Windows Metafile Functions & Aldus Placeable Metafiles

The information in this article applies to:

• Microsoft Windows Software Development Kit (SDK) for Windows versions 3.0 and 3.1

SUMMARY

Many Windows-based applications import or export Windows metafiles in a format known as the Aldus Placeable Metafile (APM) format. In this format, these metafiles cannot be used with the Windows metafile functions such as GetMetaFile(), CopyMetaFile(), PlayMetaFile(), etc. To use these metafiles, the APM header must be removed from the metafile and the remaining metafile bits must be written to a newly created metafile.

MORE INFORMATION

The APM header is 22 bytes in length and is defined as follows:

typedef struct

  {
  DWORD   key;
  HANDLE  hmf;
  RECT    bbox;
  WORD    inch;
  DWORD   reserved;
  WORD    checksum;
  } APMFILEHEADER;

More information regarding the APM format is available from the Aldus FAX Info System via a fax machine telephone at (206) 628-5737. It will ask for the document number, which is 9108 for the APM format. It will then ask you to push start on your FAX machine.

The Placeable Windows Metafiles are also documented on pages 26-27 of the "Programmer's Reference, Volume 4: Resources" manual from the Windows 3.1 SDK documentation.

NOTE: This an open line and no registration fees are required.

The phone number for Aldus Technical Information is (206) 628-2040.

BOOL RenderAPM (fh)

int   fh; // a file handle to the APM metafile is passed in

    HANDLE           hData;
    LPSTR            lpData;
    DWORD            OffsetToMeta;
    METAHEADER       mfHeader;
    APMFILEHEADER    APMHeader;

    OffsetToMeta = sizeof(APMHeader);

// Seek to beginning of file and read APM header
    _llseek(fh, 0, 0);
    if (!_lread(fh, (LPSTR)&APMHeader, sizeof(APMFILEHEADER)))
        // Error in reading the file
        return(FALSE);

// Return to read metafile header
    _llseek(fh, OffsetToMeta, 0);
    if (!_lread(fh, (LPSTR)&mfHeader, sizeof(METAHEADER)))
        // Error in reading
        return(FALSE);

// Allocate memory for memory based metafile
    if (!(hData = GlobalAlloc(GHND, (mfHeader.mtSize * 2L))))
        return(FALSE);
// Were we successful?
    if (!(lpData = GlobalLock(hData)))
    {
        // Error in allocation
        GlobalFree(hData);
        return(FALSE);
    }

// Read metafile bits
    _llseek(fh, OffsetToMeta, 0);
    if (!_lread(fh, lpData, (mfHeader.mtSize * 2L)))
    {
        // Error in reading
        GlobalUnlock(hData);
        GlobalFree(hData);
        return(FALSE);
    }

// Create the METAFILE with the bits we read in.
    if (!(hMF = SetMetaFileBits(hData)))
        return(FALSE);

    GlobalUnlock(hData);

// Close the APM file
    _lclose(fh);

// Return success
    return(TRUE);