PtBuffer: the pointer move buffer

Found in: examples\Graphics\WS\PtBuffer\

These are the main files contained in the examples. Some extra files may be needed to run the examples, and these will be found in the appropriate examples directory.

Note: This example is designed to work properly only with techview, there is no guarantee that it will work properly with other interfaces

// AppHolder.cpp
//
// Copyright (c) 2005 Symbian Softwares Ltd.  All rights reserved.
//


#include "AppHolder.h"
#include "PointerMoveBuffer.h"
#include <EikStart.h>
//
// EXPORTed functions
//

EXPORT_C CApaApplication* NewApplication()
    {
    return new CAppholderApplication;
    }

//  The below section is added to make the code compatible with v9.1
//  This is because only exe files are compatible with v9.1
#if (defined __WINS__ && !defined EKA2)        //  E32Dll used only when WINS defined and EKA2 not defined
GLDEF_C TInt E32Dll(enum TDllReason)     
    {
    return KErrNone;
    }
#else                                       //   else E32Main is used
GLDEF_C TInt E32Main()        
    {
    return EikStart::RunApplication(NewApplication);
    }
#endif

////////////////////////////////////////////////////////////////
//
// Application class, CAppholderApplication
//
////////////////////////////////////////////////////////////////

TUid CAppholderApplication::AppDllUid() const
    {
    return KUidAppholder;
    }

CApaDocument* CAppholderApplication::CreateDocumentL()
    {
    // Construct the document using its NewL() function, rather 
    // than using new(ELeave), because it requires two-phase
    // construction.
    return new (ELeave) CAppholderDocument(*this);
    }


////////////////////////////////////////////////////////////////
//
// Document class, CAppholderDocument
//
////////////////////////////////////////////////////////////////

// C++ constructor
CAppholderDocument::CAppholderDocument(CEikApplication& aApp)
        : CEikDocument(aApp)
    {
    }

CEikAppUi* CAppholderDocument::CreateAppUiL()
    {
    return new(ELeave) CAppholderAppUi;
    }

CAppholderDocument::~CAppholderDocument()
    {
    }

////////////////////////////////////////////////////////////////
//
// App UI class, CAppholderAppUi
//
////////////////////////////////////////////////////////////////

void CAppholderAppUi::ConstructL()
    {
    BaseConstructL();
    iClient=CExampleWsClient::NewL(ClientRect());
    }

CAppholderAppUi::~CAppholderAppUi()
    {
    delete iClient;
    }

void CAppholderAppUi::HandleCommandL(TInt aCommand)
    {
    switch (aCommand)
        {
    case EEikCmdExit: 
        Exit();
        break;
        }
    }

// Base.CPP
//
// Copyright (c) 2005 Symbian Softwares Ltd.  All rights reserved.
//

#include <w32std.h>
#include "Base.h"

///////////////////////////////////////////////////////////////////////////////
//                          CWindow implementation
///////////////////////////////////////////////////////////////////////////////

CWindow::CWindow(CWsClient* aClient)
    : iClient(aClient)
    {
    }

void CWindow::ConstructL (const TRect& aRect, const TRgb& aColor, CWindow* aParent)
    {
    // If a parent window was specified, use it; if not, use the window group
    // (aParent defaults to 0).
    RWindowTreeNode* parent= aParent ? (RWindowTreeNode*) &(aParent->Window()) : &(iClient->iGroup);
    // Allocate and construct the window
    iWindow=RWindow(iClient->iWs);
    User::LeaveIfError(iWindow.Construct(*parent,(TUint32)this));
    // Store the window's extent
    iRect = aRect;
    // Set up the new window's extent
    iWindow.SetExtent(iRect.iTl, iRect.Size());
    // Set its background color
    iWindow.SetBackgroundColor (aColor);
    // Set pointer grab to enable drag and drop
    iWindow.SetPointerGrab (ETrue);
    // Allocate pointer move buffer for freehand drawing
    iWindow.AllocPointerMoveBuffer(KPointerMoveBufferSize, 0);
    iWindow.DisablePointerMoveBuffer();
    // Tell the window server to deliver drag events
    iWindow.PointerFilter(EPointerFilterDrag, 0);
    // Activate the window
    iWindow.Activate();
    }

CWindow::~CWindow()
    {
    iWindow.FreePointerMoveBuffer();
    iWindow.Close();
    }

RWindow& CWindow::Window()
    {
    return iWindow;
    }

CWindowGc* CWindow::SystemGc()
    {
    return iClient->iGc;
    }

CWsScreenDevice* CWindow::Screen()
    {
    return iClient->iScreen;
    }

///////////////////////////////////////////////////////////////////////////////
//                          CWsRedrawer implementation
///////////////////////////////////////////////////////////////////////////////

CWsRedrawer::CWsRedrawer()
    : CActive(CActive::EPriorityLow)
    {
    }

void CWsRedrawer::ConstructL(CWsClient* aClient)
    {
    iClient=aClient; // remember WsClient that owns us
    CActiveScheduler::Add(this); // add ourselves to the scheduler
    IssueRequest(); // issue request to draw
    }

CWsRedrawer::~CWsRedrawer()
    {
    Cancel();
    }

void CWsRedrawer::IssueRequest()
    {
    iClient->iWs.RedrawReady(&iStatus);
    SetActive();
    }

void CWsRedrawer::DoCancel()
    {
    iClient->iWs.RedrawReadyCancel();
    }

void CWsRedrawer::RunL()
    {   
    // find out what needs to be done in response to the event
    TWsRedrawEvent redrawEvent;
    iClient->iWs.GetRedraw(redrawEvent); // get event
    CWindow* window=(CWindow*)(redrawEvent.Handle()); // get window
    if (window)
        {
        TRect rect=redrawEvent.Rect(); // and rectangle that needs redrawing
        // now do drawing
        iClient->iGc->Activate(window->Window());
        window->Window().BeginRedraw();
        window->Draw(rect);
        window->Window().EndRedraw();
        iClient->iGc->Deactivate();
        }
    // maintain outstanding request
    IssueRequest();
    }


/////////////////////////////////////////////////////////////////////////////////////
//                              CWsClient implementation
/////////////////////////////////////////////////////////////////////////////////////
CWsClient::CWsClient()
    : CActive(CActive::EPriorityStandard)
    {
    }

void CWsClient::ConstructL()
    {
    // add ourselves to scheduler
    CActiveScheduler::Add(this);
    // get a session going
    User::LeaveIfError(iWs.Connect());
    // construct our one and only window group
    iGroup=RWindowGroup(iWs);
    User::LeaveIfError(iGroup.Construct(2,ETrue)); // '2' is a meaningless handle
    // construct screen device and graphics context
    iScreen=new (ELeave) CWsScreenDevice(iWs); // make device for this session
    User::LeaveIfError(iScreen->Construct()); // and complete its construction
    User::LeaveIfError(iScreen->CreateContext(iGc)); // create graphics context
    // construct redrawer
    iRedrawer=new (ELeave) CWsRedrawer;
    iRedrawer->ConstructL(this);
    // construct main window
    ConstructMainWindowL();
    // request first event and start scheduler
    IssueRequest();
    }

CWsClient::~CWsClient()
    {
    // neutralize us as an active object
    Deque(); // cancels and removes from scheduler
    // get rid of everything we allocated
    delete iGc;
    delete iScreen;
    delete iRedrawer;
    // destroy window group
    iGroup.Close();
    // finish with window server
    iWs.Close();
    }

void CWsClient::IssueRequest()
    {
    iWs.EventReady(&iStatus); // request an event
    SetActive(); // so we're now active
    }

void CWsClient::DoCancel()
    {
    iWs.EventReadyCancel(); // cancel event request
    }

void CWsClient::ConstructMainWindowL()
    {
    }

// PointerMoveBuffer.CPP
//
// Copyright (c) 2005 Symbian Softwares Ltd.  All rights reserved.
//

// Hold down the SHIFT key and drag the mouse (with left mouse button down)
// for freehand drawing.

#include <w32std.h>
#include "Base.h"
#include "PointerMoveBuffer.h"



//////////////////////////////////////////////////////////////////////////////
//                   CMainWindow implementation
//////////////////////////////////////////////////////////////////////////////


/****************************************************************************\
|   Function:    Constructor/Destructor for CMainWindow
|   Input:       aClient      Client application that owns the window
\****************************************************************************/
CMainWindow::CMainWindow (CWsClient* aClient)
: CWindow (aClient)
    {
    }


CMainWindow::~CMainWindow ()
    {
    iWindow.Close();
    }

/****************************************************************************\
|   Function:    CMainWindow::Draw
|   Purpose: Redraws the contents of CMainWindow within a given
|               rectangle.
|   Input:       aRect    Rectangle that needs redrawing
|   Output:      None
\****************************************************************************/

void CMainWindow::Draw(const TRect& aRect)
    {
    CWindowGc* gc=SystemGc(); // get a gc
    gc->SetClippingRect(aRect); // clip outside this rect
    gc->Clear(aRect); // clear
}

/****************************************************************************\
|   Function:    CMainWindow::HandlePointerBufferReady
\****************************************************************************/

void CMainWindow::HandlePointerMoveBufferReady ()
    {       
    TPoint pnts[KPointerMoveBufferSize];
    TPtr8 ptr((TUint8 *)&pnts,sizeof(pnts));
    TInt numPnts=Window().RetrievePointerMoveBuffer(ptr);
    TSize size = Window().Size();
    TPoint position = Window().Position();
    TRect redrawRect (position, size);
    CWindowGc* gc=SystemGc();
    gc->Activate(Window());
    Window().Invalidate();
    Window().BeginRedraw(redrawRect); // N.B. Redrawer::RunL() gets called with this 
                                      // rectangle - must give it a non-zero value
    for(TInt index=0;index<numPnts;index++) gc->DrawLineTo(pnts[index]);
    Window().EndRedraw();
    gc->Deactivate();
    }

/****************************************************************************\
|   Function:    CMainWindow::HandlePointerEvent
|   Purpose: Handles pointer events for CMainWindow.
|   Input:       aPointerEvent    The pointer event!
|   Output:      None
\****************************************************************************/

void CMainWindow::HandlePointerEvent (TPointerEvent& aPointerEvent)
    {   
    switch (aPointerEvent.iType)
        {
        case TPointerEvent::EButton1Down:
            {
            if (aPointerEvent.iModifiers&EModifierShift)
                {
                Window().EnablePointerMoveBuffer();
                CWindowGc* gc = SystemGc();
                gc->Activate(Window());
                gc->MoveTo(aPointerEvent.iPosition);
                gc->Deactivate();
                }
            break;
            }
        case TPointerEvent::EButton1Up:
            {
            Window().DisablePointerMoveBuffer();
            break;
            }
        default:
            break;
        }
}


//////////////////////////////////////////////////////////////////////////////
//                   CExampleWsClient implementation
//////////////////////////////////////////////////////////////////////////////

CExampleWsClient* CExampleWsClient::NewL(const TRect& aRect)
    {
    // make new client
    CExampleWsClient* client=new (ELeave) CExampleWsClient(aRect); 
    CleanupStack::PushL(client); // push, just in case
    client->ConstructL(); // construct and run
    CleanupStack::Pop();
    return client;
    }

/****************************************************************************\
|   Function:    Constructor/Destructor for CExampleWsClient
|               Destructor deletes everything that was allocated by
|               ConstructMainWindowL()
\****************************************************************************/

CExampleWsClient::CExampleWsClient(const TRect& aRect)
:iRect(aRect)
    {
    }

CExampleWsClient::~CExampleWsClient ()
    {
    delete iMainWindow;
    }


/****************************************************************************\
|   Function:    CExampleWsClient::ConstructMainWindowL()
|               Called by base class's ConstructL
|   Purpose: Allocates and creates all the windows owned by this client
|               (See list of windows in CExampleWsCLient declaration).
\****************************************************************************/

void CExampleWsClient::ConstructMainWindowL()
    {
    // Resources allocated in this function are freed in the CExampleWsClient destructor     
    iMainWindow=new (ELeave) CMainWindow(this);
    iMainWindow->ConstructL(iRect, TRgb (255,255,255));
    }

/****************************************************************************\
|   Function:    CExampleWsClient::HandleKeyEventL()
|   Purpose: Processes key events for CExampleWsClient
\****************************************************************************/
void CExampleWsClient::HandleKeyEventL (TKeyEvent& /*aKeyEvent*/)
    {
    }


/****************************************************************************\
|   Function:    CExampleWsClient::RunL()
|               Called by active scheduler when an even occurs
|   Purpose: Processes events according to their type
|               For key events: calls HandleKeyEventL() (global to client)
|               For pointer event: calls HandlePointerEvent() for window
|                                  event occurred in.
\****************************************************************************/
void CExampleWsClient::RunL()
    {
    // get the event
    iWs.GetEvent(iWsEvent);
    TInt eventType=iWsEvent.Type();
    // take action on it
    switch (eventType)
        {
    // events global within window group
    case EEventNull:
    case EEventKey:
    case EEventModifiersChanged:
    case EEventKeyUp:
    case EEventKeyDown:
    case EEventFocusLost:
    case EEventFocusGained:
    case EEventSwitchOn:
    case EEventPassword:
    case EEventWindowGroupsChanged:
    case EEventErrorMessage:
        break;
    // events local to specific windows
    case EEventPointer:
        {
        CWindow* window=(CWindow*)(iWsEvent.Handle()); // get window
        TPointerEvent& pointerEvent=*iWsEvent.Pointer();
        window->HandlePointerEvent (pointerEvent);
        break;
        }
    case EEventPointerExit:
    case EEventPointerEnter:
        break;
    case EEventPointerBufferReady:
        {
        CWindow* window=(CWindow*)(iWsEvent.Handle()); // get window
        window->HandlePointerMoveBufferReady ();
        break;
        }
    case EEventDragDrop:
        break;
    default:
        break;
        }
    IssueRequest(); // maintain outstanding request
    }

// AppHolder.h
//


#ifndef __APPHOLDER_H
#define __APPHOLDER_H

#include <coeccntx.h>

#include <eikenv.h>
#include <eikappui.h>
#include <eikapp.h>
#include <eikdoc.h>
#include <eikmenup.h>

#include <eikon.hrh>

const TUid KUidAppholder = { 0x100098e4 };

class CWsClient;

//
// CAppholderAppUi
//

class CAppholderAppUi : public CEikAppUi
    {
public:
    void ConstructL();
    ~CAppholderAppUi();
private: // from CEikAppUi
    void HandleCommandL(TInt aCommand);
private:
    CWsClient* iClient;
    };


//
// CAppholderDocument
//

class CAppholderDocument : public CEikDocument
    {
public:
    // construct/destruct
    CAppholderDocument(CEikApplication& aApp);
    ~CAppholderDocument();
private: // from CEikDocument
    CEikAppUi* CreateAppUiL();
    };


//
// CAppholderApplication
//

class CAppholderApplication : public CEikApplication
    {
private: // from CApaApplication
    CApaDocument* CreateDocumentL();
    TUid AppDllUid() const;
    };

#endif

// Base.H
//
// Copyright (c) 2005 Symbian Softwares Ltd.  All rights reserved.
//


#if !defined(__WINORD_H__)
#define __WINORD_H__

// Forward declarations
class CWsRedrawer;
class CWindow;


/////////////////////////////////////////////////////////////////////////
//                      Declaration of CWsClient
/////////////////////////////////////////////////////////////////////////

class CWsClient : public CActive
    {
public:
    void ConstructL();
    // destruct
    ~CWsClient();
    // main window
    virtual void ConstructMainWindowL();
    // terminate cleanly
    void Exit();
    // active object protocol
    void IssueRequest(); // request an event
    void DoCancel(); // cancel the request
    virtual void RunL() = 0; // handle completed request
    virtual void HandleKeyEventL (TKeyEvent& aKeyEvent) = 0;
protected:
    //construct
    CWsClient();
    CWsScreenDevice* iScreen;
    CWsRedrawer* iRedrawer;
    RWsSession iWs;
    TWsEvent iWsEvent;
private:
    RWindowGroup iGroup;
    CWindowGc* iGc;
    friend class CWsRedrawer; // needs to get at session
    friend class CWindow; // needs to get at session
    };



////////////////////////////////////////////////////////////////////////////
//                      CWsRedrawer declaration
////////////////////////////////////////////////////////////////////////////

class CWsRedrawer : public CActive
    {
public:
    // construct/destruct
    CWsRedrawer();
    void ConstructL(CWsClient* aClient);
    ~CWsRedrawer();
    // drawing
    void IssueRequest();
    void DoCancel();
    void RunL();
protected:
        CWsClient* iClient;
    };


//////////////////////////////////////////////////////////////////////////////
//                          CWindow declaration
//////////////////////////////////////////////////////////////////////////////

class CWindow : public CBase
    {
protected:
    RWindow iWindow; // window server window
    TRect iRect; // window's extent
public:
    enum {KPointerMoveBufferSize=32};
    CWindow(CWsClient* aClient);
    void ConstructL (const TRect& aRect, const TRgb& aColor, CWindow* aParent=0);
    ~CWindow();
    // access
    RWindow& Window(); // our own window
    CWindowGc* SystemGc(); // system graphics context
    CWsScreenDevice* Screen();
    // drawing
    virtual void Draw(const TRect& aRect) = 0;
    virtual void HandlePointerEvent (TPointerEvent& aPointerEvent) = 0;
    virtual void HandlePointerMoveBufferReady () = 0;
private:
    CWsClient* iClient; // client including session and group
    };


#endif

// PtBuffer.mmp
//
// Copyright (c) 2005 Symbian Softwares Ltd.  All rights reserved.
//

// From 9.1 builds supporting EKA2 with Winscw, os will treat all
// applications with the extension exe.
TARGET          PtBuffer.exe  
TARGETTYPE      exe
UID             0x100098e4
VENDORID       0x70000001

SOURCEPATH      .
SOURCE          AppHolder.cpp Base.cpp PointerMoveBuffer.cpp
USERINCLUDE     .
SYSTEMINCLUDE   \epoc32\include
SYSTEMINCLUDE   \epoc32\include\techview

// To support the new resource compilation practice from 9.1
// provide the following details to generate .rss files

START RESOURCE PtBuffer.rss       
TARGET          PtBuffer.rsc
TARGETPATH      \Resource\Apps
HEADER
LANG 01       // Build English language versions
END

// In v8.1, both aif files and registration files are supported,
// but from v9.0 onwards, only registration files are supported.
start resource    PtBuffer_reg.rss 
targetpath         \private\10003a3f\apps
//lang          01
end

// To support localisation for the UI applicatons
start resource PtBuffer_loc.rss       
//targetpath    \resource\apps
lang           01
end

LIBRARY         euser.lib
LIBRARY         apparc.lib
LIBRARY         cone.lib
LIBRARY         eikcore.lib 
LIBRARY         ws32.lib    

// PointerMoveBuffer.rss
//


NAME MEAD

#include <eikon.rh>
#include <eikcore.rsg>

RESOURCE RSS_SIGNATURE { }

RESOURCE TBUF
    {
    buf = "";
    }

RESOURCE EIK_APP_INFO
    {
    menubar = r_appholder_menubar;
    hotkeys = r_appholder_hotkeys;
    }

RESOURCE HOTKEYS r_appholder_hotkeys
    {
    control =
        {
        HOTKEY
            {
            command = EEikCmdExit;
            key = 'e';
            }
        };
    }

RESOURCE MENU_BAR r_appholder_menubar
    {
    titles =
        {
        MENU_TITLE
            {
            menu_pane = r_appholder_file_menu;
            txt = "File";
            }
    };
    }

RESOURCE MENU_PANE r_appholder_file_menu
    {
    items =
        {
        MENU_ITEM
            {
            command = EEikCmdExit;
            txt = "Close";
            }
        };
    }

#include <appinfo.rh>
   
RESOURCE LOCALISABLE_APP_INFO
{
short_caption = "PtBuffer";
caption_and_icon =
    {
    CAPTION_AND_ICON_INFO
        {
        caption = "PtBuffer";
        number_of_icons = 0; // each icon must be a bitmap/mask pair
        }
    };
}     

// PtBuffer.RSS
//
// Copyright (c) 2005 Symbian Software Ltd.  All rights reserved.
//

#include <appinfo.rh>

UID2 KUidAppRegistrationResourceFile
UID3 0x100098e4
RESOURCE APP_REGISTRATION_INFO
 { 
 app_file = PtBuffer;
 localisable_resource_file="\\resource\\apps\\PtBuffer_loc.rss";
 hidden=KAppNotHidden;
 embeddability=KAppNotEmbeddable;
 newfile=KAppDoesNotSupportNewFile;
 launch=KAppLaunchInForeground;
 }

This example implements simple freehand drawing. The example illustrates the use of RWindowBase's pointer move buffer functions: AllocPointerMoveBuffer(), EnablePointerMoveBuffer(), RetrievePointerMoveBuffer() and DisablePointerMoveBuffer().

Hold down the shift key and drag the mouse (with left mouse button down) for freehand drawing.

Hold down the shift key and draw using the pointer device.

The example demonstrates the pointer move buffer functions defined in class RWindowBase.