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bitmap dissapears on window resize

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Join Date: Jan 2008

Posts: 119

Reputation: kux is on a distinguished road

Solved Threads: 10

kux

Offline

Junior Poster

bitmap dissapears on window resize

Nov 18th, 2008

I have a document/view aplication that opens a bitmap

I use the following OnDraw override to draw the bitmap on a window and OnOpenDocument to opening the image from file

The bitmap handle ( HBITMAP bmaphandle ) is taken from the Document object that does LoadImage in it's OnOpenDocument method
HBITMAP bmaphandle = pDoc->GetHandleToBitmap();

The problem I have is that on resizeing the window or when i move another window over it the image dissapears from the view. How do I make it persistent?

thx

 Help with Code Tags 
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BOOL CImageFilterDoc::OnOpenDocument( LPCTSTR strFilename )
{
	if ( ( m_hBitmap = (HBITMAP)LoadImage(NULL, strFilename, IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE) )  == NULL ) 
		return FALSE;
 
	return TRUE;
 
}
 
void CImageFilterView::OnDraw(CDC* pDC)
{
	CImageFilterDoc* pDoc = GetDocument();
	ASSERT_VALID(pDoc);
	if (!pDoc)
		return;
 
	// TODO: add draw code for native data here
	HBITMAP bmaphandle = pDoc->GetHandleToBitmap();
	if ( bmaphandle )
	{
		CClientDC dc(this);
		CDC *mdc=new CDC;
		mdc->CreateCompatibleDC(&dc);
 
		CBitmap bitmap;
 
		bitmap.m_hObject = bmaphandle;
 
		mdc->SelectObject(bitmap);
		CRect rect;
		GetClientRect(&rect);
 
		dc.BitBlt(0,0,rect.right,rect.bottom,mdc,0,0,SRCCOPY);
 
		delete mdc;
 
	}
}
BOOL CImageFilterDoc::OnOpenDocument( LPCTSTR strFilename )
{
	if ( ( m_hBitmap = (HBITMAP)LoadImage(NULL, strFilename, IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE) )  == NULL ) 
		return FALSE;

	return TRUE;

}

void CImageFilterView::OnDraw(CDC* pDC)
{
	CImageFilterDoc* pDoc = GetDocument();
	ASSERT_VALID(pDoc);
	if (!pDoc)
		return;

	// TODO: add draw code for native data here
	HBITMAP bmaphandle = pDoc->GetHandleToBitmap();
	if ( bmaphandle )
	{
		CClientDC dc(this);
		CDC *mdc=new CDC;
		mdc->CreateCompatibleDC(&dc);

		CBitmap bitmap;
		
		bitmap.m_hObject = bmaphandle;
		
		mdc->SelectObject(bitmap);
		CRect rect;
		GetClientRect(&rect);

		dc.BitBlt(0,0,rect.right,rect.bottom,mdc,0,0,SRCCOPY);

		delete mdc;

	}
}

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Join Date: Oct 2006

Posts: 2,979

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niek_e

Online

Cenosillicaphobiac

Re: bitmap dissapears on window resize

Nov 18th, 2008

I'm not sure, and I haven't done this for a few years, but you could try a this->refresh() when you're done resizing

Last edited by niek_e; Nov 18th, 2008 at 9:11 am.

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