Alpha is no longer included in the transparent pixel, although it may be useful in the future. The boolean GLX attributes of the visual that is returned will match the specification exactly. The integer GLX attributes will meet or exceed the specified minimum values. The enumerated GLX attributes are matched in an attribute-specific manner. If no conforming visual exists, NULL is returned.
All integer attributes default to zero.
Default specifications are superseded by the attributes included in . Integer attributes are immediately followed by the corresponding desired value. The list is terminated with None. NULL is returned if an undefined GLX attribute is encountered, or if an unacceptable enumerated attribute value is encountered.