antiflickpl.cpp

wxGTK 是 wxWidgets 的 linux GTK+ (>2.2.3)版本。wxWidgets 是一个跨平台的 GUI 框架

/////////////////////////////////////////////////////////////////////////////
// Name:        antiflickpl.cpp
// Purpose:     Double-buffering plugin class for reducing flickering.
// Author:      Aleksandras Gluchovas (@Lithuania)
// Modified by:
// Created:     23/10/98
// RCS-ID:      $Id: antiflickpl.cpp,v 1.4 2005/09/23 12:47:41 MR Exp $
// 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/antiflickpl.h"

/***** Implementation for class cbAntiflickerPlugin *****/

IMPLEMENT_DYNAMIC_CLASS( cbAntiflickerPlugin, cbPluginBase )

BEGIN_EVENT_TABLE( cbAntiflickerPlugin, cbPluginBase )

    EVT_PL_START_DRAW_IN_AREA  ( cbAntiflickerPlugin::OnStartDrawInArea  )
    EVT_PL_FINISH_DRAW_IN_AREA ( cbAntiflickerPlugin::OnFinishDrawInArea )

END_EVENT_TABLE()

// initialization of static members

int cbAntiflickerPlugin::mRefCount    = 0;

wxBitmap*   cbAntiflickerPlugin::mpVertBuf    = 0;
wxBitmap*   cbAntiflickerPlugin::mpHorizBuf   = 0;
wxMemoryDC* cbAntiflickerPlugin::mpVertBufDc  = 0;
wxMemoryDC* cbAntiflickerPlugin::mpHorizBufDc = 0;

// constructors

cbAntiflickerPlugin::cbAntiflickerPlugin(void)
    : mpLRUBufDc  ( NULL ),
      mLRUArea    ( -1,-1, -1,-1 )
{
    ++mRefCount;
}

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

    : cbPluginBase( pPanel, paneMask ),
      mpLRUBufDc  ( NULL ),
      mLRUArea    ( -1,-1, -1,-1 )
{
    ++mRefCount;
}

cbAntiflickerPlugin::~cbAntiflickerPlugin()
{
    if ( --mRefCount == 0 )
    {
        if ( mpHorizBuf )
        {
            mpHorizBufDc->SelectObject( wxNullBitmap );
            delete mpHorizBuf;
            delete mpHorizBufDc;
            mpHorizBuf   = 0;
            mpHorizBufDc = 0;
        }

        if ( mpVertBuf ) 
        {
            mpVertBufDc->SelectObject( wxNullBitmap );
            delete mpVertBuf; 
            delete mpVertBufDc;
            mpVertBuf   = 0;
            mpVertBufDc = 0;
        }
    }
}

wxDC* cbAntiflickerPlugin::FindSuitableBuffer( const wxRect& forArea )
{
    if ( mpVertBuf )
    {
        if ( mpVertBuf->GetHeight() >= forArea.height &&
             mpVertBuf->GetWidth()  >= forArea.width )
            return mpVertBufDc;
    }
    else
        if ( mpHorizBuf )
        {
            if ( mpHorizBuf->GetHeight() >= forArea.height &&
                 mpHorizBuf->GetWidth()  >= forArea.width )
                return mpHorizBufDc;
        }

    return 0;
}

wxDC* cbAntiflickerPlugin::AllocNewBuffer( const wxRect& forArea )
{
    // TBD:: preallocate bit larger bitmap at once, to avoid
    //       excessive realocations later

    // check whether the given area is oriented horizontally
    // or vertically and choose corresponding bitmap to create or
    // recreate

    if ( forArea.height > forArea.width )
    {
        wxSize prevDim( 0,0 );

        if ( mpVertBuf ) 
        {
            prevDim.x = mpVertBuf->GetWidth();
            prevDim.y = mpVertBuf->GetHeight();

            mpVertBufDc->SelectObject( wxNullBitmap );
            delete mpVertBuf;
        }
        else
            mpVertBufDc = new wxMemoryDC();

        mpVertBuf = new wxBitmap( int( wxMax(forArea.width,  prevDim.x ) ), 
                                  int( wxMax(forArea.height, prevDim.y ) )
                                );

        mpVertBufDc->SelectObject( *mpVertBuf );

        return mpVertBufDc;
    }
    else
    {
        wxSize prevDim( 0,0 );

        if ( mpHorizBuf ) 
        {
            prevDim.x = mpHorizBuf->GetWidth();
            prevDim.y = mpHorizBuf->GetHeight();

            mpHorizBufDc->SelectObject( wxNullBitmap );
            delete mpHorizBuf;
        }
        else
            mpHorizBufDc = new wxMemoryDC();

        mpHorizBuf = new wxBitmap( int( wxMax(forArea.width,  prevDim.x ) ), 
                                   int( wxMax(forArea.height, prevDim.y ) )
                                 );

        mpHorizBufDc->SelectObject( *mpHorizBuf );

        return mpHorizBufDc;
    }
}

void cbAntiflickerPlugin::OnStartDrawInArea( cbStartDrawInAreaEvent& event )
{
    wxASSERT( mpLRUBufDc == NULL ); // DBG:: see comments in OnFinishDrawInArea(..) method

    // short-cut
    wxRect& area = event.mArea;

    if ( event.mArea.width  < 0 || 
         event.mArea.height < 0 ) return;

    // memorize given area
    mLRUArea.x      = area.x;
    mLRUArea.y      = area.y;
    mLRUArea.width  = area.width;
    mLRUArea.height = area.height;

    wxDC* pBufDc = FindSuitableBuffer( area );

    if ( !pBufDc )
        pBufDc = AllocNewBuffer( area );

    pBufDc->SetDeviceOrigin( -area.x, -area.y );

    pBufDc->SetClippingRegion( area.x,     area.y,
                               area.width, area.height );

    wxClientDC clntDc( &mpLayout->GetParentFrame() );

    (*event.mppDc) = pBufDc;

    mpLRUBufDc = pBufDc; // memorize buffer, which will be flushed to screen
                         // upon "commiting" the drawing

    /*
    // OLD STUFF::
    mpLRUBufDc->Blit( pos.x, pos.y, size.x, size.y,
                      &clntDc, pos.x, pos.y, wxCOPY );
                    */
}

void cbAntiflickerPlugin::OnFinishDrawInArea( cbFinishDrawInAreaEvent& event )
{
    wxRect& area = event.mArea;

    if ( event.mArea.width  < 0 || 
         event.mArea.height < 0 ) return;

    wxASSERT( mpLRUBufDc ); // DBG:: OnStartDrawInArea should be called first

    // FOR NOW:: OnStartDrawInArea(..) should be immediately followed
    //           by OnFinishDrawInArea(..) for the same area

    wxASSERT( mLRUArea.x      == area.x      );
    wxASSERT( mLRUArea.y      == area.y      );
    wxASSERT( mLRUArea.width  == area.width  );
    wxASSERT( mLRUArea.height == area.height );

    wxClientDC clntDc( &mpLayout->GetParentFrame() );

    // "commit" drawings in one-shot
    clntDc.Blit( area.x, area.y, area.width, area.height,
                 mpLRUBufDc, area.x, area.y, wxCOPY );

    mpLRUBufDc->DestroyClippingRegion();
    mpLRUBufDc = 0;
}