RenderViewportBase<ParentDataClass extends ContainerParentDataMixin<RenderSliver>> constructor

RenderViewportBase<ParentDataClass extends ContainerParentDataMixin<RenderSliver>>(
  1. {AxisDirection axisDirection: AxisDirection.down,
  2. @required AxisDirection crossAxisDirection,
  3. @required ViewportOffset offset,
  4. double cacheExtent,
  5. CacheExtentStyle cacheExtentStyle: CacheExtentStyle.pixel}
)

Initializes fields for subclasses.

Implementation

RenderViewportBase({
  AxisDirection axisDirection = AxisDirection.down,
  @required AxisDirection crossAxisDirection,
  @required ViewportOffset offset,
  double cacheExtent,
  CacheExtentStyle cacheExtentStyle = CacheExtentStyle.pixel,
}) : assert(axisDirection != null),
     assert(crossAxisDirection != null),
     assert(offset != null),
     assert(axisDirectionToAxis(axisDirection) != axisDirectionToAxis(crossAxisDirection)),
     assert(cacheExtentStyle != null),
     assert(cacheExtent != null || cacheExtentStyle == CacheExtentStyle.pixel),
     _axisDirection = axisDirection,
     _crossAxisDirection = crossAxisDirection,
     _offset = offset,
     _cacheExtent = cacheExtent ?? RenderAbstractViewport.defaultCacheExtent,
     _cacheExtentStyle = cacheExtentStyle;