pan method

void pan(double deltaX, double deltaY)

Implementation

void pan(double deltaX, double deltaY) {
  final element = scope.domElement;

  if (scope.object is PerspectiveCamera) {
    // perspective
    final position = scope.object.position;
    offset.setFrom(position).sub(scope.target);
    double targetDistance = offset.length;

    // half of the fov is center to top of screen
    targetDistance *= math.tan((scope.object.fov / 2) * math.pi / 180.0);

    // we use only clientHeight here so aspect ratio does not distort speed
    panLeft(2 * deltaX * targetDistance / element.clientHeight,
        scope.object.matrix);
    panUp(2 * deltaY * targetDistance / element.clientHeight,
        scope.object.matrix);
  } else if (scope.object is OrthographicCamera) {
    // orthographic
    panLeft(
        deltaX *
            (scope.object.right - scope.object.left) /
            scope.object.zoom /
            element.clientWidth,
        scope.object.matrix);
    panUp(
        deltaY *
            (scope.object.top - scope.object.bottom) /
            scope.object.zoom /
            element.clientHeight,
        scope.object.matrix);
  } else {
    // camera neither orthographic nor perspective
    console.warning('OrbitControls.js encountered an unknown camera type - pan disabled.');
    scope.enablePan = false;
  }
}