src/generic/vscroll.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        src/generic/vscroll.cpp
   3 // Purpose:     wxVScrolledWindow implementation
   4 // Author:      Vadim Zeitlin
   5 // Modified by:
   6 // Created:     30.05.03
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) 2003 Vadim Zeitlin <vadim@wxwindows.org>
   9 // Licence:     wxWindows licence
  10 /////////////////////////////////////////////////////////////////////////////
  11
  12 // ============================================================================
  13 // declarations
  14 // ============================================================================
  15
  16 // ----------------------------------------------------------------------------
  17 // headers
  18 // ----------------------------------------------------------------------------
  19
  20 // For compilers that support precompilation, includes "wx.h".
  21 #include "wx/wxprec.h"
  22
  23 #ifdef __BORLANDC__
  24 #pragma hdrstop
  25 #endif
  26
  27 #ifndef WX_PRECOMP
  28     #include "wx/sizer.h"
  29 #endif
  30
  31 #include "wx/vscroll.h"
  32
  33 // ----------------------------------------------------------------------------
  34 // event tables
  35 // ----------------------------------------------------------------------------
  36
  37 BEGIN_EVENT_TABLE(wxVScrolledWindow, wxPanel)
  38     EVT_SIZE(wxVScrolledWindow::OnSize)
  39     EVT_SCROLLWIN(wxVScrolledWindow::OnScroll)
  40 #if wxUSE_MOUSEWHEEL
  41     EVT_MOUSEWHEEL(wxVScrolledWindow::OnMouseWheel)
  42 #endif
  43 END_EVENT_TABLE()
  44
  45
  46 // ============================================================================
  47 // implementation
  48 // ============================================================================
  49
  50 IMPLEMENT_ABSTRACT_CLASS(wxVScrolledWindow, wxPanel)
  51
  52 // ----------------------------------------------------------------------------
  53 // initialization
  54 // ----------------------------------------------------------------------------
  55
  56 void wxVScrolledWindow::Init()
  57 {
  58     // we're initially empty
  59     m_lineMax =
  60     m_lineFirst = 0;
  61
  62     // this one should always be strictly positive
  63     m_nVisible = 1;
  64
  65     m_heightTotal = 0;
  66
  67 #if wxUSE_MOUSEWHEEL
  68     m_sumWheelRotation = 0;
  69 #endif
  70 }
  71
  72 // ----------------------------------------------------------------------------
  73 // various helpers
  74 // ----------------------------------------------------------------------------
  75
  76 wxCoord wxVScrolledWindow::EstimateTotalHeight() const
  77 {
  78     // estimate the total height: it is impossible to call
  79     // OnGetLineHeight() for every line because there may be too many of
  80     // them, so we just make a guess using some lines in the beginning,
  81     // some in the end and some in the middle
  82     static const size_t NUM_LINES_TO_SAMPLE = 10;
  83
  84     wxCoord heightTotal;
  85     if ( m_lineMax < 3*NUM_LINES_TO_SAMPLE )
  86     {
  87         // in this case calculating exactly is faster and more correct than
  88         // guessing
  89         heightTotal = GetLinesHeight(0, m_lineMax);
  90     }
  91     else // too many lines to calculate exactly
  92     {
  93         // look at some lines in the beginning/middle/end
  94         heightTotal =
  95             GetLinesHeight(0, NUM_LINES_TO_SAMPLE) +
  96                 GetLinesHeight(m_lineMax - NUM_LINES_TO_SAMPLE, m_lineMax) +
  97                     GetLinesHeight(m_lineMax/2 - NUM_LINES_TO_SAMPLE/2,
  98                                    m_lineMax/2 + NUM_LINES_TO_SAMPLE/2);
  99
 100         // use the height of the lines we looked as the average
 101         heightTotal = (wxCoord)
 102                 (((float)heightTotal / (3*NUM_LINES_TO_SAMPLE)) * m_lineMax);
 103     }
 104
 105     return heightTotal;
 106 }
 107
 108 wxCoord wxVScrolledWindow::GetLinesHeight(size_t lineMin, size_t lineMax) const
 109 {
 110     if ( lineMin == lineMax )
 111         return 0;
 112     else if ( lineMin > lineMax )
 113         return -GetLinesHeight(lineMax, lineMin);
 114     //else: lineMin < lineMax
 115
 116     // let the user code know that we're going to need all these lines
 117     OnGetLinesHint(lineMin, lineMax);
 118
 119     // do sum up their heights
 120     wxCoord height = 0;
 121     for ( size_t line = lineMin; line < lineMax; line++ )
 122     {
 123         height += OnGetLineHeight(line);
 124     }
 125
 126     return height;
 127 }
 128
 129 size_t wxVScrolledWindow::FindFirstFromBottom(size_t lineLast, bool full)
 130 {
 131     const wxCoord hWindow = GetClientSize().y;
 132
 133     // go upwards until we arrive at a line such that lineLast is not visible
 134     // any more when it is shown
 135     size_t lineFirst = lineLast;
 136     wxCoord h = 0;
 137     for ( ;; )
 138     {
 139         h += OnGetLineHeight(lineFirst);
 140
 141         if ( h > hWindow )
 142         {
 143             // for this line to be fully visible we need to go one line
 144             // down, but if it is enough for it to be only partly visible then
 145             // this line will do as well
 146             if ( full )
 147             {
 148                 lineFirst++;
 149             }
 150
 151             break;
 152         }
 153
 154         if ( !lineFirst )
 155             break;
 156
 157         lineFirst--;
 158     }
 159
 160     return lineFirst;
 161 }
 162
 163 void wxVScrolledWindow::UpdateScrollbar()
 164 {
 165     // see how many lines can we fit on screen
 166     const wxCoord hWindow = GetClientSize().y;
 167
 168     wxCoord h = 0;
 169     size_t line;
 170     for ( line = m_lineFirst; line < m_lineMax; line++ )
 171     {
 172         if ( h > hWindow )
 173             break;
 174
 175         h += OnGetLineHeight(line);
 176     }
 177
 178     // if we still have remaining space below, maybe we can fit everything?
 179     if ( h < hWindow )
 180     {
 181         wxCoord hAll = h;
 182         for ( size_t lineFirst = m_lineFirst; lineFirst > 0; lineFirst-- )
 183         {
 184             hAll += OnGetLineHeight(m_lineFirst - 1);
 185             if ( hAll > hWindow )
 186                 break;
 187         }
 188
 189         if ( hAll < hWindow )
 190         {
 191             // we don't need scrollbar at all
 192             m_lineFirst = 0;
 193             SetScrollbar(wxVERTICAL, 0, 0, 0);
 194         }
 195     }
 196
 197     m_nVisible = line - m_lineFirst;
 198
 199     int pageSize = m_nVisible;
 200     if ( h > hWindow )
 201     {
 202         // last line is only partially visible, we still need the scrollbar and
 203         // so we have to "fix" pageSize because if it is equal to m_lineMax the
 204         // scrollbar is not shown at all under MSW
 205         pageSize--;
 206     }
 207
 208     // set the scrollbar parameters to reflect this
 209     SetScrollbar(wxVERTICAL, m_lineFirst, pageSize, m_lineMax);
 210 }
 211
 212 // ----------------------------------------------------------------------------
 213 // operations
 214 // ----------------------------------------------------------------------------
 215
 216 void wxVScrolledWindow::SetLineCount(size_t count)
 217 {
 218     // save the number of lines
 219     m_lineMax = count;
 220
 221     // and our estimate for their total height
 222     m_heightTotal = EstimateTotalHeight();
 223
 224     // recalculate the scrollbars parameters
 225     m_lineFirst = 1;    // make sure it is != 0
 226     ScrollToLine(0);
 227 }
 228
 229 void wxVScrolledWindow::RefreshLine(size_t line)
 230 {
 231     // is this line visible?
 232     if ( !IsVisible(line) )
 233     {
 234         // no, it is useless to do anything
 235         return;
 236     }
 237
 238     // calculate the rect occupied by this line on screen
 239     wxRect rect;
 240     rect.width = GetClientSize().x;
 241     rect.height = OnGetLineHeight(line);
 242     for ( size_t n = GetVisibleBegin(); n < line; n++ )
 243     {
 244         rect.y += OnGetLineHeight(n);
 245     }
 246
 247     // do refresh it
 248     RefreshRect(rect);
 249 }
 250
 251 void wxVScrolledWindow::RefreshLines(size_t from, size_t to)
 252 {
 253     wxASSERT_MSG( from <= to, _T("RefreshLines(): empty range") );
 254
 255     // clump the range to just the visible lines -- it is useless to refresh
 256     // the other ones
 257     if ( from < GetVisibleBegin() )
 258         from = GetVisibleBegin();
 259
 260     if ( to >= GetVisibleEnd() )
 261         to = GetVisibleEnd();
 262     else
 263         to++;
 264
 265     // calculate the rect occupied by these lines on screen
 266     wxRect rect;
 267     rect.width = GetClientSize().x;
 268     for ( size_t nBefore = GetVisibleBegin(); nBefore < from; nBefore++ )
 269     {
 270         rect.y += OnGetLineHeight(nBefore);
 271     }
 272
 273     for ( size_t nBetween = from; nBetween < to; nBetween++ )
 274     {
 275         rect.height += OnGetLineHeight(nBetween);
 276     }
 277
 278     // do refresh it
 279     RefreshRect(rect);
 280 }
 281
 282 void wxVScrolledWindow::RefreshAll()
 283 {
 284     UpdateScrollbar();
 285
 286     Refresh();
 287 }
 288
 289 bool wxVScrolledWindow::Layout()
 290 {
 291     if ( GetSizer() )
 292     {
 293         // adjust the sizer dimensions/position taking into account the
 294         // virtual size and scrolled position of the window.
 295
 296         int w, h;
 297         GetVirtualSize(&w, &h);
 298
 299         // x is always 0 so no variable needed
 300         int y = -GetLinesHeight(0, GetFirstVisibleLine());
 301
 302         GetSizer()->SetDimension(0, y, w, h);
 303         return true;
 304     }
 305
 306     // fall back to default for LayoutConstraints
 307     return wxPanel::Layout();
 308 }
 309
 310 int wxVScrolledWindow::HitTest(wxCoord WXUNUSED(x), wxCoord y) const
 311 {
 312     const size_t lineMax = GetVisibleEnd();
 313     for ( size_t line = GetVisibleBegin(); line < lineMax; line++ )
 314     {
 315         y -= OnGetLineHeight(line);
 316         if ( y < 0 )
 317             return line;
 318     }
 319
 320     return wxNOT_FOUND;
 321 }
 322
 323 // ----------------------------------------------------------------------------
 324 // scrolling
 325 // ----------------------------------------------------------------------------
 326
 327 bool wxVScrolledWindow::ScrollToLine(size_t line)
 328 {
 329     if ( !m_lineMax )
 330     {
 331         // we're empty, code below doesn't make sense in this case
 332         return false;
 333     }
 334
 335     // determine the real first line to scroll to: we shouldn't scroll beyond
 336     // the end
 337     size_t lineFirstLast = FindFirstFromBottom(m_lineMax - 1, true);
 338     if ( line > lineFirstLast )
 339         line = lineFirstLast;
 340
 341     // anything to do?
 342     if ( line == m_lineFirst )
 343     {
 344         // no
 345         return false;
 346     }
 347
 348
 349     // remember the currently shown lines for the refresh code below
 350     size_t lineFirstOld = GetVisibleBegin(),
 351            lineLastOld = GetVisibleEnd();
 352
 353     m_lineFirst = line;
 354
 355
 356     // the size of scrollbar thumb could have changed
 357     UpdateScrollbar();
 358
 359
 360     // finally refresh the display -- but only redraw as few lines as possible
 361     // to avoid flicker
 362     if ( GetVisibleBegin() >= lineLastOld ||
 363             GetVisibleEnd() <= lineFirstOld )
 364     {
 365         // the simplest case: we don't have any old lines left, just redraw
 366         // everything
 367         Refresh();
 368     }
 369     else // overlap between the lines we showed before and should show now
 370     {
 371         ScrollWindow(0, GetLinesHeight(GetVisibleBegin(), lineFirstOld));
 372     }
 373
 374     return true;
 375 }
 376
 377 bool wxVScrolledWindow::ScrollLines(int lines)
 378 {
 379     lines += m_lineFirst;
 380     if ( lines < 0 )
 381         lines = 0;
 382
 383     return ScrollToLine(lines);
 384 }
 385
 386 bool wxVScrolledWindow::ScrollPages(int pages)
 387 {
 388     bool didSomething = false;
 389
 390     while ( pages )
 391     {
 392         int line;
 393         if ( pages > 0 )
 394         {
 395             line = GetVisibleEnd();
 396             if ( line )
 397                 line--;
 398             pages--;
 399         }
 400         else // pages < 0
 401         {
 402             line = FindFirstFromBottom(GetVisibleBegin());
 403             pages++;
 404         }
 405
 406         didSomething = ScrollToLine(line);
 407     }
 408
 409     return didSomething;
 410 }
 411
 412 // ----------------------------------------------------------------------------
 413 // event handling
 414 // ----------------------------------------------------------------------------
 415
 416 void wxVScrolledWindow::OnSize(wxSizeEvent& event)
 417 {
 418     UpdateScrollbar();
 419
 420     event.Skip();
 421 }
 422
 423 void wxVScrolledWindow::OnScroll(wxScrollWinEvent& event)
 424 {
 425     size_t lineFirstNew;
 426
 427     const wxEventType evtType = event.GetEventType();
 428
 429     if ( evtType == wxEVT_SCROLLWIN_TOP )
 430     {
 431         lineFirstNew = 0;
 432     }
 433     else if ( evtType == wxEVT_SCROLLWIN_BOTTOM )
 434     {
 435         lineFirstNew = m_lineMax;
 436     }
 437     else if ( evtType == wxEVT_SCROLLWIN_LINEUP )
 438     {
 439         lineFirstNew = m_lineFirst ? m_lineFirst - 1 : 0;
 440     }
 441     else if ( evtType == wxEVT_SCROLLWIN_LINEDOWN )
 442     {
 443         lineFirstNew = m_lineFirst + 1;
 444     }
 445     else if ( evtType == wxEVT_SCROLLWIN_PAGEUP )
 446     {
 447         lineFirstNew = FindFirstFromBottom(m_lineFirst);
 448     }
 449     else if ( evtType == wxEVT_SCROLLWIN_PAGEDOWN )
 450     {
 451         lineFirstNew = GetVisibleEnd();
 452         if ( lineFirstNew )
 453             lineFirstNew--;
 454     }
 455     else if ( evtType == wxEVT_SCROLLWIN_THUMBRELEASE )
 456     {
 457         lineFirstNew = event.GetPosition();
 458     }
 459     else if ( evtType == wxEVT_SCROLLWIN_THUMBTRACK )
 460     {
 461         lineFirstNew = event.GetPosition();
 462     }
 463
 464     else // unknown scroll event?
 465     {
 466         wxFAIL_MSG( _T("unknown scroll event type?") );
 467         return;
 468     }
 469
 470     ScrollToLine(lineFirstNew);
 471
 472 #ifdef __WXMAC__
 473     Update();
 474 #endif // __WXMAC__
 475 }
 476
 477 #if wxUSE_MOUSEWHEEL
 478
 479 void wxVScrolledWindow::OnMouseWheel(wxMouseEvent& event)
 480 {
 481     m_sumWheelRotation += event.GetWheelRotation();
 482     int delta = event.GetWheelDelta();
 483
 484     // how much to scroll this time
 485     int units_to_scroll = -(m_sumWheelRotation/delta);
 486     if ( !units_to_scroll )
 487         return;
 488
 489     m_sumWheelRotation += units_to_scroll*delta;
 490
 491     if ( !event.IsPageScroll() )
 492         ScrollLines( units_to_scroll*event.GetLinesPerAction() );
 493     else
 494         // scroll pages instead of lines
 495         ScrollPages( units_to_scroll );
 496 }
 497
 498 #endif // wxUSE_MOUSEWHEEL
 499