samples/web/charts/lib/behaviors/initial_hint_animation.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.

/// Example of initial hint animation behavior.
///
/// To see the animation, please run the example app and select
/// "Initial hint animation".
///
/// This behavior is intended to be used with charts that also have pan/zoom
/// behaviors added and/or the initial viewport set in [AxisSpec].
///
/// Adding this behavior will cause the chart to animate from a scale and/or
/// offset of the desired final viewport. If the user taps the widget prior
/// to the animation being completed, animation will stop.
///
/// [maxHintScaleFactor] is the amount the domain axis will be scaled at the
/// start of te hint. By default, this is null, indicating that there will be
/// no scale factor hint. A value of 1.0 means the viewport is showing all
/// domains in the viewport. If a value is provided, it cannot be less than 1.0.
///
/// [maxHintTranslate] is the amount of ordinal values to translate the viewport
/// from the desired initial viewport. Currently only works for ordinal axis.
///
/// In this example, the series list has ordinal data from year 2014 to 2030,
/// and we have the initial viewport set to start at 2018 that shows 4 values by
/// specifying an [OrdinalViewport] in [OrdinalAxisSpec]. We can add the hint
/// animation by adding behavior [InitialHintBehavior] with [maxHintTranslate]
/// of 4. When the chart is drawn for the first time, the viewport will show
/// 2022 as the first value and the viewport will animate by panning values to
/// the right until 2018 is the first value in the viewport.

// EXCLUDE_FROM_GALLERY_DOCS_START
import 'dart:math';
// EXCLUDE_FROM_GALLERY_DOCS_END
import 'package:charts_flutter/flutter.dart' as charts;
import 'package:flutter/material.dart';

class InitialHintAnimation extends StatelessWidget {
  final List<charts.Series> seriesList;
  final bool animate;

  const InitialHintAnimation(this.seriesList, {this.animate, Key key})
      : super(key: key);

  /// Creates a [BarChart] with sample data and no transition.
  factory InitialHintAnimation.withSampleData() {
    return InitialHintAnimation(
      _createSampleData(),
      // Disable animations for image tests.
      animate: false,
    );
  }

  // EXCLUDE_FROM_GALLERY_DOCS_START
  // This section is excluded from being copied to the gallery.
  // It is used for creating random series data to demonstrate animation in
  // the example app only.
  factory InitialHintAnimation.withRandomData() {
    return InitialHintAnimation(_createRandomData());
  }

  /// Create random data.
  static List<charts.Series<OrdinalSales, String>> _createRandomData() {
    final random = Random();

    final data = [
      OrdinalSales('2014', random.nextInt(100)),
      OrdinalSales('2015', random.nextInt(100)),
      OrdinalSales('2016', random.nextInt(100)),
      OrdinalSales('2017', random.nextInt(100)),
      OrdinalSales('2018', random.nextInt(100)),
      OrdinalSales('2019', random.nextInt(100)),
      OrdinalSales('2020', random.nextInt(100)),
      OrdinalSales('2021', random.nextInt(100)),
      OrdinalSales('2022', random.nextInt(100)),
      OrdinalSales('2023', random.nextInt(100)),
      OrdinalSales('2024', random.nextInt(100)),
      OrdinalSales('2025', random.nextInt(100)),
      OrdinalSales('2026', random.nextInt(100)),
      OrdinalSales('2027', random.nextInt(100)),
      OrdinalSales('2028', random.nextInt(100)),
      OrdinalSales('2029', random.nextInt(100)),
      OrdinalSales('2030', random.nextInt(100)),
    ];

    return [
      charts.Series<OrdinalSales, String>(
        id: 'Sales',
        colorFn: (_, __) => charts.MaterialPalette.blue.shadeDefault,
        domainFn: (OrdinalSales sales, _) => sales.year,
        measureFn: (OrdinalSales sales, _) => sales.sales,
        data: data,
      )
    ];
  }
  // EXCLUDE_FROM_GALLERY_DOCS_END

  @override
  Widget build(BuildContext context) {
    return charts.BarChart(
      seriesList,
      animate: animate,
      // Optionally turn off the animation that animates values up from the
      // bottom of the domain axis. If animation is on, the bars will animate up
      // and then animate to the final viewport.
      animationDuration: Duration.zero,
      // Set the initial viewport by providing a new AxisSpec with the
      // desired viewport: a starting domain and the data size.
      domainAxis:
          charts.OrdinalAxisSpec(viewport: charts.OrdinalViewport('2018', 4)),
      behaviors: [
        // Add this behavior to show initial hint animation that will pan to the
        // final desired viewport.
        // The duration of the animation can be adjusted by pass in
        // [hintDuration]. By default this is 3000ms.
        charts.InitialHintBehavior(maxHintTranslate: 4.0),
        // Optionally add a pan or pan and zoom behavior.
        // If pan/zoom is not added, the viewport specified remains the viewport
        charts.PanAndZoomBehavior(),
      ],
    );
  }

  /// Create one series with sample hard coded data.
  static List<charts.Series<OrdinalSales, String>> _createSampleData() {
    final data = [
      OrdinalSales('2014', 5),
      OrdinalSales('2015', 25),
      OrdinalSales('2016', 100),
      OrdinalSales('2017', 75),
      OrdinalSales('2018', 33),
      OrdinalSales('2019', 80),
      OrdinalSales('2020', 21),
      OrdinalSales('2021', 77),
      OrdinalSales('2022', 8),
      OrdinalSales('2023', 12),
      OrdinalSales('2024', 42),
      OrdinalSales('2025', 70),
      OrdinalSales('2026', 77),
      OrdinalSales('2027', 55),
      OrdinalSales('2028', 19),
      OrdinalSales('2029', 66),
      OrdinalSales('2030', 27),
    ];

    return [
      charts.Series<OrdinalSales, String>(
        id: 'Sales',
        colorFn: (_, __) => charts.MaterialPalette.blue.shadeDefault,
        domainFn: (OrdinalSales sales, _) => sales.year,
        measureFn: (OrdinalSales sales, _) => sales.sales,
        data: data,
      )
    ];
  }
}

/// Sample ordinal data type.
class OrdinalSales {
  final String year;
  final int sales;

  OrdinalSales(this.year, this.sales);
}