Fix outlines on images, rules, split boxes and invert

- Paint the outline for replaced elements and <hr>
- Copy the outline when a box gets cloned
- Treat outline-color: invert as currentColor

Author: eXpl0it3r

Source/HtmlRenderer/Core/Dom/CssBoxProperties.cs

@@ -793,6 +793,7 @@ public RColor ActualOutlineColor
                 // treated the same as unset, since an invisible-by-default outline would defeat the point
                 // of the property entirely.
                 return string.IsNullOrEmpty(OutlineColor) || OutlineColor == "transparent"
+                       || OutlineColor.Equals("invert", StringComparison.OrdinalIgnoreCase)
                     ? ActualColor
                     : GetActualColor(OutlineColor);
             }
@@ -1997,6 +1998,9 @@ protected void InheritStyle(CssBox p, bool everything)
                     _borderRightStyle = p._borderRightStyle;
                     _borderBottomStyle = p._borderBottomStyle;
                     _borderLeftStyle = p._borderLeftStyle;
+                    _outlineStyle = p._outlineStyle;
+                    _outlineColor = p._outlineColor;
+                    _outlineWidth = p._outlineWidth;
                     _bottom = p._bottom;
                     _borderTopLeftRadius = p._borderTopLeftRadius;
                     _borderTopRightRadius = p._borderTopRightRadius;

Source/HtmlRenderer/Core/Paint/Content/HrFragmentPainter.cs

@@ -2,6 +2,7 @@
 using TheArtOfDev.HtmlRenderer.Adapters.Entities;
 using TheArtOfDev.HtmlRenderer.Core.Dom;
 using TheArtOfDev.HtmlRenderer.Core.Fragments;
+using TheArtOfDev.HtmlRenderer.Core.Handlers;
 
 namespace TheArtOfDev.HtmlRenderer.Core.Paint.Content
 {
@@ -25,6 +26,7 @@ public void Paint(FragmentPainter painter, RGraphics g, BoxFragment fragment)
             var rect = fragment.PrimaryRect;
             rect.Offset(offset);
             box.DrawHrContent(g, rect);
+            OutlineDrawHandler.Draw(g, box, rect);
         }
     }
 }

Source/HtmlRenderer/Core/Paint/Content/ReplacedFragmentPainter.cs

@@ -31,6 +31,7 @@ public void Paint(FragmentPainter painter, RGraphics g, BoxFragment fragment)
 
             box.PaintBackground(g, rect, true, true);
             BordersDrawHandler.DrawBoxBorders(g, box, rect, true, true);
+            OutlineDrawHandler.Draw(g, box, rect);
 
             DrawContent(g, fragment, painter.LiveTreeOffset(box.IsFixed));
 

Source/Test/HtmlRenderer.IntegrationTest/Painting/OutlineStylePaintIntegrationTests.cs

@@ -130,4 +130,45 @@ public void OutlineOffset_PushesTheRingFurtherFromTheBorderBox()
 
         Assert.AreEqual(borderBox.Y - 10 - 5, top.Y, 0.1);
     }
+
+    [TestMethod]
+    public void OutlineColorInvert_FallsBackToCurrentColor()
+    {
+        var (_, container) = PaintHarness.Layout(PaintHarness.Wrap(
+            "<div style='width:100px;height:50px;color:rgb(51,51,51);outline:5px solid invert'></div>"));
+
+        var g = PaintHarness.PaintPage(container);
+        var rects = g.Log.OfType<RecordingGraphics.DrawRectCall>()
+            .Where(r => r.Color == RColor.FromArgb(51, 51, 51)).ToList();
+
+        Assert.AreEqual(4, rects.Count);
+    }
+
+    [TestMethod]
+    [DataRow("<img id='e' style='width:20px;height:20px;outline:5px solid rgb(51,51,51)'>")]
+    [DataRow("<hr id='e' style='outline:5px solid rgb(51,51,51)'>")]
+    public void ReplacedAndRuleElements_PaintTheirOutline(string element)
+    {
+        var (_, container) = PaintHarness.Layout(PaintHarness.Wrap(element));
+
+        var g = PaintHarness.PaintPage(container);
+        var rects = g.Log.OfType<RecordingGraphics.DrawRectCall>()
+            .Where(r => r.Color == RColor.FromArgb(51, 51, 51)).ToList();
+
+        Assert.AreEqual(4, rects.Count);
+    }
+
+    [TestMethod]
+    public void InlineSplitAroundABlock_KeepsTheOutlineOnEveryPart()
+    {
+        // The span gets split into a part before and a part after the block, and both parts are copies.
+        var (_, container) = PaintHarness.Layout(PaintHarness.Wrap(
+            "<span style='outline:2px solid rgb(51,51,51)'>before<div>block</div>after</span>"));
+
+        var g = PaintHarness.PaintPage(container);
+        var rects = g.Log.OfType<RecordingGraphics.DrawRectCall>()
+            .Where(r => r.Color == RColor.FromArgb(51, 51, 51)).ToList();
+
+        Assert.IsGreaterThanOrEqualTo(8, rects.Count, "both the part before and the part after the block need a ring");
+    }
 }