Added layer shapes, editor is still WIP

src/Artemis.Core/Plugins/LayerBrush/LayerBrush.cs

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+using System;
+using Artemis.Core.Models.Profile;
+using SkiaSharp;
+
+namespace Artemis.Core.Plugins.LayerBrush
+{
+    public abstract class LayerBrush : IDisposable
+    {
+        protected LayerBrush(Layer layer, LayerBrushSettings settings, LayerBrushDescriptor descriptor)
+        {
+            Layer = layer;
+            Settings = settings;
+            Descriptor = descriptor;
+        }
+
+        public Layer Layer { get; }
+        public LayerBrushSettings Settings { get; }
+        public LayerBrushDescriptor Descriptor { get; }
+
+        public virtual void Dispose()
+        {
+        }
+
+        /// <summary>
+        ///     Called by the profile editor to populate the brush properties panel
+        /// </summary>
+        /// <returns></returns>
+        public abstract LayerBrushViewModel GetViewModel();
+
+        /// <summary>
+        ///     Called before rendering every frame, write your update logic here
+        /// </summary>
+        /// <param name="deltaTime"></param>
+        public virtual void Update(double deltaTime)
+        {
+        }
+
+        /// <summary>
+        ///     The main method of rendering anything to the layer. The provided <see cref="SKCanvas" /> is specific to the layer
+        ///     and matches it's width and height.
+        ///     <para>Called during rendering, in the order configured on the layer</para>
+        /// </summary>
+        /// <param name="canvas">The layer canvas</param>
+        public virtual void Render(SKCanvas canvas)
+        {
+        }
+    }
+}

src/Artemis.Core/Plugins/LayerBrush/LayerBrushDescriptor.cs

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+using System;
+
+namespace Artemis.Core.Plugins.LayerBrush
+{
+    public class LayerBrushDescriptor
+    {
+        internal LayerBrushDescriptor(string displayName, string description, string icon, Type layerBrushType, LayerBrushProvider layerBrushProvider)
+        {
+            DisplayName = displayName;
+            Description = description;
+            Icon = icon;
+            LayerBrushType = layerBrushType;
+            LayerBrushProvider = layerBrushProvider;
+        }
+
+        public string DisplayName { get; }
+        public string Description { get; }
+        public string Icon { get; }
+        public Type LayerBrushType { get; }
+        public LayerBrushProvider LayerBrushProvider { get; }
+    }
+}

src/Artemis.Core/Plugins/LayerBrush/LayerBrushProvider.cs

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+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using Artemis.Core.Plugins.Abstract;
+using Artemis.Core.Plugins.Models;
+
+namespace Artemis.Core.Plugins.LayerBrush
+{
+    /// <inheritdoc />
+    /// <summary>
+    ///     Allows you to create one or more <see cref="LayerBrush" />s usable by profile layers.
+    /// </summary>
+    public abstract class LayerBrushProvider : Plugin
+    {
+        private readonly List<LayerBrushDescriptor> _layerBrushDescriptors;
+
+        protected LayerBrushProvider(PluginInfo pluginInfo) : base(pluginInfo)
+        {
+            _layerBrushDescriptors = new List<LayerBrushDescriptor>();
+        }
+
+        public ReadOnlyCollection<LayerBrushDescriptor> LayerBrushDescriptors => _layerBrushDescriptors.AsReadOnly();
+
+        protected void AddLayerBrushDescriptor<T>(string displayName, string description, string icon) where T : LayerBrush
+        {
+            _layerBrushDescriptors.Add(new LayerBrushDescriptor(displayName, description, icon, typeof(T), this));
+        }
+    }
+}

src/Artemis.Core/Plugins/LayerBrush/LayerBrushSettings.cs

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+using System;
+using Stylet;
+
+namespace Artemis.Core.Plugins.LayerBrush
+{
+    public abstract class LayerBrushSettings : PropertyChangedBase
+    {
+        private Action<Action> _propertyChangedDispatcher = Execute.DefaultPropertyChangedDispatcher;
+
+        /// <summary>
+        /// Gets or sets the dispatcher to use to dispatch PropertyChanged events. Defaults to Execute.DefaultPropertyChangedDispatcher
+        /// </summary>
+        [System.Xml.Serialization.XmlIgnore]
+        [Newtonsoft.Json.JsonIgnore]
+        public override Action<Action> PropertyChangedDispatcher
+        {
+            get { return this._propertyChangedDispatcher; }
+            set { this._propertyChangedDispatcher = value; }
+        }
+    }
+}

src/Artemis.Core/Plugins/LayerBrush/LayerBrushViewModel.cs

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+using Stylet;
+
+namespace Artemis.Core.Plugins.LayerBrush
+{
+    public abstract class LayerBrushViewModel : PropertyChangedBase
+    {
+        protected LayerBrushViewModel(LayerBrush brush)
+        {
+            Brush = brush;
+        }
+
+        public LayerBrush Brush { get; }
+    }
+}