148       (noUnitsY < m_yScrollLines && ypos > pixelsPerUnitY*noUnitsY) ||
 149       (xPos != m_xScrollPosition) ||
 150       (yPos != m_yScrollPosition)
 151 //       (pixelsPerUnitX != m_xScrollPixelsPerLine) ||
 152 //       (pixelsPerUnitY != m_yScrollPixelsPerLine)
 153     );
 154
 155     m_xScrollPixelsPerLine = pixelsPerUnitX;
 156     m_yScrollPixelsPerLine = pixelsPerUnitY;
 157     m_xScrollPosition = xPos;
 158     m_yScrollPosition = yPos;
 159     m_xScrollLines = noUnitsX;
 160     m_yScrollLines = noUnitsY;
 161
 162 #ifdef __WXMOTIF__
 163     // Sorry, some Motif-specific code to implement a backing pixmap
 164     // for the wxRETAINED style. Implementing a backing store can't
 165     // be entirely generic because it relies on the wxWindowDC implementation
 166     // to duplicate X drawing calls for the backing pixmap.
 167
 168     if ((m_windowStyle & wxRETAINED) == wxRETAINED)
 169     {
 170         Display* dpy = XtDisplay((Widget) GetMainWidget());
 171
 172         int totalPixelWidth = m_xScrollLines * m_xScrollPixelsPerLine;
 173         int totalPixelHeight = m_yScrollLines * m_yScrollPixelsPerLine;
 174         if (m_backingPixmap &&
 175            !((m_pixmapWidth == totalPixelWidth) &&
 176              (m_pixmapHeight == totalPixelHeight)))
 177         {
 178             XFreePixmap (dpy, (Pixmap) m_backingPixmap);
 179             m_backingPixmap = (WXPixmap) 0;
 180         }
 181
 182         if (!m_backingPixmap &&
 183            (noUnitsX != 0) && (noUnitsY != 0))
 184         {
 185             int depth = wxDisplayDepth();
 186             m_pixmapWidth = totalPixelWidth;
 187             m_pixmapHeight = totalPixelHeight;
 188             m_backingPixmap = (WXPixmap) XCreatePixmap (dpy, RootWindow (dpy, DefaultScreen (dpy)),
 189             m_pixmapWidth, m_pixmapHeight, depth);
 190         }
 191
 192     }
 193 #endif // Motif
 194
 195     AdjustScrollbars();
 196
 197     if (do_refresh && !noRefresh)
 198         m_targetWindow->Refresh();
 199
 200 #ifdef __WXMSW__
 201     // GRG: if this turns out to be really necessary, we could
 202     //   at least move it to the above if { ... } so that it is
 203     //   only done if noRefresh = FALSE (the default). OTOH, if
 204     //   this doesn't break anything, which seems to be the
 205     //   case, we could just leave it out.
 206
 207     // Necessary?
 208     // UpdateWindow ((HWND) m_targetWindow->GetHWND());
 209 #endif
 210 #ifdef __WXMAC__
 211     m_targetWindow->MacUpdateImmediately() ;
 212 #endif
 213 }
 214
 215 // ----------------------------------------------------------------------------
 216 // target window handling
 217 // ----------------------------------------------------------------------------
 218
 219 void wxScrolledWindow::SetTargetWindow( wxWindow *target )
 220 {
 221     wxASSERT_MSG( target, wxT("target window must not be NULL") );
 222     m_targetWindow = target;
 223 }
 224
 225 wxWindow *wxScrolledWindow::GetTargetWindow()
 226 {
 227     return m_targetWindow;
 228 }
 229
 230 // ----------------------------------------------------------------------------
 231 // scrolling implementation itself
 232 // ----------------------------------------------------------------------------
 233
 234 void wxScrolledWindow::OnScroll(wxScrollWinEvent& event)
 235 {
 236     int orient = event.GetOrientation();
 237
 238     int nScrollInc = CalcScrollInc(event);
 239     if (nScrollInc == 0) return;
 240
 241     if (orient == wxHORIZONTAL)
 242     {
 243         int newPos = m_xScrollPosition + nScrollInc;
 244         SetScrollPos(wxHORIZONTAL, newPos, TRUE );
 245     }
 246     else
 247     {
 248         int newPos = m_yScrollPosition + nScrollInc;
 249         SetScrollPos(wxVERTICAL, newPos, TRUE );
 250     }
 251
 252     if (orient == wxHORIZONTAL)
 253     {
 254         m_xScrollPosition += nScrollInc;
 255     }
 256     else
 257     {
 258         m_yScrollPosition += nScrollInc;
 259     }
 260
 261     if (orient == wxHORIZONTAL)
 262     {
 263        if (m_xScrollingEnabled)
 264             m_targetWindow->ScrollWindow(-m_xScrollPixelsPerLine * nScrollInc, 0, (const wxRect *) NULL);
 265        else
 266             m_targetWindow->Refresh();
 267     }
 268     else
 269     {
 270         if (m_yScrollingEnabled)
 271             m_targetWindow->ScrollWindow(0, -m_yScrollPixelsPerLine * nScrollInc, (const wxRect *) NULL);
 272         else
 273             m_targetWindow->Refresh();
 274     }
 275 #ifdef __WXMAC__
 276     m_targetWindow->MacUpdateImmediately() ;
 277 #endif
 278 }
 279
 280 int wxScrolledWindow::CalcScrollInc(wxScrollWinEvent& event)
 281 {
 282     int pos = event.GetPosition();
 283     int orient = event.GetOrientation();
 284
 285     int nScrollInc = 0;
 286     switch (event.GetEventType())
 287     {
 288         case wxEVT_SCROLLWIN_TOP:
 289         {
 290             if (orient == wxHORIZONTAL)
 291                 nScrollInc = - m_xScrollPosition;
 292             else
 293                 nScrollInc = - m_yScrollPosition;
 294             break;
 295         }
 296         case wxEVT_SCROLLWIN_BOTTOM:
 297         {
 298             if (orient == wxHORIZONTAL)
 299                 nScrollInc = m_xScrollLines - m_xScrollPosition;
 300             else
 301                 nScrollInc = m_yScrollLines - m_yScrollPosition;
 302             break;
 303         }
 304         case wxEVT_SCROLLWIN_LINEUP:
 305         {
 306             nScrollInc = -1;
 307             break;
 308         }
 309         case wxEVT_SCROLLWIN_LINEDOWN:
 310         {
 311             nScrollInc = 1;
 312             break;
 313         }
 314         case wxEVT_SCROLLWIN_PAGEUP:
 315         {
 316             if (orient == wxHORIZONTAL)
 317                 nScrollInc = -GetScrollPageSize(wxHORIZONTAL);
 318             else
 319                 nScrollInc = -GetScrollPageSize(wxVERTICAL);
 320             break;
 321         }
 322         case wxEVT_SCROLLWIN_PAGEDOWN:
 323         {
 324             if (orient == wxHORIZONTAL)
 325                 nScrollInc = GetScrollPageSize(wxHORIZONTAL);
 326             else
 327                 nScrollInc = GetScrollPageSize(wxVERTICAL);
 328             break;
 329         }
 330         case wxEVT_SCROLLWIN_THUMBTRACK:
 331         case wxEVT_SCROLLWIN_THUMBRELEASE:
 332         {
 333             if (orient == wxHORIZONTAL)
 334                 nScrollInc = pos - m_xScrollPosition;
 335             else
 336                 nScrollInc = pos - m_yScrollPosition;
 337             break;
 338         }
 339         default:
 340         {
 341             break;
 342         }
 343     }
 344
 345     if (orient == wxHORIZONTAL)
 346     {
 347         if (m_xScrollPixelsPerLine > 0)
 348         {
 349             int w, h;
 350             m_targetWindow->GetClientSize(&w, &h);
 351
 352             int nMaxWidth = m_xScrollLines*m_xScrollPixelsPerLine;
 353             int noPositions = (int) ( ((nMaxWidth - w)/(double)m_xScrollPixelsPerLine) + 0.5 );
 354             if (noPositions < 0)
 355                 noPositions = 0;
 356
 357             if ( (m_xScrollPosition + nScrollInc) < 0 )
 358                 nScrollInc = -m_xScrollPosition; // As -ve as we can go
 359             else if ( (m_xScrollPosition + nScrollInc) > noPositions )
 360                 nScrollInc = noPositions - m_xScrollPosition; // As +ve as we can go
 361         }
 362         else
 363             m_targetWindow->Refresh();
 364     }
 365     else
 366     {
 367         if (m_yScrollPixelsPerLine > 0)
 368         {
 369             int w, h;
 370             m_targetWindow->GetClientSize(&w, &h);
 371
 372             int nMaxHeight = m_yScrollLines*m_yScrollPixelsPerLine;
 373             int noPositions = (int) ( ((nMaxHeight - h)/(double)m_yScrollPixelsPerLine) + 0.5 );
 374             if (noPositions < 0)
 375                 noPositions = 0;
 376
 377             if ( (m_yScrollPosition + nScrollInc) < 0 )
 378                 nScrollInc = -m_yScrollPosition; // As -ve as we can go
 379             else if ( (m_yScrollPosition + nScrollInc) > noPositions )
 380                 nScrollInc = noPositions - m_yScrollPosition; // As +ve as we can go
 381         }
 382         else
 383             m_targetWindow->Refresh();
 384     }
 385
 386     return nScrollInc;
 387 }
 388
 389 // Adjust the scrollbars - new version.
 390 void wxScrolledWindow::AdjustScrollbars()
 391 {
 392     int w, h;
 393     m_targetWindow->GetClientSize(&w, &h);
 394
 395     int oldXScroll = m_xScrollPosition;
 396     int oldYScroll = m_yScrollPosition;
 397
 398     if (m_xScrollLines > 0)
 399     {
 400         // Calculate page size i.e. number of scroll units you get on the
 401         // current client window
 402         int noPagePositions = (int) ( (w/(double)m_xScrollPixelsPerLine) + 0.5 );
 403         if (noPagePositions < 1) noPagePositions = 1;
 404
 405         // Correct position if greater than extent of canvas minus
 406         // the visible portion of it or if below zero
 407         m_xScrollPosition = wxMin( m_xScrollLines-noPagePositions, m_xScrollPosition);
 408         m_xScrollPosition = wxMax( 0, m_xScrollPosition );
 409
 410         SetScrollbar(wxHORIZONTAL, m_xScrollPosition, noPagePositions, m_xScrollLines);
 411         // The amount by which we scroll when paging
 412         SetScrollPageSize(wxHORIZONTAL, noPagePositions);
 413     }
 414     else
 415     {
 416         m_xScrollPosition = 0;
 417         SetScrollbar (wxHORIZONTAL, 0, 0, 0, FALSE);
 418     }
 419
 420     if (m_yScrollLines > 0)
 421     {
 422         // Calculate page size i.e. number of scroll units you get on the
 423         // current client window
 424         int noPagePositions = (int) ( (h/(double)m_yScrollPixelsPerLine) + 0.5 );
 425         if (noPagePositions < 1) noPagePositions = 1;
 426
 427         // Correct position if greater than extent of canvas minus
 428         // the visible portion of it or if below zero
 429         m_yScrollPosition = wxMin( m_yScrollLines-noPagePositions, m_yScrollPosition );
 430         m_yScrollPosition = wxMax( 0, m_yScrollPosition );
 431
 432         SetScrollbar(wxVERTICAL, m_yScrollPosition, noPagePositions, m_yScrollLines);
 433         // The amount by which we scroll when paging
 434         SetScrollPageSize(wxVERTICAL, noPagePositions);
 435     }
 436     else
 437     {
 438         m_yScrollPosition = 0;
 439         SetScrollbar (wxVERTICAL, 0, 0, 0, FALSE);
 440     }
 441
 442     if (oldXScroll != m_xScrollPosition)
 443     {
 444        if (m_xScrollingEnabled)
 445             m_targetWindow->ScrollWindow( m_xScrollPixelsPerLine * (oldXScroll-m_xScrollPosition), 0, (const wxRect *) NULL );
 446        else
 447             m_targetWindow->Refresh();
 448     }
 449
 450     if (oldYScroll != m_yScrollPosition)
 451     {
 452         if (m_yScrollingEnabled)
 453             m_targetWindow->ScrollWindow( 0, m_yScrollPixelsPerLine * (oldYScroll-m_yScrollPosition), (const wxRect *) NULL );
 454         else
 455             m_targetWindow->Refresh();
 456     }
 457 }
 458
 459 // Override this function if you don't want to have wxScrolledWindow
 460 // automatically change the origin according to the scroll position.
 461 void wxScrolledWindow::PrepareDC(wxDC& dc)
 462 {
 463     dc.SetDeviceOrigin( -m_xScrollPosition * m_xScrollPixelsPerLine,
 464                         -m_yScrollPosition * m_yScrollPixelsPerLine );
 465     dc.SetUserScale( m_scaleX, m_scaleY );
 466 }
 467
 468 #if WXWIN_COMPATIBILITY
 469 void wxScrolledWindow::GetScrollUnitsPerPage (int *x_page, int *y_page) const
 470 {
 471       *x_page = GetScrollPageSize(wxHORIZONTAL);
 472       *y_page = GetScrollPageSize(wxVERTICAL);
 473 }
 474
 475 void wxScrolledWindow::CalcUnscrolledPosition(int x, int y, float *xx, float *yy) const
 476 {
 477     if ( xx )
 478         *xx = (float)(x + m_xScrollPosition * m_xScrollPixelsPerLine);
 479     if ( yy )
 480         *yy = (float)(y + m_yScrollPosition * m_yScrollPixelsPerLine);
 481 }
 482 #endif // WXWIN_COMPATIBILITY
 483
 484 void wxScrolledWindow::GetScrollPixelsPerUnit (int *x_unit, int *y_unit) const
 485 {
 486     if ( x_unit )
 487         *x_unit = m_xScrollPixelsPerLine;
 488     if ( y_unit )
 489         *y_unit = m_yScrollPixelsPerLine;
 490 }
 491
 492 int wxScrolledWindow::GetScrollPageSize(int orient) const
 493 {
 494     if ( orient == wxHORIZONTAL )
 495         return m_xScrollLinesPerPage;
 496     else
 497         return m_yScrollLinesPerPage;
 498 }
 499
 500 void wxScrolledWindow::SetScrollPageSize(int orient, int pageSize)
 501 {
 502     if ( orient == wxHORIZONTAL )
 503         m_xScrollLinesPerPage = pageSize;
 504     else
 505         m_yScrollLinesPerPage = pageSize;
 506 }
 507
 508 /*
 509  * Scroll to given position (scroll position, not pixel position)
 510  */
 511 void wxScrolledWindow::Scroll( int x_pos, int y_pos )
 512 {
 513     if (!m_targetWindow)
 514         return;
 515
 516     if (((x_pos == -1) || (x_pos == m_xScrollPosition)) &&
 517         ((y_pos == -1) || (y_pos == m_yScrollPosition))) return;
 518
 519     int w, h;
 520     m_targetWindow->GetClientSize(&w, &h);
 521
 522     if ((x_pos != -1) && (m_xScrollPixelsPerLine))
 523     {
 524         int old_x = m_xScrollPosition;
 525         m_xScrollPosition = x_pos;
 526
 527         // Calculate page size i.e. number of scroll units you get on the
 528         // current client window
 529         int noPagePositions = (int) ( (w/(double)m_xScrollPixelsPerLine) + 0.5 );
 530         if (noPagePositions < 1) noPagePositions = 1;
 531
 532         // Correct position if greater than extent of canvas minus
 533         // the visible portion of it or if below zero
 534         m_xScrollPosition = wxMin( m_xScrollLines-noPagePositions, m_xScrollPosition );
 535         m_xScrollPosition = wxMax( 0, m_xScrollPosition );
 536
 537         if (old_x == m_xScrollPosition) return;
 538
 539         m_targetWindow->SetScrollPos( wxHORIZONTAL, m_xScrollPosition, TRUE );
 540         m_targetWindow->ScrollWindow( (old_x-m_xScrollPosition)*m_xScrollPixelsPerLine, 0 );
 541     }
 542     if ((y_pos != -1) && (m_yScrollPixelsPerLine))
 543     {
 544         int old_y = m_yScrollPosition;
 545         m_yScrollPosition = y_pos;
 546
 547         // Calculate page size i.e. number of scroll units you get on the
 548         // current client window
 549         int noPagePositions = (int) ( (h/(double)m_yScrollPixelsPerLine) + 0.5 );
 550         if (noPagePositions < 1) noPagePositions = 1;
 551
 552         // Correct position if greater than extent of canvas minus
 553         // the visible portion of it or if below zero
 554         m_yScrollPosition = wxMin( m_yScrollLines-noPagePositions, m_yScrollPosition );
 555         m_yScrollPosition = wxMax( 0, m_yScrollPosition );
 556
 557         if (old_y == m_yScrollPosition) return;
 558
 559         m_targetWindow->SetScrollPos( wxVERTICAL, m_yScrollPosition, TRUE );
 560         m_targetWindow->ScrollWindow( 0, (old_y-m_yScrollPosition)*m_yScrollPixelsPerLine );
 561     }
 562
 563 #ifdef __WXMAC__
 564     m_targetWindow->MacUpdateImmediately();
 565 #endif
 566 }
 567
 568 void wxScrolledWindow::EnableScrolling (bool x_scroll, bool y_scroll)
 569 {
 570     m_xScrollingEnabled = x_scroll;
 571     m_yScrollingEnabled = y_scroll;
 572 }
 573
 574 void wxScrolledWindow::GetVirtualSize (int *x, int *y) const
 575 {
 576     if ( x )
 577         *x = m_xScrollPixelsPerLine * m_xScrollLines;
 578     if ( y )
 579         *y = m_yScrollPixelsPerLine * m_yScrollLines;
 580 }
 581
 582 // Where the current view starts from
 583 void wxScrolledWindow::GetViewStart (int *x, int *y) const
 584 {
 585     if ( x )
 586         *x = m_xScrollPosition;
 587     if ( y )
 588         *y = m_yScrollPosition;
 589 }
 590
 591 void wxScrolledWindow::CalcScrolledPosition(int x, int y, int *xx, int *yy) const
 592 {
 593     if ( xx )
 594         *xx = x - m_xScrollPosition * m_xScrollPixelsPerLine;
 595     if ( yy )
 596         *yy = y - m_yScrollPosition * m_yScrollPixelsPerLine;
 597 }
 598
 599 void wxScrolledWindow::CalcUnscrolledPosition(int x, int y, int *xx, int *yy) const
 600 {
 601     if ( xx )
 602         *xx = x + m_xScrollPosition * m_xScrollPixelsPerLine;
 603     if ( yy )
 604         *yy = y + m_yScrollPosition * m_yScrollPixelsPerLine;
 605 }
 606
 607 // ----------------------------------------------------------------------------
 608 // event handlers
 609 // ----------------------------------------------------------------------------
 610
 611 // Default OnSize resets scrollbars, if any
 612 void wxScrolledWindow::OnSize(wxSizeEvent& WXUNUSED(event))
 613 {
 614 #if wxUSE_CONSTRAINTS
 615     if (GetAutoLayout())
 616         Layout();
 617 #endif
 618
 619     AdjustScrollbars();
 620 }
 621
 622 // This calls OnDraw, having adjusted the origin according to the current
 623 // scroll position
 624 void wxScrolledWindow::OnPaint(wxPaintEvent& WXUNUSED(event))
 625 {
 626     wxPaintDC dc(this);
 627     PrepareDC(dc);
 628
 629     OnDraw(dc);
 630 }
 631
 632 // kbd handling: notice that we use OnChar() and not OnKeyDown() for
 633 // compatibility here - if we used OnKeyDown(), the programs which process
 634 // arrows themselves in their OnChar() would never get the message and like
 635 // this they always have the priority
 636 void wxScrolledWindow::OnChar(wxKeyEvent& event)
 637 {
 638     int stx, sty,       // view origin
 639         szx, szy,       // view size (total)
 640         clix, cliy;     // view size (on screen)
 641
 642     ViewStart(&stx, &sty);
 643     GetClientSize(&clix, &cliy);
 644     GetVirtualSize(&szx, &szy);
 645
 646     if( m_xScrollPixelsPerLine )
 647     {
 648         clix /= m_xScrollPixelsPerLine;
 649         szx /= m_xScrollPixelsPerLine;
 650     }
 651     else
 652     {
 653         clix = 0;
 654         szx = -1;
 655     }
 656     if( m_yScrollPixelsPerLine )
 657     {
 658         cliy /= m_yScrollPixelsPerLine;
 659         szy /= m_yScrollPixelsPerLine;
 660     }
 661     else
 662     {
 663         cliy = 0;
 664         szy = -1;
 665     }
 666
 667     int dsty;
 668     switch ( event.KeyCode() )
 669     {
 670         case WXK_PAGEUP:
 671         case WXK_PRIOR:
 672             dsty = sty - (5 * cliy / 6);
 673             Scroll(-1, (dsty == -1) ? 0 : dsty);
 674             break;
 675
 676         case WXK_PAGEDOWN:
 677         case WXK_NEXT:
 678             Scroll(-1, sty + (5 * cliy / 6));
 679             break;
 680
 681         case WXK_HOME:
 682             Scroll(0, event.ControlDown() ? 0 : -1);
 683             break;
 684
 685         case WXK_END:
 686             Scroll(szx - clix, event.ControlDown() ? szy - cliy : -1);
 687             break;
 688
 689         case WXK_UP:
 690             Scroll(-1, sty - 1);
 691             break;
 692
 693         case WXK_DOWN:
 694             Scroll(-1, sty + 1);
 695             break;
 696
 697         case WXK_LEFT:
 698             Scroll(stx - 1, -1);
 699             break;
 700
 701         case WXK_RIGHT:
 702             Scroll(stx + 1, -1);
 703             break;
 704
 705         default:
 706             // not for us
 707             event.Skip();
 708     }
 709 }