fix(Geometries): Relative line drawing

src/Avalonia.Base/Media/PathMarkupParser.cs

@@ -259,7 +259,7 @@ private void AddLine(ref ReadOnlySpan<char> span, bool relative)
         {
             ThrowIfDisposed();
 
-            _currentPoint = relative
+            var next = relative
                                 ? ReadRelativePoint(ref span, _currentPoint)
                                 : ReadPoint(ref span);
 
@@ -268,14 +268,15 @@ private void AddLine(ref ReadOnlySpan<char> span, bool relative)
                 CreateFigure();
             }
 
-            _geometryContext.LineTo(_currentPoint);
+            _geometryContext.LineTo(next);
+            _currentPoint = next;
         }
 
         private void AddHorizontalLine(ref ReadOnlySpan<char> span, bool relative)
         {
             ThrowIfDisposed();
 
-            _currentPoint = relative
+            var next = relative
                                 ? new Point(_currentPoint.X + ReadDouble(ref span), _currentPoint.Y)
                                 : _currentPoint.WithX(ReadDouble(ref span));
 
@@ -284,14 +285,15 @@ private void AddHorizontalLine(ref ReadOnlySpan<char> span, bool relative)
                 CreateFigure();
             }
 
-            _geometryContext.LineTo(_currentPoint);
+            _geometryContext.LineTo(next);
+            _currentPoint = next;
         }
 
         private void AddVerticalLine(ref ReadOnlySpan<char> span, bool relative)
         {
             ThrowIfDisposed();
 
-            _currentPoint = relative
+            var next = relative
                                 ? new Point(_currentPoint.X, _currentPoint.Y + ReadDouble(ref span))
                                 : _currentPoint.WithY(ReadDouble(ref span));
 
@@ -300,7 +302,8 @@ private void AddVerticalLine(ref ReadOnlySpan<char> span, bool relative)
                 CreateFigure();
             }
 
-            _geometryContext.LineTo(_currentPoint);
+            _geometryContext.LineTo(next);
+            _currentPoint = next;
         }
 
         private void AddCubicBezierCurve(ref ReadOnlySpan<char> span, bool relative)

tests/Avalonia.RenderTests/Media/GeometryDrawingTests.cs

@@ -4,9 +4,6 @@
 #if AVALONIA_SKIA
 namespace Avalonia.Skia.RenderTests
 #else
-
-using Avalonia.Direct2D1.RenderTests;
-
 namespace Avalonia.Direct2D1.RenderTests.Media
 #endif
 {
@@ -47,6 +44,35 @@ public void DrawingGeometry_WithoutPen()
             Assert.Equal(200, geometryDrawing.GetBounds().Width);
         }
 
+        [Theory]
+        [InlineData("l", "F1 M50,50z l -5,-5")]
+        [InlineData("h", "F1 M50,50z h 10")]
+        [InlineData("v", "F1 M50,50z v 10")]
+        [InlineData("m", "M50,50z l -5,-5")]
+        public async void DrawingGeometry_RelativeLine_Commands(string name, string command)
+        {
+            var target = new Avalonia.Controls.Decorator
+            {
+                Width = 200,
+                Height = 200,
+                Child = new Avalonia.Controls.Image()
+                {
+                    Width = 200,
+                    Height = 200,
+                    Source = new DrawingImage()
+                    {
+                        Drawing = new GeometryDrawing()
+                        {
+                            Geometry = StreamGeometry.Parse(command),
+                            Pen = new Pen(Brushes.Black, 2, lineCap: PenLineCap.Round, lineJoin: PenLineJoin.Round)
+                        }
+                    },
 
+                }
+            };
+            var testName = $"Relative_Line_{name}";
+            await RenderToFile(target, testName);
+            CompareImages(testName);
+        }
     }
 }