RE: [GD-Windows] In memory bitmap to HBITMAP

[Andrew G. <And...@ho...>]

I've had this before, I can't remember what caused it but it turned out to
be a "duh" error on my part. Code Guru (www.codeguru) is a great site for
all sorts of GDI programming trickery. It's MFC based but the techniques are
sound and it's not a great deal of pain to implment any of the samples in
Win32. In this case http://www.codeguru.com/bitmap/bitmap_from_bmp.shtml. 

On another note, have you thought about using LoadImage() instead rather
than doing it manually?

Andrew Grant
Hothouse Creations 



> -----Original Message-----
> From: Brian Hook [mailto:bri...@py...]
> Sent: 07 December 2001 02:04
> To: gam...@li...
> Subject: [GD-Windows] In memory bitmap to HBITMAP
> 
> 
> I'm struggling with something fairly basic -- I want to load a BMP out
> of a compressed file, convert to an HBITMAP, then blit it into a DDraw
> surface.  I know how to do the first and last part, but the middle is
> causing problems.  Even worse, I'm not getting any errors.
> 
> Loading the bitmap doesn't seem to be a problem.  I load it 
> up and parse
> and find the BITMAPFILEHEADER and BITMAPINFOHEADER no probs.  I also
> locate the raw bits no problem (and inspect with the debugger to make
> sure I'm getting what I think I'm getting -- in this case, solid
> magenta).  Looks fine.
> 
> The next step is to create a DC compatible with the desktop:
> 
> HDC hDC = CreateCompatibleDC( NULL );
> 
> I then create a HBITMAP compatible with DC, and using the 
> bits I pulled:
> 
> HBITMAP hbm;
> 
> hbm = CreateDIBitmap( hDC, lpBMIH, CBM_INIT, lpBits, lpBMIH,
> DIB_RGB_COLORS );
> 
> lpBMIH are simply pointers to the appropriate BITMAPINFOHEADER.  They
> have correct values in them.  The bitmap is returned successfully.
> 
> To verify things, I grab the bits out of the Bitmap to make sure
> everything is cool:
> 
> GetDIBits( hDC, hbm, 0, iHeight, tempbuffer, &bmi, DIB_RGB_COLORS );
> 
> It returns the correct number of scan lines, but tempbuffer is filled
> with black.  This means either the CreateDIBitmap() filled in 
> the bitmap
> with black, or the GetDIBits() failed somehow.  I can't 
> figure out which
> is the real culprit, but the bitmap is pretty much a black square.
> 
> Any suggestions on how to hunt this down?
> 
> 
> 


This email is covered by the following disclaimer, please read before
accepting this email. http://www.hothouse.org/disclaimer/