About the Window server example code

These examples show how to use the Window Server Client-Side API. Note that these examples create windows directly rather than going through the UI Control Framework, as standard applications would do.

The source files for each example are similiar. They can be found in: examples\Graphics\WS\BackedUp\

• AppHolder.cpp provides the standard GUI application framework classes. The only command handling provided is a menu with a Close command.

• Base.cpp provides base classes that use the window server. CWsClient handles the connection to the window server: it is an active object that issues a request for window server events, and handles them in its RunL(). CWindow encapsulates a basic window.

• project-name.cpp provides most of the code specific to a particular example. Typically, they sub-class CWsClient and CWindow.

Example Code

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

#include "AppHolder.h"
#include "BackedUp.h"

#include <EikStart.h>

//
// EXPORTed functions
//

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

// updated for 9.1. not conditional as not expected to be used pre 9.1.

GLDEF_C TInt E32Main()                        
    {
    return EikStart::RunApplication(NewApplication);
    }


////////////////////////////////////////////////////////////////
//
// 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, CBackedUpWindow* aParent)
    {
    _LIT(KFontName,"Swiss");
    // 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
    User::LeaveIfError(iWindow.SetExtentErr(iRect.iTl, iRect.Size()));
    // Set its background color
    iWindow.SetBackgroundColor (aColor);
    // Set pointer grab to enable drag and drop
    iWindow.SetPointerGrab (ETrue);
    // Set up font for displaying text
    TFontSpec fontSpec(KFontName,200);
    User::LeaveIfError(iClient->iScreen->GetNearestFontInTwips(iFont,fontSpec));
    // Activate the window
    iWindow.Activate();
    }

CWindow::~CWindow()
    {
    iWindow.FreePointerMoveBuffer();
    iWindow.Close();
    iClient->iScreen->ReleaseFont(iFont);
    }

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

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

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

CFont* CWindow::Font()
    {
    return iFont;
    }

/////////////////////////////////////////////////////////////////////////
CBackedUpWindow::CBackedUpWindow(CWsClient* aClient)
    : iClient(aClient)
    {
    }

void CBackedUpWindow::ConstructL (const TRect& aRect, CWindow* aParent)
    {
    _LIT(KFontName,"Swiss");
    // 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=RBackedUpWindow(iClient->iWs);
    User::LeaveIfError(iWindow.Construct(*parent, EGray4, (TUint32)this));
    // Store the window's extent
    iRect = aRect;
    // Set up the new window's extent
    User::LeaveIfError(iWindow.SetExtentErr(iRect.iTl, iRect.Size()));
    // Set its background color
    iWindow.AllocPointerMoveBuffer(KPointerMoveBufferSize, 0);
    iWindow.DisablePointerMoveBuffer();
    iWindow.PointerFilter(EPointerFilterDrag, 0);
    // Set pointer grab to enable drag and drop
    iWindow.SetPointerGrab (ETrue);
    // Set up font for displaying text
    TFontSpec fontSpec(KFontName,200);
    User::LeaveIfError(iClient->iScreen->GetNearestFontInTwips(iFont,fontSpec));
    // Activate the window
    iWindow.Activate();
    }

CBackedUpWindow::~CBackedUpWindow()
    {
    iWindow.Close();
    iClient->iScreen->ReleaseFont(iFont);
    }

RBackedUpWindow& CBackedUpWindow::Window()
    {
    return iWindow;
    }

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

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

CFont* CBackedUpWindow::Font()
    {
    return iFont;
    }


///////////////////////////////////////////////////////////////////////////////
//                          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(rect);
        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 active 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(); // what's the difference between this and destroy?
    // 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()
    {
    }