## Presentation Device Driver Reference for OS/2

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### Colors

All colors are passed as 32-bit signed values. These are either indexes into the Logical Color table, logical palette indexes, or representations of 24-bit Red-Green-Blue (RGB) values. Some special attribute values can be passed to the graphics engine and returned by GreGetAttributes:

CLR_FALSE All color planes or bits, or both, are 0.

CLR_TRUE All color planes or bits, or both, are 1.

CLR_WHITE This index is never loaded explicitly. It always produces White when the default color table is in force or when the index is set to RGB. With a realized color table and an index that is not RGB, the value CLR_ WHITE produces the background color CLR_BACKGROUND.

CLR_BLACK This index is never loaded explicitly. It always produces Black when the default color table is in force or when the index is set to RGB. With a realized color table and an index that is not RGB, CLR_BLACK produces the neutral color CLR_NEUTRAL. See Color Functions.

CLR_FALSE and CLR_TRUE provide useful operands for BitBlt logical operations. CLR_DEFAULT is the default value at the API. It is a reserved value and is not passed to the presentation driver.