public int getSample() {
    return mSample;
  }
ZOOM     PERCENT     SAMPLE
0        100%        1
1        50%         2
2        25%         4
3        12.5%       8
4        6.25%       16
5        3.125%      32
...
handy math:
get percent from zoom: (1 >> zoom) / 1f (number of digits is precision, so (100 >> zoom) / 100f will give .012
get percent from sample: 1 / sample
get sample from zoom: 1 << zoom
get zoom from sample: Maths.log2(sample)
tileview/src/main/java/com/moagrius/tileview/Detail.java