Code can set the color keys for surface when created

Figure 10-4: Transparency using source and destination color keys

DWORD dwFlags, // 1

LPDDCOLORKEY lpDDColorKey // 2

DDCKEY_COLORSPACE

DDCKEY_DESTBLT

The structure specifies a color key or color space to be used as a destination color key for blit operations.

The structure specifies a color key or color space to be used as a destination color key for overlay operations.

DirectDrawSurface object. If this value is NULL, then the existing color key is removed from

the surface.

DDERR_INVALIDPARAMS

DDERR_INVALIDSURFACETYPE