constrain method

Implementation

@override
void constrain(ActorNode node) {
  ActorNode? t = target as ActorNode?;
  ActorNode p = parent!;
  ActorNode? grandParent = p.parent;

  Mat2D transformA = parent!.worldTransform;
  Mat2D transformB = Mat2D();
  Mat2D.decompose(transformA, _componentsA);
  if (t == null) {
    Mat2D.copy(transformB, transformA);
    _componentsB[0] = _componentsA[0];
    _componentsB[1] = _componentsA[1];
    _componentsB[2] = _componentsA[2];
    _componentsB[3] = _componentsA[3];
    _componentsB[4] = _componentsA[4];
    _componentsB[5] = _componentsA[5];
  } else {
    Mat2D.copy(transformB, t.worldTransform);
    if (sourceSpace == TransformSpace.local) {
      ActorNode? sourceGrandParent = t.parent;
      if (sourceGrandParent != null) {
        Mat2D inverse = Mat2D();
        Mat2D.invert(inverse, sourceGrandParent.worldTransform);
        Mat2D.multiply(transformB, inverse, transformB);
      }
    }
    Mat2D.decompose(transformB, _componentsB);

    if (!copyX) {
      _componentsB[2] =
          destSpace == TransformSpace.local ? 1.0 : _componentsA[2];
    } else {
      _componentsB[2] *= scaleX;
      if (offset) {
        _componentsB[2] *= parent!.scaleX;
      }
    }

    if (!copyY) {
      _componentsB[3] =
          destSpace == TransformSpace.local ? 0.0 : _componentsA[3];
    } else {
      _componentsB[3] *= scaleY;

      if (offset) {
        _componentsB[3] *= parent!.scaleY;
      }
    }

    if (destSpace == TransformSpace.local) {
      // Destination space is in parent transform coordinates.
      // Recompose the parent local transform and get it in world,
      // then decompose the world for interpolation.
      if (grandParent != null) {
        Mat2D.compose(transformB, _componentsB);
        Mat2D.multiply(transformB, grandParent.worldTransform, transformB);
        Mat2D.decompose(transformB, _componentsB);
      }
    }
  }

  bool clampLocal =
      minMaxSpace == TransformSpace.local && grandParent != null;
  if (clampLocal) {
    // Apply min max in local space, so transform to local coordinates first.
    Mat2D.compose(transformB, _componentsB);
    Mat2D inverse = Mat2D();
    Mat2D.invert(inverse, grandParent.worldTransform);
    Mat2D.multiply(transformB, inverse, transformB);
    Mat2D.decompose(transformB, _componentsB);
  }
  if (enableMaxX && _componentsB[2] > maxX) {
    _componentsB[2] = maxX;
  }
  if (enableMinX && _componentsB[2] < minX) {
    _componentsB[2] = minX;
  }
  if (enableMaxY && _componentsB[3] > maxY) {
    _componentsB[3] = maxY;
  }
  if (enableMinY && _componentsB[3] < minY) {
    _componentsB[3] = minY;
  }
  if (clampLocal) {
    // Transform back to world.
    Mat2D.compose(transformB, _componentsB);
    Mat2D.multiply(transformB, grandParent.worldTransform, transformB);
    Mat2D.decompose(transformB, _componentsB);
  }

  double ti = 1.0 - strength;

  _componentsB[4] = _componentsA[4];
  _componentsB[0] = _componentsA[0];
  _componentsB[1] = _componentsA[1];
  _componentsB[2] = _componentsA[2] * ti + _componentsB[2] * strength;
  _componentsB[3] = _componentsA[3] * ti + _componentsB[3] * strength;
  _componentsB[5] = _componentsA[5];

  Mat2D.compose(parent!.worldTransform, _componentsB);
}