src/fl/bardragpl.cpp

/////////////////////////////////////////////////////////////////////////////
// Name:        bardragpl.cpp
// Purpose:     cbBarDragPlugin implementation
// Author:      Aleksandras Gluchovas
// Modified by:
// Created:     23/09/98
// RCS-ID:      $Id: bardragpl.cpp 35650 2005-09-23 12:56:45Z MR $
// Copyright:   (c) Aleksandras Gluchovas
// Licence:     wxWindows licence
/////////////////////////////////////////////////////////////////////////////

// For compilers that support precompilation, includes "wx.h".
#include "wx/wxprec.h"

#ifdef __BORLANDC__
#pragma hdrstop
#endif

#ifndef WX_PRECOMP
#include "wx/wx.h"
#endif

#include "wx/fl/bardragpl.h"

#define POS_UNDEFINED -32768

// helpers, FOR NOW:: static

static inline bool rect_hits_rect( const wxRect& r1, const wxRect& r2 )
{
    if ( ( r2.x >= r1.x && r2.x <= r1.x + r1.width ) ||
         ( r1.x >= r2.x && r1.x <= r2.x + r2.width ) )
        if ( ( r2.y >= r1.y && r2.y <= r1.y + r1.height ) ||
             ( r1.y >= r2.y && r1.y <= r2.y + r2.height ) )
            return true;
    return false;
}

static inline bool rect_contains_point( const wxRect& rect, int x, int y )
{
    return ( x >= rect.x &&
             y >= rect.y &&
             x <  rect.x + rect.width  &&
             y <  rect.y + rect.height );
}

/***** Implementation for class cbBarDragPlugin *****/

IMPLEMENT_DYNAMIC_CLASS( cbBarDragPlugin, cbPluginBase )

BEGIN_EVENT_TABLE( cbBarDragPlugin, cbPluginBase )

    //EVT_PL_LEFT_DOWN        ( cbBarDragPlugin::OnLButtonDown      )
    EVT_PL_LEFT_UP            ( cbBarDragPlugin::OnLButtonUp        )
    EVT_PL_MOTION             ( cbBarDragPlugin::OnMouseMove        )
    EVT_PL_DRAW_HINT_RECT     ( cbBarDragPlugin::OnDrawHintRect     )
    EVT_PL_START_BAR_DRAGGING ( cbBarDragPlugin::OnStartBarDragging )
    EVT_PL_LEFT_DCLICK        ( cbBarDragPlugin::OnLDblClick        )

END_EVENT_TABLE()

cbBarDragPlugin::cbBarDragPlugin(void)

    : mBarDragStarted    ( false ),
      mCanStick          ( true ),
      mpScrDc            ( NULL ),
      mpCurCursor        ( NULL ),
      mpDraggedBar       ( NULL ),
      mInClientHintBorder( 4 )
{}

cbBarDragPlugin::cbBarDragPlugin( wxFrameLayout* pPanel, int paneMask )

    : cbPluginBase( pPanel, paneMask ),

      mBarDragStarted    ( false ),
      mCanStick          ( true ),
      mpScrDc            ( NULL ),
      mpCurCursor        ( NULL ),
      mpDraggedBar       ( NULL ),
      mInClientHintBorder( 4 )
{}

cbBarDragPlugin::~cbBarDragPlugin()
{
    // nothing
}

// helper methods (protected)

// clips (top/bottom) or (right/left) edges against the frame's bounding rect.

void do_clip_edges( int len, int& rectPos, int& rectLen )
{
    if ( rectPos < 0 )
    {
        rectLen += rectPos;
        rectPos = 0;
        if ( rectLen < 0 )
            rectLen = 1;
    }
    else
        if ( rectPos > len-1 )
        {
            rectPos = len-1;
            rectLen = 1;
        }
        else
            if ( rectPos + rectLen - 1 > len )
                 rectLen -= (rectPos + rectLen) - len + 1;
}

void cbBarDragPlugin::ClipRectInFrame( wxRect& rect )
{
    int w, h;
    mpLayout->GetParentFrame().GetClientSize( &w, &h );

    do_clip_edges( w, rect.x, rect.width  );
    do_clip_edges( h, rect.y, rect.height );
}

void cbBarDragPlugin::ClipPosInFrame( wxPoint& pos )
{
    int w, h;
    mpLayout->GetParentFrame().GetClientSize( &w, &h );

    if ( pos.x < 0 )
        pos.x = 0;
    if ( pos.y < 0 )
        pos.y = 0;
    if ( pos.x > w )
        pos.x = w-1;
    if ( pos.y > h )
        pos.y = h-1;
}

void cbBarDragPlugin::AdjustHintRect( wxPoint& mousePos )
{
    mHintRect.x = mousePos.x - mMouseInRectX;
    mHintRect.y = mousePos.y - mMouseInRectY;
}

cbDockPane* cbBarDragPlugin::HitTestPanes( wxRect& rect )
{
    //wxRect clipped = rect;

    //ClipRectInFrame( clipped );

    cbDockPane** pPanes = mpLayout->GetPanesArray();

    for( int i = 0; i != MAX_PANES; ++i )
        if ( rect_hits_rect( pPanes[i]->mBoundsInParent, rect ) )
            return pPanes[i];

    return NULL;
}

cbDockPane* cbBarDragPlugin::HitTestPanes( wxPoint& pos )
{
    wxPoint clipped = pos;

    //ClipPosInFrame( pos );

    cbDockPane** pPanes = mpLayout->GetPanesArray();

    for( int i = 0; i != MAX_PANES; ++i )
        if ( rect_contains_point( pPanes[i]->mBoundsInParent, clipped.x, clipped.y ) )
            return pPanes[i];

    return NULL;
}

bool cbBarDragPlugin::HitsPane( cbDockPane* pPane, wxRect& rect )
{
    return rect_hits_rect( pPane->mBoundsInParent, rect );
}

int cbBarDragPlugin::GetDistanceToPane( cbDockPane* pPane, wxPoint& mousePos )
{
    wxRect& bounds = pPane->mBoundsInParent;

    switch( pPane->mAlignment )
    {
        case FL_ALIGN_TOP    : return mousePos.y - ( bounds.y + bounds.height );
        case FL_ALIGN_BOTTOM : return bounds.y - mousePos.y;
        case FL_ALIGN_LEFT   : return mousePos.x - ( bounds.x + bounds.width  );
        case FL_ALIGN_RIGHT  : return bounds.x - mousePos.x;
        default : return 0; // never reached
    }

//    return 0;
}

bool cbBarDragPlugin::IsInOtherPane( wxPoint& mousePos )
{
    cbDockPane* pPane = HitTestPanes( mousePos );

    if ( pPane && pPane != mpCurPane ) return true;
    else return false;
}

bool cbBarDragPlugin::IsInClientArea( wxPoint& mousePos )
{
    return  ( HitTestPanes( mousePos ) == NULL );
}

bool cbBarDragPlugin::IsInClientArea( wxRect& rect )
{
    return ( HitTestPanes( rect ) == NULL );
}

void cbBarDragPlugin::CalcOnScreenDims( wxRect& rect )
{
    if ( !mpCurPane || mpDraggedBar->IsFixed() ) return;

    wxRect inPane = rect;

    mpCurPane->FrameToPane( &inPane );

    int rowNo = mpCurPane->GetRowAt( inPane.y, inPane.y + inPane.height );

    bool isMaximized = ( rowNo >= (int)mpCurPane->GetRowList().Count() || rowNo < 0 );

    if ( isMaximized )
    {
        inPane.x = 0;
        inPane.width = mpCurPane->mPaneWidth;

        mpCurPane->PaneToFrame( &inPane );

        rect = inPane;
    }
}

// helpers

static inline void check_upper_overrun( int& pos, int width, int mousePos )
{
    if ( mousePos >= pos + width )
        pos = mousePos - width/2;
}

static inline void check_lower_overrun( int& pos, int width, int mousePos )
{
    if ( mousePos <= pos )
        pos = mousePos - width/2;
}

void cbBarDragPlugin::StickToPane( cbDockPane* pPane, wxPoint& mousePos )
{
    int wInPane = GetBarWidthInPane ( pPane );
    int hInPane = GetBarHeightInPane( pPane );

    // adjsut hint-rect horizontally (in pane's orientation)

    if ( pPane->IsHorizontal() )
    {
        mHintRect.width  = wInPane;
        mHintRect.height = hInPane;
    }
    else
    {
        mHintRect.height = wInPane;
        mHintRect.width  = hInPane;
    }

    // adjsut hint-rect vertically (in pane's orientation)

    wxRect& bounds = pPane->mBoundsInParent;

    // true, if hint enters the pane through it's lower edge

    bool fromLowerEdge = ( pPane->IsHorizontal() )
                           ? mousePos.y > bounds.y
                           : mousePos.x > bounds.x;

    // NOTE:: about all the below min/max things: they are meant to ensure
    //        that the mouse pointer doesn't overrun (leave) the hint-rectangle
    //        when its dimensions are recalculated upon sticking it to the pane

    if ( pPane->IsHorizontal() && fromLowerEdge )
    {
        int paneBottomEdgeY = bounds.y + bounds.height;

        mHintRect.y = wxMin( paneBottomEdgeY, mousePos.y );

        check_lower_overrun( mHintRect.y, hInPane, mousePos.y );

    }
    else
        if ( pPane->IsHorizontal() && !fromLowerEdge )
        {
            int paneTopEdgeY = bounds.y;

            mHintRect.y = wxMax( paneTopEdgeY - hInPane, mousePos.y - hInPane );

            check_upper_overrun( mHintRect.y, hInPane, mousePos.y );
        }
        else
            if ( !pPane->IsHorizontal() && fromLowerEdge )
            {
                int paneRightEdgeX = bounds.x + bounds.width;

                mHintRect.x = wxMin( paneRightEdgeX, mousePos.x );

                check_lower_overrun( mHintRect.x, hInPane, mousePos.x );
            }
            else
                if ( !pPane->IsHorizontal() && !fromLowerEdge )
                {
                    int paneLeftEdgeX = bounds.x;

                    mHintRect.x = wxMax( paneLeftEdgeX - hInPane, mousePos.x - hInPane );

                    check_upper_overrun( mHintRect.x, hInPane, mousePos.x );
                }

    mMouseInRectX = mousePos.x - mHintRect.x;
    mMouseInRectY = mousePos.y - mHintRect.y;

    mpCurPane = pPane; // memorize pane to which the hint is currently sticked
}

void cbBarDragPlugin::UnstickFromPane( cbDockPane* pPane, wxPoint& mousePos )
{
    // unsticking causes rectangle to get the shape in which
    // dragged control-bar would be when floated

    int newWidth  = mpDraggedBar->mDimInfo.mSizes[wxCBAR_FLOATING].x;
    int newHeight = mpDraggedBar->mDimInfo.mSizes[wxCBAR_FLOATING].y;

    wxRect& flBounds = mpDraggedBar->mDimInfo.mBounds[wxCBAR_FLOATING];

    if ( flBounds.width != -1 )
    {
        newWidth  = flBounds.width;
        newHeight = flBounds.height;
    }

    mHintRect.width  = newWidth;
    mHintRect.height = newHeight;

    wxRect& bounds = pPane->mBoundsInParent;

    // true, if hint leaves the pane through it's lower edge

    bool fromLowerEdge = ( pPane->IsHorizontal() )
                           ? mousePos.y > bounds.y
                           : mousePos.x > bounds.x;

    // NOTE:: ...all the below min/max things - see comments about it in StickToPane(..)

    if ( pPane->IsHorizontal() && fromLowerEdge )
    {
        // bool fromLowerEdge = mousePos.y > bounds.y;

        mHintRect.y = wxMax( bounds.y + bounds.height + 1, mousePos.y - newHeight );

        check_upper_overrun( mHintRect.y, newHeight, mousePos.y );

        // this is how MFC's hint behaves:

        if ( mMouseInRectX > newWidth )
            mHintRect.x = mousePos.x - ( newWidth / 2 );
    }
    else
        if ( pPane->IsHorizontal() && !fromLowerEdge )
        {
            mHintRect.y = wxMin( bounds.y - newHeight - 1, mousePos.y );

            // -/-

            if ( mMouseInRectX > newWidth )
                mHintRect.x = mousePos.x - ( newWidth / 2 );

            check_lower_overrun( mHintRect.y, newHeight, mousePos.y );
        }
        else
            if ( !pPane->IsHorizontal() && fromLowerEdge )
            {
                mHintRect.x = wxMax( bounds.x + bounds.width, mousePos.x - newWidth );

                // -/-

                if ( mMouseInRectY > newHeight )
                    mHintRect.y = mousePos.y - ( newHeight / 2 );

                check_upper_overrun( mHintRect.x, newWidth, mousePos.x );
            }
            else
                if ( !pPane->IsHorizontal() && !fromLowerEdge )
                {
                    mHintRect.x = wxMin( bounds.x - newWidth - 1, mousePos.x );

                    // -/-

                    if ( mMouseInRectY > newHeight )
                        mHintRect.y = mousePos.y - ( newHeight / 2 );

                    check_lower_overrun( mHintRect.x, newWidth, mousePos.x );
                }

    mMouseInRectX = mousePos.x - mHintRect.x;
    mMouseInRectY = mousePos.y - mHintRect.y;

    mpCurPane = NULL;
}

int cbBarDragPlugin::GetBarWidthInPane( cbDockPane* pPane )
{
    if ( pPane == mpSrcPane )
        return mBarWidthInSrcPane;

    // this is how MFC's bars behave:

    if ( pPane->IsHorizontal() )
        return mpDraggedBar->mDimInfo.mSizes[wxCBAR_DOCKED_HORIZONTALLY].x;
    else
        return mpDraggedBar->mDimInfo.mSizes[wxCBAR_DOCKED_VERTICALLY  ].x;
}

int cbBarDragPlugin::GetBarHeightInPane( cbDockPane* pPane )
{
    if ( pPane->IsHorizontal() )
        return mpDraggedBar->mDimInfo.mSizes[wxCBAR_DOCKED_HORIZONTALLY].y;
    else
        return mpDraggedBar->mDimInfo.mSizes[wxCBAR_DOCKED_VERTICALLY  ].y;
}

void cbBarDragPlugin::ShowHint( bool prevWasInClient )
{
    bool wasDocked = false;

    if ( mpSrcPane->mProps.mRealTimeUpdatesOn == false )
    {
        // do heavy calculations first

        wxRect actualRect = mHintRect; // will be adjusted depending on drag-settings

        if ( mpSrcPane->mProps.mExactDockPredictionOn && mpCurPane )
        {
#ifdef  __WXDEBUG__
            bool success =
#endif
                           mpLayout->RedockBar( mpDraggedBar, mHintRect, mpCurPane, false );

            wxASSERT( success ); // DBG::

            actualRect = mpDraggedBar->mBounds;

            mpCurPane->PaneToFrame( &actualRect );
        }
        else
            CalcOnScreenDims( actualRect );

        // release previous hint

        if ( mPrevHintRect.x != POS_UNDEFINED )
        {
            // erase previous rectangle

            cbDrawHintRectEvent evt( mPrevHintRect, prevWasInClient, true, false );

            mpLayout->FirePluginEvent( evt );
        }

        // draw new hint

        cbDrawHintRectEvent evt( actualRect, mpCurPane == NULL, false, false );

        mpLayout->FirePluginEvent( evt );

        mPrevHintRect = actualRect;
    }
    else
    {
        // otherwise, if real-time updates option is ON

        if ( mpDraggedBar->mState != wxCBAR_FLOATING && !mpCurPane )
        {
            mpLayout->SetBarState( mpDraggedBar, wxCBAR_FLOATING, true );
        }
        else
            if ( mpDraggedBar->mState == wxCBAR_FLOATING && mpCurPane )
            {
                mpLayout->SetBarState( mpDraggedBar, wxCBAR_DOCKED_HORIZONTALLY, false );

                wasDocked = true;
            }

        if ( mpCurPane )
        {
            mpLayout->GetUpdatesManager().OnStartChanges();

            if ( wasDocked )

            mpDraggedBar->mUMgrData.SetDirty( true );

#ifdef  __WXDEBUG__
            bool success =
#endif
                           mpLayout->RedockBar( mpDraggedBar, mHintRect, mpCurPane, false );

            wxASSERT( success ); // DBG ::

            mpLayout->GetUpdatesManager().OnFinishChanges();
            mpLayout->GetUpdatesManager().UpdateNow();
        }
        else
        {
            if ( mpLayout->mFloatingOn )
            {
                // move the top-most floated bar around as user drags the hint

                mpDraggedBar->mDimInfo.mBounds[ wxCBAR_FLOATING ] = mHintRect;

                mpLayout->ApplyBarProperties( mpDraggedBar );
            }
        }
    }
}

/*** event handlers ***/

void cbBarDragPlugin::OnMouseMove( cbMotionEvent& event )
{
    // calculate postion in frame's coordiantes

    if ( !mBarDragStarted )
    {
        event.Skip(); // pass event to the next plugin
        return;
    }

    wxPoint mousePos = event.mPos;

    event.mpPane->PaneToFrame( &mousePos.x, &mousePos.y );

    bool   prevIsInClient = ( mpCurPane == 0 );

    AdjustHintRect( mousePos );

    // if the hint-rect is not "tempted" to any pane yet

    if ( mpCurPane == NULL )
    {
        cbDockPane* pPane = HitTestPanes( mHintRect );

        // enable sticking again, if we've left the pane completely
        if ( !pPane )
            mCanStick = true;

        if ( mCanStick && pPane &&
             GetDistanceToPane( pPane, mousePos ) < GetBarHeightInPane( pPane ) )
            StickToPane( pPane, mousePos );
        else
            if ( pPane && HitTestPanes( mousePos ) == pPane && 0 ) // FOR NOW:: disabled

        StickToPane( pPane, mousePos );
    }
    else
    {
        // otherwise, when rect is now sticked to some of the panes
        // check if it should still remain in this pane

        mCanStick = true;

        bool mouseInOther = IsInOtherPane( mousePos );

        if ( mouseInOther )
        {
            cbDockPane* pPane = HitTestPanes( mousePos );

            StickToPane( pPane, mousePos );
        }
        else
        {
            if ( IsInClientArea( mousePos ) )
            {
                cbDockPane* pPane = HitTestPanes( mHintRect );

                if ( pPane &&
                     pPane != mpCurPane &&
                     GetDistanceToPane( pPane, mousePos ) < GetBarHeightInPane( pPane ) )
                    StickToPane( pPane, mousePos );
                else
                    if ( !pPane )
                    {
                        UnstickFromPane( mpCurPane, mousePos );

                        // FOR NOW:: disabled, would cause some mess
                        // mCanStick = false; // prevents from sticking to this
                        // pane again, flag is reset when hint-rect
                        // leaves the pane completely
                    }
                    else
                        if ( GetDistanceToPane( pPane, mousePos ) > GetBarHeightInPane( pPane ) )
                        {
                            if ( !HitsPane( mpCurPane, mHintRect ) )
                            {
                                UnstickFromPane( mpCurPane, mousePos );

                                // FOR NOW:: disabled, would cause some mess
                                // mCanStick = false; // prevents from sticking to this
                                // pane again, flag is reset when hint-rect
                                // leaves the pane completely
                            }
                        }

            }
        }
    }

    ShowHint( prevIsInClient );

    wxCursor* pPrevCurs = mpCurCursor;

    if ( mpCurPane )
    {
        mpCurCursor = mpLayout->mpNormalCursor;
    }
    else
    {
        // if floating is off, and we are in the client
        // area, the cursor will be invalid, otherwise
        // it will be the normal cursor

        if (mpLayout->mFloatingOn)
        {
            mpCurCursor = mpLayout->mpNormalCursor;
        }
        else
        {
            mpCurCursor = mpLayout->mpNECursor;
        }

    }
    if ( pPrevCurs != mpCurCursor )
        mpLayout->GetParentFrame().SetCursor( *mpCurCursor );
}

void cbBarDragPlugin::OnLButtonDown( cbLeftDownEvent& event )
{
    if ( mBarDragStarted  )
    {
        wxMessageBox(wxT("DblClick!"));
    }

    event.Skip();
}

void cbBarDragPlugin::OnLButtonUp( cbLeftUpEvent& event )
{
    if ( mBarDragStarted  )
    {
        if ( mpSrcPane->mProps.mRealTimeUpdatesOn == false )
        {
            // erase current rectangle, and finsih on-screen drawing session

            cbDrawHintRectEvent evt( mPrevHintRect, mpCurPane == NULL, true, true );

            mpLayout->FirePluginEvent( evt );

            if ( mpCurPane != NULL )
            {
                if ( mpSrcPane->mProps.mExactDockPredictionOn )
                {
                    mpLayout->RedockBar( mpDraggedBar, mHintRect, mpCurPane, false );

                    mpLayout->GetUpdatesManager().OnFinishChanges();
                    mpLayout->GetUpdatesManager().UpdateNow();
                }
                else
                {
                    if (mpDraggedBar->mState == wxCBAR_FLOATING)
                    {
                        mpLayout->SetBarState( mpDraggedBar, wxCBAR_DOCKED_HORIZONTALLY, true);
                    }

                    mpLayout->RedockBar( mpDraggedBar, mHintRect, mpCurPane );
                }
            }
            else
            {
                if (mpDraggedBar->mState != wxCBAR_FLOATING)
                {
                    mpLayout->SetBarState(mpDraggedBar, wxCBAR_FLOATING, true);
                }

                mpDraggedBar->mDimInfo.mBounds[ wxCBAR_FLOATING ] = mHintRect;
                mpLayout->ApplyBarProperties( mpDraggedBar );
            }
        }

        mHintRect.width = -1;

        // In Windows, at least, the frame needs to have a null cursor
        // else child windows (such as text windows) inherit the cursor
#if 1
        mpLayout->GetParentFrame().SetCursor( wxNullCursor );
#else
        mpLayout->GetParentFrame().SetCursor( *mpLayout->mpNormalCursor );
#endif

        mpLayout->ReleaseEventsFromPane( event.mpPane );
        mpLayout->ReleaseEventsFromPlugin( this );

        mBarDragStarted = false;

        if ( mBarWasFloating && mpDraggedBar->mState != wxCBAR_FLOATING )
        {
            // save bar's floating position before it was docked

            mpDraggedBar->mDimInfo.mBounds[ wxCBAR_FLOATING ] = mFloatedBarBounds;
        }
    }
    else
        event.Skip(); // pass event to the next plugin
}

void cbBarDragPlugin::OnLDblClick( cbLeftDClickEvent& event )
{
    int avoidCompilerWarning = 1;
    if ( avoidCompilerWarning )
    {
        cbBarInfo* pHittedBar;
        cbRowInfo* pRow;

        if ( event.mpPane->HitTestPaneItems( event.mPos,   // in pane's coordiantes
                                             &pRow,
                                             &pHittedBar ) == CB_BAR_CONTENT_HITTED
           )
        {
            mpLayout->SetBarState( pHittedBar, wxCBAR_FLOATING, true );

            mpLayout->RepositionFloatedBar( pHittedBar );

            return; // event is "eaten" by this plugin
        }

        mBarDragStarted = false;

        event.Skip();
    }

    //wxMessageBox("Hi, dblclick arrived!");
}

void cbBarDragPlugin::OnStartBarDragging( cbStartBarDraggingEvent& event )
{
    mpDraggedBar = event.mpBar;
    mpSrcPane    = event.mpPane;

    mpLayout->CaptureEventsForPane( event.mpPane );
    mpLayout->CaptureEventsForPlugin( this );

    mpLayout->GetParentFrame().SetCursor( *mpLayout->mpNormalCursor );

    mBarDragStarted = true;

    wxRect inParent = mpDraggedBar->mBounds;

    mBarWasFloating = mpDraggedBar->mState == wxCBAR_FLOATING;

    if ( mBarWasFloating )
    {
        inParent = mpDraggedBar->mDimInfo.mBounds[ wxCBAR_FLOATING ];
        mFloatedBarBounds = inParent;
    }
    else
        event.mpPane->PaneToFrame( &inParent );

    mHintRect.x = POS_UNDEFINED;

    mHintRect.width  = inParent.width;
    mHintRect.height = inParent.height;

    mMouseInRectX = event.mPos.x - inParent.x;
    mMouseInRectY = event.mPos.y - inParent.y;

    mpSrcPane = event.mpPane;

    if ( mpDraggedBar->mState == wxCBAR_FLOATING )

        mpCurPane = NULL;
    else
        mpCurPane = event.mpPane;

    mPrevHintRect.x = POS_UNDEFINED;

    mCanStick = false; // we're not stuck into any pane now -
                       // there's nowhere to "stick-twice"

    mBarWidthInSrcPane = mpDraggedBar->mDimInfo.mSizes[ mpDraggedBar->mState ].x;

    if ( mpSrcPane->mProps.mRealTimeUpdatesOn == false &&
         mpSrcPane->mProps.mExactDockPredictionOn  )
        mpLayout->GetUpdatesManager().OnStartChanges(); // capture initial state of layout

    // simulate the first mouse movement

    int x = event.mPos.x, y = event.mPos.y;
    mpSrcPane->FrameToPane( &x, &y );

    wxPoint pt(x,y);
    cbMotionEvent motionEvt( pt, event.mpPane );
    this->OnMouseMove( motionEvt );

    return; // event is "eaten" by this plugin
}

/*** on-screen hint-tracking related methods ***/

void cbBarDragPlugin::OnDrawHintRect( cbDrawHintRectEvent& event )
{
    if ( !mpScrDc ) StartTracking();

    DoDrawHintRect( event.mRect, event.mIsInClient );

    if ( event.mLastTime )
        FinishTracking();
}

#define _IMG_A  0xAA    // Note: modified from _A to _IMG_A, _A was already defined (cygwin)
#define _IMG_B  0x00    // Note: modified from _B to _IMG_A, _B was already defined (cygwin)
#define _IMG_C  0x55    // Note: modified from _C to _IMG_C, for consistency reasons.
#define _IMG_D  0x00    // Note: modified from _D to _IMG_D, for consistency reasons.

// FOR NOW:: static

static const unsigned char _gCheckerImg[16] = { _IMG_A,_IMG_B,_IMG_C,_IMG_D,
                                                _IMG_A,_IMG_B,_IMG_C,_IMG_D,
                                                _IMG_A,_IMG_B,_IMG_C,_IMG_D,
                                                _IMG_A,_IMG_B,_IMG_C,_IMG_D
                                              };

void cbBarDragPlugin::StartTracking()
{
    mpScrDc = new wxScreenDC;

    wxScreenDC::StartDrawingOnTop(&mpLayout->GetParentFrame());
}

void cbBarDragPlugin::DoDrawHintRect( wxRect& rect, bool isInClientRect)
{
    wxRect scrRect;

    RectToScr( rect, scrRect );

    int prevLF = mpScrDc->GetLogicalFunction();

    mpScrDc->SetLogicalFunction( wxINVERT );

    if ( isInClientRect )
    {
        // BUG BUG BUG (wx):: somehow stippled brush works only
        // when the bitmap created on stack, not
        // as a member of the class

        wxBitmap checker( (const char*)_gCheckerImg, 8,8 );

        wxBrush checkerBrush( checker );

        mpScrDc->SetPen( mpLayout->mNullPen );
        mpScrDc->SetBrush( checkerBrush );

        int half = mInClientHintBorder / 2;

        mpScrDc->DrawRectangle( scrRect.x - half, scrRect.y - half,
                                scrRect.width + 2*half, mInClientHintBorder );

        mpScrDc->DrawRectangle( scrRect.x - half, scrRect.y + scrRect.height - half,
                                scrRect.width + 2*half, mInClientHintBorder );

        mpScrDc->DrawRectangle( scrRect.x - half, scrRect.y + half - 1,
                                mInClientHintBorder, scrRect.height - 2*half + 2);

        mpScrDc->DrawRectangle( scrRect.x + scrRect.width - half,
                                scrRect.y + half - 1,
                                mInClientHintBorder, scrRect.height - 2*half + 2);

        mpScrDc->SetBrush( wxNullBrush );
    }
    else
    {
        mpScrDc->SetPen( mpLayout->mBlackPen );

        mpScrDc->DrawLine( scrRect.x, scrRect.y,
                           scrRect.x + scrRect.width, scrRect.y );

        mpScrDc->DrawLine( scrRect.x, scrRect.y + 1,
                           scrRect.x, scrRect.y + scrRect.height );

        mpScrDc->DrawLine( scrRect.x+1, scrRect.y + scrRect.height,
                           scrRect.x + scrRect.width, scrRect.y + scrRect.height );

        mpScrDc->DrawLine( scrRect.x + scrRect.width , scrRect.y,
                           scrRect.x + scrRect.width, scrRect.y + scrRect.height + 1);
    }

    mpScrDc->SetLogicalFunction( prevLF );
}

void cbBarDragPlugin::DrawHintRect ( wxRect& rect, bool isInClientRect)
{
    DoDrawHintRect( rect, isInClientRect );
}

void cbBarDragPlugin::EraseHintRect( wxRect& rect, bool isInClientRect)
{
    DoDrawHintRect( rect, isInClientRect );
}

void cbBarDragPlugin::FinishTracking()
{
    wxScreenDC::EndDrawingOnTop();

    delete mpScrDc;

    mpScrDc = NULL;
}

void cbBarDragPlugin::RectToScr( wxRect& frameRect, wxRect& scrRect )
{
    scrRect = frameRect;

    int x = frameRect.x, y = frameRect.y;

    mpLayout->GetParentFrame().ClientToScreen( &x, &y );

    scrRect.x = x;
    scrRect.y = y;
}