Q66949: INFO: Windows Metafile Functions & Aldus Placeable Metafiles

Article: Q66949
Product(s): Microsoft Windows Software Development Kit
Version(s): WINDOWS:3.0,3.1
Operating System(s): 
Keyword(s): kb16bitonly
Last Modified: 06-NOV-1999

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The information in this article applies to:

- Microsoft Windows Software Development Kit (SDK) versions 3.0, 3.1 
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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(), and so on. 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;

The following code fragment demonstrates how to create a memory-based Windows
metafile from an Aldus Placeable Metafile that will work with the metafile
functions provided by Windows.

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.

Sample Code
-----------

     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);
     }

Additional query words: CloseMetaFile CopyMetaFile CreateMetaFile EnumMetaFile GetMetaFile PlayMetaFile PlayMetaFileRecord SetMetaFileBits SetMetaFileBitsBetter

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Keywords          : kb16bitonly 
Technology        : kbAudDeveloper kbWin3xSearch kbSDKSearch kbWinSDKSearch kbWinSDK300 kbWinSDK310
Version           : WINDOWS:3.0,3.1

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