WTL Metafile Helper

// Meta.h : include file for loading metafiles
// Version 1.0	October 10, 2002
// Copyright (C) 2002 Softgee.	All rights reserved.
//
// This extension to atlgdi.h is designed for use with the Windows
// Template Library (WTL). It supports loading windows and enhanced
// metafiles from resource or disk file.
//
// You may use this code in your own programs for free as long as the
// copyright notices are maintained. This software is provided "as-is"
// without warranty of any kind, either expressed or implied.
////////////////////////////////////////////////////////////////////////

#if !defined(_META_H_)
#define _META_H_

#pragma once

#include <atlgdi.h>

//////////////////////////////////////////////////////////
/* METAFILEHEADER (22 bytes) placeable metafile header. */
//////////////////////////////////////////////////////////
#include <pshpack2.h>
typedef struct tagMETAFILEHEADER {
	DWORD mfKey;	  // Magic number (always 0x9AC6CDD7)
	WORD mfHandle;	  // Metafile HANDLE number (always 0)
	WORD mfLeft;	  // Left coordinate in metafile units (twips)
	WORD mfTop;	  // Top coordinate in metafile units
	WORD mfRight;	  // Right coordinate in metafile units
	WORD mfBottom;	  // Bottom coordinate in metafile units
	WORD mfInch;	  // Number of metafile units per inch.
					  // Unscaled = 1440; 720 = 2:1; 2880 = 1:2; etc.
	DWORD mfReserved; // Reserved (always 0)
	WORD mfChecksum;  // Checksum value for previous 10 WORDs
} METAFILEHEADER, FAR *LPMETAFILEHEADER;
#include <poppack.h>


//template <class T>
class CMeta : public CEnhMetaFile 
{
public:
	BOOL CreateMeta(BOOL bEMF, DWORD dwSize, BYTE* pBytes)
	{
		BOOL bSuccess = FALSE;
		if (bEMF)
		{	// Enhanced Metafile
			LPENHMETAHEADER lpEMF = (LPENHMETAHEADER)pBytes;
			if (lpEMF->dSignature == ENHMETA_SIGNATURE)
			{
				m_hEMF = ::SetEnhMetaFileBits(dwSize, pBytes);
				if (m_hEMF != NULL) bSuccess = TRUE;
			}
		}
		else
		{	// Windows Metafile
			LPMETAFILEHEADER lpMF = (LPMETAFILEHEADER)pBytes;
			if (lpMF->mfKey == 0x9AC6CDD7)
			{
				dwSize -= sizeof(METAFILEHEADER);
				pBytes += sizeof(METAFILEHEADER);
				m_hEMF = ::SetWinMetaFileBits(dwSize, pBytes, NULL, NULL);
				if (m_hEMF != NULL) bSuccess = TRUE;
			}
		}
		return bSuccess;
	}

	void LoadMetaResource(_U_STRINGorID rsrcID, BOOL bEMF = TRUE)
	{
		TCHAR szType[12];
		if (bEMF) lstrcpy(szType, "ENHMETAFILE");
		else lstrcpy(szType, "METAFILE");

		// get a byte pointer to the resource
		HINSTANCE hInst = _Module.GetResourceInstance();
		HRSRC hRsrc = ::FindResource(hInst, rsrcID.m_lpstr, szType);
		ATLASSERT(hRsrc != NULL);
		HGLOBAL hGlobal = ::LoadResource(hInst, hRsrc);
		BYTE* pBytes = (BYTE*)::LockResource(hGlobal);

		// if bytes are valid, assign the metafile
		if (pBytes != NULL)
		{
			DWORD dwSize = ::SizeofResource(hInst, hRsrc);
			CreateMeta(bEMF, dwSize, pBytes);
		}
	}	

	void LoadMetaFile(BOOL bEMF = TRUE, LPCTSTR lpName = NULL)
	{
		BOOL bSuccess = FALSE;
		LPCTSTR lpFilters;
		TCHAR szName[_MAX_PATH];

		// launch file open dialog
		if (lpName == NULL)
		{
			if (bEMF)
				lpFilters = 
				_T("Enhanced MetaFiles (*.emf)\0*.emf\0All Files (*.*)\0*.*\0");
			else
				lpFilters = 
				_T("Windows MetaFiles (*.wmf)\0*.wmf\0All Files (*.*)\0*.*\0");


			CFileDialog dlg(TRUE, NULL, NULL, OFN_HIDEREADONLY, lpFilters, NULL);

			if (dlg.DoModal() == IDOK) lstrcpy(szName, dlg.m_szFileName);
			else return;
		}
		else lstrcpy(szName, lpName);

		// read the file
		HANDLE hFile = ::CreateFile(szName, GENERIC_READ, 0, NULL, OPEN_EXISTING, 0, NULL);
		if (hFile != INVALID_HANDLE_VALUE)
		{
		DWORD dwRead = 0;
			DWORD dwSize = ::GetFileSize(hFile, NULL);
			BYTE* pBytes = (BYTE*)::CoTaskMemAlloc(dwSize);
			if (pBytes != NULL && dwSize > 0)
			{
				if (::ReadFile(hFile, pBytes, dwSize, &dwRead, NULL))
					bSuccess = CreateMeta(bEMF, dwSize, pBytes);
			}
		}
		::CloseHandle(hFile);

		if (!bSuccess)
			::MessageBox(NULL, "Can't read file", "Error", MB_OK | MB_ICONERROR);
	}
};

#endif // !defined(_META_H_)