Merge branch 'fil/brush-dataless' into fil/brush-data-options

Author: Fil

docs/interactions/brush.md

@@ -294,7 +294,7 @@ The brush value dispatched on [_input_ events](#input-events). When the brush is
 - **data** - when the brush has data, the filtered subset
 - **pending** - `true` during interaction; absent when committed
 
-By convention, *x1* < *x2* and *y1* < *y2*. The brushX value does not include *y1* and *y2*; similarly, the brushY value does not include *x1* and *x2*.
+By convention, *x1* < *x2* and *y1* < *y2*. The brushX value does not include *y1* and *y2*; similarly, the brushY value does not include *x1* and *x2*. Values are automatically rounded to the optimal precision that distinguishes neighboring pixels.
 
 The **pending** property indicates the user is still interacting with the brush. To skip intermediate values and react only to committed selections: