Gradient editor - WIP commit

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

@@ -0,0 +1,46 @@
+using System.ComponentModel;
+using System.Linq;
+using Artemis.Core.Models.Profile;
+using Stylet;
+
+namespace Artemis.UI.Shared.Screens.GradientEditor
+{
+    public class GradientEditorViewModel : Screen
+    {
+        public GradientEditorViewModel(ColorGradient colorGradient)
+        {
+            ColorGradient = colorGradient;
+            ColorStopViewModels = new BindableCollection<ColorStopViewModel>();
+
+            ColorGradient.PropertyChanged += ColorGradientOnPropertyChanged;
+            UpdateColorStopViewModels();
+        }
+        
+        public BindableCollection<ColorStopViewModel> ColorStopViewModels { get; set; }
+
+        public ColorGradient ColorGradient { get; }
+        public double PreviewWidth => 440;
+
+        private void ColorGradientOnPropertyChanged(object sender, PropertyChangedEventArgs e)
+        {
+            if (e.PropertyName == nameof(ColorGradient.Stops))
+                UpdateColorStopViewModels();
+        }
+
+        private void UpdateColorStopViewModels()
+        {
+            while (ColorGradient.Stops.Count > ColorStopViewModels.Count)
+                ColorStopViewModels.Add(new ColorStopViewModel(this));
+            while (ColorGradient.Stops.Count < ColorStopViewModels.Count)
+                ColorStopViewModels.RemoveAt(0);
+
+            var index = 0;
+            foreach (var colorStop in ColorGradient.Stops.OrderBy(s => s.Position))
+            {
+                var viewModel = ColorStopViewModels[index];
+                viewModel.Update(colorStop);
+                index++;
+            }
+        }
+    }
+}