Why "Invalid Parameter" for CreateDIBitmap ?

[flipsflops]

I am trying to display a 24bit True Colour image, using a block of uncompressed BGR data.


BITMAPINFO bitInfo;
BITMAPINFOHEADER biH;
HDC hdc, hdcdest;
HBITMAP hbm, oldhbm;
unsigned char *hPicPtr; // Holds bitmap data serially in 3 byte groups of Blue Green Red
.
.
hdc = CreateCompatibleDC( hdcdest );
hbm = CreateDIBitmap( hdc, &biH, CBM_INIT, hPicPtr, &bitInfo, DIB_RGB_COLORS );
check=GetLastError();
oldhbm = SelectObject(hdc, hbm);
.




The HBITMAP handle hbm is NULL after the CreateDIBitmap function has run, and GetLastError() returns 87 which is ROR_INVALID_PARAMETER. Have you any suggestions why the CreateDIBitmap function returns NULL ?

what does your initialization of the bitInfo and biH structures look like? I have noticed that sometimes these functions don't work correctly if they have a 'size' member in the structure that has not been initialized since they can not tell what kind of memory block you have passed it without this size parameter being initialized

HTH

[flipsflops]

Hi HTH,

Here is the structure initialisation:


biH.biSize = bitInfo.bmiHeader.biSize = sizeof(BITMAPINFO);
biH.biCompression = bitInfo.bmiHeader.biCompression = BI_RGB;
biH.biBitCount = bitInfo.bmiHeader.biBitCount = 24;
biH.biPlanes = bitInfo.bmiHeader.biPlanes = 1;
biH.biSizeImage = bitInfo.bmiHeader.biSizeImage = 0;
biH.biClrImportant = bitInfo.bmiHeader.biClrImportant = 0;
biH.biWidth = bitInfo.bmiHeader.biWidth = (long)(pcxheader.xmax - pcxheader.xmin);
biH.biHeight = bitInfo.bmiHeader.biHeight = -(long)(pcxheader.ymax - pcxheader.ymin);
biH.biXPelsPerMeter = bitInfo.bmiHeader.biXPelsPerMeter = 0L;
biH.biYPelsPerMeter = bitInfo.bmiHeader.biYPelsPerMeter = 0L;
biH.biClrUsed = bitInfo.bmiHeader.biClrUsed = 0L;
biH.biClrImportant = bitInfo.bmiHeader.biClrImportant = 0L;




The values I get in debug are:
biSize = 44
biCompression = 0
biBitCount = 24
biPlanes = 1
biSizeImage = 0 (also tried with bitmap size of 1601808)
biClrImportant = 0;
biWidth = 883
biHeight = -603 (negative for top down bitmap)
biXPelsPerMeter = 0
biYPelsPerMeter = 0
biClrUsed = 0
biClrImportant = 0

I used two structures in case I was not presenting the address of the second parameter
in the function CreateDIBitmap correctly.

Could it be because bmiColors != 0 in the BITMAPINFO structure ?