samples/web/charts/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/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<dynamic, String>> seriesList;
  final bool? animate;

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

  factory SparkBar.withSampleData() {
    return 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 SparkBar(_createRandomData());
  }

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

    final globalSalesData = [
      OrdinalSales('2007', random.nextInt(100)),
      OrdinalSales('2008', random.nextInt(100)),
      OrdinalSales('2009', random.nextInt(100)),
      OrdinalSales('2010', random.nextInt(100)),
      OrdinalSales('2011', random.nextInt(100)),
      OrdinalSales('2012', random.nextInt(100)),
      OrdinalSales('2013', random.nextInt(100)),
      OrdinalSales('2014', random.nextInt(100)),
      OrdinalSales('2015', random.nextInt(100)),
      OrdinalSales('2016', random.nextInt(100)),
      OrdinalSales('2017', random.nextInt(100)),
    ];

    return [
      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 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:
          const charts.NumericAxisSpec(renderSpec: charts.NoneRenderSpec()),

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

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

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

    return [
      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);
}