How to draw image to screen directly

最新推荐文章于 2022-09-13 01:31:35 发布

大浪捉鱼

最新推荐文章于 2022-09-13 01:31:35 发布

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文章标签： image null symbian delete access buffer

本文介绍了一种在Symbian操作系统上实现流畅游戏动画的方法：通过直接访问屏幕缓冲区来提高图像绘制速度。文章详细展示了如何使用CDisplay类进行屏幕的开始、停止及更新操作，并提供了具体的实现代码。

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draw, How, directly, image, screen
The speed of image drawing is very important in game development, but the Symbian OS window frame does not offer full support for games. We need to access the screen buffer directly to provide fluent animation.

Display.h
class CDisplay : public MDirectScreenAccess
{
public:
        static CDisplay*NewL( RWsSession& pClient, CWsScreenDevice& pScreenDevice, RWindow& pWindow );
        static CDisplay*NewLC( RWsSession& pClient, CWsScreenDevice& pScreenDevice, RWindow& pWindow );
        ~CDisplay();

        inline CWsScreenDevice& GetScreenDevice()
        {
                return m_pScreenDevice;
        }

        inline RWindow& GetWindow()
        {
                return m_pWindow;
        }

        inline CFbsBitGc* GetScreenGc()
        {
                return m_pGc;
        }

        void Start();
        void Stop();
        void Update();

private:
        CDisplay( RWsSession& pClient, CWsScreenDevice& pScreenDevice, RWindow& pWindow );
        void ConstructL();
        void Restart( RDirectScreenAccess::TTerminationReasons aReason );
        void AbortNow( RDirectScreenAccess::TTerminationReasons aReason );

private:
        CWsScreenDevice&        m_pScreenDevice;
        RWsSession&                m_pClient;
        RWindow&                m_pWindow;

        CDirectScreenAccess*        m_pDirectScreenAccess;
        RRegion*                m_pRegion;
        CFbsBitGc*                m_pGc;

TBool m_bDrawing;
};

Display.cpp
CDisplay* CDisplay::NewL( RWsSession& pClient, CWsScreenDevice& pScreenDevice, RWindow& pWindow )
{
        CDisplay* self = NewLC( pClient, pScreenDevice, pWindow );
        CleanupStack::Pop( self );
        return self;
}

CDisplay* CDisplay::NewLC( RWsSession& pClient, CWsScreenDevice& pScreenDevice, RWindow& pWindow )
{
        CDisplay* self = new ( ELeave ) CDisplay( pClient, pScreenDevice, pWindow );
        CleanupStack::PushL( self );
        self->ConstructL();
        return self;
}

CDisplay::CDisplay( RWsSession& pClient, CWsScreenDevice& pScreenDevice, RWindow& pWindow ) :
m_pClient( pClient ),
m_pScreenDevice( pScreenDevice ),
m_pWindow( pWindow )
{
        m_pDirectScreenAccess = NULL;
        m_pRegion = NULL;
        m_pGc = NULL;

m_bDrawing = EFalse;
}

CDisplay::~CDisplay()
{
delete m_pDirectScreenAccess;
}

void CDisplay::ConstructL()
{
m_pDirectScreenAccess = CDirectScreenAccess::NewL( m_pClient, m_pScreenDevice, m_pWindow, *this );
}

void CDisplay::Start()
{
        if( !m_bDrawing )
        {
                TRAPD( dsaErr, m_pDirectScreenAccess->StartL() );
                if( dsaErr == KErrNone )
                {
                        m_pGc = m_pDirectScreenAccess->Gc();
                        m_pRegion = m_pDirectScreenAccess->DrawingRegion();
                        m_pGc->SetClippingRegion( m_pRegion );
                        m_bDrawing = ETrue;
                }
        }
}

void CDisplay::Stop()
{
        if( m_bDrawing )
        {
                m_bDrawing = EFalse;
        }
}

void CDisplay::Update()
{
m_pDirectScreenAccess->ScreenDevice()->Update();
}

void CDisplay::Restart( RDirectScreenAccess::TTerminationReasons /*aReason*/ )
{
Start();
}

void CDisplay::AbortNow( RDirectScreenAccess::TTerminationReasons /*aReason*/ )
{
m_pDirectScreenAccess->Cancel();
m_bDrawing = EFalse;
}