KnowledgeBase Archive

An Archive of Early Microsoft KnowledgeBase Articles

View on GitHub

Q28344: PRB: PlayMetaFile() Not as Fast as More Complex Technique

Article: Q28344
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

-------------------------------------------------------------------------------
The information in this article applies to:

- Microsoft Windows Software Development Kit (SDK) versions 3.0, 3.1 
-------------------------------------------------------------------------------

SYMPTOMS
========

The PlayMetaFile() function is slower than using a loop that contains the
EnumMetaFile() and PlayMetaFileRecord() commands.

CAUSE
=====

PlayMetaFile() takes longer because it plays the metafile records, and it also
performs several additional steps:

1. Verifies that its handle parameter points to a valid metafile.

2. Locks the metafile.

3. Saves all objects in the device context (pens, brushes, regions, etc.).

4. Plays the metafile records.

5. Restores all objects in the display context. PlayMetaFile() will restore
  default objects if other restoration fails.

6. Unlocks the metafiles.

7. Deletes all objects created while playing the metafile.

To achieve this speed advantage, the callback function specified in
EnumMetaFile() would call only PlayMetaFileRecord(). The actual speed of
execution is determined by the amount of processing done in the EnumMetaFile()
callback function.

Additional query words: 3.00 3.10 no32bit

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

=============================================================================

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY.