Core - Added ColorGradient type to use for.. gradients!

Core - Initialisation process no longer takes place in core constructor and is no longer async
UI - Fixed exceptions during init not being shown
Gradient editor - Started work on this

src/Artemis.UI.Shared/Artemis.UI.Shared.csproj

@@ -43,6 +43,16 @@
   <ItemGroup>
     <None Remove="Resources\Fonts\RobotoMono-Regular.ttf" />
   </ItemGroup>
+  <ItemGroup>
+    <ProjectReference Include="..\Artemis.Core\Artemis.Core.csproj">
+      <Private>false</Private>
+    </ProjectReference>
+  </ItemGroup>
+  <ItemGroup>
+    <Reference Include="MaterialDesignExtensions">
+      <HintPath>..\..\..\..\.nuget\materialdesignextensions\3.0.0\lib\netcoreapp3.0\MaterialDesignExtensions.dll</HintPath>
+    </Reference>
+  </ItemGroup>
   <ItemGroup>
     <Resource Include="Resources\Fonts\RobotoMono-Regular.ttf" />
   </ItemGroup>

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

@@ -0,0 +1,42 @@
+using System;
+using System.Globalization;
+using System.Windows.Data;
+using System.Windows.Media;
+using Artemis.Core.Models.Profile;
+using SkiaSharp;
+
+namespace Artemis.UI.Shared.Converters
+{
+    /// <inheritdoc />
+    /// <summary>
+    ///     Converts  <see cref="T:Artemis.Core.Models.Profile.ColorGradient" /> into a
+    ///     <see cref="T:System.Windows.Media.GradientStopCollection" />.
+    /// </summary>
+    [ValueConversion(typeof(ColorGradient), typeof(GradientStopCollection))]
+    public class ColorGradientToGradientStopsConverter : IValueConverter
+    {
+        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
+        {
+            var colorGradient = (ColorGradient) value;
+            var collection = new GradientStopCollection();
+            if (colorGradient == null)
+                return collection;
+
+            foreach (var c in colorGradient.Colors)
+                collection.Add(new GradientStop(Color.FromArgb(c.Color.Alpha, c.Color.Red, c.Color.Green, c.Color.Blue), c.Position));
+            return collection;
+        }
+
+        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
+        {
+            var collection = (GradientStopCollection) value;
+            var colorGradient = new ColorGradient();
+            if (collection == null)
+                return colorGradient;
+
+            foreach (var c in collection)
+                colorGradient.Colors.Add(new ColorGradientColor(new SKColor(c.Color.R, c.Color.G, c.Color.B, c.Color.A), (float) c.Offset));
+            return colorGradient;
+        }
+    }
+}

src/Artemis.UI.Shared/Converters/ColorToSKColorConverter.cs

@@ -8,7 +8,7 @@ namespace Artemis.UI.Shared.Converters
 {
     /// <inheritdoc />
     /// <summary>
-    ///     Converts  <see cref="T:SkiaSharp.SKColor" /> into a <see cref="T:System.Windows.Media.Color" />.
+    ///     Converts <see cref="T:SkiaSharp.SKColor" /> into a <see cref="T:System.Windows.Media.Color" />.
     /// </summary>
     [ValueConversion(typeof(Color), typeof(SKColor))]
     public class SKColorToColorConverter : IValueConverter

src/Artemis.UI.Shared/GradientPicker.xaml

@@ -0,0 +1,51 @@
+<UserControl x:Class="Artemis.UI.Shared.GradientPicker"
+             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+             xmlns:local="clr-namespace:Artemis.UI.Shared"
+             xmlns:converters="clr-namespace:Artemis.UI.Shared.Converters"
+             mc:Ignorable="d"
+             d:DesignHeight="450" d:DesignWidth="800">
+    <UserControl.Resources>
+        <ResourceDictionary>
+            <ResourceDictionary.MergedDictionaries>
+                <ResourceDictionary Source="pack://application:,,,/MaterialDesignThemes.Wpf;component/Themes/MaterialDesignTheme.ColorPicker.xaml" />
+                <ResourceDictionary Source="pack://application:,,,/MaterialDesignThemes.Wpf;component/Themes/MaterialDesignTheme.Defaults.xaml" />
+            </ResourceDictionary.MergedDictionaries>
+            <converters:ColorGradientToGradientStopsConverter x:Key="ColorGradientToGradientStopsConverter" />
+            <VisualBrush x:Key="Checkerboard" TileMode="Tile" Stretch="Uniform" ViewportUnits="Absolute" Viewport="0,0,10,10">
+                <VisualBrush.Visual>
+                    <Grid Width="10" Height="10">
+                        <Grid.RowDefinitions>
+                            <RowDefinition />
+                            <RowDefinition />
+                        </Grid.RowDefinitions>
+                        <Grid.ColumnDefinitions>
+                            <ColumnDefinition />
+                            <ColumnDefinition />
+                        </Grid.ColumnDefinitions>
+                        <Rectangle Grid.Row="0" Grid.Column="0" Fill="Gray" />
+                        <Rectangle Grid.Row="0" Grid.Column="1" Fill="White" />
+                        <Rectangle Grid.Row="1" Grid.Column="0" Fill="White" />
+                        <Rectangle Grid.Row="1" Grid.Column="1" Fill="Gray" />
+                    </Grid>
+                </VisualBrush.Visual>
+            </VisualBrush>
+        </ResourceDictionary>
+    </UserControl.Resources>
+
+    <Border Height="15"
+            CornerRadius="5"
+            Margin="0,0,0,2"
+            HorizontalAlignment="Stretch"
+            Background="{StaticResource Checkerboard}">
+        <Ellipse Stroke="{DynamicResource NormalBorderBrush}" Cursor="Hand" MouseUp="UIElement_OnMouseUp">
+            <Ellipse.Fill>
+                <LinearGradientBrush
+                    GradientStops="{Binding ColorGradient, Mode=OneWay, RelativeSource={RelativeSource AncestorType={x:Type UserControl}}, Converter={StaticResource ColorGradientToGradientStopsConverter}}" />
+            </Ellipse.Fill>
+        </Ellipse>
+    </Border>
+
+</UserControl>

src/Artemis.UI.Shared/GradientPicker.xaml.cs

@@ -0,0 +1,65 @@
+using System.ComponentModel;
+using System.Runtime.CompilerServices;
+using System.Windows;
+using System.Windows.Controls;
+using System.Windows.Input;
+using Artemis.Core.Models.Profile;
+using Artemis.UI.Shared.Annotations;
+using Artemis.UI.Shared.Screens.GradientEditor;
+
+namespace Artemis.UI.Shared
+{
+    /// <summary>
+    ///     Interaction logic for GradientPicker.xaml
+    /// </summary>
+    public partial class GradientPicker : UserControl, INotifyPropertyChanged
+    {
+        public static readonly DependencyProperty ColorGradientProperty = DependencyProperty.Register(nameof(ColorGradient), typeof(ColorGradient), typeof(GradientPicker),
+            new FrameworkPropertyMetadata(default(ColorGradient), FrameworkPropertyMetadataOptions.BindsTwoWayByDefault, ColorGradientPropertyChangedCallback));
+
+        public static readonly RoutedEvent ColorGradientChangedEvent =
+            EventManager.RegisterRoutedEvent(
+                nameof(ColorGradient),
+                RoutingStrategy.Bubble,
+                typeof(RoutedPropertyChangedEventHandler<ColorGradient>),
+                typeof(GradientPicker));
+
+        private bool _inCallback;
+
+        public GradientPicker()
+        {
+            InitializeComponent();
+        }
+
+        public ColorGradient ColorGradient
+        {
+            get => (ColorGradient) GetValue(ColorGradientProperty);
+            set => SetValue(ColorGradientProperty, value);
+        }
+
+        public event PropertyChangedEventHandler PropertyChanged;
+
+        [NotifyPropertyChangedInvocator]
+        protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
+        {
+            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
+        }
+
+        private static void ColorGradientPropertyChangedCallback(DependencyObject d, DependencyPropertyChangedEventArgs e)
+        {
+            var colorPicker = (GradientPicker) d;
+            if (colorPicker._inCallback)
+                return;
+
+            colorPicker._inCallback = true;
+            colorPicker.OnPropertyChanged(nameof(ColorGradient));
+            colorPicker._inCallback = false;
+        }
+
+        private void UIElement_OnMouseUp(object sender, MouseButtonEventArgs e)
+        {
+            var gradientEditor = new GradientEditor(ColorGradientProperty);
+            gradientEditor.ShowDialog();
+        }
+    }
+}

src/Artemis.UI.Shared/Screens/GradientEditor/GradientEditor.xaml

@@ -0,0 +1,24 @@
+<controls:MaterialWindow x:Class="Artemis.UI.Shared.Screens.GradientEditor.GradientEditor"
+                         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+                         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+                         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+                         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+                         xmlns:local="clr-namespace:Artemis.UI.Shared.Screens.GradientEditor"
+                         xmlns:controls="clr-namespace:MaterialDesignExtensions.Controls;assembly=MaterialDesignExtensions"
+                         xmlns:s="https://github.com/canton7/Stylet"
+                         xmlns:materialDesign="http://materialdesigninxaml.net/winfx/xaml/themes"
+                         mc:Ignorable="d"
+                         Title="Gradient Editor"
+                         Background="{DynamicResource MaterialDesignPaper}"
+                         FontFamily="pack://application:,,,/MaterialDesignThemes.Wpf;component/Resources/Roboto/#Roboto"
+                         UseLayoutRounding="True"
+                         Width="800"
+                         Height="450"
+                         ResizeMode="NoResize"
+                         Icon="/Resources/Images/Logo/logo-512.png"
+                         d:DesignHeight="450"
+                         d:DesignWidth="800">
+    <Grid>
+
+    </Grid>
+</controls:MaterialWindow>

src/Artemis.UI.Shared/Screens/GradientEditor/GradientEditor.xaml.cs

@@ -0,0 +1,26 @@
+using System.Windows;
+using Artemis.Core.Models.Profile;
+using MaterialDesignExtensions.Controls;
+
+namespace Artemis.UI.Shared.Screens.GradientEditor
+{
+    /// <summary>
+    ///     Interaction logic for GradientEditor.xaml
+    /// </summary>
+    public partial class GradientEditor : MaterialWindow
+    {
+        public GradientEditor(DependencyProperty colorGradientProperty)
+        {
+            ColorGradientProperty = colorGradientProperty;
+            InitializeComponent();
+        }
+
+        public DependencyProperty ColorGradientProperty { get; }
+
+        public ColorGradient ColorGradient
+        {
+            get => (ColorGradient) GetValue(ColorGradientProperty);
+            set => SetValue(ColorGradientProperty, value);
+        }
+    }
+}