CImagePalette::PreparePalette

The PreparePalette method sets up a palette, based on a media type from the owning filter.

Syntax

HRESULT PreparePalette(
    const CMediaType *pmtNew,
    const CMediaType *pmtOld,
    LPSTR szDevice
);

Parameters

pmtNew

Pointer to the new media type. The format block must be a VIDEOINFOHEADER structure.

pmtOld

Pointer to the old media type. If the media type is being set for the first time, this parameter can be an empty type with no format block. Otherwise, the format block must be a VIDEOINFOHEADER structure.

szDevice

Pointer to a string that contains the name of the display device, as returned by the GDI EnumDisplayDevices function. To use the main display device, set this parameter to NULL.

Return Value

Returns S_OK if the palette was updated, or S_FALSE if the palette did not change.

Remarks

If the palette needs to be updated, this method performs the following actions:

• Calls CImagePalette::MakePalette to create a new logical palette.
• Sends an EC_PALETTE_CHANGED event to the Filter Graph Manager.
• Calls CBaseWindow::SetPalette on the CBaseWindow object.
• Calls CDrawImage::IncrementPaletteVersion on the CDrawImage object.

See Also

• CImagePalette Class