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samples/web/charts/flutter/lib/src/util.dart
2019-05-07 13:32:08 -07:00

46 lines
1.8 KiB
Dart

// Copyright 2018 the Charts project authors. Please see the AUTHORS file
// for details.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
import 'package:flutter_web/rendering.dart'
show
RenderBox,
RenderSemanticsGestureHandler,
RenderPointerListener,
RenderCustomMultiChildLayoutBox;
import 'chart_container.dart' show ChartContainerRenderObject;
/// Get the [ChartContainerRenderObject] from a [RenderBox].
///
/// [RenderBox] is expected to be a [RenderSemanticsGestureHandler] with child
/// of [RenderPointerListener] with child of [ChartContainerRenderObject].
ChartContainerRenderObject getChartContainerRenderObject(RenderBox box) {
assert(box is RenderCustomMultiChildLayoutBox);
final semanticHandler = (box as RenderCustomMultiChildLayoutBox)
.getChildrenAsList()
.firstWhere((child) => child is RenderSemanticsGestureHandler);
assert(semanticHandler is RenderSemanticsGestureHandler);
final renderPointerListener =
(semanticHandler as RenderSemanticsGestureHandler).child;
assert(renderPointerListener is RenderPointerListener);
final chartContainerRenderObject =
(renderPointerListener as RenderPointerListener).child;
assert(chartContainerRenderObject is ChartContainerRenderObject);
return chartContainerRenderObject as ChartContainerRenderObject;
}