WinAttr sets the attribute for the next write (or draw) to the window pointed to by w
to Attr. This attribute will be used in all drawing commands which have not an
attribute as explicite parameter. The interpretation of the attribute depends of concrete
graphic command. Some attributes are only valid for certain graphic operation. Legal attribute
values are defined in enum Attrs. In a general, the following attributes
are supported:
A_REVERSE | Destination pixels turned off |
A_NORMAL | Destination pixels turned on |
A_XOR | Source pixels XORed with destination pixels |
A_SHADED | Destination pixels masked so that every other pixel turned off |
A_REPLACE | Source pixels replace destination pixels |
A_OR | Source pixels ORed with destination pixels |