void clipRRect(RRect rrect)

Reduces the clip region to the intersection of the current clip and the given rounded rectangle.

If isAntiAlias is true, then the clip will be anti-aliased. If multiple draw commands intersect with the clip boundary, this can result in incorrect blending at the clip boundary. See saveLayer for a discussion of how to address that and some examples of using clipRRect.

Source

void clipRRect(RRect rrect) {
  assert(_rrectIsValid(rrect));
  _clipRRect(rrect._value);
}