samples/web/charts/lib/bar_chart/stacked_fill_color.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.

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

/// Example of a stacked bar chart with three series, each rendered with
/// different fill colors.
class StackedFillColorBarChart extends StatelessWidget {
  final List<charts.Series> seriesList;
  final bool animate;

  StackedFillColorBarChart(this.seriesList, {this.animate});

  factory StackedFillColorBarChart.withSampleData() {
    return new StackedFillColorBarChart(
      _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 StackedFillColorBarChart.withRandomData() {
    return new StackedFillColorBarChart(_createRandomData());
  }

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

    final desktopSalesData = [
      new OrdinalSales('2014', random.nextInt(100)),
      new OrdinalSales('2015', random.nextInt(100)),
      new OrdinalSales('2016', random.nextInt(100)),
      new OrdinalSales('2017', random.nextInt(100)),
    ];

    final tableSalesData = [
      new OrdinalSales('2014', random.nextInt(100)),
      new OrdinalSales('2015', random.nextInt(100)),
      new OrdinalSales('2016', random.nextInt(100)),
      new OrdinalSales('2017', random.nextInt(100)),
    ];

    final mobileSalesData = [
      new OrdinalSales('2014', random.nextInt(100)),
      new OrdinalSales('2015', random.nextInt(100)),
      new OrdinalSales('2016', random.nextInt(100)),
      new OrdinalSales('2017', random.nextInt(100)),
    ];

    return [
      // Blue bars with a lighter center color.
      new charts.Series<OrdinalSales, String>(
        id: 'Desktop',
        domainFn: (OrdinalSales sales, _) => sales.year,
        measureFn: (OrdinalSales sales, _) => sales.sales,
        data: desktopSalesData,
        colorFn: (_, __) => charts.MaterialPalette.blue.shadeDefault,
        fillColorFn: (_, __) =>
            charts.MaterialPalette.blue.shadeDefault.lighter,
      ),
      // Solid red bars. Fill color will default to the series color if no
      // fillColorFn is configured.
      new charts.Series<OrdinalSales, String>(
        id: 'Tablet',
        domainFn: (OrdinalSales sales, _) => sales.year,
        measureFn: (OrdinalSales sales, _) => sales.sales,
        data: tableSalesData,
        colorFn: (_, __) => charts.MaterialPalette.red.shadeDefault,
      ),
      // Hollow green bars.
      new charts.Series<OrdinalSales, String>(
        id: 'Mobile',
        domainFn: (OrdinalSales sales, _) => sales.year,
        measureFn: (OrdinalSales sales, _) => sales.sales,
        data: mobileSalesData,
        colorFn: (_, __) => charts.MaterialPalette.green.shadeDefault,
        fillColorFn: (_, __) => charts.MaterialPalette.transparent,
      ),
    ];
  }
  // EXCLUDE_FROM_GALLERY_DOCS_END

  @override
  Widget build(BuildContext context) {
    return new charts.BarChart(
      seriesList,
      animate: animate,
      // Configure a stroke width to enable borders on the bars.
      defaultRenderer: new charts.BarRendererConfig(
          groupingType: charts.BarGroupingType.stacked, strokeWidthPx: 2.0),
    );
  }

  /// Create series list with multiple series
  static List<charts.Series<OrdinalSales, String>> _createSampleData() {
    final desktopSalesData = [
      new OrdinalSales('2014', 5),
      new OrdinalSales('2015', 25),
      new OrdinalSales('2016', 100),
      new OrdinalSales('2017', 75),
    ];

    final tableSalesData = [
      new OrdinalSales('2014', 25),
      new OrdinalSales('2015', 50),
      new OrdinalSales('2016', 10),
      new OrdinalSales('2017', 20),
    ];

    final mobileSalesData = [
      new OrdinalSales('2014', 10),
      new OrdinalSales('2015', 50),
      new OrdinalSales('2016', 50),
      new OrdinalSales('2017', 45),
    ];

    return [
      // Blue bars with a lighter center color.
      new charts.Series<OrdinalSales, String>(
        id: 'Desktop',
        domainFn: (OrdinalSales sales, _) => sales.year,
        measureFn: (OrdinalSales sales, _) => sales.sales,
        data: desktopSalesData,
        colorFn: (_, __) => charts.MaterialPalette.blue.shadeDefault,
        fillColorFn: (_, __) =>
            charts.MaterialPalette.blue.shadeDefault.lighter,
      ),
      // Solid red bars. Fill color will default to the series color if no
      // fillColorFn is configured.
      new charts.Series<OrdinalSales, String>(
        id: 'Tablet',
        measureFn: (OrdinalSales sales, _) => sales.sales,
        data: tableSalesData,
        colorFn: (_, __) => charts.MaterialPalette.red.shadeDefault,
        domainFn: (OrdinalSales sales, _) => sales.year,
      ),
      // Hollow green bars.
      new charts.Series<OrdinalSales, String>(
        id: 'Mobile',
        domainFn: (OrdinalSales sales, _) => sales.year,
        measureFn: (OrdinalSales sales, _) => sales.sales,
        data: mobileSalesData,
        colorFn: (_, __) => charts.MaterialPalette.green.shadeDefault,
        fillColorFn: (_, __) => charts.MaterialPalette.transparent,
      ),
    ];
  }
}

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

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