xrandr: compute gamma-correction in [0,2^sigbits)
The gamma-correction lookup table values are 16:16:16 X Colors, where the
MSBs are programmed into the hardware lookup table. Rather than compute
values over the entire range [0,65536) (where values below 2^(16 - sigbits)
will receive the same hardware value), compute values over the range
[0,2^sigbits) and left shift by (16 - sigbits) into the MSBs.
Signed-off-by: Andy Ritger <aritger@nvidia.com>
Reviewed-by: Aaron Plattner <aplattner@nvidia.com>
Signed-off-by: Aaron Plattner <aplattner@nvidia.com>