corodinates used by hdc??

[pinnachio]

what type of co-ordinates is used by standard hDC object when initialised by GetsafeDC()??

[VictorN]

I guess it depends upon how you initialized this HDC object and what you did with it before this call.
Read about GDI coordinate space here: http://msdn.microsoft.com/en-us/libr...66(VS.85).aspx

[pinnachio]

void CPflowView::OnLButtonDown(UINT nFlags, CPoint point) 
{
	// TODO: Add your message handler code here and/or call default
	long tempx=point.x ;
	long tempy=point.y ;
	CPflowDoc* pDoc = GetDocument();
	pDC=GetDC();
	OnPrepareDC(pDC);
	pDC->DPtoLP(&point);
	x2=point.x;
	y2=point.y ;
	HDC hDC= pDC->GetSafeHdc();
	
	if(bCheckBusOpt==FALSE)
	{
		if(GetPixel(hDC,point.x,point.y)==RGB(0,0,128))
		{
			busindex=pDoc->InBus (x2 ,y2 );
			/*char temp[10];
			ltoa(busindex,temp,10);
			MessageBox(temp);*/
			if(busindex>=0)
			{SetCapture();m_dragging=TRUE;}
		}
	}
	
	if(bCheckBusOpt==TRUE)
		DrawBus();
		
	CScrollView::OnLButtonDown(nFlags, point);
}

this is method am using can you please tell what type of initialisation is taking place and what coordinates is being used??

[VictorN]

Perhaps, GetDeviceCaps and Coordinate Space and Transformation Functions could help you?

[hoxsiew]

void CPflowView::OnLButtonDown(UINT nFlags, CPoint point) 
{
	// TODO: Add your message handler code here and/or call default
	long tempx=point.x ;
	long tempy=point.y ;
	CPflowDoc* pDoc = GetDocument();
	pDC=GetDC();
	OnPrepareDC(pDC);
	pDC->DPtoLP(&point);
	x2=point.x;
	y2=point.y ;
	HDC hDC= pDC->GetSafeHdc();
	
	if(bCheckBusOpt==FALSE)
	{
		if(GetPixel(hDC,point.x,point.y)==RGB(0,0,128))
		{
			busindex=pDoc->InBus (x2 ,y2 );
			/*char temp[10];
			ltoa(busindex,temp,10);
			MessageBox(temp);*/
			if(busindex>=0)
			{SetCapture();m_dragging=TRUE;}
		}
	}
	
	if(bCheckBusOpt==TRUE)
		DrawBus();
		
	CScrollView::OnLButtonDown(nFlags, point);
}

this is method am using can you please tell what type of initialisation is taking place and what coordinates is being used??

By the looks of it, this would be determined in the OnPrepareDC() call. A default CScrollView::OnPrepareDC() adjusts the viewport offset relative to the scroll position of the scroll view's scroll bars so coordinates are relative to a virtual "document", a section of which is visible through the client window of the view. You maybe should use CClientDC() instead of GetDC() in line 7 of your code.