Gradient editor - Initial implementation

src/Avalonia/Artemis.UI.Shared/Controls/GradientPicker/GradientPicker.cs

@@ -0,0 +1,135 @@
+using System;
+using System.Collections.Specialized;
+using System.Linq;
+using Artemis.Core;
+using Avalonia;
+using Avalonia.Controls.Primitives;
+using Avalonia.Data;
+using Avalonia.Input;
+using Avalonia.Media;
+
+namespace Artemis.UI.Shared.Controls.GradientPicker;
+
+public class GradientPicker : TemplatedControl
+{
+    private LinearGradientBrush _linearGradientBrush = new();
+
+    /// <summary>
+    ///     Gets or sets the color gradient.
+    /// </summary>
+    public static readonly StyledProperty<ColorGradient> ColorGradientProperty =
+        AvaloniaProperty.Register<GradientPicker, ColorGradient>(nameof(Core.ColorGradient), notifying: ColorGradientChanged, defaultValue: ColorGradient.GetUnicornBarf());
+
+    /// <summary>
+    ///     Gets or sets the currently selected color stop.
+    /// </summary>
+    public static readonly StyledProperty<ColorGradientStop?> SelectedColorStopProperty =
+        AvaloniaProperty.Register<GradientPicker, ColorGradientStop?>(nameof(SelectedColorStop), defaultBindingMode: BindingMode.TwoWay);
+
+    /// <summary>
+    /// Gets the linear gradient brush representing the color gradient.
+    /// </summary>
+    public static readonly DirectProperty<GradientPicker, LinearGradientBrush> LinearGradientBrushProperty =
+        AvaloniaProperty.RegisterDirect<GradientPicker, LinearGradientBrush>(nameof(LinearGradientBrush), g => g.LinearGradientBrush);
+
+    /// <summary>
+    ///     Gets or sets the color gradient.
+    /// </summary>
+    public ColorGradient ColorGradient
+    {
+        get => GetValue(ColorGradientProperty);
+        set => SetValue(ColorGradientProperty, value);
+    }
+
+    /// <summary>
+    ///     Gets or sets the currently selected color stop.
+    /// </summary>
+    public ColorGradientStop? SelectedColorStop
+    {
+        get => GetValue(SelectedColorStopProperty);
+        set => SetValue(SelectedColorStopProperty, value);
+    }
+
+    /// <summary>
+    /// Gets the linear gradient brush representing the color gradient.
+    /// </summary>
+    public LinearGradientBrush LinearGradientBrush
+    {
+        get => _linearGradientBrush;
+        private set => SetAndRaise(LinearGradientBrushProperty, ref _linearGradientBrush, value);
+    }
+
+    private static void ColorGradientChanged(IAvaloniaObject sender, bool before)
+    {
+        if (before)
+            (sender as GradientPicker)?.Unsubscribe();
+        else
+            (sender as GradientPicker)?.Subscribe();
+    }
+
+    private void Subscribe()
+    {
+        ColorGradient.CollectionChanged += ColorGradientOnCollectionChanged;
+        ColorGradient.StopChanged += ColorGradientOnStopChanged;
+
+        UpdateGradient();
+        SelectedColorStop = ColorGradient.FirstOrDefault();
+    }
+
+    private void Unsubscribe()
+    {
+        ColorGradient.CollectionChanged -= ColorGradientOnCollectionChanged;
+        ColorGradient.StopChanged -= ColorGradientOnStopChanged;
+    }
+
+    private void ColorGradientOnCollectionChanged(object? sender, NotifyCollectionChangedEventArgs e)
+    {
+        UpdateGradient();
+    }
+
+    private void ColorGradientOnStopChanged(object? sender, EventArgs e)
+    {
+        UpdateGradient();
+    }
+
+    private void UpdateGradient()
+    {
+        // Remove old stops
+
+        // ReSharper disable once ConditionIsAlwaysTrueOrFalse
+        if (ColorGradient == null)
+            return;
+
+        // Add new stops
+
+        // Update the display gradient
+        GradientStops collection = new();
+        foreach (ColorGradientStop c in ColorGradient.OrderBy(s => s.Position))
+            collection.Add(new GradientStop(Color.FromArgb(c.Color.Alpha, c.Color.Red, c.Color.Green, c.Color.Blue), c.Position));
+        LinearGradientBrush = new LinearGradientBrush {GradientStops = collection};
+    }
+
+    private void SelectColorStop(object? sender, PointerReleasedEventArgs e)
+    {
+        if (sender is IDataContextProvider dataContextProvider && dataContextProvider.DataContext is ColorGradientStop colorStop)
+            SelectedColorStop = colorStop;
+    }
+
+    #region Overrides of Visual
+
+    /// <inheritdoc />
+    protected override void OnAttachedToVisualTree(VisualTreeAttachmentEventArgs e)
+    {
+        Subscribe();
+        base.OnAttachedToVisualTree(e);
+    }
+
+    /// <inheritdoc />
+    protected override void OnDetachedFromVisualTree(VisualTreeAttachmentEventArgs e)
+    {
+        Unsubscribe();
+        base.OnDetachedFromVisualTree(e);
+    }
+
+    #endregion
+}

src/Avalonia/Artemis.UI.Shared/Controls/GradientPicker/GradientPickerColorStop.cs

@@ -0,0 +1,199 @@
+using System;
+using Artemis.Core;
+using Avalonia;
+using Avalonia.Controls;
+using Avalonia.Controls.Metadata;
+using Avalonia.Controls.Primitives;
+using Avalonia.Input;
+
+namespace Artemis.UI.Shared.Controls.GradientPicker;
+
+public class GradientPickerColorStop : TemplatedControl
+{
+    private static ColorGradientStop? _draggingStop;
+    private static IPointer? _dragPointer;
+
+    /// <summary>
+    ///     Gets or sets the gradient picker.
+    /// </summary>
+    public static readonly StyledProperty<GradientPicker?> GradientPickerProperty =
+        AvaloniaProperty.Register<GradientPickerColorStop, GradientPicker?>(nameof(GradientPicker), notifying: Notifying);
+
+    private static void Notifying(IAvaloniaObject sender, bool before)
+    {
+        if (sender is not GradientPickerColorStop self)
+            return;
+
+        if (before && self.GradientPicker != null)
+            self.GradientPicker.PropertyChanged -= self.GradientPickerOnPropertyChanged;
+        else if (self.GradientPicker != null)
+            self.GradientPicker.PropertyChanged += self.GradientPickerOnPropertyChanged;
+
+        self.IsSelected = self.GradientPicker?.SelectedColorStop == self.ColorStop;
+    }
+
+    /// <summary>
+    ///     Gets or sets the color stop.
+    /// </summary>
+    public static readonly StyledProperty<ColorGradientStop> ColorStopProperty =
+        AvaloniaProperty.Register<GradientPickerColorStop, ColorGradientStop>(nameof(ColorStop));
+
+    /// <summary>
+    ///     Gets or sets the position reference to use when positioning and dragging this color stop.
+    ///     <para>If <see langword="null" /> then dragging is not enabled.</para>
+    /// </summary>
+    public static readonly StyledProperty<IControl?> PositionReferenceProperty =
+        AvaloniaProperty.Register<GradientPickerColorStop, IControl?>(nameof(PositionReference));
+
+    /// <summary>
+    ///     Gets the linear gradient brush representing the color gradient.
+    /// </summary>
+    public static readonly DirectProperty<GradientPickerColorStop, bool> IsSelectedProperty =
+        AvaloniaProperty.RegisterDirect<GradientPickerColorStop, bool>(nameof(IsSelected), g => g.IsSelected);
+
+    private bool _isSelected;
+    private double _dragOffset;
+
+    /// <summary>
+    ///     Gets or sets the gradient picker.
+    /// </summary>
+    public GradientPicker? GradientPicker
+    {
+        get => GetValue(GradientPickerProperty);
+        set => SetValue(GradientPickerProperty, value);
+    }
+
+    /// <summary>
+    ///     Gets or sets the color stop.
+    /// </summary>
+    public ColorGradientStop ColorStop
+    {
+        get => GetValue(ColorStopProperty);
+        set => SetValue(ColorStopProperty, value);
+    }
+
+    /// <summary>
+    ///     Gets or sets the position reference to use when positioning and dragging this color stop.
+    ///     <para>If <see langword="null" /> then dragging is not enabled.</para>
+    /// </summary>
+    public IControl? PositionReference
+    {
+        get => GetValue(PositionReferenceProperty);
+        set => SetValue(PositionReferenceProperty, value);
+    }
+
+    /// <summary>
+    ///     Gets the linear gradient brush representing the color gradient.
+    /// </summary>
+    public bool IsSelected
+    {
+        get => _isSelected;
+        private set
+        {
+            SetAndRaise(IsSelectedProperty, ref _isSelected, value);
+            if (IsSelected)
+                PseudoClasses.Add(":selected");
+            else
+                PseudoClasses.Remove(":selected");
+        }
+    }
+
+    private void GradientPickerOnPropertyChanged(object? sender, AvaloniaPropertyChangedEventArgs e)
+    {
+        if (GradientPicker != null && e.Property == GradientPicker.SelectedColorStopProperty)
+        {
+            IsSelected = GradientPicker.SelectedColorStop == ColorStop;
+        }
+    }
+
+    private void OnPointerPressed(object? sender, PointerPressedEventArgs e)
+    {
+        if (!e.GetCurrentPoint(this).Properties.IsLeftButtonPressed || PositionReference == null)
+            return;
+
+        _dragOffset = e.GetCurrentPoint(PositionReference).Position.X - GetPixelPosition();
+        e.Pointer.Capture(this);
+
+        // Store these in case the control is being recreated due to an array resort
+        // it's a bit ugly but it gives us a way to pick up dragging again with the new control
+        _dragPointer = e.Pointer;
+        _draggingStop = ColorStop;
+        e.Handled = true;
+
+        if (GradientPicker != null)
+            GradientPicker.SelectedColorStop = ColorStop;
+    }
+
+    private void OnPointerMoved(object? sender, PointerEventArgs e)
+    {
+        if (!e.GetCurrentPoint(this).Properties.IsLeftButtonPressed || !ReferenceEquals(e.Pointer.Captured, this) || PositionReference == null)
+        {
+            if (_draggingStop != ColorStop)
+                return;
+
+            _dragOffset = e.GetCurrentPoint(PositionReference).Position.X - GetPixelPosition();
+        }
+
+        double position = e.GetCurrentPoint(PositionReference).Position.X - _dragOffset;
+        ColorStop.Position = MathF.Round((float) Math.Clamp(position / PositionReference.Bounds.Width, 0, 1), 3, MidpointRounding.AwayFromZero);
+        e.Handled = true;
+    }
+
+    private void OnPointerReleased(object? sender, PointerReleasedEventArgs e)
+    {
+        if (e.InitialPressMouseButton != MouseButton.Left)
+            return;
+
+        e.Pointer.Capture(null);
+        e.Handled = true;
+        _draggingStop = null;
+    }
+
+    private double GetPixelPosition()
+    {
+        if (PositionReference == null)
+            return 0;
+
+        return PositionReference.Bounds.Width * ColorStop.Position;
+    }
+
+    #region Overrides of Visual
+
+    /// <inheritdoc />
+    protected override void OnAttachedToVisualTree(VisualTreeAttachmentEventArgs e)
+    {
+        if (GradientPicker != null)
+            GradientPicker.PropertyChanged += GradientPickerOnPropertyChanged;
+
+        if (PositionReference != null)
+        {
+            PointerPressed += OnPointerPressed;
+            PointerMoved += OnPointerMoved;
+            PointerReleased += OnPointerReleased;
+
+            // If this stop was previously being dragged, carry on dragging again
+            // This can happen if the control was recreated due to an array sort
+            if (_draggingStop == ColorStop && _dragPointer != null)
+            {
+                _dragPointer.Capture(this);
+                IsSelected = true;
+            }
+        }
+
+        base.OnAttachedToVisualTree(e);
+    }
+
+    /// <inheritdoc />
+    protected override void OnDetachedFromVisualTree(VisualTreeAttachmentEventArgs e)
+    {
+        if (GradientPicker != null)
+            GradientPicker.PropertyChanged -= GradientPickerOnPropertyChanged;
+        PointerPressed -= OnPointerPressed;
+        PointerMoved -= OnPointerMoved;
+        PointerReleased -= OnPointerReleased;
+
+        base.OnDetachedFromVisualTree(e);
+    }
+
+    #endregion
+}

src/Avalonia/Artemis.UI.Shared/Converters/ColorGradientToGradientStopsConverter.cs

@@ -0,0 +1,41 @@
+using System;
+using System.Globalization;
+using System.Linq;
+using Artemis.Core;
+using Avalonia.Data.Converters;
+using Avalonia.Media;
+using SkiaSharp;
+
+namespace Artemis.UI.Shared.Converters;
+
+/// <summary>
+///     Converts  <see cref="T:Artemis.Core.ColorGradient" /> into a <see cref="T:Avalonia.Media.GradientStops" />.
+/// </summary>
+public class ColorGradientToGradientStopsConverter : IValueConverter
+{
+    /// <inheritdoc />
+    public object Convert(object? value, Type targetType, object? parameter, CultureInfo culture)
+    {
+        ColorGradient? colorGradient = value as ColorGradient;
+        GradientStops collection = new();
+        if (colorGradient == null)
+            return collection;
+
+        foreach (ColorGradientStop c in colorGradient.OrderBy(s => s.Position))
+            collection.Add(new GradientStop(Color.FromArgb(c.Color.Alpha, c.Color.Red, c.Color.Green, c.Color.Blue), c.Position));
+        return collection;
+    }
+
+    /// <inheritdoc />
+    public object ConvertBack(object? value, Type targetType, object? parameter, CultureInfo culture)
+    {
+        GradientStops? collection = value as GradientStops;
+        ColorGradient colorGradients = new();
+        if (collection == null)
+            return colorGradients;
+
+        foreach (GradientStop c in collection.OrderBy(s => s.Offset))
+            colorGradients.Add(new ColorGradientStop(new SKColor(c.Color.R, c.Color.G, c.Color.B, c.Color.A), (float) c.Offset));
+        return colorGradients;
+    }
+}

src/Avalonia/Artemis.UI.Shared/Converters/ParentWidthPercentageConverter.cs

@@ -0,0 +1,34 @@
+using System;
+using System.Globalization;
+using Avalonia.Controls;
+using Avalonia.Data.Converters;
+
+namespace Artemis.UI.Shared.Converters;
+
+/// <summary>
+///     Converts the width in percentage to a real number based on the width of the given parent
+/// </summary>
+public class ParentWidthPercentageConverter : IValueConverter
+{
+    #region Implementation of IValueConverter
+
+    /// <inheritdoc />
+    public object? Convert(object? value, Type targetType, object? parameter, CultureInfo culture)
+    {
+        if (parameter is not IControl parent || value is not double percentage)
+            return value;
+
+        return parent.Width / 100.0 * percentage;
+    }
+
+    /// <inheritdoc />
+    public object? ConvertBack(object? value, Type targetType, object? parameter, CultureInfo culture)
+    {
+        if (parameter is not IControl parent || value is not double real)
+            return value;
+
+        return real / parent.Width * 100.0;
+    }
+
+    #endregion
+}

src/Avalonia/Artemis.UI.Shared/Converters/SKColorToStringConverter.cs

@@ -3,7 +3,7 @@ using System.Globalization;
 using Avalonia.Data.Converters;
 using SkiaSharp;
 
-namespace Artemis.UI.Converters;
+namespace Artemis.UI.Shared.Converters;
 
 /// <inheritdoc />
 /// <summary>

src/Avalonia/Artemis.UI.Shared/Converters/WidthNormalizedConverter.cs

@@ -0,0 +1,29 @@
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.Linq;
+using Avalonia.Controls;
+using Avalonia.Data.Converters;
+
+namespace Artemis.UI.Shared.Converters;
+
+/// <summary>
+///     Converts the width in percentage to a real number based on the width of the given parent
+/// </summary>
+public class WidthNormalizedConverter : IMultiValueConverter
+{
+    #region Implementation of IMultiValueConverter
+
+    /// <inheritdoc />
+    public object? Convert(IList<object?> values, Type targetType, object? parameter, CultureInfo culture)
+    {
+        object? first = values.FirstOrDefault();
+        object? second = values.Skip(1).FirstOrDefault();
+        if (first is float value && second is double totalWidth)
+            return (totalWidth / 1.0) * value;
+
+        return 0.0;
+    }
+
+    #endregion
+}

src/Avalonia/Artemis.UI.Shared/Services/GradientPickerService.cs

@@ -0,0 +1,11 @@
+using Artemis.UI.Shared.Services.Interfaces;
+
+namespace Artemis.UI.Shared.Services;
+
+public class GradientPickerService : IGradientPickerService
+{
+}
+
+public interface IGradientPickerService : IArtemisSharedUIService
+{
+}

src/Avalonia/Artemis.UI.Shared/Styles/Artemis.axaml

@@ -32,6 +32,8 @@
     <StyleInclude Source="/Styles/NumberBox.axaml" />
     <StyleInclude Source="/Styles/TreeView.axaml" />
 
+    <StyleInclude Source="/Styles/Controls/GradientPicker.axaml" />
+
     <Style Selector="Window:windows:windows10 /template/ Border#RootBorder">
         <!-- This will show if custom accent color setting is used in Settings page-->
         <Setter Property="BorderBrush" Value="{DynamicResource SystemAccentColor}" />

src/Avalonia/Artemis.UI.Shared/Styles/Controls/GradientPicker.axaml

@@ -0,0 +1,192 @@
+<Styles xmlns="https://github.com/avaloniaui"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        xmlns:controls="using:Artemis.UI.Shared.Controls.GradientPicker"
+        xmlns:avalonia="clr-namespace:Material.Icons.Avalonia;assembly=Material.Icons.Avalonia"
+        xmlns:core="clr-namespace:Artemis.Core;assembly=Artemis.Core"
+        xmlns:controls1="clr-namespace:FluentAvalonia.UI.Controls;assembly=FluentAvalonia"
+        xmlns:converters="clr-namespace:Artemis.UI.Shared.Converters">
+    <Design.PreviewWith>
+        <controls:GradientPicker Width="800" />
+    </Design.PreviewWith>
+
+    <Style Selector="controls|GradientPickerColorStop /template/ Border.stop-handle">
+        <Setter Property="CornerRadius" Value="18" />
+        <Setter Property="Width" Value="18" />
+        <Setter Property="Height" Value="60" />
+        <Setter Property="Margin" Value="-9 -10 0 0"></Setter>
+        <Setter Property="BorderThickness" Value="2" />
+        <Setter Property="BorderBrush" Value="{DynamicResource SolidBackgroundFillColorSecondaryBrush}" />
+        <Setter Property="Cursor" Value="Hand" />
+    </Style>
+    <Style Selector="controls|GradientPickerColorStop /template/ Border.stop-handle > Border">
+        <Setter Property="CornerRadius" Value="18" />
+        <Setter Property="BorderThickness" Value="2" />
+        <Setter Property="BorderBrush" Value="{DynamicResource SolidBackgroundFillColorQuarternaryBrush}" />
+    </Style>
+    <Style Selector="controls|GradientPickerColorStop /template/ Border.stop-handle > Border > Border">
+        <Setter Property="CornerRadius" Value="18" />
+        <Setter Property="BorderThickness" Value="2" />
+        <Setter Property="BorderBrush" Value="{DynamicResource SolidBackgroundFillColorSecondaryBrush}" />
+    </Style>
+
+    <Style Selector="controls|GradientPickerColorStop:selected /template/ Border.stop-handle > Border">
+        <Setter Property="BorderBrush" Value="{DynamicResource SystemAccentColorLight2}" />
+    </Style>
+
+    <Style Selector="Border.stop-position">
+        <Setter Property="Background" Value="{DynamicResource SolidBackgroundFillColorBaseBrush}" />
+        <Setter Property="BorderBrush" Value="{DynamicResource ButtonBorderBrush}" />
+        <Setter Property="BorderThickness" Value="1" />
+        <Setter Property="Width" Value="40" />
+        <Setter Property="Height" Value="30" />
+        <Setter Property="Margin" Value="-20 -15 0 0"></Setter>
+        <Setter Property="CornerRadius" Value="{DynamicResource ControlCornerRadius}" />
+    </Style>
+
+    <Style Selector="Border.stop-position TextBlock">
+        <Setter Property="VerticalAlignment" Value="Center" />
+        <Setter Property="HorizontalAlignment" Value="Center" />
+    </Style>
+
+    <Style Selector="controls|GradientPicker">
+        <Style.Resources>
+            <converters:ColorGradientToGradientStopsConverter x:Key="ColorGradientToGradientStopsConverter" />
+            <converters:SKColorToColorConverter x:Key="SKColorToColorConverter" />
+            <converters:SKColorToStringConverter x:Key="SKColorToStringConverter" />
+            <converters:WidthNormalizedConverter x:Key="WidthNormalizedConverter" />
+        </Style.Resources>
+        <Setter Property="Template">
+            <ControlTemplate>
+                <Grid>
+                    <Border Name="Background" Background="{TemplateBinding LinearGradientBrush}" />
+                    <Border Classes="card" Margin="20" Padding="20" Background="{DynamicResource SolidBackgroundFillColorBaseBrush}">
+                        <Grid RowDefinitions="Auto,Auto,*" ColumnDefinitions="Auto,*">
+                            <Border Name="Gradient" Grid.Row="0" Grid.ColumnSpan="2" Height="40" CornerRadius="4" Background="{TemplateBinding LinearGradientBrush}">
+                                <ItemsControl Items="{TemplateBinding ColorGradient}" ClipToBounds="False">
+                                    <ItemsControl.Styles>
+                                        <Style Selector="ContentPresenter">
+                                            <Setter Property="Canvas.Left">
+                                                <Setter.Value>
+                                                    <MultiBinding Converter="{StaticResource WidthNormalizedConverter}">
+                                                        <Binding Path="Position" />
+                                                        <Binding Path="Bounds.Width" ElementName="Gradient" />
+                                                    </MultiBinding>
+                                                </Setter.Value>
+                                            </Setter>
+                                        </Style>
+                                    </ItemsControl.Styles>
+                                    <ItemsControl.ItemTemplate>
+                                        <DataTemplate DataType="core:ColorGradientStop">
+                                            <controls:GradientPickerColorStop ColorStop="{Binding}"
+                                                                              GradientPicker="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type controls:GradientPicker}}}"
+                                                                              PositionReference="{Binding $parent[Border]}">
+                                                <controls:GradientPickerColorStop.Styles>
+                                                    <Style Selector="controls|GradientPickerColorStop">
+                                                        <Setter Property="ClipToBounds" Value="False"></Setter>
+                                                        <Setter Property="Template">
+                                                            <ControlTemplate>
+                                                                <Border Classes="stop-handle">
+                                                                    <Border>
+                                                                        <Border>
+                                                                            <Border.Background>
+                                                                                <SolidColorBrush Color="{CompiledBinding Color, Converter={StaticResource SKColorToColorConverter}}" />
+                                                                            </Border.Background>
+                                                                        </Border>
+                                                                    </Border>
+                                                                </Border>
+                                                            </ControlTemplate>
+                                                        </Setter>
+                                                    </Style>
+                                                </controls:GradientPickerColorStop.Styles>
+                                            </controls:GradientPickerColorStop>
+                                        </DataTemplate>
+                                    </ItemsControl.ItemTemplate>
+                                    <ItemsControl.ItemsPanel>
+                                        <ItemsPanelTemplate>
+                                            <Canvas />
+                                        </ItemsPanelTemplate>
+                                    </ItemsControl.ItemsPanel>
+                                </ItemsControl>
+                            </Border>
+
+                            <Border Grid.Row="1"
+                                    Grid.Column="0"
+                                    Grid.ColumnSpan="2"
+                                    BorderBrush="{DynamicResource ButtonBorderBrush}"
+                                    BorderThickness="0 0 0 1"
+                                    Margin="-20 30"
+                                    Height="2"
+                                    VerticalAlignment="Center">
+                            </Border>
+
+                            <ItemsControl Grid.Row="1"
+                                          Grid.Column="0"
+                                          Grid.ColumnSpan="2"
+                                          VerticalAlignment="Center"
+                                          Items="{TemplateBinding ColorGradient}"
+                                          ClipToBounds="False">
+                                <ItemsControl.Styles>
+                                    <Style Selector="ContentPresenter">
+                                        <Setter Property="Canvas.Left">
+                                            <Setter.Value>
+                                                <MultiBinding Converter="{StaticResource WidthNormalizedConverter}">
+                                                    <Binding Path="Position" />
+                                                    <Binding Path="Bounds.Width" ElementName="Gradient" />
+                                                </MultiBinding>
+                                            </Setter.Value>
+                                        </Setter>
+                                    </Style>
+                                </ItemsControl.Styles>
+                                <ItemsControl.ItemTemplate>
+                                    <DataTemplate DataType="core:ColorGradientStop">
+                                        <Border Classes="stop-position">
+                                            <TextBlock Text="{Binding Position}"></TextBlock>
+                                        </Border>
+                                    </DataTemplate>
+                                </ItemsControl.ItemTemplate>
+                                <ItemsControl.ItemsPanel>
+                                    <ItemsPanelTemplate>
+                                        <Canvas />
+                                    </ItemsPanelTemplate>
+                                </ItemsControl.ItemsPanel>
+                            </ItemsControl>
+
+                            <controls1:ColorPicker Grid.Row="2" Grid.Column="0"
+                                                   ColorTextType="HexAlpha"
+                                                   UseColorWheel="True"
+                                                   UseColorTriangle="True"
+                                                   IsMoreButtonVisible="True"
+                                                   IsCompact="True"
+                                                   IsVisible="{TemplateBinding SelectedColorStop, Converter={x:Static ObjectConverters.IsNotNull}}"
+                                                   Color="{Binding SelectedColorStop.Color, RelativeSource={RelativeSource TemplatedParent}, Converter={StaticResource SKColorToColorConverter}}" />
+
+                            <ListBox Grid.Row="2"
+                                     Grid.Column="1"
+                                     BorderBrush="{DynamicResource ButtonBorderBrush}"
+                                     Items="{TemplateBinding ColorGradient}"
+                                     BorderThickness="1 0 0 0"
+                                     Margin="10 0 0 0">
+                                <ListBox.ItemTemplate>
+                                    <DataTemplate DataType="core:ColorGradientStop">
+                                        <Grid VerticalAlignment="Center" ColumnDefinitions="34,*,Auto,Auto">
+                                            <Border Grid.Column="0" Width="28" Height="28" CornerRadius="4" HorizontalAlignment="Left">
+                                                <Border.Background>
+                                                    <SolidColorBrush Color="{Binding Color, Converter={StaticResource SKColorToColorConverter}}"></SolidColorBrush>
+                                                </Border.Background>
+                                            </Border>
+                                            <TextBox Grid.Column="1" Text="{Binding Color, Converter={StaticResource SKColorToStringConverter}}"></TextBox>
+                                            <NumericUpDown Grid.Column="2" Value="{Binding Position}" FormatString="F3" ShowButtonSpinner="False" Margin="5 0"></NumericUpDown>
+                                            <Button Grid.Column="3" Classes="icon-button">
+                                                <avalonia:MaterialIcon Kind="Close"></avalonia:MaterialIcon>
+                                            </Button>
+                                        </Grid>
+                                    </DataTemplate>
+                                </ListBox.ItemTemplate>
+                            </ListBox>
+                        </Grid>
+                    </Border>
+                </Grid>
+            </ControlTemplate>
+        </Setter>
+    </Style>
+</Styles>

src/Avalonia/Artemis.UI/DefaultTypes/PropertyInput/SKColorPropertyInputView.axaml

@@ -5,6 +5,7 @@
              xmlns:controls="clr-namespace:FluentAvalonia.UI.Controls;assembly=FluentAvalonia"
              xmlns:converters="clr-namespace:Artemis.UI.Converters"
              xmlns:propertyInput="clr-namespace:Artemis.UI.DefaultTypes.PropertyInput"
+             xmlns:shared="clr-namespace:Artemis.UI.Shared.Converters;assembly=Artemis.UI.Shared"
              mc:Ignorable="d" d:DesignWidth="200" d:DesignHeight="450"
              x:Class="Artemis.UI.DefaultTypes.PropertyInput.SKColorPropertyInputView"
              x:DataType="propertyInput:SKColorPropertyInputViewModel">
@@ -44,7 +45,7 @@
         </Style>
     </UserControl.Styles>
     <UserControl.Resources>
-        <converters:SKColorToStringConverter x:Key="SKColorToStringConverter" />
+        <shared:SKColorToStringConverter x:Key="SKColorToStringConverter" />
         <converters:SKColorToColor2Converter x:Key="SKColorToColor2Converter" />
     </UserControl.Resources>
     <Grid Height="24" ColumnDefinitions="*">

src/Avalonia/Artemis.UI/Screens/Workshop/WorkshopView.axaml

@@ -7,6 +7,7 @@
              xmlns:controls1="clr-namespace:FluentAvalonia.UI.Controls;assembly=FluentAvalonia"
              xmlns:attachedProperties="clr-namespace:Artemis.UI.Shared.AttachedProperties;assembly=Artemis.UI.Shared"
              xmlns:workshop="clr-namespace:Artemis.UI.Screens.Workshop"
+             xmlns:gradientPicker="clr-namespace:Artemis.UI.Shared.Controls.GradientPicker;assembly=Artemis.UI.Shared"
              mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
              x:Class="Artemis.UI.Screens.Workshop.WorkshopView"
              x:DataType="workshop:WorkshopViewModel">
@@ -45,6 +46,8 @@
                         </Border>
                         <controls:EnumComboBox Value="{CompiledBinding SelectedCursor}"></controls:EnumComboBox>
                     </StackPanel>
+
+                    <gradientPicker:GradientPicker ColorGradient="{CompiledBinding ColorGradient}"></gradientPicker:GradientPicker>
                 </StackPanel>
             </Border>
         </StackPanel>

src/Avalonia/Artemis.UI/Screens/Workshop/WorkshopViewModel.cs

@@ -1,5 +1,6 @@
 using System.Reactive;
 using System.Reactive.Linq;
+using Artemis.Core;
 using Artemis.UI.Shared.Services.Builders;
 using Artemis.UI.Shared.Services.Interfaces;
 using Avalonia.Input;
@@ -32,6 +33,8 @@ namespace Artemis.UI.Screens.Workshop
 
         public Cursor Cursor => _cursor.Value;
 
+        public ColorGradient ColorGradient { get; set; } = ColorGradient.GetUnicornBarf();
+
         private void ExecuteShowNotification(NotificationSeverity severity)
         {
             _notificationService.CreateNotification().WithTitle("Test title").WithMessage("Test message").WithSeverity(severity).Show();