How to display a part of an Image from Web

[somnathbanik]

Hi,
I am trying to display a part of the image. I have an image in web. I can download to c:\\Data\\Images\\ and could also display it on to the screen, but how do I display a part of the image on the screen, as what happens in the MAP. I would like to pass the latitude and longitude to display a part of the image. is there any function for that. i am using LBSSample example where I see that I can pass latitude and longitude to get a part of the google map. In place of google map URL I put _LIT(KGoogleMapURL,"http://abc.com/som/drew.jpg") and could display the image. But do I display a part of the image.

Please suggest me.

[A.A.M.]

Actually for your goals would be better to learn more about using Google Maps API - http://code.google.com/apis/maps/

[somnathbanik]

My goal is not to use the Google MAP rather to display an image. I need to display a part of an Image. any suggessation please.

[A.A.M.]

You can use these functions:

CWindowGc:rawBitmap(const TRect &aDestRect, const CFbsBitmap *aDevice, const TRect &aSourceRect);
CWindowGc::BitBlt(const TPoint &aDestination, const CFbsBitmap *aBitmap, const TRect &aSource);
CWindowGc::BitBltMasked(const TPoint &aPoint, const CFbsBitmap *aBitmap, const TRect &aSourceRect, const CFbsBitmap *aMaskBitmap, TBool aInvertMask);

For getting more details see SDK help.

[somnathbanik]

will it work on BMP images? I need to get a portion of a PNG image.

[A.A.M.]

Yes, it will work. How you display image now? Most likely using DrawBitmap() or BitBlt(). So using functions above you can draw only part of original image.

[somnathbanik]

I tried both of this function DrawBitmap() or BitBlt(). But not that much useful for me. I don't want this. Ok let me explain. Let say I have a n image of height = 100, and width =100. how can I display a portion of the Image like, height =(0,0) to (0,50) and width = ( 0,0) to (50,0), where (..) are the co-ordinates.

Please suggest me something.

[A.A.M.]

Can you show how you trying to do this?

[somnathbanik]

Appui.cpp The code below is called first

case ECommand1:
			{
			
			iAppView->GetGPSInfoL();
			}
			break;

appview.cpp

void CLBSSampleAppView::GetGPSInfoL()
	    {
	    // create CGpsPositionRequest object and put it into cleanup stack;
	    // pass application name as argument
	    CGpsPositionRequest* request = CGpsPositionRequest::NewL(
	        _L("LBS_0xEA962394"));

	    CleanupStack::PushL( request );
	    // get current location (this operation can be long up to 30 seconds);
	    // progress dialog is shown to user during this time
	    TBool result = request->FetchCurrentPostionL(latitude, longitude);

	    // delete request object
	    CleanupStack::PopAndDestroy(request);

	    if(result)
	    	{
				// Setup a file in the filesystem to download the map
	    	SetupFileDownload();
	    	// send HtTp request to download map
	    	SendHTTPRequestL();
	    	}


	    }

void CLBSSampleAppView::Draw( const TRect& aRect ) const
	{
	// Get the standard graphics context
	CWindowGc& gc = SystemGc();

	// Gets the control's extent
	TRect drawRect( Rect());

	// Clears the screen
	gc.Clear( drawRect );


	// Display the Map
	if(iJPG_Reader)
	 	{
	 		if(iJPG_Reader->Bitmap())
	 		{
	 			if(iJPG_Reader->Bitmap()->Handle())
	 			{
	 				gc.DrawBitmap(aRect, iJPG_Reader->Bitmap());
	 		
	 			}
	 		}
	 	}

	}

void CLBSSampleAppView::SendHTTPRequestL()
{



const TInt KMaxFolatLength = 8;
const TInt KDecimalPos = 5;

TRealFormat format( KMaxFolatLength, KDecimalPos );
format.iType = KRealFormatFixed | KDoNotUseTriads;

		TBuf8<KDefaultBufferSize> uri8;

		uri8.Append( KGoogleMapURL );
		//uri8.Append( KGoogleMapKey );



		HBufC8* longitudeDes = HBufC8::NewLC(257);
		longitudeDes->Des().Num(longitude,format);

		HBufC8* latitudeDes = HBufC8::NewLC(257);
		latitudeDes->Des().Num(latitude,format);


		TBuf8<KDefaultBufferSize> TempBuffer;
		TempBuffer.Format(uri8,latitudeDes,longitudeDes);

		CleanupStack::PopAndDestroy(2);

		// Start transaction
		TRAPD(err, iEngine->IssueHTTPGetL(TempBuffer));
		// TODO: Error handling
		if (err)
		    {
		    }
}

// -----------------------------------------------------------------------------
// CLBSSampleAppView::SetupFileDownload()
// wset up a file in the filesystem where to download and save the corresponding map
// -----------------------------------------------------------------------------
//

void CLBSSampleAppView::SetupFileDownload()
	{


	_LIT(KXMLFilePath, "c:\\Data\\Images\\");
	 TFileName iCurrentFileName;
	 iCurrentFileName.Append(KXMLFilePath);
	iCurrentFileName.Append(_L("drew.jpg"));
	TInt err=iRLbsImage.Open(CCoeEnv::Static()->FsSession(),iCurrentFileName,EFileWrite);

	if (err==KErrNotFound) // file does not exist - create it
	{

	err=iRLbsImage.Create(CCoeEnv::Static()->FsSession(),iCurrentFileName,EFileWrite);
	}

	}


	// -----------------------------------------------------------------------------
	//
	// 	// Listener from the client engine
	// -----------------------------------------------------------------------------
	//



void CLBSSampleAppView::ClientEvent(const TDesC& aEventDescription)
	{

	}


	// -----------------------------------------------------------------------------
	//
	// 	// Listener from the client engine to save map
	// -----------------------------------------------------------------------------
	//
void CLBSSampleAppView::ClientBodyReceived(const TDesC8& aBodyData)
	{

		TInt aPos=0;
		iRLbsImage.Seek(ESeekCurrent, aPos);
		iRLbsImage.Write(aBodyData); //save the file being downloaded

	}

	// -----------------------------------------------------------------------------
	//
	// 	// Listener from the client engine saying that map download is completed
	// -----------------------------------------------------------------------------
	//
void CLBSSampleAppView::ClientBodyCompleted()
	{
	iRLbsImage.Close();
//delete	iRLbsImage;
	SetImage();


	}


void CLBSSampleAppView::SetImageL()
	{
	DrawNow();
	}

	// -----------------------------------------------------------------------------
	//
	// 	// Listener from the CImageReader that creation of the map to be displayed is completed.
	// -----------------------------------------------------------------------------
	//
void CLBSSampleAppView::ImageReadyL(const TInt&  state)
	{
	DrawNow();
	}


	// -----------------------------------------------------------------------------
	//
	// 	//Start creation of the map to be displayed
	// -----------------------------------------------------------------------------
	//
_LIT(KTxtFileName, "c:\\Data\\Images\\drew.jpg");
void CLBSSampleAppView::SetImage()
	{
	iJPG_Reader = new(ELeave)CImageReader(*this);
	iJPG_Reader->ConstructL(KTxtFileName);

	}

_LIT(KGoogleMapURL,"http://abc.com/som/image.jpg");
//global declaration

I am using LBSSample example http://wiki.forum.nokia.com/index.ph...Api_in_Symbian

Please suggest me.

[A.A.M.]

gc.DrawBitmap(aRect, iJPG_Reader->Bitmap());

So where you are trying to use functions that I've mentioned?

Try this:

gc.DrawBitmap(aRect, iJPG_Reader->Bitmap(), TRect(TPoint(0,0),TSize(50,50)));

[somnathbanik]

So where you are trying to use functions that I've mentioned?

Try this:

gc.DrawBitmap(aRect, iJPG_Reader->Bitmap(), TRect(TPoint(0,0),TSize(50,50)));

i tried this but its not displaying a portion of the image even getting a blank white screen. Rather if I put it in this way

gc.DrawBitmap(TRect(TPoint(35,25), TSize(150,85)), iJPG_Reader->Bitmap());

the while image displays but the size becomes small.

please suggest me.

[somnathbanik]

thank you its working now.