Providing a User Interface (deprecated)
This page documents a feature that may be unavailable in future versions of Windows Media Player and the Windows Media Player SDK.
Rendering plug-ins can provide a property page so that a user interface can be created. To do this, the plug-in must include a property page object that provides an implementation of an IPropertyPage interface. The rendering plug-in object must implement ISpecifyPropertyPages::GetPages, which allows Windows Media Player to locate and identify the correct property page for the plug-in.
Displaying a Status Graphic
Rendering plug-ins can display a small graphic, or series of graphics, in the Windows Media Player status area to notify the user that a plug-in is active. To support this feature, the plug-in must implement the IPropertyBag interface. Windows Media Player calls IPropertyBag::Read, providing a pointer to the requested property name "IconStreams", which is case-sensitive, and a pointer to a VARIANT structure that receives the data for the graphic. The plug-in creates an IStream object (or a SAFEARRAY of IStream objects if there are multiple graphics), then loads the graphic data, including header information, into the stream, and then returns a pointer to the IStream object using the punkVal member of the VARIANT structure. If the plug-in only supplies one graphic, it specifies the vt member of the VARIANT structure as VT_UNKNOWN. If the plug-in supplies multiple graphic IStream objects using a SAFEARRAY, it specifies the vt member of the VARIANT structure as VT_ARRAY.
Graphics can be stored in a variety of file formats, including:
BMP
Microsoft Windows Bitmap images are uncompressed.
JPEG
Compressed image format commonly used for webpages. JPEG format files usually have .jpg file name extensions.
GIF
Compressed image format commonly used for webpages.
PNG
Compressed image format commonly used for webpages.
The maximum dimensions for rendering plug-in graphics are 38 pixels wide and 14 pixels high.
The IStream byte stream containing the status graphic must include header information. Without header information, Windows Media Player cannot properly identify the type of graphic and therefore will not load the image.