Microsoft KB Archive/253262

HOWTO: Store the Contents of an RTF Control in an EMF File

Q253262

The information in this article applies to:

Microsoft Win32 Application Programming Interface (API)
Microsoft Win32 Software Development Kit (SDK)
Microsoft Windows 98
Microsoft Windows 95
Microsoft Windows NT Server
Microsoft Windows NT Workstation
Microsoft Windows 2000 Advanced Server
Microsoft Windows 2000 Server
Microsoft Windows 2000 Professional

SUMMARY

Sometimes, you may want to store the contents of a rich edit control in a metafile. This article outlines an approach that stores this type of control's contents in enhanced metafiles, one page per metafile. This approach can be used to work around a problem in rich edit controls, which is described in the following Knowledge Base article:

Q142320 PRB: Rich Edit Control Improperly Displays Print Preview

MORE INFORMATION

The following code demonstrates one method to dump the contents of a rich edit control into EMF files (one per page):

// GetPrinterDC()
// returns a printer DC - uses Printer Common Dialog
HDC GetPrinterDC(void)
{
    PRINTDLG pdlg;

    memset( &pdlg, 0, sizeof( PRINTDLG ) );
    pdlg.lStructSize = sizeof( PRINTDLG );
    pdlg.Flags = PD_RETURNDC; // PD_RETURNDEFAULT
    PrintDlg( &pdlg );
    return pdlg.hDC;
}

// Get the length, in characters, of the text in the control
int GetRTFTextLength( HWND hWndRTF )
{
    GETTEXTLENGTHEX gtlex = { GTL_PRECISE, CP_ACP };
    return SendMessage( hWndRTF, EM_GETTEXTLENGTHEX, (WPARAM)&gtlex, 0 );
}

// RTFToEMF - Tell the control to draw itself on the EMF
// Parameters:
//     hRefDC is used to create the EMF
//     pszMetaFileName is the file name of the new EMF (can be NULL)
//     prcMeta is the RECT used to in CreateEnhMetaFile(), in 0.01mm
//          units (should not be NULL)
//     hWndRTF is the control of interest
//     nStart is the starting character location
//     *pEnd is a pointer to an int which receives the position of
//          the next character to print after this page (can be NULL)
HENHMETAFILE RTFToEMF( HDC hRefDC, LPCTSTR pszMetaFileName, LPCRECT prcMeta,
                      HWND hWndRTF, int nStart, int *pEnd )
{
    HDC             hMetaDC;
    FORMATRANGE     fr;
    int             nTextPrinted;

    // Create the EMF
    hMetaDC = CreateEnhMetaFile( hRefDC, pszMetaFileName, prcMeta, NULL );
    if( hMetaDC == NULL )
        return NULL;

    ZeroMemory(&fr, sizeof(fr));
    // Set up the page (convert 0.01mm to twips)
    fr.rcPage.top       = prcMeta->left*1440/2540;
    fr.rcPage.left      = prcMeta->top*1440/2540;
    fr.rcPage.right     = prcMeta->right*1440/2540;
    fr.rcPage.bottom    = prcMeta->bottom*1440/2540;
    // Set up no margins all around.
    fr.rc = fr.rcPage;
    // Set up the range of text to print as nStart to end of document
    fr.chrg.cpMin = nStart;
    fr.chrg.cpMax = -1;
    fr.hdc = fr.hdcTarget = hMetaDC;
    // Tell the control to draw itself on our (meta) DC
    nTextPrinted = SendMessage(hWndRTF, EM_FORMATRANGE, TRUE, (LPARAM)&fr);
    if( pEnd != NULL )
        *pEnd = nTextPrinted;
    return CloseEnhMetaFile( hMetaDC );
}

// DumpRTFToPagedEMFs - demonstrates using RTFToEMF() to create an EMF
//                      for each page in an RTF control
// Parameters:
//     hWndRTFControl - the control
//     szEMFFileTitleBase - base filename for EMF files, number is appended
void DumpRTFToPagedEMFs( HWND hWndRTFControl, LPTSTR szEMFFileTitleBase )
{
    TCHAR           szMetaName[MAX_PATH];
    int             nRTFTextLength, nStart, nPage;
    HDC             hRefDC;
    RECT            rcMeta;
    HENHMETAFILE    hEMF;

    // First, determine how many chars are in the RTF
    nRTFTextLength = GetRTFTextLength( hWndRTFControl );
    // Get a reference DC (based on a printer)
    hRefDC = GetPrinterDC();
    // Set up the meta RECT for 0.01mm units
    SetRect( &rcMeta, 0, 0, GetDeviceCaps(hRefDC, HORZSIZE)*100, 
                            GetDeviceCaps(hRefDC, VERTSIZE)*100 );

    // Loop while we've not reached the end of the text in the control
    for(nPage=0,nStart=0;nStart<nRTFTextLength;)
    {
        // construct a file name for this page
        wsprintf(szMetaName, TEXT("%s%d.EMF"), szEMFFileTitleBase, nPage);
        // call function above to draw this portion of the RTF on the EMF
        hEMF = RTFToEMF( hRefDC, szMetaName, &rcMeta, hWndRTFControl,
                         nStart, &nStart );
        // clean up
        DeleteEnhMetaFile( hEMF );
        nPage++;
    }
}

Additional query words: rtf rich edit control bug problem print preview EMF enhanced metafile

Keywords : kbGDI kbMetafile kbRichEdit kbSDKPlatform kbSDKWin32 _IK kbGrpDSGDI
Issue type : kbhowto
Technology : kbWinNTsearch kbWinNTWsearch kbwin2000AdvServ kbwin2000AdvServSearch kbwin2000Serv kbWinNTSsearch kbwin2000ServSearch kbwin2000Search kbwin2000ProSearch kbwin2000Pro kbWin32SDKSearch kbAudDeveloper kbWin95search kbWin98search kbSDKSearch kbWinAdvServSearch kbZNotKeyword3 kbWin32sSearch kbWin32API kbWin98