CImageDecoder PANIC -6 on mask loading

[sergey.kish]

Hi all!
I'm want to load png file with alfa channel, but after WaitForRequest status equal -6 and the bitmaps are clean.

_LIT8(MimeType, "image/png");

CImageDecoder* imageDecoder = CImageDecoder::FileNewL(iEikonEnv->FsSession(),
    _L("c:\\test.png"), MimeType, CImageDecoder::EOptionAlwaysThread);
CFbsBitmap* bitmap = new (ELeave) CFbsBitmap();
CFbsBitmap* mask   = new (ELeave) CFbsBitmap();
bitmap->Create( imageDecoder->FrameInfo().iOverallSizeInPixels, EColor4K );
mask->Create( imageDecoder->FrameInfo().iOverallSizeInPixels, EGray2 );

TRequestStatus status;
imageDecoder->Convert( &status, *bitmap, *mask );
User::WaitForRequest( status );

bitmap->Save( _L("c:\\Nokia\\images\\test.bmp") );
mask->Save( _L("c:\\Nokia\\images\\test_mask.bmp") );
delete bitmap;
delete mask;
delete imageDecoder;

Also use this code in CActive derived class, same result

iImageDecoder->Convert( &iStatus, *iBmp, *iBmpMask );
SetActive();

Any problem with my code?

[parag_purkar]

Dont use A.O..
using EOptionAlwaysThread which does the conversion in it's own thread.

Refer this ..

http://www.symbian.com/developer/tec...dFeatures.html


Try the below code ....Hopefully it will work for you!!!!

class CImageHandler : public CBase
{
public:
static CImageHandler* NewL(RFs& fs);
~CImageHandler();

private:
CImageHandler(RFs& fs);

public:
CFbsBitmap* LoadFileL(const TDesC& aFilename);

private:
CImageDecoder* iLoadUtil;
RFs& iFs;
}; 
***********************************************************

CImageHandler* CImageHandler::NewL(RFs& fs)
{
CImageHandler* p=new (ELeave) CImageHandler(fs);
return p;
}

CImageHandler::CImageHandler(RFs& fs) :
iFs(fs)
{
}

CImageHandler::~CImageHandler()
{
delete iLoadUtil;
}


//the decoder function
CFbsBitmap* CImageHandler::LoadFileL(const TDesC& aFilename)
{

delete iLoadUtil;
iLoadUtil = NULL;
iLoadUtil = CImageDecoder::FileNewL(iFs, aFilename,
CImageDecoder::EOptionAlwaysThread);

// Bitmap
CFbsBitmap* pBitmap = new CFbsBitmap();
if(pBitmap)
{
//some line to create the CFbsBitmap

TRequestStatus stat = KRequestPending;
iLoadUtil->Convert(&stat, *pBitmap, 0);
User::WaitForRequest(stat);
if(stat.Int() != KErrNone)
{
delete pBitmap;
pBitmap = NULL;
}

}

return pBitmap;
}

Regards,
Parag Purkar

[cdavies]

To get a mask from the alpha channel, you need to specify the "EAllowGeneratedMask" option in FileNewL.

Also, don't listen to any advice not to use Active Objects.

[sergey.kish]

Thanks. All work after replaced by following code

iImageDecoder = CImageDecoder::FileNewL( iFs, _L("c:\\test.png"),
MimeType, CImageDecoder::EAllowGeneratedMask );

By translating code in project discover that panic continue.
Its funny system. Now I see that changed not only flag.
The real punic source is different DisplayMode in file and params.

iBmp->Create(iImageDecoder->FrameInfo().iOverallSizeInPixels, 
    iImageDecoder->FrameInfo().iFrameDisplayMode /*was EColor4K*/);
   // its a EColor16M for me
iBmpMask->Create(iImageDecoder->FrameInfo().iOverallSizeInPixels,
    EGray256 /*was EGray2*/ );

So the bitmap and mask can be obtained without EAllowGeneratedMask

[wizard_hu_]

Th documentation says

Pre-Condition

The destination bitmap aDestination, must be created before the call to Convert() is made. aDestination must be large enough to contain the frame and be set to the required display mode. FrameInfo() can be used to obtain the size and display mode of the frame. The destination mask aDestinationMask must be created before the call to Convert() is made and must be large enough for the mask. The display mode must be EGray2 or EGray256 and must be EGray256 if the image contains alpha-blending information. This information can be obtained from the iFlags property of TFrameInfo obtained from a FrameInfo() call.

This excerpt is taken from the 3rd ed. help, but 2nd ed. also has these sentences - although in the "Parameters" section. So empty bitmaps may not be enough.

You can also try letting CImageDecoder to find out the mime type: FileNewL(RFs &aFs, TDesC &aSourceFilename, TOptions aOptions=EOptionNone, TUid aImageType=TUid::Null(), TUid aImageSubType=TUid::Null(), TUid aDecoderUid=TUid::Null());

Problems stemming in the lack of Active Object might or might not appear, you will obviously find out if the User::WaitForRequest never returns.