Linear Gradients

View model

using LiveChartsCore;
using LiveChartsCore.SkiaSharpView;
using LiveChartsCore.SkiaSharpView.Painting;
using SkiaSharp;

namespace ViewModelsSamples.Design.LinearGradients;

public class ViewModel
{
    public ViewModel()
    {
        // linear gradients are based on SkiaSharp linear gradients
        // for more info please see:
        // https://docs.microsoft.com/en-us/xamarin/xamarin-forms/user-interface/graphics/skiasharp/effects/shaders/linear-gradient

        var colors = new[]
        {
                new SKColor(45, 64, 89),
                new SKColor(255, 212, 96)
                // ...

                // you can add as many colors as you require to build the gradient
                // by default all the distance between each color is equal
                // use the colorPos parameter in the constructor of the LinearGradientPaint class
                // to specify the distance between each color
            };

        Series = new ISeries[]
        {
                new ColumnSeries<int>
                {
                    Values = new []{ 3, 7, 2, 9, 4 },
                    Stroke = null,

                    // this is an easy way to set a linear gradient:
                    // Fill = new LinearGradientPaint(new SKColor(255, 140, 148), new SKColor(220, 237, 194))

                    // but you can customize the gradient
                    Fill = new LinearGradientPaint(
                        // the gradient will use the following colors array
                        new [] { new SKColor(255, 140, 148), new SKColor(220, 237, 194) },

                        // now with the following points we are specifying the orientation of the gradient
                        // by default the gradient is orientated horizontally
                        // defined by the points: (0, 0.5) and (1, 0.5)
                        // but for this sample we will use a vertical gradient:

                        // to build a vertical gradient we must specify 2 points that will draw a imaginary line
                        // the gradient will interpolate colors lineally as it moves following this imaginary line
                        // the coordinates of these points (X, Y) go from 0 to 1
                        // where 0 is the start of the axis and 1 the end. Then to build our vertical gradient

                        // we must go from the point:
                        // (x0, y0) where x0 could be read as "the middle of the x axis" (0.5) and y0 as "the start of the y axis" (0)
                        new SKPoint(0.5f, 0),

                        // to the point:
                        // (x1, y1) where x1 could be read as "the middle of the x axis" (0.5) and y0 as "the end of the y axis" (1)
                        new SKPoint(0.5f, 1))
                },
                new LineSeries<int>
                {
                    Values = new []{ 4, 2, 8, 5, 3 },
                    GeometrySize = 22,
                    Stroke = new LinearGradientPaint(colors) { StrokeThickness = 10 },
                    GeometryStroke = new LinearGradientPaint(colors) { StrokeThickness = 10 },
                    Fill = null
                }
        };
    }

    public ISeries[] Series { get; set; }
}

XAML

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage x:Class="MauiSample.Design.LinearGradients.View"
             xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:lvc="clr-namespace:LiveChartsCore.SkiaSharpView.Maui;assembly=LiveChartsCore.SkiaSharpView.Maui"
             xmlns:vms="clr-namespace:ViewModelsSamples.Design.LinearGradients;assembly=ViewModelsSamples"
             >
    <ContentPage.BindingContext>
        <vms:ViewModel/>
    </ContentPage.BindingContext>
	<ContentPage.Content>
        <Grid>
            <Grid.RowDefinitions>
                <RowDefinition Height="*"/>
            </Grid.RowDefinitions>
            <lvc:CartesianChart Series="{Binding Series}" LegendPosition="Right"></lvc:CartesianChart>
        </Grid>
    </ContentPage.Content>
</ContentPage>