showInViewport static method

Rect? showInViewport({ RenderObject? descendant, Rect? rect, required RenderLayoutBox viewport, Duration duration = Duration.zero, Curve curve = Curves.ease, AxisDirection? axisDirection, })

Implementation

static Rect? showInViewport({
  RenderObject? descendant,
  Rect? rect,
  required RenderLayoutBox viewport,
  Duration duration = Duration.zero,
  Curve curve = Curves.ease,
  AxisDirection? axisDirection,
}) {
  if (descendant == null) {
    return rect;
  }

  Rect? showVertical(Rect? rect) {
    return _showInViewportForAxisDirection(
      descendant: descendant,
      viewport: viewport,
      axis: Axis.vertical,
      rect: rect,
      duration: duration,
      curve: curve,
    );
  }

  Rect? showHorizontal(Rect? rect) {
    return _showInViewportForAxisDirection(
      descendant: descendant,
      viewport: viewport,
      axis: Axis.horizontal,
      rect: rect,
      duration: duration,
      curve: curve,
    );
  }

  switch (axisDirection) {
    case AxisDirection.left:
    case AxisDirection.right:
      return showHorizontal(rect);
    case AxisDirection.up:
    case AxisDirection.down:
      return showVertical(rect);
    case null:
      // Update rect after revealing in one axis before revealing in the next.
      rect = showHorizontal(rect) ?? rect;
      // We only return the final rect after both have been revealed.
      rect = showVertical(rect);
      if (rect == null) {
        // `descendant` is between leading and trailing edge and hence already
        //  fully shown on screen.
        assert(viewport.parent != null);
        final Matrix4 transform = descendant.getTransformTo(viewport.parent);
        return MatrixUtils.transformRect(
          transform,
          rect ?? descendant.paintBounds,
        );
      }
      return rect;
  }
}