src/gtk1/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/gtk/scrolwin.h"
  35 #include "wx/panel.h"
  36
  37 #include <gtk/gtk.h>
  38 #include "wx/gtk/win_gtk.h"
  39
  40 // ----------------------------------------------------------------------------
  41 // event tables
  42 // ----------------------------------------------------------------------------
  43
  44 BEGIN_EVENT_TABLE(wxScrolledWindow, wxPanel)
  45     EVT_SCROLLWIN(wxScrolledWindow::OnScroll)
  46     EVT_SIZE(wxScrolledWindow::OnSize)
  47     EVT_PAINT(wxScrolledWindow::OnPaint)
  48     EVT_CHAR(wxScrolledWindow::OnChar)
  49 END_EVENT_TABLE()
  50
  51 IMPLEMENT_DYNAMIC_CLASS(wxScrolledWindow, wxPanel)
  52
  53 // ============================================================================
  54 // implementation
  55 // ============================================================================
  56
  57 //-----------------------------------------------------------------------------
  58 // data
  59 //-----------------------------------------------------------------------------
  60
  61 extern bool       g_blockEventsOnDrag;
  62
  63 //-----------------------------------------------------------------------------
  64 // idle system
  65 //-----------------------------------------------------------------------------
  66
  67 extern void wxapp_install_idle_handler();
  68 extern bool g_isIdle;
  69
  70 //-----------------------------------------------------------------------------
  71 // "value_changed" from m_vAdjust
  72 //-----------------------------------------------------------------------------
  73
  74 static void gtk_scrolled_window_vscroll_callback( GtkAdjustment *adjust, wxScrolledWindow *win )
  75 {
  76     if (g_isIdle)
  77         wxapp_install_idle_handler();
  78
  79     if (g_blockEventsOnDrag) return;
  80
  81     if (!win->m_hasVMT) return;
  82
  83     win->GtkVScroll( adjust->value );
  84 }
  85
  86 //-----------------------------------------------------------------------------
  87 // "value_changed" from m_hAdjust
  88 //-----------------------------------------------------------------------------
  89
  90 static void gtk_scrolled_window_hscroll_callback( GtkAdjustment *adjust, wxScrolledWindow *win )
  91 {
  92     if (g_isIdle)
  93         wxapp_install_idle_handler();
  94
  95     if (g_blockEventsOnDrag) return;
  96     if (!win->m_hasVMT) return;
  97
  98     win->GtkHScroll( adjust->value );
  99 }
 100
 101 //-----------------------------------------------------------------------------
 102 // InsertChild for wxScrolledWindow
 103 //-----------------------------------------------------------------------------
 104
 105 static void wxInsertChildInScrolledWindow( wxWindow* parent, wxWindow* child )
 106 {
 107     /* the window might have been scrolled already, do we
 108        have to adapt the position */
 109     GtkPizza *pizza = GTK_PIZZA(parent->m_wxwindow);
 110     child->m_x += pizza->xoffset;
 111     child->m_y += pizza->yoffset;
 112
 113     gtk_pizza_put( GTK_PIZZA(parent->m_wxwindow),
 114                      GTK_WIDGET(child->m_widget),
 115                      child->m_x,
 116                      child->m_y,
 117                      child->m_width,
 118                      child->m_height );
 119 }
 120
 121 // ----------------------------------------------------------------------------
 122 // wxScrolledWindow creation
 123 // ----------------------------------------------------------------------------
 124
 125 wxScrolledWindow::wxScrolledWindow()
 126 {
 127     m_xScrollPixelsPerLine = 0;
 128     m_yScrollPixelsPerLine = 0;
 129     m_xScrollingEnabled = TRUE;
 130     m_yScrollingEnabled = TRUE;
 131     m_xScrollPosition = 0;
 132     m_yScrollPosition = 0;
 133     m_xScrollLines = 0;
 134     m_yScrollLines = 0;
 135     m_xScrollLinesPerPage = 0;
 136     m_yScrollLinesPerPage = 0;
 137     m_targetWindow = (wxWindow*) NULL;
 138     m_scaleX = 1.0;
 139     m_scaleY = 1.0;
 140 }
 141
 142 bool wxScrolledWindow::Create(wxWindow *parent,
 143                               wxWindowID id,
 144                               const wxPoint& pos,
 145                               const wxSize& size,
 146                               long style,
 147                               const wxString& name)
 148 {
 149     if (!PreCreation( parent, pos, size ) ||
 150         !CreateBase( parent, id, pos, size, style, wxDefaultValidator, name ))
 151     {
 152         wxFAIL_MSG( wxT("wxWindow creation failed") );
 153         return FALSE;
 154     }
 155
 156     m_insertCallback = wxInsertChildInScrolledWindow;
 157
 158     m_xScrollPixelsPerLine = 0;
 159     m_yScrollPixelsPerLine = 0;
 160     m_xScrollingEnabled = TRUE;
 161     m_yScrollingEnabled = TRUE;
 162     m_xScrollPosition = 0;
 163     m_yScrollPosition = 0;
 164     m_xScrollLines = 0;
 165     m_yScrollLines = 0;
 166     m_xScrollLinesPerPage = 0;
 167     m_yScrollLinesPerPage = 0;
 168
 169     m_targetWindow = this;
 170
 171     m_widget = gtk_scrolled_window_new( (GtkAdjustment *) NULL, (GtkAdjustment *) NULL );
 172     GTK_WIDGET_UNSET_FLAGS( m_widget, GTK_CAN_FOCUS );
 173
 174     GtkScrolledWindow *scrolledWindow = GTK_SCROLLED_WINDOW(m_widget);
 175
 176     GtkScrolledWindowClass *scroll_class = GTK_SCROLLED_WINDOW_CLASS( GTK_OBJECT_GET_CLASS(m_widget) );
 177     scroll_class->scrollbar_spacing = 0;
 178
 179     gtk_scrolled_window_set_policy( scrolledWindow, GTK_POLICY_AUTOMATIC, GTK_POLICY_AUTOMATIC );
 180
 181     m_hAdjust = gtk_range_get_adjustment( GTK_RANGE(scrolledWindow->hscrollbar) );
 182     m_vAdjust = gtk_range_get_adjustment( GTK_RANGE(scrolledWindow->vscrollbar) );
 183
 184     m_wxwindow = gtk_pizza_new();
 185
 186     gtk_container_add( GTK_CONTAINER(m_widget), m_wxwindow );
 187
 188     GtkPizza *pizza = GTK_PIZZA(m_wxwindow);
 189
 190     if (HasFlag(wxRAISED_BORDER))
 191     {
 192         gtk_pizza_set_shadow_type( pizza, GTK_MYSHADOW_OUT );
 193     }
 194     else if (HasFlag(wxSUNKEN_BORDER))
 195     {
 196         gtk_pizza_set_shadow_type( pizza, GTK_MYSHADOW_IN );
 197     }
 198     else if (HasFlag(wxSIMPLE_BORDER))
 199     {
 200         gtk_pizza_set_shadow_type( pizza, GTK_MYSHADOW_THIN );
 201     }
 202     else
 203     {
 204         gtk_pizza_set_shadow_type( pizza, GTK_MYSHADOW_NONE );
 205     }
 206
 207     GTK_WIDGET_SET_FLAGS( m_wxwindow, GTK_CAN_FOCUS );
 208     m_acceptsFocus = TRUE;
 209
 210     // I _really_ don't want scrollbars in the beginning
 211     m_vAdjust->lower = 0.0;
 212     m_vAdjust->upper = 1.0;
 213     m_vAdjust->value = 0.0;
 214     m_vAdjust->step_increment = 1.0;
 215     m_vAdjust->page_increment = 1.0;
 216     gtk_signal_emit_by_name( GTK_OBJECT(m_vAdjust), "changed" );
 217     m_hAdjust->lower = 0.0;
 218     m_hAdjust->upper = 1.0;
 219     m_hAdjust->value = 0.0;
 220     m_hAdjust->step_increment = 1.0;
 221     m_hAdjust->page_increment = 1.0;
 222     gtk_signal_emit_by_name( GTK_OBJECT(m_hAdjust), "changed" );
 223
 224     // these handlers get notified when screen updates are required either when
 225     // scrolling or when the window size (and therefore scrollbar configuration)
 226     // has changed
 227     gtk_signal_connect( GTK_OBJECT(m_hAdjust), "value_changed",
 228           (GtkSignalFunc) gtk_scrolled_window_hscroll_callback, (gpointer) this );
 229     gtk_signal_connect( GTK_OBJECT(m_vAdjust), "value_changed",
 230           (GtkSignalFunc) gtk_scrolled_window_vscroll_callback, (gpointer) this );
 231
 232     gtk_widget_show( m_wxwindow );
 233
 234     if (m_parent)
 235         m_parent->DoAddChild( this );
 236
 237     PostCreation();
 238
 239     Show( TRUE );
 240
 241     return TRUE;
 242 }
 243
 244 wxScrolledWindow::~wxScrolledWindow()
 245 {
 246 }
 247
 248 // ----------------------------------------------------------------------------
 249 // setting scrolling parameters
 250 // ----------------------------------------------------------------------------
 251
 252 /*
 253  * pixelsPerUnitX/pixelsPerUnitY: number of pixels per unit (e.g. pixels per text line)
 254  * noUnitsX/noUnitsY:        : no. units per scrollbar
 255  */
 256 void wxScrolledWindow::SetScrollbars (int pixelsPerUnitX, int pixelsPerUnitY,
 257                int noUnitsX, int noUnitsY,
 258                int xPos, int yPos, bool noRefresh )
 259 {
 260     m_xScrollPixelsPerLine = pixelsPerUnitX;
 261     m_yScrollPixelsPerLine = pixelsPerUnitY;
 262     m_xScrollPosition = xPos;
 263     m_yScrollPosition = yPos;
 264     m_xScrollLines = noUnitsX;
 265     m_yScrollLines = noUnitsY;
 266
 267     m_hAdjust->lower = 0.0;
 268     m_hAdjust->upper = noUnitsX;
 269     m_hAdjust->value = xPos;
 270     m_hAdjust->step_increment = 1.0;
 271     m_hAdjust->page_increment = 1.0;
 272
 273     m_vAdjust->lower = 0.0;
 274     m_vAdjust->upper = noUnitsY;
 275     m_vAdjust->value = yPos;
 276     m_vAdjust->step_increment = 1.0;
 277     m_vAdjust->page_increment = 1.0;
 278
 279     AdjustScrollbars();
 280 }
 281
 282 void wxScrolledWindow::AdjustScrollbars()
 283 {
 284     int w, h;
 285     m_targetWindow->GetClientSize( &w, &h );
 286
 287     if (m_xScrollPixelsPerLine == 0)
 288         m_hAdjust->page_size = 1.0;
 289     else
 290         m_hAdjust->page_size = (w / m_xScrollPixelsPerLine);
 291
 292     if (m_yScrollPixelsPerLine == 0)
 293         m_vAdjust->page_size = 1.0;
 294     else
 295         m_vAdjust->page_size = (h / m_yScrollPixelsPerLine);
 296
 297     gtk_signal_emit_by_name( GTK_OBJECT(m_vAdjust), "changed" );
 298     gtk_signal_emit_by_name( GTK_OBJECT(m_hAdjust), "changed" );
 299 }
 300
 301 // ----------------------------------------------------------------------------
 302 // target window handling
 303 // ----------------------------------------------------------------------------
 304
 305 void wxScrolledWindow::SetTargetWindow( wxWindow *target )
 306 {
 307     wxASSERT_MSG( target, wxT("target window must not be NULL") );
 308     m_targetWindow = target;
 309 }
 310
 311 wxWindow *wxScrolledWindow::GetTargetWindow()
 312 {
 313     return m_targetWindow;
 314 }
 315
 316 // Override this function if you don't want to have wxScrolledWindow
 317 // automatically change the origin according to the scroll position.
 318 void wxScrolledWindow::PrepareDC(wxDC& dc)
 319 {
 320     dc.SetDeviceOrigin( -m_xScrollPosition * m_xScrollPixelsPerLine,
 321                         -m_yScrollPosition * m_yScrollPixelsPerLine );
 322 }
 323
 324 void wxScrolledWindow::GetScrollPixelsPerUnit (int *x_unit, int *y_unit) const
 325 {
 326     if ( x_unit )
 327         *x_unit = m_xScrollPixelsPerLine;
 328     if ( y_unit )
 329         *y_unit = m_yScrollPixelsPerLine;
 330 }
 331
 332 int wxScrolledWindow::GetScrollPageSize(int orient) const
 333 {
 334     if ( orient == wxHORIZONTAL )
 335         return m_xScrollLinesPerPage;
 336     else
 337         return m_yScrollLinesPerPage;
 338 }
 339
 340 void wxScrolledWindow::SetScrollPageSize(int orient, int pageSize)
 341 {
 342     if ( orient == wxHORIZONTAL )
 343         m_xScrollLinesPerPage = pageSize;
 344     else
 345         m_yScrollLinesPerPage = pageSize;
 346 }
 347
 348 void wxScrolledWindow::OnScroll(wxScrollWinEvent& event)
 349 {
 350     int orient = event.GetOrientation();
 351
 352     int nScrollInc = CalcScrollInc(event);
 353     if (nScrollInc == 0) return;
 354
 355     if (orient == wxHORIZONTAL)
 356     {
 357         int newPos = m_xScrollPosition + nScrollInc;
 358         SetScrollPos(wxHORIZONTAL, newPos, TRUE );
 359     }
 360     else
 361     {
 362         int newPos = m_yScrollPosition + nScrollInc;
 363         SetScrollPos(wxVERTICAL, newPos, TRUE );
 364     }
 365
 366     if (orient == wxHORIZONTAL)
 367     {
 368         m_xScrollPosition += nScrollInc;
 369     }
 370     else
 371     {
 372         m_yScrollPosition += nScrollInc;
 373     }
 374
 375     if (orient == wxHORIZONTAL)
 376     {
 377        if (m_xScrollingEnabled)
 378             m_targetWindow->ScrollWindow(-m_xScrollPixelsPerLine * nScrollInc, 0, (const wxRect *) NULL);
 379        else
 380             m_targetWindow->Refresh();
 381     }
 382     else
 383     {
 384         if (m_yScrollingEnabled)
 385             m_targetWindow->ScrollWindow(0, -m_yScrollPixelsPerLine * nScrollInc, (const wxRect *) NULL);
 386         else
 387             m_targetWindow->Refresh();
 388     }
 389 }
 390
 391 void wxScrolledWindow::Scroll( int x_pos, int y_pos )
 392 {
 393     if (!m_targetWindow)
 394         return;
 395
 396     if (((x_pos == -1) || (x_pos == m_xScrollPosition)) &&
 397         ((y_pos == -1) || (y_pos == m_yScrollPosition))) return;
 398
 399     if ((x_pos != -1) && (m_xScrollPixelsPerLine))
 400     {
 401         int old_x = m_xScrollPosition;
 402         m_xScrollPosition = x_pos;
 403         m_hAdjust->value = x_pos;
 404
 405         wxEventType command = wxEVT_SCROLLWIN_THUMBTRACK;
 406         wxScrollWinEvent event( command, m_xScrollPosition, wxHORIZONTAL );
 407         event.SetEventObject( this );
 408         GetEventHandler()->ProcessEvent( event );
 409
 410         m_targetWindow->ScrollWindow( (old_x-m_xScrollPosition)*m_xScrollPixelsPerLine, 0 );
 411
 412         gtk_signal_emit_by_name( GTK_OBJECT(m_hAdjust), "value_changed" );
 413     }
 414
 415     if ((y_pos != -1) && (m_yScrollPixelsPerLine))
 416     {
 417         int old_y = m_yScrollPosition;
 418         m_yScrollPosition = y_pos;
 419         m_vAdjust->value = y_pos;
 420
 421         wxEventType command = wxEVT_SCROLLWIN_THUMBTRACK;
 422         wxScrollWinEvent event( command, m_yScrollPosition, wxVERTICAL );
 423         event.SetEventObject( this );
 424         GetEventHandler()->ProcessEvent( event );
 425
 426         m_targetWindow->ScrollWindow( 0, (old_y-m_yScrollPosition)*m_yScrollPixelsPerLine );
 427
 428         gtk_signal_emit_by_name( GTK_OBJECT(m_vAdjust), "value_changed" );
 429     }
 430 }
 431
 432 void wxScrolledWindow::GtkVScroll( float value )
 433 {
 434     if (!m_targetWindow)
 435         return;
 436
 437     if (m_yScrollPixelsPerLine == 0)
 438         return;
 439
 440     int y_pos = (int)(value+0.5);
 441
 442     if (y_pos == m_yScrollPosition)
 443         return;
 444
 445     int old_y = m_yScrollPosition;
 446     m_yScrollPosition = y_pos;
 447
 448     GtkScrolledWindow *scrolledWindow = GTK_SCROLLED_WINDOW(m_widget);
 449     GtkRange *range = GTK_RANGE(scrolledWindow->hscrollbar);
 450
 451     wxEventType command = wxEVT_SCROLLWIN_THUMBTRACK;
 452     if      (range->scroll_type == GTK_SCROLL_STEP_BACKWARD) command = wxEVT_SCROLLWIN_LINEUP;
 453     else if (range->scroll_type == GTK_SCROLL_STEP_FORWARD)  command = wxEVT_SCROLLWIN_LINEDOWN;
 454     else if (range->scroll_type == GTK_SCROLL_PAGE_BACKWARD) command = wxEVT_SCROLLWIN_PAGEUP;
 455     else if (range->scroll_type == GTK_SCROLL_PAGE_FORWARD)  command = wxEVT_SCROLLWIN_PAGEDOWN;
 456
 457     wxScrollWinEvent event( command, m_yScrollPosition, wxVERTICAL );
 458     event.SetEventObject( this );
 459     GetEventHandler()->ProcessEvent( event );
 460
 461     m_targetWindow->ScrollWindow( 0, (old_y-m_yScrollPosition)*m_yScrollPixelsPerLine );
 462 }
 463
 464 void wxScrolledWindow::GtkHScroll( float value )
 465 {
 466     if (!m_targetWindow)
 467         return;
 468
 469     if (m_xScrollPixelsPerLine == 0)
 470         return;
 471
 472     int x_pos = (int)(value+0.5);
 473
 474     if (x_pos == m_xScrollPosition)
 475         return;
 476
 477     int old_x = m_xScrollPosition;
 478     m_xScrollPosition = x_pos;
 479
 480     GtkScrolledWindow *scrolledWindow = GTK_SCROLLED_WINDOW(m_widget);
 481     GtkRange *range = GTK_RANGE(scrolledWindow->hscrollbar);
 482
 483     wxEventType command = wxEVT_SCROLLWIN_THUMBTRACK;
 484     if      (range->scroll_type == GTK_SCROLL_STEP_BACKWARD) command = wxEVT_SCROLLWIN_LINEUP;
 485     else if (range->scroll_type == GTK_SCROLL_STEP_FORWARD)  command = wxEVT_SCROLLWIN_LINEDOWN;
 486     else if (range->scroll_type == GTK_SCROLL_PAGE_BACKWARD) command = wxEVT_SCROLLWIN_PAGEUP;
 487     else if (range->scroll_type == GTK_SCROLL_PAGE_FORWARD)  command = wxEVT_SCROLLWIN_PAGEDOWN;
 488
 489     wxScrollWinEvent event( command, m_xScrollPosition, wxHORIZONTAL );
 490     event.SetEventObject( this );
 491     GetEventHandler()->ProcessEvent( event );
 492
 493     m_targetWindow->ScrollWindow( (old_x-m_xScrollPosition)*m_xScrollPixelsPerLine, 0 );
 494 }
 495
 496 void wxScrolledWindow::EnableScrolling (bool x_scroll, bool y_scroll)
 497 {
 498     m_xScrollingEnabled = x_scroll;
 499     m_yScrollingEnabled = y_scroll;
 500 }
 501
 502 void wxScrolledWindow::GetVirtualSize (int *x, int *y) const
 503 {
 504     if ( x )
 505         *x = m_xScrollPixelsPerLine * m_xScrollLines;
 506     if ( y )
 507         *y = m_yScrollPixelsPerLine * m_yScrollLines;
 508 }
 509
 510 // Where the current view starts from
 511 void wxScrolledWindow::GetViewStart (int *x, int *y) const
 512 {
 513     if ( x )
 514         *x = m_xScrollPosition;
 515     if ( y )
 516         *y = m_yScrollPosition;
 517 }
 518
 519 void wxScrolledWindow::CalcScrolledPosition(int x, int y, int *xx, int *yy) const
 520 {
 521     if ( xx )
 522         *xx = x - m_xScrollPosition * m_xScrollPixelsPerLine;
 523     if ( yy )
 524         *yy = y - m_yScrollPosition * m_yScrollPixelsPerLine;
 525 }
 526
 527 void wxScrolledWindow::CalcUnscrolledPosition(int x, int y, int *xx, int *yy) const
 528 {
 529     if ( xx )
 530         *xx = x + m_xScrollPosition * m_xScrollPixelsPerLine;
 531     if ( yy )
 532         *yy = y + m_yScrollPosition * m_yScrollPixelsPerLine;
 533 }
 534
 535 int wxScrolledWindow::CalcScrollInc(wxScrollWinEvent& event)
 536 {
 537     int pos = event.GetPosition();
 538     int orient = event.GetOrientation();
 539
 540     int nScrollInc = 0;
 541     if (event.GetEventType() == wxEVT_SCROLLWIN_TOP)
 542     {
 543             if (orient == wxHORIZONTAL)
 544                 nScrollInc = - m_xScrollPosition;
 545             else
 546                 nScrollInc = - m_yScrollPosition;
 547     } else
 548     if (event.GetEventType() == wxEVT_SCROLLWIN_BOTTOM)
 549     {
 550             if (orient == wxHORIZONTAL)
 551                 nScrollInc = m_xScrollLines - m_xScrollPosition;
 552             else
 553                 nScrollInc = m_yScrollLines - m_yScrollPosition;
 554     } else
 555     if (event.GetEventType() == wxEVT_SCROLLWIN_LINEUP)
 556     {
 557             nScrollInc = -1;
 558     } else
 559     if (event.GetEventType() == wxEVT_SCROLLWIN_LINEDOWN)
 560     {
 561             nScrollInc = 1;
 562     } else
 563     if (event.GetEventType() == wxEVT_SCROLLWIN_PAGEUP)
 564     {
 565             if (orient == wxHORIZONTAL)
 566                 nScrollInc = -GetScrollPageSize(wxHORIZONTAL);
 567             else
 568                 nScrollInc = -GetScrollPageSize(wxVERTICAL);
 569     } else
 570     if (event.GetEventType() == wxEVT_SCROLLWIN_PAGEDOWN)
 571     {
 572             if (orient == wxHORIZONTAL)
 573                 nScrollInc = GetScrollPageSize(wxHORIZONTAL);
 574             else
 575                 nScrollInc = GetScrollPageSize(wxVERTICAL);
 576     } else
 577     if ((event.GetEventType() == wxEVT_SCROLLWIN_THUMBTRACK) ||
 578         (event.GetEventType() == wxEVT_SCROLLWIN_THUMBRELEASE))
 579     {
 580             if (orient == wxHORIZONTAL)
 581                 nScrollInc = pos - m_xScrollPosition;
 582             else
 583                 nScrollInc = pos - m_yScrollPosition;
 584     }
 585
 586     if (orient == wxHORIZONTAL)
 587     {
 588         if (m_xScrollPixelsPerLine > 0)
 589         {
 590             int w, h;
 591             m_targetWindow->GetClientSize(&w, &h);
 592
 593             int nMaxWidth = m_xScrollLines*m_xScrollPixelsPerLine;
 594             int noPositions = (int) ( ((nMaxWidth - w)/(double)m_xScrollPixelsPerLine) + 0.5 );
 595             if (noPositions < 0)
 596                 noPositions = 0;
 597
 598             if ( (m_xScrollPosition + nScrollInc) < 0 )
 599                 nScrollInc = -m_xScrollPosition; // As -ve as we can go
 600             else if ( (m_xScrollPosition + nScrollInc) > noPositions )
 601                 nScrollInc = noPositions - m_xScrollPosition; // As +ve as we can go
 602         }
 603         else
 604             m_targetWindow->Refresh();
 605     }
 606     else
 607     {
 608         if (m_yScrollPixelsPerLine > 0)
 609         {
 610             int w, h;
 611             m_targetWindow->GetClientSize(&w, &h);
 612
 613             int nMaxHeight = m_yScrollLines*m_yScrollPixelsPerLine;
 614             int noPositions = (int) ( ((nMaxHeight - h)/(double)m_yScrollPixelsPerLine) + 0.5 );
 615             if (noPositions < 0)
 616                 noPositions = 0;
 617
 618             if ( (m_yScrollPosition + nScrollInc) < 0 )
 619                 nScrollInc = -m_yScrollPosition; // As -ve as we can go
 620             else if ( (m_yScrollPosition + nScrollInc) > noPositions )
 621                 nScrollInc = noPositions - m_yScrollPosition; // As +ve as we can go
 622         }
 623         else
 624             m_targetWindow->Refresh();
 625     }
 626
 627     return nScrollInc;
 628 }
 629
 630 // ----------------------------------------------------------------------------
 631 // event handlers
 632 // ----------------------------------------------------------------------------
 633
 634 // Default OnSize resets scrollbars, if any
 635 void wxScrolledWindow::OnSize(wxSizeEvent& WXUNUSED(event))
 636 {
 637 #if wxUSE_CONSTRAINTS
 638     if (GetAutoLayout())
 639         Layout();
 640 #endif
 641
 642     AdjustScrollbars();
 643 }
 644
 645 // This calls OnDraw, having adjusted the origin according to the current
 646 // scroll position
 647 void wxScrolledWindow::OnPaint(wxPaintEvent& WXUNUSED(event))
 648 {
 649     wxPaintDC dc(this);
 650     PrepareDC(dc);
 651
 652     OnDraw(dc);
 653 }
 654
 655 // kbd handling: notice that we use OnChar() and not OnKeyDown() for
 656 // compatibility here - if we used OnKeyDown(), the programs which process
 657 // arrows themselves in their OnChar() would never get the message and like
 658 // this they always have the priority
 659 void wxScrolledWindow::OnChar(wxKeyEvent& event)
 660 {
 661     int stx, sty,       // view origin
 662         szx, szy,       // view size (total)
 663         clix, cliy;     // view size (on screen)
 664
 665     ViewStart(&stx, &sty);
 666     GetClientSize(&clix, &cliy);
 667     GetVirtualSize(&szx, &szy);
 668
 669     if( m_xScrollPixelsPerLine )
 670     {
 671         clix /= m_xScrollPixelsPerLine;
 672         szx /= m_xScrollPixelsPerLine;
 673     }
 674     else
 675     {
 676         clix = 0;
 677         szx = -1;
 678     }
 679     if( m_yScrollPixelsPerLine )
 680     {
 681         cliy /= m_yScrollPixelsPerLine;
 682         szy /= m_yScrollPixelsPerLine;
 683     }
 684     else
 685     {
 686         cliy = 0;
 687         szy = -1;
 688     }
 689
 690     int dsty;
 691     switch ( event.KeyCode() )
 692     {
 693         case WXK_PAGEUP:
 694         case WXK_PRIOR:
 695             dsty = sty - (5 * cliy / 6);
 696             Scroll(-1, (dsty == -1) ? 0 : dsty);
 697             break;
 698
 699         case WXK_PAGEDOWN:
 700         case WXK_NEXT:
 701             Scroll(-1, sty + (5 * cliy / 6));
 702             break;
 703
 704         case WXK_HOME:
 705             Scroll(0, event.ControlDown() ? 0 : -1);
 706             break;
 707
 708         case WXK_END:
 709             Scroll(szx - clix, event.ControlDown() ? szy - cliy : -1);
 710             break;
 711
 712         case WXK_UP:
 713             Scroll(-1, sty - 1);
 714             break;
 715
 716         case WXK_DOWN:
 717             Scroll(-1, sty + 1);
 718             break;
 719
 720         case WXK_LEFT:
 721             Scroll(stx - 1, -1);
 722             break;
 723
 724         case WXK_RIGHT:
 725             Scroll(stx + 1, -1);
 726             break;
 727
 728         default:
 729             // not for us
 730             event.Skip();
 731     }
 732 }