Something is Fishy in MFC Land

[Zyrenthian]

Ok, this is a weird one. I do some image processing with our software. I load an image and blt it onto the screen. However, it seems that all my bits are 255 and i just get a white image. Well, that is not what my image looks like. I initially thought it was a problem opening the actual bmp file so i poped upt the path with an AfxMessageBox. Well here is the weird part

// pseudo code
DisplayImage(); // Shows a white image

but when i do this

// pseudo code
AfxMessageBox("HI"
DisplayImage(); // Show the image correctly

Can anyone tell me why when I pop up a message box all works well?

Matt

 

[dds82]

Does your DisplayImage() function call InvalidateRect()? It sounds like you might have a painting problem here. The message box that pops up may be forcing your window to get a WM_PAINT message it never would have otherwise received.

Just my thoughts...

 

[Zyrenthian]

Nope... thats not it. Great idea though. I forgot to mention in the above that this works perfectly fine in DEBUG. I know there is some hidden "FEATURE" of MFC i am missing but I just dont know what.

Matt

 

[dds82]

I've had some graphics-related problems of my own when switching from debug to release in the past. I just switched off compiler optimizations and kept rebuilding until the problem went away, and I knew I switched off the offending "optimization".

There are plenty of known bugs in Microsoft's compiler optimizations, maybe you're encountering one now?

Gotta love all these hidden "features".

:-D

 

[Zyrenthian]

I solved the problem. Dont ask me what is different though becasue as far as I can tell, this code does the same thing but only in a smaller block of code. Here is what I had to do to process my BMP file.

*********************************************************************************************************

#if !defined _DEBUG
		
		BITMAPFILEHEADER bfh;
		BITMAPINFO* bi;
		CStdioFile bmpFile;
		bmpFile.Open(smpteName,CFile::modeRead|CFile::shareDenyNone|CFile::typeBinary);
		bmpFile.Read(&bfh,sizeof(bfh));
		BYTE* info = new BYTE[bfh.bfOffBits];
		bmpFile.Read(info,bfh.bfOffBits);
		bi = (BITMAPINFO*)info;
		int sizeImg = bfh.bfSize-bfh.bfOffBits;
		m_pBitmapBits = new BYTE[sizeImg];
		bmpFile.SeekToBegin();
		bmpFile.Read(m_pBitmapBits,bfh.bfOffBits );
		bmpFile.Read(m_pBitmapBits,sizeImg);
		m_ctrlImageWindow.SetMaxFrameSize(CPoint(bi->bmiHeader.biWidth,bi->bmiHeader.biHeight), 8, 1, "BI_RGB" );
		m_ctrlImageWindow.DisplayFrame(m_pBitmapBits);
		bmpFile.Close();

		delete[] info;
#else
// do debug way
#endif

Hopefully, this will help someone else who runs into this bug. The bit encoding of the image is contained in m_pBitmapBits.

Matt