(No version information available, might only be in SVN)
CairoContent is used to describe the content that a surface will contain, whether color information, alpha information (translucence vs. opacity), or both.
Note: The large values here are designed to keep CairoContent values distinct from CairoContent values so that the implementation can detect the error if users confuse the two types.
The surface will hold color content only.
The surface will hold alpha content only.
The surface will hold color and alpha content.