hitTest method

bool hitTest (HitTestResult result, { Offset position })

Determines the set of render objects located at the given position.

Returns true if the given point is contained in this render object or one of its descendants. Adds any render objects that contain the point to the given hit test result.

The position argument is in the coordinate system of the render view, which is to say, in logical pixels. This is not necessarily the same coordinate system as that expected by the root Layer, which will normally be in physical (device) pixels.

Implementation 

bool hitTest(HitTestResult result, { Offset position }) {
  if (child != null)
    child.hitTest(result, position: position);
  result.add(HitTestEntry(this));
  return true;
}