UI - Added reusable device visualizer

Settings - Show device LED images in settings
Editor - Improved performance on big surfaces

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

@@ -0,0 +1,83 @@
+using System;
+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.Services.Interfaces;
+
+namespace Artemis.UI.Shared.Controls
+{
+    /// <summary>
+    ///     Interaction logic for GradientPicker.xaml
+    /// </summary>
+    public partial class GradientPicker : UserControl, INotifyPropertyChanged
+    {
+        private static IGradientPickerService _gradientPickerService;
+        private bool _inCallback;
+
+        public GradientPicker()
+        {
+            InitializeComponent();
+        }
+
+        /// <summary>
+        ///     Used by the gradient picker to load saved gradients, do not touch or it'll just throw an exception
+        /// </summary>
+        public static IGradientPickerService GradientPickerService
+        {
+            private get => _gradientPickerService;
+            set
+            {
+                if (_gradientPickerService != null)
+                    throw new AccessViolationException("This is not for you to touch");
+                _gradientPickerService = value;
+            }
+        }
+
+        /// <summary>
+        ///     Gets or sets the currently selected color gradient
+        /// </summary>
+        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 gradientPicker = (GradientPicker) d;
+            if (gradientPicker._inCallback)
+                return;
+
+            gradientPicker._inCallback = true;
+            gradientPicker.OnPropertyChanged(nameof(ColorGradient));
+            gradientPicker._inCallback = false;
+        }
+
+        private void UIElement_OnMouseUp(object sender, MouseButtonEventArgs e)
+        {
+            GradientPickerService.ShowGradientPicker(ColorGradient);
+        }
+
+        #region Static WPF fields
+
+        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));
+
+        #endregion
+    }
+}