samples/web/charts/example/lib/bar_chart/spark_bar.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.

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

/// Example of a Spark Bar by hiding both axis, reducing the chart margins.
class SparkBar extends StatelessWidget {
  final List<charts.Series> seriesList;
  final bool animate;

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

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

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

    final globalSalesData = [
      new OrdinalSales('2007', random.nextInt(100)),
      new OrdinalSales('2008', random.nextInt(100)),
      new OrdinalSales('2009', random.nextInt(100)),
      new OrdinalSales('2010', random.nextInt(100)),
      new OrdinalSales('2011', random.nextInt(100)),
      new OrdinalSales('2012', random.nextInt(100)),
      new OrdinalSales('2013', random.nextInt(100)),
      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 [
      new charts.Series<OrdinalSales, String>(
        id: 'Global Revenue',
        domainFn: (OrdinalSales sales, _) => sales.year,
        measureFn: (OrdinalSales sales, _) => sales.sales,
        data: globalSalesData,
      ),
    ];
  }
  // EXCLUDE_FROM_GALLERY_DOCS_END

  @override
  Widget build(BuildContext context) {
    return new charts.BarChart(
      seriesList,
      animate: animate,

      /// Assign a custom style for the measure axis.
      ///
      /// The NoneRenderSpec only draws an axis line (and even that can be hidden
      /// with showAxisLine=false).
      primaryMeasureAxis:
          new charts.NumericAxisSpec(renderSpec: new charts.NoneRenderSpec()),

      /// This is an OrdinalAxisSpec to match up with BarChart's default
      /// ordinal domain axis (use NumericAxisSpec or DateTimeAxisSpec for
      /// other charts).
      domainAxis: new charts.OrdinalAxisSpec(
          // Make sure that we draw the domain axis line.
          showAxisLine: true,
          // But don't draw anything else.
          renderSpec: new charts.NoneRenderSpec()),

      // With a spark chart we likely don't want large chart margins.
      // 1px is the smallest we can make each margin.
      layoutConfig: new charts.LayoutConfig(
          leftMarginSpec: new charts.MarginSpec.fixedPixel(0),
          topMarginSpec: new charts.MarginSpec.fixedPixel(0),
          rightMarginSpec: new charts.MarginSpec.fixedPixel(0),
          bottomMarginSpec: new charts.MarginSpec.fixedPixel(0)),
    );
  }

  /// Create series list with single series
  static List<charts.Series<OrdinalSales, String>> _createSampleData() {
    final globalSalesData = [
      new OrdinalSales('2007', 3100),
      new OrdinalSales('2008', 3500),
      new OrdinalSales('2009', 5000),
      new OrdinalSales('2010', 2500),
      new OrdinalSales('2011', 3200),
      new OrdinalSales('2012', 4500),
      new OrdinalSales('2013', 4400),
      new OrdinalSales('2014', 5000),
      new OrdinalSales('2015', 5000),
      new OrdinalSales('2016', 4500),
      new OrdinalSales('2017', 4300),
    ];

    return [
      new charts.Series<OrdinalSales, String>(
        id: 'Global Revenue',
        domainFn: (OrdinalSales sales, _) => sales.year,
        measureFn: (OrdinalSales sales, _) => sales.sales,
        data: globalSalesData,
      ),
    ];
  }
}

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

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