feat: Implement InkCanvas and InkPresenter controls

UI/Controls/Ink/DrawingAttributes.cs

@@ -0,0 +1,11 @@
+using System.Windows.Media;
+
+namespace InkkSlinger.UI.Controls.Ink
+{
+    public class DrawingAttributes
+    {
+        public Color Color { get; set; } = Colors.Black;
+        public double Width { get; set; } = 2.0;
+        public double Height { get; set; } = 2.0;
+    }
+}

UI/Controls/Ink/InkCanvas.cs

@@ -0,0 +1,74 @@
+using System;
+using System.Collections.Generic;
+using System.Windows;
+using System.Windows.Controls;
+using System.Windows.Input;
+using System.Windows.Media;
+
+namespace InkkSlinger.UI.Controls.Ink
+{
+    public class InkCanvas : FrameworkElement
+    {
+        public static readonly DependencyProperty StrokesProperty =
+            DependencyProperty.Register(nameof(Strokes), typeof(StrokeCollection), typeof(InkCanvas),
+                new FrameworkPropertyMetadata(new StrokeCollection(), FrameworkPropertyMetadataOptions.AffectsRender));
+
+        public static readonly DependencyProperty DefaultDrawingAttributesProperty =
+            DependencyProperty.Register(nameof(DefaultDrawingAttributes), typeof(DrawingAttributes), typeof(InkCanvas),
+                new FrameworkPropertyMetadata(new DrawingAttributes(), FrameworkPropertyMetadataOptions.AffectsRender));
+
+        public StrokeCollection Strokes
+        {
+            get => (StrokeCollection)GetValue(StrokesProperty);
+            set => SetValue(StrokesProperty, value);
+        }
+
+        public DrawingAttributes DefaultDrawingAttributes
+        {
+            get => (DrawingAttributes)GetValue(DefaultDrawingAttributesProperty);
+            set => SetValue(DefaultDrawingAttributesProperty, value);
+        }
+
+        private StylusPointCollection _currentPoints;
+        private bool _isDrawing;
+
+        protected override void OnRender(DrawingContext dc)
+        {
+            base.OnRender(dc);
+            foreach (var stroke in Strokes)
+            {
+                var geo = stroke.GetGeometry();
+                if (geo != Geometry.Empty)
+                    dc.DrawGeometry(null, new Pen(new SolidColorBrush(stroke.DrawingAttributes.Color), stroke.DrawingAttributes.Width), geo);
+            }
+        }
+
+        protected override void OnMouseDown(MouseButtonEventArgs e)
+        {
+            base.OnMouseDown(e);
+            _isDrawing = true;
+            var p = e.GetPosition(this);
+            _currentPoints = new StylusPointCollection { new StylusPoint(p.X, p.Y) };
+            CaptureMouse();
+        }
+
+        protected override void OnMouseMove(MouseEventArgs e)
+        {
+            if (!_isDrawing) return;
+            var p = e.GetPosition(this);
+            _currentPoints.Add(new StylusPoint(p.X, p.Y));
+            InvalidateVisual();
+        }
+
+        protected override void OnMouseUp(MouseButtonEventArgs e)
+        {
+            if (!_isDrawing) return;
+            var p = e.GetPosition(this);
+            _currentPoints.Add(new StylusPoint(p.X, p.Y));
+            Strokes.Add(new Stroke(_currentPoints, DefaultDrawingAttributes));
+            _isDrawing = false;
+            ReleaseMouseCapture();
+            InvalidateVisual();
+        }
+    }
+}

UI/Controls/Ink/InkPresenter.cs

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+using System.Windows;
+using System.Windows.Media;
+
+namespace InkkSlinger.UI.Controls.Ink
+{
+    public class InkPresenter : FrameworkElement
+    {
+        public static readonly DependencyProperty StrokesProperty =
+            DependencyProperty.Register(nameof(Strokes), typeof(StrokeCollection), typeof(InkPresenter),
+                new FrameworkPropertyMetadata(null, FrameworkPropertyMetadataOptions.AffectsRender));
+
+        public StrokeCollection Strokes
+        {
+            get => (StrokeCollection)GetValue(StrokesProperty);
+            set => SetValue(StrokesProperty, value);
+        }
+
+        protected override void OnRender(DrawingContext dc)
+        {
+            base.OnRender(dc);
+            if (Strokes == null) return;
+            foreach (var stroke in Strokes)
+            {
+                var geo = stroke.GetGeometry();
+                if (geo != Geometry.Empty)
+                    dc.DrawGeometry(null, new Pen(new SolidColorBrush(stroke.DrawingAttributes.Color), stroke.DrawingAttributes.Width), geo);
+            }
+        }
+    }
+}

UI/Controls/Ink/Stroke.cs

@@ -0,0 +1,26 @@
+using System.Windows;
+using System.Windows.Media;
+
+namespace InkkSlinger.UI.Controls.Ink
+{
+    public class Stroke
+    {
+        public StylusPointCollection StylusPoints { get; }
+        public DrawingAttributes DrawingAttributes { get; set; }
+
+        public Stroke(StylusPointCollection stylusPoints, DrawingAttributes drawingAttributes)
+        {
+            StylusPoints = stylusPoints;
+            DrawingAttributes = drawingAttributes;
+        }
+
+        public Geometry GetGeometry()
+        {
+            if (StylusPoints.Count < 2) return Geometry.Empty;
+            var fig = new PathFigure { StartPoint = new Point(StylusPoints[0].X, StylusPoints[0].Y) };
+            for (int i = 1; i < StylusPoints.Count; i++)
+                fig.Segments.Add(new LineSegment(new Point(StylusPoints[i].X, StylusPoints[i].Y), true));
+            return new PathGeometry { Figures = { fig } };
+        }
+    }
+}

UI/Controls/Ink/StrokeCollection.cs

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+using System.Collections.ObjectModel;
+
+namespace InkkSlinger.UI.Controls.Ink
+{
+    public class StrokeCollection : ObservableCollection<Stroke> { }
+}

UI/Controls/Ink/StylusPoint.cs

@@ -0,0 +1,16 @@
+namespace InkkSlinger.UI.Controls.Ink
+{
+    public struct StylusPoint
+    {
+        public double X { get; }
+        public double Y { get; }
+        public float PressureFactor { get; }
+
+        public StylusPoint(double x, double y, float pressureFactor = 0.5f)
+        {
+            X = x;
+            Y = y;
+            PressureFactor = pressureFactor;
+        }
+    }
+}

UI/Controls/Ink/StylusPointCollection.cs

@@ -0,0 +1,6 @@
+using System.Collections.Generic;
+
+namespace InkkSlinger.UI.Controls.Ink
+{
+    public class StylusPointCollection : List<StylusPoint> { }
+}