tree f4ce915ab8e8d41a2b14bff9877115c862591afd
parent b72ab8fe2c4264bf70df1893d4e0ab994a22e547
author Urvang Joshi <urvang@google.com> 1494032982 -0700
committer Urvang Joshi <urvang@google.com> 1494277062 +0000

Palette: Special case for 2 unique colors.

When a block only contains 2 unique colors, there's no need to run
K-means, as 'lb' and 'ub' can directly be used as the centroids.

Two benefits:
1. Encoding will be faster for this special case, and
2. Can potentially avoid sub-optimal/duplicate centroids generation
(due to integer rounding) when 'ub' and 'lb' values are very close.

Change-Id: Ice04fc8577e3cc8c74f87d623a16ac8de3257cdd