| 摘要 |
A graphics system for use with a computer in a gray-scale mode. The graphics system utilizes a lookup table having index values to be stored in a frame buffer. The lookup table is addressed by convening color information, such as RGB color information, to a luminance value, which is then used to access the table. The index values may be used to index a second lookup table for providing luminance information. The present invention further discloses methods of insuring index values provided by the lookup table closely approximate the desired luminance value within the available gray-scale space. Further, the present invention provides methods for performing arithmetic transfer operations on gray-scales represented by indices in the frame buffer.
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