PRB: Using Enhanced Metafiles in COleServerItem

The information in this article applies to:

• The Microsoft Foundation Classes (MFC), included with: Microsoft Visual C++, 32-bit Edition, version 4.0, 4.1, 4.2

SYMPTOMS

Enhanced metafiles do not appear in a non-active state in a OLE client when they are used by the server to render the image. A call to CDC::PlayMetaFile() in the OnDraw of the COleServerItem-derived class fails if it is passed an enhanced metafile.

CAUSE

When an OLE client application asks the server for a metafile representation of the server data when it is in an inactive state or using Paste Special, the application asks for it in a standard metafile format (CF_METAFILEPICT). The server cannot respond to this request. However, most images can be rendered without a problem using standard metafiles.

When COleClientItem::Draw calls the IViewObject2::Draw to render the cached metafile representation, it needs to receive a metafile and not an enhanced metafile. When COleServerItem::OnDraw is called, the DC passed is for a standard metafile, not an enhanced metafile, so the rendering into the DCneeds to be limited to items understood by a standard metafile.

RESOLUTION

If your server is using enhanced metafiles, and the client is asking it to render to an standard metafile, you need to make a conversion. You can use GetEnhMetafileBits() to get each command of the enhanced metafile and copy the commands to a standard metafile using SetMetafileBitsEx(), or you can use the GetWinMetaFileBits() function to make the conversion.

STATUS

This behavior is by design.

MORE INFORMATION

Use the metafile format rather than the enhanced metafile. Check the documentation on the features of enhanced metafiles to determine whether this usage is appropriate for your application.

REFERENCES

For more information on enhanced metafiles, see the "Enhanced-Format Metafiles" section in Online Help.