pkidropsource.cpp

PGP8.0源码 请认真阅读您的文件包然后写出其具体功能

/*____________________________________________________________________________
	Copyright (C) 2002 PGP Corporation
	All rights reserved.

	PKIDropSource.cpp - implements OLE IDropSource for drag and drop

	$Id: PKIDropSource.cpp,v 1.7 2002/09/23 20:18:43 sdas Exp $
____________________________________________________________________________*/
#include "pgpPFLConfig.h"

// system header files
#include <windows.h>
#include <commctrl.h>

// project header files
#include "PKIDropSource.h"
#include "resource.h"
#include "TreeList.h"

extern "C" {
typedef struct _PK *PPGPKEYSSTRUCT;
extern HINSTANCE g_hinst;
BOOL PKFindWindowFromPoint (POINT* ppt, HWND* phwnd);
}

//	________________________________________
//
//	IUnknown Methods

STDMETHODIMP CDropSource::QueryInterface (
		REFIID 			iid, 
		void FAR* FAR* 	ppv) 
{
	if ((iid == IID_IUnknown) || (iid == IID_IDropSource)) 
	{
		*ppv = this;
		++m_refs;
		return NOERROR;
	}
	*ppv = NULL;

	return E_NOINTERFACE;
}


STDMETHODIMP_(ULONG) CDropSource::AddRef (void) 
{
	return ++m_refs;
}


STDMETHODIMP_(ULONG) CDropSource::Release (void) 
{
	if (--m_refs == 0) 
	{
		delete this;
		return 0;
	}
	return m_refs;
}  


//	________________________________________
//
//	calculate cursor offsets

static VOID
sCalcOffsets (
		HWND 	hwnd, 
		ULONG* 	pulXOff, 
		ULONG* 	pulYOff)
{
	NONCLIENTMETRICS	ncm;

	// get offset number to convert client to window coordinates
	ncm.cbSize = sizeof(NONCLIENTMETRICS);
	SystemParametersInfo (SPI_GETNONCLIENTMETRICS, 
			sizeof(NONCLIENTMETRICS), &ncm, 0);
	*pulXOff = ncm.iBorderWidth;
	*pulYOff = ncm.iBorderWidth + ncm.iCaptionHeight;
	if (GetMenu (hwnd))
		*pulYOff += ncm.iMenuHeight;
}
 
//	________________________________________
//
//	CDropSource Constructor
 
CDropSource::CDropSource (
		VOID*	pKeysStruct, 
		HWND	hwnd, 
		HWND	hwndTree,
		BOOL	bRenderAll) 
{
	HIMAGELIST			hIml;
	TL_DRAGBITMAP		tldb;
	DWORD				dwPos;
	POINTS				pts;

    m_refs = 1; 
	m_hwnd = hwnd;
	m_pKeysStruct = pKeysStruct;

	sCalcOffsets (hwnd, &m_ncxoffset, &m_ncyoffset);

	dwPos = GetMessagePos ();
	pts = MAKEPOINTS (dwPos);
	tldb.ptCursorPos.x = pts.x;
	tldb.ptCursorPos.y = pts.y;
	ScreenToClient (hwndTree, &tldb.ptCursorPos);

	if (!bRenderAll)
		tldb.ulFlags = TLRB_TOPLEVELONLY;
	else
		tldb.ulFlags = 0;
	TreeList_RenderDragBitmap (hwndTree, &tldb);
	hIml = ImageList_Create (tldb.sizeDrag.cx, tldb.sizeDrag.cy, 
			ILC_MASK|ILC_COLORDDB, 1, 1);
	ImageList_AddMasked (hIml, tldb.hbmDrag, GetSysColor (COLOR_WINDOW));
	DeleteObject (tldb.hbmDrag);
 
	ImageList_BeginDrag (hIml, 0, tldb.ptHotSpot.x, tldb.ptHotSpot.y);
	ImageList_Destroy (hIml);

	tldb.ptCursorPos.x = pts.x;
	tldb.ptCursorPos.y = pts.y;
	ScreenToClient (hwnd, &tldb.ptCursorPos);
	ImageList_DragEnter (hwnd, tldb.ptCursorPos.x + m_ncxoffset, 
			tldb.ptCursorPos.y + m_ncyoffset);
}

CDropSource::~CDropSource() 
{
	if (m_hwnd)
		ImageList_DragLeave (m_hwnd);
	ImageList_EndDrag ();
}


//	________________________________________
//
//	IDropSource Methods

STDMETHODIMP CDropSource::QueryContinueDrag (
		BOOL	fEscapePressed, 
		DWORD	grfKeyState) 
{  
    if (fEscapePressed)
        return DRAGDROP_S_CANCEL;
    else if (!(grfKeyState & MK_LBUTTON) && !(grfKeyState & MK_RBUTTON))
        return DRAGDROP_S_DROP;
    else
        return NOERROR;                  
}

//enables application to give visual feedback to end-user during drag and
//drop operation by providing IDataObject::DoDragDrop() with an enumeration
//value specifying the visual effect
STDMETHODIMP CDropSource::GiveFeedback (DWORD dwEffect) 
{
	BOOL	bInWindow		= FALSE;
	BOOL	bInvalidate		= FALSE;
	HWND	hwnd			= NULL;
	HWND	hwndSys;
	BOOL	bDragLeave;
	POINT	pt;

	GetCursorPos (&pt);

	//check if the point is within any of pgp main windows
	bDragLeave = PKFindWindowFromPoint (&pt, &hwnd);

	//get the window at the point as reported by the system
	hwndSys = WindowFromPoint (pt);
	
	//if(GetParent (hwndSys) != hwnd)
	if ((hwndSys != hwnd) && !IsChild(hwnd, hwndSys))
	{
		//WFP reports a window that is not one of pgp's main windows nor
		//is a child or descendant of any of the pgp main windows
		hwnd = NULL;
		bDragLeave = FALSE;
	}

	if (hwnd != m_hwnd) 
	{
		if (m_hwnd)
		{
			ImageList_DragLeave (m_hwnd);
			if (!bDragLeave)
			{
				bInvalidate = TRUE;
				if (m_hwnd)
					InvalidateRect (m_hwnd, NULL, FALSE);
			}
		}

		m_hwnd = hwnd;
		if (m_hwnd) 
		{
			sCalcOffsets (m_hwnd, &m_ncxoffset, &m_ncyoffset);
			ScreenToClient (m_hwnd, &pt);
			ImageList_DragEnter (m_hwnd, 
					pt.x + m_ncxoffset, pt.y + m_ncyoffset);
		}
	}

	if (!(dwEffect & DROPEFFECT_SCROLL)) 
	{
		if (m_hwnd)
		{
			ScreenToClient (m_hwnd, &pt);
			ImageList_DragMove (pt.x + m_ncxoffset, pt.y + m_ncyoffset);
		}
	}

	if (bInvalidate)
	{
		InvalidateRect (hwndSys, NULL, TRUE);
		UpdateWindow (hwndSys);
	}

	return DRAGDROP_S_USEDEFAULTCURSORS;//use standard OLE cursors to show the drop effect
}


//	________________________________________
//
//	Interface to C code 

extern "C" {
LPDROPSOURCE PKCreateDropSource (
		VOID* 	pKeysStruct, 
		HWND 	hwnd, 
		HWND 	hwndTree,
		BOOL	bRenderAll) 
{
	return ((LPDROPSOURCE) new CDropSource (
		pKeysStruct, hwnd, hwndTree, bRenderAll));
}
}