C / C++ / MFC

m_Flex.SetRedraw(FALSE);<br />
<br />
//insert lots of records here.<br />
<br />
m_Flex.SetRedraw(TRUE);

OnOK()<br />
{<br />
//CDialog::OnOK(); //Comment this one out.<br />
}

// ----------
// ZoomBitmap
// ----------
/**
 * Returns a new bitmap that fits proportionally into the specified rectangle.
 *
 * @return The returned CBitmap is created by using the new operator. You have to delete it yourself.
 */
CBitmap* CMyDialog::ZoomBitmap(CBitmap* pBitmap, const CRect& FitInto)
{
	// check size
	if (FitInto.IsRectEmpty()) return 0;

	// get current bitmap rect
	CRect bmpRect = doGetBitmapRect(pBitmap);

	// check size
	if (bmpRect.IsRectEmpty()) return 0;

	// get zoomed bitmap rect
	CRect zoomedRect = doGetZoomedBitmapRect(pBitmap, FitInto);

	// check size
	if (zoomedRect.IsRectEmpty()) return 0;

	// get device context
	CDC* pDC = GetDC();

	// check device context
	if (pDC == 0) return 0;

	// create memory device context (source bitmap)
	CDC* memDC1 = new CDC;
	if (memDC1->CreateCompatibleDC(pDC) == 0)
	{
		delete memDC1;

		ReleaseDC(pDC);

		return 0;
	}

	// create memory device context (zoomed bitmap)
	CDC* memDC2 = new CDC;
	if (memDC2->CreateCompatibleDC(pDC) == 0)
	{
		delete memDC1;
		delete memDC2;

		ReleaseDC(pDC);

		return 0;
	}

	// create new bitmap
	CBitmap* zoomed = new CBitmap;

	// initialize bitmap
	if (zoomed->CreateCompatibleBitmap(pDC, zoomedRect.Width(), zoomedRect.Height()) == 0)
	{
		delete memDC1;
		delete memDC2;
		delete zoomed;

		ReleaseDC(pDC);

		return 0;
	}

	// not needed anymore
	ReleaseDC(pDC);

	// select bitmaps
	CBitmap* old1 = memDC1->SelectObject(pBitmap);
	CBitmap* old2 = memDC2->SelectObject(zoomed);

	// stretch bitmap
	memDC2->SetStretchBltMode(HALFTONE);
	BOOL result = memDC2->StretchBlt
	(
		0,			// specifies the x-coordinate (in logical units) of the upper-left corner of the destination rectangle
		0,			// specifies the y-coordinate (in logical units) of the upper-left corner of the destination rectangle
		zoomedRect.Width(),	// specifies the width (in logical units) of the destination rectangle
		zoomedRect.Height(),	// specifies the height (in logical units) of the destination rectangle
		memDC1,			// specifies the source device context
		0,			// specifies the x-coordinate (in logical units) of the upper-left corner of the source rectangle
		0,			// specifies the x-coordinate (in logical units) of the upper-left corner of the source rectangle
		bmpRect.Width(),	// specifies the width (in logical units) of the source rectangle
		bmpRect.Height(),	// specifies the height (in logical units) of the source rectangle
		SRCCOPY			// specifies the raster operation to be performed
	);

	// check operation
	if (result == FALSE)
	{
		// free memory
		delete zoomed;

		// reset pointer
		zoomed = 0;
	}

	// reselect old bitmaps
	memDC2->SelectObject(old2);
	memDC1->SelectObject(old1);

	// delete temporary device contexts
	delete memDC2;
	delete memDC1;

	// the zoomed bitmap
	return zoomed;
}

 Exmaple:
BOOL ZoomBitmap(Bitmap& zoomed, Bitmap& srcBitmap, const CRect& FitInto )
{...}<br>
void OnZoom()
{
CBitmap zoomed;
if( ZoomBitmap(zoomed,srcBitmap,FitInto) )
    // do some thing with zoomed
}

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