← Gallery

Trend Line

Request volume and its trend

Explore the example, download the output or use the C# source in your own project.

Preview
Request volume and its trendChart with 2 data series: Observations, Least-squares trend.Request volume and its trendThe same data in a compact viewObservationsLeast-squares trendMonTueWedThuFriSat010203040
Request volume and its trend
Request volume and its trendChart with 2 data series: Observations, Least-squares trend.Request volume and its trendThe same data in a compact viewObservationsLeast-squares trendMonTueWedThuFriSat010203040
Request volume and its trend
360 × 360 pixels

Create this example

Create a console project, add the ChartForgeX package, and replace Program.cs with this source. Run it to write SVG, PNG and HTML with the default system fonts.

For the same typography as the gallery, download the gallery-font recipe and copy the gallery’s fonts directory beside your program.

using System;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Linq;
using ChartForgeX.Core;
using ChartForgeX.Primitives;
using ChartForgeX.Rendering;
using ChartForgeX.Themes;
using ChartForgeX.Topology;
using ChartForgeX.Typography;
using ChartForgeX.VisualArtifacts;
using ChartForgeX.VisualBlocks;

var mode = VisualThemeMode.Light;
var theme = VisualTheme.Graphite();
var model = TrendLineRecipe.Create("compact", mode);
var context = new VisualRenderContext(
    new VisualLayoutOptions(new VisualSize(360, 360)), theme, mode,
    new VisualFrame("Request volume and its trend", "The same data in a compact view", showLegend: null, showSurface: false));
var prepared = model.Prepare(context);
File.WriteAllText("visual.svg", prepared.ToSvg());
File.WriteAllBytes("visual.png", prepared.ToPng());
File.WriteAllText("visual.html", prepared.ToArtifact("example", VisualArtifactKind.Chart).ToHtmlPage());

/// <summary>Builds a least-squares trend while retaining the observations used to fit it.</summary>
public static class TrendLineRecipe {
    /// <summary>Creates the selected trend example, including the small-drift precision case.</summary>
    public static Chart Create(string variant = "wide", VisualThemeMode mode = VisualThemeMode.Light) {
        if (variant is not ("wide" or "compact" or "sparse" or "options" or "compact-options" or "precision" or "compact-precision"))
            throw new ArgumentOutOfRangeException(nameof(variant));
        if (variant is "precision" or "compact-precision") {
            var drift = ChartSeries.CreateTrendLine(new ChartSeriesId("least-squares-drift"), "Least-squares drift",
                Enumerable.Range(0, 4096).Select(index => new ChartPoint(index % 10 + .5, index % 7 - 3)));
            return Chart.Create().WithXAxis("Measurement").WithYAxis("Fitted drift").AddSeries(drift);
        }
        var points = Enumerable.Range(1, 6).Where(index => variant != "sparse" || index is 1 or 3 or 6)
            .Select(index => new ChartPoint(index, 20 + index * 7 % 29, variant == "sparse" && index == 6)).ToArray();
        var observations = ChartSeries.CreateScatter(new ChartSeriesId("observations"), "Observations", points);
        var trend = ChartSeries.CreateTrendLine(new ChartSeriesId("least-squares-trend"), "Least-squares trend", points);
        return Chart.Create().WithXLabels("Mon", "Tue", "Wed", "Thu", "Fri", "Sat").AddSeries(observations).AddSeries(trend)
            .WithValueFormat(ChartValueFormat.Number("0.##", CultureInfo.InvariantCulture));
    }
}
using System;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Linq;
using ChartForgeX.Core;
using ChartForgeX.Primitives;
using ChartForgeX.Rendering;
using ChartForgeX.Themes;
using ChartForgeX.Topology;
using ChartForgeX.Typography;
using ChartForgeX.VisualArtifacts;
using ChartForgeX.VisualBlocks;

var mode = VisualThemeMode.Dark;
var theme = VisualTheme.Graphite();
var model = TrendLineRecipe.Create("compact", mode);
var context = new VisualRenderContext(
    new VisualLayoutOptions(new VisualSize(360, 360)), theme, mode,
    new VisualFrame("Request volume and its trend", "The same data in a compact view", showLegend: null, showSurface: false));
var prepared = model.Prepare(context);
File.WriteAllText("visual.svg", prepared.ToSvg());
File.WriteAllBytes("visual.png", prepared.ToPng());
File.WriteAllText("visual.html", prepared.ToArtifact("example", VisualArtifactKind.Chart).ToHtmlPage());

/// <summary>Builds a least-squares trend while retaining the observations used to fit it.</summary>
public static class TrendLineRecipe {
    /// <summary>Creates the selected trend example, including the small-drift precision case.</summary>
    public static Chart Create(string variant = "wide", VisualThemeMode mode = VisualThemeMode.Light) {
        if (variant is not ("wide" or "compact" or "sparse" or "options" or "compact-options" or "precision" or "compact-precision"))
            throw new ArgumentOutOfRangeException(nameof(variant));
        if (variant is "precision" or "compact-precision") {
            var drift = ChartSeries.CreateTrendLine(new ChartSeriesId("least-squares-drift"), "Least-squares drift",
                Enumerable.Range(0, 4096).Select(index => new ChartPoint(index % 10 + .5, index % 7 - 3)));
            return Chart.Create().WithXAxis("Measurement").WithYAxis("Fitted drift").AddSeries(drift);
        }
        var points = Enumerable.Range(1, 6).Where(index => variant != "sparse" || index is 1 or 3 or 6)
            .Select(index => new ChartPoint(index, 20 + index * 7 % 29, variant == "sparse" && index == 6)).ToArray();
        var observations = ChartSeries.CreateScatter(new ChartSeriesId("observations"), "Observations", points);
        var trend = ChartSeries.CreateTrendLine(new ChartSeriesId("least-squares-trend"), "Least-squares trend", points);
        return Chart.Create().WithXLabels("Mon", "Tue", "Wed", "Thu", "Fri", "Sat").AddSeries(observations).AddSeries(trend)
            .WithValueFormat(ChartValueFormat.Number("0.##", CultureInfo.InvariantCulture));
    }
}