C / C++ / MFC

<br />
CWindowDC dc(hwnd);<br />
CDC memDC;<br />
memDC.CreateCompatibleDC(dc);<br />
<br />
CBitmap bmp;<br />
bmp.LoadBitmap("C:\\winnt\\bubbles.bmp");<br />
<br />
memDC.SelectObject(bmp);<br />

<br />
CDC memCropDC;<br />
memCropDC.CreateCompatibleDC(memDC);<br />
// get the size and color settings of the original bitmap.<br />
BITMAP bm;<br />
bmp.GetBitmap(&bm);<br />
//reset the dimensions (width and height) of hte bitmap.  Lets make it 50% smaller in width.<br />
bm.bmWidth = bm.bmWidth / 2;<br />
<br />
CBitmap bmpCrop;<br />
bmpCrop.CreateBitmapIndirect(&bm);<br />
//C: Select your cropped bitmap into the cropped memDC.<br />
memCropDC.SelectObject(bmpCrop);<br />

<br />
// this code will copy the left half of the image into your cropped image.<br />
memCropDC.BitBlt(0, 0, bm.bmWidth, bm.bmheight, &memDC, 0, 0, SRCCOPY);<br />
// this code will copy the right half of the image into your cropped image.<br />
memCropDC.BitBlt(0, 0, bm.bmWidth, bm.bmheight, &memDC, bm.bmWidth, 0, SRCCOPY);<br />
// this code will copy the middle half of the image into your cropped image.<br />
memCropDC.BitBlt(0, 0, bm.bmWidth, bm.bmheight, &memDC, bm.bmWidth / 2, 0, SRCCOPY);<br />

//call
CBitmap temp;
GetBitmapFromResource("c:\\mybitmap.bmp", 0, 0, temp);
m_cMyButton.SetBitmap(temp);
GetBitmapFromResource("c:\\mybitmap.bmp", 1, 0, temp);
m_cMyButton2.SetBitmap(temp);

/
// function
*static*/ bool GetBitmapFromResource(const CString& filename, const int xOffset, const int yOffset, CBitmap &bitmap)
{
	CBitmap sourceCBitmap;
	bool status	= true;
	//	Load resource.
	HBITMAP hBmp = (HBITMAP)::LoadImage(AfxGetInstanceHandle(), filename, IMAGE_BITMAP, 0, 0, LR_CREATEDIBSECTION  | LR_LOADFROMFILE);
	status = sourceCBitmap.Attach(hBmp);

	if (!status) {
		TRACE0("Failure to load bitmap.\n");
		return false;
	}
	//Create destination bitmap.
	BITMAP sourceBitmap;
	sourceCBitmap.GetBitmap(&sourceBitmap);
	sourceBitmap.bmHeight = kBitmapHeight;
	sourceBitmap.bmWidth = kBitmapWidth;

	if (bitmap.m_hObject != NULL) {
		bitmap.Detach();
	}

	status = (bitmap.CreateBitmapIndirect(&sourceBitmap) != 0);
	if (!status) {
		TRACE0("Failure to create indirect bitmap for source.\n");
		return false;
	}
	//Create DCs and select bitmaps.
	CDC sourceCDC;
	status = (sourceCDC.CreateCompatibleDC(NULL) != 0 );
	if (status) {
		void* gdiObject1 = sourceCDC.SelectObject(sourceCBitmap);
		CDC targetCDC;

		status = (targetCDC.CreateCompatibleDC(NULL) != 0);
		if (status) {
			void* gdiObject2 = targetCDC.SelectObject(bitmap);
			//	Copy bits
			status = (targetCDC.BitBlt(0, 0, kBitmapWidth, kBitmapHeight, &sourceCDC,
					xOffset * kBitmapWidth, yOffset * kBitmapHeight, SRCCOPY) != 0);
			targetCDC.SelectObject(gdiObject2);
		} else {
			TRACE0("Failure to create DC for target.\n");
		}
		sourceCDC.SelectObject(gdiObject1);
	} else {
		TRACE0("Failure to create DC for source.\n");
	}
	return status;
}

HBITMAP hBmp = (HBITMAP)::LoadImage(AfxGetInstanceHandle(), filename, IMAGE_BITMAP, 0, 0, LR_CREATEDIBSECTION  | LR_LOADFROMFILE);<br />
status = sourceCBitmap.Attach(hBmp);

int CDialog::DoModal()
{
	// can be constructed with a resource template or InitModalIndirect
	ASSERT(m_lpszTemplateName != NULL || m_hDialogTemplate != NULL ||
		m_lpDialogTemplate != NULL);

	// load resource as necessary
	LPCDLGTEMPLATE lpDialogTemplate = m_lpDialogTemplate;
	HGLOBAL hDialogTemplate = m_hDialogTemplate;
	HINSTANCE hInst = AfxGetResourceHandle();
	if (m_lpszTemplateName != NULL)
	{
		hInst = AfxFindResourceHandle(m_lpszTemplateName, RT_DIALOG);
		HRSRC hResource = ::FindResource(hInst, m_lpszTemplateName, RT_DIALOG);
		hDialogTemplate = LoadResource(hInst, hResource);
	}
	if (hDialogTemplate != NULL)
		lpDialogTemplate = (LPCDLGTEMPLATE)LockResource(hDialogTemplate);

	// return -1 in case of failure to load the dialog template resource
	if (lpDialogTemplate == NULL)
		return -1;

	// disable parent (before creating dialog)
	HWND hWndParent = PreModal();
	AfxUnhookWindowCreate();
	BOOL bEnableParent = FALSE;
	if (hWndParent != NULL && ::IsWindowEnabled(hWndParent))
	{
		::EnableWindow(hWndParent, FALSE);
		bEnableParent = TRUE;
	}

	TRY
	{
		// create modeless dialog
		AfxHookWindowCreate(this);
		if (CreateDlgIndirect(lpDialogTemplate,
						CWnd::FromHandle(hWndParent), hInst))
		{
			if (m_nFlags & WF_CONTINUEMODAL)
			{
				// enter modal loop
				DWORD dwFlags = MLF_SHOWONIDLE;
				if (GetStyle() & DS_NOIDLEMSG)
					dwFlags |= MLF_NOIDLEMSG;
				VERIFY(RunModalLoop(dwFlags) == m_nModalResult);
			}

			// hide the window before enabling the parent, etc.
			if (m_hWnd != NULL)
				SetWindowPos(NULL, 0, 0, 0, 0, SWP_HIDEWINDOW|
					SWP_NOSIZE|SWP_NOMOVE|SWP_NOACTIVATE|SWP_NOZORDER);
		}
	}
	CATCH_ALL(e)
	{
		DELETE_EXCEPTION(e);
		m_nModalResult = -1;
	}
	END_CATCH_ALL

	if (bEnableParent)
		::EnableWindow(hWndParent, TRUE);
	if (hWndParent != NULL && ::GetActiveWindow() == m_hWnd)
		::SetActiveWindow(hWndParent);

	// destroy modal window
	DestroyWindow();
	PostModal();

	// unlock/free resources as necessary
	if (m_lpszTemplateName != NULL || m_hDialogTemplate != NULL)
		UnlockResource(hDialogTemplate);
	if (m_lpszTemplateName != NULL)
		FreeResource(hDialogTemplate);

	return m_nModalResult;
}

// destroy modal window<br />
	DestroyWindow();<br />