Interactive region coloring techniques as implemented by a computing device are described to provide a user with the tactile experience of coloring in a region with digital paint, while at the same time allowing the user to manually fill the region with digital paint with more apparent skill and precision than they may input. For each of multiple pixels on the digital medium, the system obtains one or both of a distance value that indicates a distance to a nearby point (e.g., the closest point) on an outline on the digital medium and a direction value that indicates a direction to the nearby point on the outline. A manner in which the digital paint is applied to the region (e.g., forces affecting paint flow, dynamically adjusting brush size or position) is determined based on one or both of the distance value and the direction value.