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samples/web/charts/lib/line_chart/segments.dart

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// 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 a stacked area chart with changing styles within each line.
///
/// Each series of data in this example contains different values for color,
/// dashPattern, or strokeWidthPx between each datum. The line and area skirt
/// will be rendered in segments, with the styling of the series changing when
/// these data attributes change.
///
/// Note that if a dashPattern or strokeWidth value is not found for a
/// particular datum, then the chart will fall back to use the value defined in
/// the [charts.LineRendererConfig]. This could be used, for example, to define
/// a default dash pattern for the series, with only a specific datum called out
/// with a different pattern.
// 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 SegmentsLineChart extends StatelessWidget {
final List<charts.Series<dynamic, num>> seriesList;
final bool? animate;
const SegmentsLineChart(this.seriesList, {this.animate, Key? key})
: super(key: key);
/// Creates a [LineChart] with sample data and no transition.
factory SegmentsLineChart.withSampleData() {
return SegmentsLineChart(
_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 SegmentsLineChart.withRandomData() {
return SegmentsLineChart(_createRandomData());
}
/// Create random data.
static List<charts.Series<LinearSales, num>> _createRandomData() {
final random = Random();
// Series of data with static dash pattern and stroke width. The colorFn
// accessor will colorize each datum (for all three series).
final colorChangeData = [
LinearSales(0, random.nextInt(100), null, 2.0),
LinearSales(1, random.nextInt(100), null, 2.0),
LinearSales(2, random.nextInt(100), null, 2.0),
LinearSales(3, random.nextInt(100), null, 2.0),
LinearSales(4, random.nextInt(100), null, 2.0),
LinearSales(5, random.nextInt(100), null, 2.0),
LinearSales(6, random.nextInt(100), null, 2.0),
];
// Series of data with changing color and dash pattern.
final dashPatternChangeData = [
LinearSales(0, random.nextInt(100), [2, 2], 2.0),
LinearSales(1, random.nextInt(100), [2, 2], 2.0),
LinearSales(2, random.nextInt(100), [4, 4], 2.0),
LinearSales(3, random.nextInt(100), [4, 4], 2.0),
LinearSales(4, random.nextInt(100), [4, 4], 2.0),
LinearSales(5, random.nextInt(100), [8, 3, 2, 3], 2.0),
LinearSales(6, random.nextInt(100), [8, 3, 2, 3], 2.0),
];
// Series of data with changing color and stroke width.
final strokeWidthChangeData = [
LinearSales(0, random.nextInt(100), null, 2.0),
LinearSales(1, random.nextInt(100), null, 2.0),
LinearSales(2, random.nextInt(100), null, 4.0),
LinearSales(3, random.nextInt(100), null, 4.0),
LinearSales(4, random.nextInt(100), null, 4.0),
LinearSales(5, random.nextInt(100), null, 6.0),
LinearSales(6, random.nextInt(100), null, 6.0),
];
// Generate 2 shades of each color so that we can style the line segments.
final blue = charts.MaterialPalette.blue.makeShades(2);
final red = charts.MaterialPalette.red.makeShades(2);
final green = charts.MaterialPalette.green.makeShades(2);
return [
charts.Series<LinearSales, int>(
id: 'Color Change',
// Light shade for even years, dark shade for odd.
colorFn: (LinearSales sales, _) =>
sales.year % 2 == 0 ? blue[1] : blue[0],
dashPatternFn: (LinearSales sales, _) => sales.dashPattern,
strokeWidthPxFn: (LinearSales sales, _) => sales.strokeWidthPx,
domainFn: (LinearSales sales, _) => sales.year,
measureFn: (LinearSales sales, _) => sales.sales,
data: colorChangeData,
),
charts.Series<LinearSales, int>(
id: 'Dash Pattern Change',
// Light shade for even years, dark shade for odd.
colorFn: (LinearSales sales, _) =>
sales.year % 2 == 0 ? red[1] : red[0],
dashPatternFn: (LinearSales sales, _) => sales.dashPattern,
strokeWidthPxFn: (LinearSales sales, _) => sales.strokeWidthPx,
domainFn: (LinearSales sales, _) => sales.year,
measureFn: (LinearSales sales, _) => sales.sales,
data: dashPatternChangeData,
),
charts.Series<LinearSales, int>(
id: 'Stroke Width Change',
// Light shade for even years, dark shade for odd.
colorFn: (LinearSales sales, _) =>
sales.year % 2 == 0 ? green[1] : green[0],
dashPatternFn: (LinearSales sales, _) => sales.dashPattern,
strokeWidthPxFn: (LinearSales sales, _) => sales.strokeWidthPx,
domainFn: (LinearSales sales, _) => sales.year,
measureFn: (LinearSales sales, _) => sales.sales,
data: strokeWidthChangeData,
),
];
}
// EXCLUDE_FROM_GALLERY_DOCS_END
@override
Widget build(BuildContext context) {
return charts.LineChart(seriesList,
defaultRenderer:
charts.LineRendererConfig(includeArea: true, stacked: true),
animate: animate);
}
/// Create one series with sample hard coded data.
static List<charts.Series<LinearSales, int>> _createSampleData() {
// Series of data with static dash pattern and stroke width. The colorFn
// accessor will colorize each datum (for all three series).
final colorChangeData = [
LinearSales(0, 5, null, 2.0),
LinearSales(1, 15, null, 2.0),
LinearSales(2, 25, null, 2.0),
LinearSales(3, 75, null, 2.0),
LinearSales(4, 100, null, 2.0),
LinearSales(5, 90, null, 2.0),
LinearSales(6, 75, null, 2.0),
];
// Series of data with changing color and dash pattern.
final dashPatternChangeData = [
LinearSales(0, 5, [2, 2], 2.0),
LinearSales(1, 15, [2, 2], 2.0),
LinearSales(2, 25, [4, 4], 2.0),
LinearSales(3, 75, [4, 4], 2.0),
LinearSales(4, 100, [4, 4], 2.0),
LinearSales(5, 90, [8, 3, 2, 3], 2.0),
LinearSales(6, 75, [8, 3, 2, 3], 2.0),
];
// Series of data with changing color and stroke width.
final strokeWidthChangeData = [
LinearSales(0, 5, null, 2.0),
LinearSales(1, 15, null, 2.0),
LinearSales(2, 25, null, 4.0),
LinearSales(3, 75, null, 4.0),
LinearSales(4, 100, null, 4.0),
LinearSales(5, 90, null, 6.0),
LinearSales(6, 75, null, 6.0),
];
// Generate 2 shades of each color so that we can style the line segments.
final blue = charts.MaterialPalette.blue.makeShades(2);
final red = charts.MaterialPalette.red.makeShades(2);
final green = charts.MaterialPalette.green.makeShades(2);
return [
charts.Series<LinearSales, int>(
id: 'Color Change',
// Light shade for even years, dark shade for odd.
colorFn: (LinearSales sales, _) =>
sales.year % 2 == 0 ? blue[1] : blue[0],
dashPatternFn: (LinearSales sales, _) => sales.dashPattern,
strokeWidthPxFn: (LinearSales sales, _) => sales.strokeWidthPx,
domainFn: (LinearSales sales, _) => sales.year,
measureFn: (LinearSales sales, _) => sales.sales,
data: colorChangeData,
),
charts.Series<LinearSales, int>(
id: 'Dash Pattern Change',
// Light shade for even years, dark shade for odd.
colorFn: (LinearSales sales, _) =>
sales.year % 2 == 0 ? red[1] : red[0],
dashPatternFn: (LinearSales sales, _) => sales.dashPattern,
strokeWidthPxFn: (LinearSales sales, _) => sales.strokeWidthPx,
domainFn: (LinearSales sales, _) => sales.year,
measureFn: (LinearSales sales, _) => sales.sales,
data: dashPatternChangeData,
),
charts.Series<LinearSales, int>(
id: 'Stroke Width Change',
// Light shade for even years, dark shade for odd.
colorFn: (LinearSales sales, _) =>
sales.year % 2 == 0 ? green[1] : green[0],
dashPatternFn: (LinearSales sales, _) => sales.dashPattern,
strokeWidthPxFn: (LinearSales sales, _) => sales.strokeWidthPx,
domainFn: (LinearSales sales, _) => sales.year,
measureFn: (LinearSales sales, _) => sales.sales,
data: strokeWidthChangeData,
),
];
}
}
/// Sample linear data type.
class LinearSales {
final int year;
final int sales;
final List<int>? dashPattern;
final double strokeWidthPx;
LinearSales(this.year, this.sales, this.dashPattern, this.strokeWidthPx);
}