samples/web/charts/lib/axes/numeric_initial_viewport.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 setting an initial viewport for ordinal axis.
///
/// This allows for specifying the specific range of data to show that differs
/// from what was provided in the series list.
///
/// In this example, the series list has numeric data from 0 to 10, but we
/// want to show from 3 to 7.
/// We can do this by specifying an [NumericExtents] in [NumericAxisSpec].

// 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 NumericInitialViewport extends StatelessWidget {
  final List<charts.Series> seriesList;
  final bool animate;

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

  /// Creates a [LineChart] with sample data and no transition.
  factory NumericInitialViewport.withSampleData() {
    return NumericInitialViewport(
      _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 NumericInitialViewport.withRandomData() {
    return NumericInitialViewport(_createRandomData());
  }

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

    final data = [
      LinearSales(0, random.nextInt(100)),
      LinearSales(1, random.nextInt(100)),
      LinearSales(2, random.nextInt(100)),
      LinearSales(3, random.nextInt(100)),
      LinearSales(4, random.nextInt(100)),
      LinearSales(5, random.nextInt(100)),
      LinearSales(6, random.nextInt(100)),
      LinearSales(7, random.nextInt(100)),
      LinearSales(8, random.nextInt(100)),
      LinearSales(9, random.nextInt(100)),
      LinearSales(10, random.nextInt(100)),
    ];

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

  @override
  Widget build(BuildContext context) {
    return charts.LineChart(
      seriesList,
      animate: animate,
      domainAxis: const charts.NumericAxisSpec(
          // Set the initial viewport by providing a new AxisSpec with the
          // desired viewport, in NumericExtents.
          viewport: charts.NumericExtents(3.0, 7.0)),
      // Optionally add a pan or pan and zoom behavior.
      // If pan/zoom is not added, the viewport specified remains the viewport.
      behaviors: [charts.PanAndZoomBehavior()],
    );
  }

  /// Create one series with sample hard coded data.
  static List<charts.Series<LinearSales, int>> _createSampleData() {
    final data = [
      LinearSales(0, 5),
      LinearSales(1, 25),
      LinearSales(2, 100),
      LinearSales(3, 75),
      LinearSales(4, 55),
      LinearSales(5, 66),
      LinearSales(6, 110),
      LinearSales(7, 70),
      LinearSales(8, 20),
      LinearSales(9, 25),
      LinearSales(10, 45),
    ];

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

/// Sample linear data type.
class LinearSales {
  final int year;
  final int sales;

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