Re: question regarding dibsections

[Marcus Meissner]

On Mon, Apr 24, 2006 at 09:44:50PM +0200, Marcus Meissner wrote:
> Hi,
>
> While debugging twain, I came across the nativexfer method, used by 60-70%
> of all twain using programs.
>
> It has some very unfortunate programming logic.
>
> Here is a sample snippet from:
>    http://hp.vector.co.jp/authors/VA011973/prg_twain.htm
>
> TW_UINT16 rc;
>    TW_UINT32 hBitmap;
>    TW_BOOL PendingXfers = TRUE;
>    LPBITMAPINFOHEADER      lpDib;
>
> hBitmap = NULL;
>    rc = lpfnDSM_Entry(pAppId,pSourceId,DG_IMAGE,DAT_IMAGENATIVEXFER,MSG_GET,(TW_MEMREF)&hBitmap);
>    lpDib = (LPBITMAPINFOHEADER)GlobalLock((void*)hBitmap);
>    /* ... */
>    if(lpdib!=NULL){
>    	GlobalUnlock((void*)hBitmap);
>    	GlobalFree((void*)hBitmap);
>    }
>
> (hBitmap is the return value of CreateDIBSection()).
>
> This sample code apparently assumes that GlobalLock(HBITMAP) gives it
> a pointer to a BITMAPINFOHEADER.

It also expects the DIB bits right behind this header (+ palette), which absolutely
does not match our currently DIB memory layouts.

I expect much fun :)

Ciao, Marcus