]> git.saurik.com Git - wxWidgets.git/blobdiff - demos/life/life.cpp
Added wxFileHistory demo
[wxWidgets.git] / demos / life / life.cpp
index 7d22f091ebd2e62d427dab029b0a2be1a014ee0c..cf63a5124a3e1a958381ccbcdc879d4dbc298403 100644 (file)
 #endif
 
 #include "wx/statline.h"
+#include "wx/wfstream.h"
+#include "wx/filedlg.h"
 
 #include "life.h"
 #include "game.h"
 #include "dialogs.h"
+#include "reader.h"
 
 // --------------------------------------------------------------------------
 // resources
 // --------------------------------------------------------------------------
 
-#if defined(__WXGTK__) || defined(__WXMOTIF__)
+#if defined(__WXGTK__) || defined(__WXMOTIF__) || defined(__WXMAC__) || defined(__WXMGL__) || defined(__WXX11__)
     // application icon
     #include "mondrian.xpm"
 
     // bitmap buttons for the toolbar
     #include "bitmaps/reset.xpm"
+    #include "bitmaps/open.xpm"
     #include "bitmaps/play.xpm"
     #include "bitmaps/stop.xpm"
     #include "bitmaps/zoomin.xpm"
     #include "bitmaps/zoomout.xpm"
+    #include "bitmaps/info.xpm"
 
     // navigator
     #include "bitmaps/north.xpm"
@@ -67,22 +72,14 @@ enum
     // timer
     ID_TIMER = 1001,
 
-    // menu items and toolbar buttons
-    ID_RESET,
+    // file menu
+    ID_NEW,
+    ID_OPEN,
     ID_SAMPLES,
     ID_ABOUT,
     ID_EXIT,
-    ID_START,
-    ID_STEP,
-    ID_STOP,
-    ID_ZOOMIN,
-    ID_ZOOMOUT,
-    ID_TOPSPEED,
-
-    // speed selection slider
-    ID_SLIDER,
 
-    // navigation
+    // view menu
     ID_SHOWNAV,
     ID_ORIGIN,
     ID_CENTER,
@@ -90,6 +87,18 @@ enum
     ID_SOUTH,
     ID_EAST,
     ID_WEST,
+    ID_ZOOMIN,
+    ID_ZOOMOUT,
+    ID_INFO,
+
+    // game menu
+    ID_START,
+    ID_STEP,
+    ID_STOP,
+    ID_TOPSPEED,
+
+    // speed selection slider
+    ID_SLIDER,
 };
 
 // --------------------------------------------------------------------------
@@ -98,14 +107,11 @@ enum
 
 // Event tables
 BEGIN_EVENT_TABLE(LifeFrame, wxFrame)
+    EVT_MENU            (ID_NEW,      LifeFrame::OnMenu)
+    EVT_MENU            (ID_OPEN,     LifeFrame::OnOpen)
     EVT_MENU            (ID_SAMPLES,  LifeFrame::OnSamples)
-    EVT_MENU            (ID_RESET,    LifeFrame::OnMenu)
     EVT_MENU            (ID_ABOUT,    LifeFrame::OnMenu)
     EVT_MENU            (ID_EXIT,     LifeFrame::OnMenu)
-    EVT_MENU            (ID_START,    LifeFrame::OnMenu)
-    EVT_MENU            (ID_STEP,     LifeFrame::OnMenu)
-    EVT_MENU            (ID_STOP,     LifeFrame::OnMenu)
-    EVT_MENU            (ID_TOPSPEED, LifeFrame::OnMenu)
     EVT_MENU            (ID_SHOWNAV,  LifeFrame::OnMenu)
     EVT_MENU            (ID_ORIGIN,   LifeFrame::OnNavigate)
     EVT_BUTTON          (ID_CENTER,   LifeFrame::OnNavigate)
@@ -115,6 +121,11 @@ BEGIN_EVENT_TABLE(LifeFrame, wxFrame)
     EVT_BUTTON          (ID_WEST,     LifeFrame::OnNavigate)
     EVT_MENU            (ID_ZOOMIN,   LifeFrame::OnZoom)
     EVT_MENU            (ID_ZOOMOUT,  LifeFrame::OnZoom)
+    EVT_MENU            (ID_INFO,     LifeFrame::OnMenu)
+    EVT_MENU            (ID_START,    LifeFrame::OnMenu)
+    EVT_MENU            (ID_STEP,     LifeFrame::OnMenu)
+    EVT_MENU            (ID_STOP,     LifeFrame::OnMenu)
+    EVT_MENU            (ID_TOPSPEED, LifeFrame::OnMenu)
     EVT_COMMAND_SCROLL  (ID_SLIDER,   LifeFrame::OnSlider)
     EVT_TIMER           (ID_TIMER,    LifeFrame::OnTimer)
     EVT_CLOSE           (             LifeFrame::OnClose)
@@ -128,7 +139,10 @@ BEGIN_EVENT_TABLE(LifeCanvas, wxWindow)
     EVT_PAINT           (             LifeCanvas::OnPaint)
     EVT_SCROLLWIN       (             LifeCanvas::OnScroll)
     EVT_SIZE            (             LifeCanvas::OnSize)
-    EVT_MOUSE_EVENTS    (             LifeCanvas::OnMouse)
+    EVT_MOTION          (             LifeCanvas::OnMouse)
+    EVT_LEFT_DOWN       (             LifeCanvas::OnMouse)
+    EVT_LEFT_UP         (             LifeCanvas::OnMouse)
+    EVT_LEFT_DCLICK     (             LifeCanvas::OnMouse)
     EVT_ERASE_BACKGROUND(             LifeCanvas::OnEraseBackground)
 END_EVENT_TABLE()
 
@@ -142,7 +156,7 @@ IMPLEMENT_APP(LifeApp)
 // ==========================================================================
 
 // some shortcuts
-#define ADD_TOOL(id, bmp, tooltip, help)     \
+#define ADD_TOOL(id, bmp, tooltip, help) \
     toolBar->AddTool(id, bmp, wxNullBitmap, FALSE, -1, -1, (wxObject *)0, tooltip, help)
 
 
@@ -160,6 +174,11 @@ bool LifeApp::OnInit()
     frame->Show(TRUE);
     SetTopWindow(frame);
 
+    // just for Motif
+#ifdef __WXMOTIF__
+    frame->UpdateInfoText();
+#endif
+
     // enter the main message loop and run the app
     return TRUE;
 }
@@ -179,32 +198,34 @@ LifeFrame::LifeFrame() : wxFrame((wxFrame *)0, -1, _("Life!"), wxPoint(200, 200)
     wxMenu *menuView = new wxMenu("", wxMENU_TEAROFF);
     wxMenu *menuGame = new wxMenu("", wxMENU_TEAROFF);
 
-    menuFile->Append(ID_RESET, _("Reset"), _("Start a new game"));
-    menuFile->Append(ID_SAMPLES, _("Sample game..."), _("Select a sample configuration"));
+    menuFile->Append(ID_NEW, _("&New"), _("Start a new game"));
+    menuFile->Append(ID_OPEN, _("&Open..."), _("Open an existing Life pattern"));
+    menuFile->Append(ID_SAMPLES, _("&Sample game..."), _("Select a sample configuration"));
     menuFile->AppendSeparator();
     menuFile->Append(ID_ABOUT, _("&About...\tCtrl-A"), _("Show about dialog"));
     menuFile->AppendSeparator();
     menuFile->Append(ID_EXIT, _("E&xit\tAlt-X"), _("Quit this program"));
 
-    menuView->Append(ID_SHOWNAV, _("Navigation toolbox"), _("Show or hide toolbox"), TRUE);
+    menuView->Append(ID_SHOWNAV, _("Navigation &toolbox"), _("Show or hide toolbox"), TRUE);
     menuView->Check (ID_SHOWNAV, TRUE);
     menuView->AppendSeparator();
-    menuView->Append(ID_ORIGIN, _("Absolute origin"), _("Go to (0, 0)"));
-    menuView->Append(ID_CENTER, _("Center of mass"), _("Find center of mass"));
-    menuView->Append(ID_NORTH, _("North"), _("Find northernmost cell"));
-    menuView->Append(ID_SOUTH, _("South"), _("Find southernmost cell"));
-    menuView->Append(ID_EAST, _("East"), _("Find easternmost cell"));
-    menuView->Append(ID_WEST, _("West"), _("Find westernmost cell"));
+    menuView->Append(ID_ORIGIN, _("&Absolute origin"), _("Go to (0, 0)"));
+    menuView->Append(ID_CENTER, _("&Center of mass"), _("Find center of mass"));
+    menuView->Append(ID_NORTH, _("&North"), _("Find northernmost cell"));
+    menuView->Append(ID_SOUTH, _("&South"), _("Find southernmost cell"));
+    menuView->Append(ID_EAST, _("&East"), _("Find easternmost cell"));
+    menuView->Append(ID_WEST, _("&West"), _("Find westernmost cell"));
     menuView->AppendSeparator();
-    menuView->Append(ID_ZOOMIN, _("Zoom &in\tCtrl-I"));
-    menuView->Append(ID_ZOOMOUT, _("Zoom &out\tCtrl-O"));
+    menuView->Append(ID_ZOOMIN, _("Zoom &in\tCtrl-I"), _("Zoom in"));
+    menuView->Append(ID_ZOOMOUT, _("Zoom &out\tCtrl-O"), _("Zoom out"));
+    menuView->Append(ID_INFO, _("&Description...\tCtrl-D"), _("View pattern description"));
 
     menuGame->Append(ID_START, _("&Start\tCtrl-S"), _("Start"));
     menuGame->Append(ID_STEP, _("&Next\tCtrl-N"), _("Single step"));
     menuGame->Append(ID_STOP, _("S&top\tCtrl-T"), _("Stop"));
     menuGame->Enable(ID_STOP, FALSE);
     menuGame->AppendSeparator();
-    menuGame->Append(ID_TOPSPEED, _("Top speed!"), _("Go as fast as possible"));
+    menuGame->Append(ID_TOPSPEED, _("T&op speed!"), _("Go as fast as possible"));
 
     wxMenuBar *menuBar = new wxMenuBar();
     menuBar->Append(menuFile, _("&File"));
@@ -213,23 +234,30 @@ LifeFrame::LifeFrame() : wxFrame((wxFrame *)0, -1, _("Life!"), wxPoint(200, 200)
     SetMenuBar(menuBar);
 
     // tool bar
-    wxBitmap tbBitmaps[5];
+    wxBitmap tbBitmaps[7];
 
     tbBitmaps[0] = wxBITMAP(reset);
-    tbBitmaps[1] = wxBITMAP(play);
-    tbBitmaps[2] = wxBITMAP(stop);
-    tbBitmaps[3] = wxBITMAP(zoomin);
-    tbBitmaps[4] = wxBITMAP(zoomout);
+    tbBitmaps[1] = wxBITMAP(open);
+    tbBitmaps[2] = wxBITMAP(zoomin);
+    tbBitmaps[3] = wxBITMAP(zoomout);
+    tbBitmaps[4] = wxBITMAP(info);
+    tbBitmaps[5] = wxBITMAP(play);
+    tbBitmaps[6] = wxBITMAP(stop);
 
     wxToolBar *toolBar = CreateToolBar();
     toolBar->SetMargins(5, 5);
     toolBar->SetToolBitmapSize(wxSize(16, 16));
-    ADD_TOOL(ID_RESET, tbBitmaps[0], _("Reset"), _("Start a new game"));
-    ADD_TOOL(ID_START, tbBitmaps[1], _("Start"), _("Start"));
-    ADD_TOOL(ID_STOP, tbBitmaps[2], _("Stop"), _("Stop"));
+
+    ADD_TOOL(ID_NEW, tbBitmaps[0], _("New"), _("Start a new game"));
+    ADD_TOOL(ID_OPEN, tbBitmaps[1], _("Open"), _("Open an existing Life pattern"));
     toolBar->AddSeparator();
-    ADD_TOOL(ID_ZOOMIN, tbBitmaps[3], _("Zoom in"), _("Zoom in"));
-    ADD_TOOL(ID_ZOOMOUT, tbBitmaps[4], _("Zoom out"), _("Zoom out"));
+    ADD_TOOL(ID_ZOOMIN, tbBitmaps[2], _("Zoom in"), _("Zoom in"));
+    ADD_TOOL(ID_ZOOMOUT, tbBitmaps[3], _("Zoom out"), _("Zoom out"));
+    ADD_TOOL(ID_INFO, tbBitmaps[4], _("Description"), _("Show description"));
+    toolBar->AddSeparator();
+    ADD_TOOL(ID_START, tbBitmaps[5], _("Start"), _("Start"));
+    ADD_TOOL(ID_STOP, tbBitmaps[6], _("Stop"), _("Stop"));
+
     toolBar->Realize();
     toolBar->EnableTool(ID_STOP, FALSE);    // must be after Realize() !
 
@@ -285,6 +313,7 @@ LifeFrame::LifeFrame() : wxFrame((wxFrame *)0, -1, _("Life!"), wxPoint(200, 200)
 
     sizer2->Add( m_text, 0, wxGROW | wxTOP, 4 );
     sizer2->Add( slider, 0, wxCENTRE | wxALL, 4 );
+
     panel2->SetSizer( sizer2 );
     panel2->SetAutoLayout( TRUE );
     sizer2->Fit( panel2 );
@@ -338,20 +367,56 @@ void LifeFrame::UpdateUI()
     GetMenuBar()->GetMenu(1)->Enable(ID_ZOOMOUT, cellsize > 1);
 }
 
-// event handlers
+// Event handlers -----------------------------------------------------------
+
+// OnMenu handles all events which don't have their own event handler
 void LifeFrame::OnMenu(wxCommandEvent& event)
 {
     switch (event.GetId())
     {
-        case ID_START   : OnStart(); break;
-        case ID_STEP    : OnStep(); break;
-        case ID_STOP    : OnStop(); break;
+        case ID_NEW:
+        {
+            // stop if it was running
+            OnStop();
+            m_life->Clear();
+            m_canvas->Recenter(0, 0);
+            m_tics = 0;
+            UpdateInfoText();
+            break;
+        }
+        case ID_ABOUT:
+        {
+            LifeAboutDialog dialog(this);
+            dialog.ShowModal();
+            break;
+        }
+        case ID_EXIT:
+        {
+            // TRUE is to force the frame to close
+            Close(TRUE);
+            break;
+        }
         case ID_SHOWNAV :
         {
             bool checked = GetMenuBar()->GetMenu(1)->IsChecked(ID_SHOWNAV);
             m_navigator->Show(checked);
             break;
         }
+        case ID_INFO:
+        {
+            wxString desc = m_life->GetDescription();
+            
+            if ( desc.IsEmpty() )
+                desc = _("Not available");
+
+            // should we make the description editable here?
+            wxMessageBox(desc, _("Description"), wxOK | wxICON_INFORMATION);
+
+            break;
+        }
+        case ID_START   : OnStart(); break;
+        case ID_STEP    : OnStep(); break;
+        case ID_STOP    : OnStop(); break;
         case ID_TOPSPEED:
         {
             m_running = TRUE;
@@ -364,41 +429,39 @@ void LifeFrame::OnMenu(wxCommandEvent& event)
             }
             break;
         }
-        case ID_RESET:
+    }
+}
+
+void LifeFrame::OnOpen(wxCommandEvent& WXUNUSED(event))
+{
+    wxFileDialog filedlg(this,
+                         _("Choose a file to open"),
+                         _(""),
+                         _(""),
+                         _("Life patterns (*.lif)|*.lif|All files (*.*)|*.*"),
+                         wxOPEN | wxFILE_MUST_EXIST);
+
+    if (filedlg.ShowModal() == wxID_OK)
+    {
+        wxFileInputStream stream(filedlg.GetPath());
+        LifeReader reader(stream);
+
+        // the reader handles errors itself, no need to do anything here
+        if (reader.IsOk())
         {
-            // stop if it was running
+            // stop if running and put the pattern
             OnStop();
             m_life->Clear();
+            m_life->SetPattern(reader.GetPattern());
+
+            // recenter canvas
             m_canvas->Recenter(0, 0);
             m_tics = 0;
             UpdateInfoText();
-            break;
-        }
-        case ID_ABOUT:
-        {
-            LifeAboutDialog dialog(this);
-            dialog.ShowModal();
-            break;
-        }
-        case ID_EXIT :
-        {
-            // TRUE is to force the frame to close
-            Close(TRUE);
-            break;
         }
     }
 }
 
-void LifeFrame::OnClose(wxCloseEvent& WXUNUSED(event))
-{
-    // Stop if it was running; this is absolutely needed because
-    // the frame won't be actually destroyed until there are no
-    // more pending events, and this in turn won't ever happen
-    // if the timer is running faster than the window can redraw.
-    OnStop();
-    Destroy();   
-}
-
 void LifeFrame::OnSamples(wxCommandEvent& WXUNUSED(event))
 {
     // stop if it was running
@@ -409,11 +472,11 @@ void LifeFrame::OnSamples(wxCommandEvent& WXUNUSED(event))
 
     if (dialog.ShowModal() == wxID_OK)
     {
-        const LifeShape shape = dialog.GetShape();
+        const LifePattern pattern = dialog.GetPattern();
 
-        // put the shape
+        // put the pattern
         m_life->Clear();
-        m_life->SetShape(shape);
+        m_life->SetPattern(pattern);
 
         // recenter canvas
         m_canvas->Recenter(0, 0);
@@ -440,11 +503,11 @@ void LifeFrame::OnZoom(wxCommandEvent& event)
 
 void LifeFrame::OnNavigate(wxCommandEvent& event)
 {
-    Cell c;
+    LifeCell c;
 
     switch (event.GetId())
     {
-        case ID_NORTH:  c = m_life->FindNorth(); break;
+               case ID_NORTH:  c = m_life->FindNorth(); break;
         case ID_SOUTH:  c = m_life->FindSouth(); break;
         case ID_WEST:   c = m_life->FindWest(); break;
         case ID_EAST:   c = m_life->FindEast(); break;
@@ -473,6 +536,16 @@ void LifeFrame::OnTimer(wxTimerEvent& WXUNUSED(event))
     OnStep();
 }
 
+void LifeFrame::OnClose(wxCloseEvent& WXUNUSED(event))
+{
+    // Stop if it was running; this is absolutely needed because
+    // the frame won't be actually destroyed until there are no
+    // more pending events, and this in turn won't ever happen
+    // if the timer is running faster than the window can redraw.
+    OnStop();
+    Destroy();   
+}
+
 void LifeFrame::OnStart()
 {
     if (!m_running)
@@ -529,7 +602,7 @@ LifeNavigator::LifeNavigator(wxWindow *parent)
         bmpe = wxBITMAP(east),  
         bmps = wxBITMAP(south);
 
-#ifdef __WXMSW__
+#if !defined(__WXGTK__) && !defined(__WXMOTIF__) && !defined(__WXMAC__)
     bmpn.SetMask(new wxMask(bmpn, *wxLIGHT_GREY));
     bmpw.SetMask(new wxMask(bmpw, *wxLIGHT_GREY));
     bmpc.SetMask(new wxMask(bmpc, *wxLIGHT_GREY));
@@ -545,11 +618,13 @@ LifeNavigator::LifeNavigator(wxWindow *parent)
         *be = new wxBitmapButton(panel, ID_EAST ,  bmpe),
         *bs = new wxBitmapButton(panel, ID_SOUTH,  bmps);
 
+#if wxUSE_TOOLTIPS
     bn->SetToolTip(_("Find northernmost cell"));
     bw->SetToolTip(_("Find westernmost cell"));
     bc->SetToolTip(_("Find center of mass"));
     be->SetToolTip(_("Find easternmost cell"));
     bs->SetToolTip(_("Find southernmost cell"));
+#endif
 
     // add buttons to sizers
     sizer2->Add( bw, 0, wxCENTRE | wxWEST,  4 );
@@ -580,6 +655,7 @@ LifeNavigator::LifeNavigator(wxWindow *parent)
 
 void LifeNavigator::OnClose(wxCloseEvent& event)
 {
+    // avoid if we can
     if (event.CanVeto())
         event.Veto();
     else
@@ -696,7 +772,7 @@ void LifeCanvas::DrawChanged()
     wxClientDC dc(this);
 
     size_t ncells;
-    Cell *cells;
+    LifeCell *cells;
     bool done = FALSE;
 
     m_life->BeginFind(m_viewportX,
@@ -748,7 +824,7 @@ void LifeCanvas::OnPaint(wxPaintEvent& event)
     j1 = YToCell(y + h - 1);
 
     size_t ncells;
-    Cell *cells;
+    LifeCell *cells;
     bool done = FALSE;
 
     m_life->BeginFind(i0, j0, i1, j1, FALSE);
@@ -811,17 +887,24 @@ void LifeCanvas::OnMouse(wxMouseEvent& event)
     msg.Printf(_("Cell: (%d, %d)"), i, j);
     ((LifeFrame *) wxGetApp().GetTopWindow())->SetStatusText(msg, 1);
 
-    // button pressed?
+    // NOTE that wxMouseEvent::LeftDown() and wxMouseEvent::LeftIsDown()
+    // have different semantics. The first one is used to signal that the
+    // button was just pressed (i.e., in "button down" events); the second
+    // one just describes the current status of the button, independently
+    // of the mouse event type. LeftIsDown is typically used in "mouse
+    // move" events, to test if the button is _still_ pressed.
+
+    // is the button down?
     if (!event.LeftIsDown())
     {
         m_status = MOUSE_NOACTION;
         return;
     }
 
-    // button just pressed?
-    if (m_status == MOUSE_NOACTION)
+    // was it pressed just now?
+    if (event.LeftDown())
     {
-        // yes, update status and toggle this cell
+        // yes: start a new action and toggle this cell
         m_status = (m_life->IsAlive(i, j)? MOUSE_ERASING : MOUSE_DRAWING);
             
         m_mi = i;
@@ -831,6 +914,7 @@ void LifeCanvas::OnMouse(wxMouseEvent& event)
     }
     else if ((m_mi != i) || (m_mj != j))
     {
+        // no: continue ongoing action
         bool alive = (m_status == MOUSE_DRAWING);
 
         // prepare DC and pen + brush to optimize drawing
@@ -937,51 +1021,65 @@ void LifeCanvas::OnScroll(wxScrollWinEvent& event)
 
     // calculate scroll increment
     int scrollinc = 0;
-    switch (type)
+    if (type == wxEVT_SCROLLWIN_TOP)
     {
-        case wxEVT_SCROLLWIN_TOP:
-        {
-            if (orient == wxHORIZONTAL)
-                scrollinc = -m_viewportW;
-            else
-                scrollinc = -m_viewportH;
-            break;    
-        }
-        case wxEVT_SCROLLWIN_BOTTOM:
-        {
-            if (orient == wxHORIZONTAL)
-                scrollinc = m_viewportW;
-            else
-                scrollinc = m_viewportH;
-            break;    
-        }
-        case wxEVT_SCROLLWIN_LINEUP:   scrollinc = -1; break;
-        case wxEVT_SCROLLWIN_LINEDOWN: scrollinc = +1; break;
-        case wxEVT_SCROLLWIN_PAGEUP:   scrollinc = -10; break;
-        case wxEVT_SCROLLWIN_PAGEDOWN: scrollinc = +10; break;
-        case wxEVT_SCROLLWIN_THUMBTRACK:
+        if (orient == wxHORIZONTAL)
+            scrollinc = -m_viewportW;
+        else
+            scrollinc = -m_viewportH;
+    }
+    else
+    if (type == wxEVT_SCROLLWIN_BOTTOM)
+    {
+        if (orient == wxHORIZONTAL)
+            scrollinc = m_viewportW;
+        else
+            scrollinc = m_viewportH;
+    }
+    else
+    if (type == wxEVT_SCROLLWIN_LINEUP)
+    {
+        scrollinc = -1;
+    }
+    else
+    if (type == wxEVT_SCROLLWIN_LINEDOWN)
+    {
+        scrollinc = +1;
+    }
+    else
+    if (type == wxEVT_SCROLLWIN_PAGEUP)
+    {
+        scrollinc = -10;
+    }
+    else
+    if (type == wxEVT_SCROLLWIN_PAGEDOWN)
+    {
+        scrollinc = -10;
+    }
+    else
+    if (type == wxEVT_SCROLLWIN_THUMBTRACK)
+    {
+        if (orient == wxHORIZONTAL)
         {
-            if (orient == wxHORIZONTAL)
-            {
-                scrollinc = pos - m_thumbX;
-                m_thumbX = pos;
-            }
-            else
-            {
-                scrollinc = pos - m_thumbY;
-                m_thumbY = pos;
-            }
-            break;
+            scrollinc = pos - m_thumbX;
+            m_thumbX = pos;
         }
-        case wxEVT_SCROLLWIN_THUMBRELEASE:
+        else
         {
-            m_thumbX = m_viewportW;
-            m_thumbY = m_viewportH;
+            scrollinc = pos - m_thumbY;
+            m_thumbY = pos;
         }
     }
+    else
+    if (type == wxEVT_SCROLLWIN_THUMBRELEASE)
+    {
+        m_thumbX = m_viewportW;
+        m_thumbY = m_viewportH;
+    }
 
-#if defined(__WXGTK__) || defined(__WXMOTIF__) // what about Motif?
-    // wxGTK updates the thumb automatically (wxMSW doesn't); reset it back
+#if defined(__WXGTK__) || defined(__WXMOTIF__)
+    // wxGTK and wxMotif update the thumb automatically (wxMSW doesn't);
+    // so reset it back as we always want it to be in the same position.
     if (type != wxEVT_SCROLLWIN_THUMBTRACK)
     {
         SetScrollbar(wxHORIZONTAL, m_viewportW, m_viewportW, 3 * m_viewportW);