Getting the dimensions of a bitmap

For CBitmap objects we can use the GetBitmap() function to determine the height and width of the bitmap.

	// The variable bitmap is a CBitmap object
	BITMAP bm;
	bitmap.GetBitmap( &bm );
	bmWidth = bm.bmWidth;
	bmHeight = bm.bmHeight;

If you have a HBITMAP, you can attach it to a CBitmap object and use the method shown above or you can use

	// The variable hBmp is a HBITMAP
	BITMAP bm;
	::GetObject( hBmp, sizeof( bm ), &bm );
	bmWidth = bm.bmWidth;
	bmHeight = bm.bmHeight;

For images in a BMP file, you can use something like

	CFile file;
	// sBMPFileName is the BMP filename
	if( !file.Open( sBMPFileName, CFile::modeRead) )
		return ;

	BITMAPFILEHEADER bmfHeader;

	// Read file header
	if (file.Read((LPSTR)&bmfHeader, sizeof(bmfHeader)) != sizeof(bmfHeader))
		return ;

	// File type should be 'BM'
	if (bmfHeader.bfType != ((WORD) ('M' << 8) | 'B'))
		return ;

	BITMAPINFOHEADER bmiHeader;
	if (file.Read((LPSTR)&bmiHeader, sizeof(bmiHeader)) != sizeof(bmiHeader))
		return ;


	int bmWidth = bmiHeader.biWidth;
	int bmHeight = bmiHeader.biHeight;