I'm using C++ Builder XE3 to develop a graph editor. All of the editing and drawing capabilities are made in a DLL that is loaded by the end user applications. To store information about the available graph objects I use a SQLite database. That database contains BMP icons that are loaded into a TImageList at run-time.
Everything works fine with Win-7, Win-8 and Win-vista but with Win-XP a "Floating point division by 0" occurs when loading the bitmap. I use a temporary memory stream to load the blob from the database and then load it into a temporary TBitmap which is used to add the new icon into the final TImageList.
Here is the function used to do so...
void TIcons::AddMaskedBitmap( TImageList *ptImgList, unsigned char *pucIcon, unsigned int uiSize )
{
TMemoryStream *ptMemStream;
// Use a memory stream
ptMemStream = new TMemoryStream();
ptMemStream->Write( pucIcon, uiSize );
ptMemStream->Position = 0;//Seek( ( int )0, ( unsigned short )soBeginning );
// Load using the cached bmp object
m_ptBmp->Transparent = true;
#warning "floatting point division by 0 error with WinXP"
m_ptBmp->LoadFromStream( ptMemStream ); // floatting point division by 0 error with WinXP
// m_ptBmp->LoadFromFile( ".\\d.bmp" ); // works
// Create a mask
m_ptBmpMask->Assign( m_ptBmp );
m_ptBmpMask->Canvas->Brush->Color = m_ptBmp->TransparentColor;
m_ptBmpMask->Monochrome = true;
// Add it to the list
ptImgList->Add( m_ptBmp, m_ptBmpMask );
// Free mem
m_ptBmp->FreeImage();
m_ptBmpMask->FreeImage();
delete ptMemStream;
}
I've traced the TBitmap::LoadFromStream function and the exception occurs in the CreateDIBSection function.
To make sure the loaded bitmap files are saved using the right encoding I've tried to load them using the TBitmap::LoadFromFile function and it works fine, so I think there's something wrong with the TBitmap::LoadFromStream function but I can't figure out what !
If anyone has an idea... Thanks.
LoadFromFile
is implemented by creating a file stream, and passing that to LoadFromStream
. This, if the contents of your memory stream are the same as the contents of the file, then the call to LoadFromStream
will succeed.
Thus the only sane conclusion is that the contents of the memory stream are invalid in some way.