C / C++ / MFC

CBitmap* bm = memDC.SelectObject(oldbm);

HBITMAP hbitmap = (HBITMAP)bm->m_hObject;

bool HBITMAPRotate										(HBITMAP& hBitmap,
														 float radians,
														 COLORREF clrBack,
														 CErrorHandler& eh)
{
	// Create a memory DC compatible with the display
	CDC sourceDC;
	CDC destDC;
	if (sourceDC.CreateCompatibleDC(NULL) == FALSE)
	{
		eh.Initialize();
		eh.Set(__FUNCTION__,__FILE__,__LINE__,EHTYPE_ERROR,LoadStringFromDLL(IDS_ERROR_CREATECOMPATIBLEDC).c_str());
		return false;
	}
	if (destDC.CreateCompatibleDC(NULL) == FALSE)
	{
		eh.Initialize();
		eh.Set(__FUNCTION__,__FILE__,__LINE__,EHTYPE_ERROR,LoadStringFromDLL(IDS_ERROR_CREATECOMPATIBLEDC).c_str());
		return false;
	}

	// Get logical coordinates
	BITMAP bm;
	if (GetObject(hBitmap,sizeof(bm),&bm) == 0)
	{
		eh.Initialize();
		eh.Set(__FUNCTION__,__FILE__,__LINE__,EHTYPE_ERROR,LoadStringFromDLL(IDS_ERROR_GETOBJECT_HBITMAP).c_str());
		return false;
	}

	float cosine = (float)cos(radians);
	float sine = (float)sin(radians);

	// Compute dimensions of the resulting bitmap
	// First get the coordinates of the 3 corners other than origin
	int x1 = (int)(bm.bmHeight * sine);
	int y1 = (int)(bm.bmHeight * cosine);
	int x2 = (int)(bm.bmWidth * cosine + bm.bmHeight * sine);
	int y2 = (int)(bm.bmHeight * cosine - bm.bmWidth * sine);
	int x3 = (int)(bm.bmWidth * cosine);
	int y3 = (int)(-bm.bmWidth * sine);

	int minx = min(0,min(x1, min(x2,x3)));
	int miny = min(0,min(y1, min(y2,y3)));
	int maxx = max(0,max(x1, max(x2,x3)));
	int maxy = max(0,max(y1, max(y2,y3)));

	int w = maxx - minx;
	int h = maxy - miny;

	// Create a bitmap to hold the result
	HBITMAP hbmResult = ::CreateCompatibleBitmap(CClientDC(NULL), w, h);
	if (hbmResult == NULL)
	{
		eh.Initialize();
		eh.Set(__FUNCTION__,__FILE__,__LINE__,EHTYPE_ERROR,LoadStringFromDLL(IDS_ERROR_CREATECOMPATIBLEBITMAP).c_str());
		return false;
	}

	HBITMAP hbmOldSource = (HBITMAP)::SelectObject( sourceDC.m_hDC, hBitmap );
	HBITMAP hbmOldDest = (HBITMAP)::SelectObject( destDC.m_hDC, hbmResult );

	// Draw the background color before we change mapping mode
	HBRUSH hbrBack = CreateSolidBrush( clrBack );
	if (hbrBack == NULL)
	{
		eh.Initialize();
		eh.Set(__FUNCTION__,__FILE__,__LINE__,EHTYPE_ERROR,LoadStringFromDLL(IDS_ERROR_CREATESOLIDBRUSH).c_str());
		return false;
	}
	HBRUSH hbrOld = (HBRUSH)::SelectObject( destDC.m_hDC, hbrBack );
	if (destDC.PatBlt(0,0,w,h,PATCOPY) == FALSE)
	{
		eh.Initialize();
		eh.Set(__FUNCTION__,__FILE__,__LINE__,EHTYPE_ERROR,LoadStringFromDLL(IDS_ERROR_PATBIT).c_str());
		return false;
	}

	::DeleteObject( ::SelectObject( destDC.m_hDC, hbrOld ) );

	// We will use world transform to rotate the bitmap
	SetGraphicsMode(destDC.m_hDC, GM_ADVANCED);
	XFORM xform;
	xform.eM11 = cosine;
	xform.eM12 = -sine;
	xform.eM21 = sine;
	xform.eM22 = cosine;
	xform.eDx = (float)-minx;
	xform.eDy = (float)-miny;

	if (SetWorldTransform(destDC.m_hDC,&xform) == FALSE)
	{
		eh.Initialize();
		eh.Set(__FUNCTION__,__FILE__,__LINE__,EHTYPE_ERROR,LoadStringFromDLL(IDS_ERROR_SETWORLDTRANSFORM).c_str());
		return false;
	}

	// Now do the actual rotating - a pixel at a time
	if (destDC.BitBlt(0,0,bm.bmWidth,bm.bmHeight,&sourceDC,0,0,SRCCOPY) == FALSE)
	{
		eh.Initialize();
		eh.Set(__FUNCTION__,__FILE__,__LINE__,EHTYPE_ERROR,LoadStringFromDLL(IDS_ERROR_BITBLT).c_str());
		return false;
	}

	// Restore DCs
	::SelectObject( sourceDC.m_hDC, hbmOldSource );
	::SelectObject( destDC.m_hDC, hbmOldDest );

	hBitmap = hbmResult;
	return true;
}

chris175 wrote:

Try __int64 for storing big numbers.

RajiRaghu wrote:

Is there any alternate way?