From 50d8e9d028642e95fc2563410a7d7d3fe65873db Mon Sep 17 00:00:00 2001
From: Florian Rappl <mail@florian-rappl.de>
Date: Fri, 16 Jun 2023 00:20:11 +0200
Subject: [PATCH] WIP #136

---
 CHANGELOG.md                                  |  3 +-
 .../Library/ComputedStyle.cs                  | 30 +++++++++++++++++++
 .../Extensions/CssOmExtensions.cs             | 11 ++++++-
 .../Extensions/StyleCollectionExtensions.cs   | 13 ++++++--
 4 files changed, 52 insertions(+), 5 deletions(-)
 create mode 100644 src/AngleSharp.Css.Tests/Library/ComputedStyle.cs

diff --git a/CHANGELOG.md b/CHANGELOG.md
index c4d2d6e7..52309a98 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,9 +9,10 @@ Released on tbd.
 - Fixed missing semicolon in `@page` rule (#135)
 - Fixed integer serialization of keyframe stops (#128)
 - Fixed ordering of rows and columns in `grid` and `grid-gap` (#137)
-- Fixed inclusion of CSS from stylesheets (#140)
+- Fixed inclusion of CSS from stylesheets (#116, #140)
 - Added further compactification of CSS tuples (#89, #93)
 - Added support for 8-digit hex color codes (#132)
+- Added more CSSOM possibilities and helpers (#6)
 
 # 0.17.0
 
diff --git a/src/AngleSharp.Css.Tests/Library/ComputedStyle.cs b/src/AngleSharp.Css.Tests/Library/ComputedStyle.cs
new file mode 100644
index 00000000..db479616
--- /dev/null
+++ b/src/AngleSharp.Css.Tests/Library/ComputedStyle.cs
@@ -0,0 +1,30 @@
+namespace AngleSharp.Css.Tests.Library
+{
+    using AngleSharp.Dom;
+    using AngleSharp.Html.Dom;
+    using NUnit.Framework;
+    using System.Threading.Tasks;
+
+    [TestFixture]
+    public class ComputedStyleTests
+    {
+        [Test]
+        [Ignore("Not implemented yet")]
+        public async Task TransformEmToPx_Issue136()
+        {
+            // .With<IRenderDevice>()
+            var config = Configuration.Default.WithCss();
+            var context = BrowsingContext.New(config);
+            var source = "<p>This is <span>only</span> a test.</p>";
+            var cssSheet = "p { font-size: 1.5em }";
+            var document = await context.OpenAsync(req => req.Content(source));
+            var style = document.CreateElement<IHtmlStyleElement>();
+            style.TextContent = cssSheet;
+            document.Head.AppendChild(style);
+            var span = document.QuerySelector("span");
+            var fontSize = span.ComputeCurrentStyle().GetProperty("font-size");
+
+            Assert.AreEqual("24px", fontSize.Value);
+        }
+    }
+}
diff --git a/src/AngleSharp.Css/Extensions/CssOmExtensions.cs b/src/AngleSharp.Css/Extensions/CssOmExtensions.cs
index e9fce611..8ad0d928 100644
--- a/src/AngleSharp.Css/Extensions/CssOmExtensions.cs
+++ b/src/AngleSharp.Css/Extensions/CssOmExtensions.cs
@@ -1,6 +1,7 @@
 namespace AngleSharp.Css.Dom
 {
     using AngleSharp.Css.Parser;
+    using AngleSharp.Css.Values;
     using AngleSharp.Text;
     using System;
     using System.Linq;
@@ -73,7 +74,15 @@ public static ICssValue GetValueOf(this ICssStyleRule rule, String propertyName)
         /// <returns>A new style declaration with the existing or computed values.</returns>
         public static ICssStyleDeclaration Compute(this ICssStyleDeclaration style, IRenderDevice device)
         {
-            //TODO
+            //var prop = style.GetProperty("font-size");
+
+            //if (prop is not null && prop.RawValue is Length length)
+            //{
+            //    var px = length.ToPixel(device, RenderMode.Horizontal);
+            //    var prio = prop.IsImportant ? CssKeywords.Important : null;
+            //    style.SetProperty(prop.Name, $"{px}px", prio);
+            //}
+
             return style;
         }
     }
diff --git a/src/AngleSharp.Css/Extensions/StyleCollectionExtensions.cs b/src/AngleSharp.Css/Extensions/StyleCollectionExtensions.cs
index 91570714..d637e6f4 100644
--- a/src/AngleSharp.Css/Extensions/StyleCollectionExtensions.cs
+++ b/src/AngleSharp.Css/Extensions/StyleCollectionExtensions.cs
@@ -42,14 +42,16 @@ public static IStyleCollection GetStyleCollection(this IWindow window)
         /// <returns>The style declaration containing all the declarations.</returns>
         public static ICssStyleDeclaration ComputeDeclarations(this IEnumerable<ICssStyleRule> rules, IElement element, String pseudoSelector = null)
         {
-            var computedStyle = new CssStyleDeclaration(element.Owner?.Context);
+            var ctx = element.Owner?.Context;
+            var device = ctx?.GetService<IRenderDevice>();
+            var computedStyle = new CssStyleDeclaration(ctx);
             var nodes = element.GetAncestors().OfType<IElement>();
 
             if (!String.IsNullOrEmpty(pseudoSelector))
             {
                 var pseudoElement = element?.Pseudo(pseudoSelector.TrimStart(':'));
 
-                if (pseudoElement != null)
+                if (pseudoElement is not null)
                 {
                     element = pseudoElement;
                 }
@@ -62,6 +64,11 @@ public static ICssStyleDeclaration ComputeDeclarations(this IEnumerable<ICssStyl
                 computedStyle.UpdateDeclarations(rules.ComputeCascadedStyle(node));
             }
 
+            if (device is not null)
+            {
+                return computedStyle.Compute(device);
+            }
+
             return computedStyle;
         }
 
@@ -90,7 +97,7 @@ public static ICssStyleDeclaration ComputeCascadedStyle(this IEnumerable<ICssSty
                 computedStyle.SetDeclarations(element.GetStyle());
             }
 
-            if (parent != null)
+            if (parent is not null)
             {
                 computedStyle.UpdateDeclarations(parent);
             }