How can I get image bytes from hbitmap if I am given an HBITMAP pointer, and my application is console application. I tryed using GetDIBits which require such parameter as HDC, which I can't get.
EDIT: I load bitmap from file:
HBITMAP bm = 0;
BITMAP Bitmap;
bm = (HBITMAP)LoadImage (0, TEXT("C:\\img1.bmp"), IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE);
I pass the HBITMAP to the function and expect to get another HBITMAP of processed image:
HBITMAP out1 = func(bm);
Where func is:
HBITMAP func(HBITMAP im);
And the problem is how to get image bytes from HBITMAP.
Answer
The easiest way is not to use GetDIBits (nor GetBitmapBits). These functions suck because they copy the data.
If you want the data directly, just use (for a DDB bitmap)
BITMAP bitmap;
GetObject(hBitmap, sizeof(bitmap), (LPVoid)&bitmap);
For a DIB bitmap use
DIBSECTION dib;
GetObject(hBitmap, sizeof(dib), (LPVOID)&dib);
GetObject info, See:
http://msdn.microsoft.com/en-us/library/windows/desktop/dd144904%28v=vs.85%29.aspx
This will not involve any copying of data, thus avoids the complicated issues associated with GetDIBits, See:
http://msdn.microsoft.com/en-us/library/windows/desktop/dd144879%28v=vs.85%29.aspx
Esp. the comments at the bottom for an explanation of the difficulties with GetDIBits.
Note that you do not get the palette info, but since most bitmaps are 24 or 32 bits anyway this is hardly an issue most of the time.