LibHTML: Fetch the box edge values needed for block width computation.

Libraries/LibHTML/CSS/Length.h

@@ -29,6 +29,13 @@ public:
         return String::format("%d [Length/Absolute]", m_value);
     }
 
+    int to_px() const
+    {
+        if (is_auto())
+            return 0;
+        return m_value;
+    }
+
 private:
     Type m_type { Type::Auto };
     int m_value { 0 };

Libraries/LibHTML/CSS/StyledNode.h

@@ -1,10 +1,11 @@
 #pragma once
 
+#include <AK/AKString.h>
 #include <AK/HashMap.h>
 #include <AK/NonnullRefPtr.h>
-#include <AK/AKString.h>
+#include <AK/Optional.h>
-#include <LibHTML/TreeNode.h>
 #include <LibHTML/CSS/StyleValue.h>
+#include <LibHTML/TreeNode.h>
 
 class Node;
 
@@ -50,6 +51,14 @@ public:
         m_property_values.set(name, move(value));
     }
 
+    Optional<NonnullRefPtr<StyleValue>> property(const String& name) const
+    {
+        auto it = m_property_values.find(name);
+        if (it == m_property_values.end())
+            return {};
+        return it->value;
+    }
+
     Display display() const;
 
 protected:

Libraries/LibHTML/Layout/LayoutBlock.cpp

@@ -1,3 +1,4 @@
+#include <LibHTML/CSS/StyledNode.h>
 #include <LibHTML/DOM/Element.h>
 #include <LibHTML/Layout/LayoutBlock.h>
 
@@ -29,6 +30,26 @@ void LayoutBlock::layout()
 
 void LayoutBlock::compute_width()
 {
+    if (!styled_node()) {
+        // I guess the size is "auto" in this case.
+        return;
+    }
+
+    auto auto_value= LengthStyleValue::create({});
+    auto& styled_node = *this->styled_node();
+    auto width = styled_node.property("width").value_or(auto_value);
+
+    auto zero_value = LengthStyleValue::create(Length(0, Length::Type::Absolute));
+
+    auto margin_left = styled_node.property("margin-left").value_or(zero_value);
+    auto margin_right = styled_node.property("margin-right").value_or(zero_value);
+    auto border_left = styled_node.property("border-left").value_or(zero_value);
+    auto border_right = styled_node.property("border-right").value_or(zero_value);
+    auto padding_left = styled_node.property("padding-left").value_or(zero_value);
+    auto padding_right = styled_node.property("padding-right").value_or(zero_value);
+
+    dbg() << " Left: " << margin_left->to_string() << "+" << border_left->to_string() << "+" << padding_left->to_string();
+    dbg() << "Right: " << margin_right->to_string() << "+" << border_right->to_string() << "+" << padding_right->to_string();
 }
 
 void LayoutBlock::compute_height()

Libraries/LibHTML/Layout/LayoutNode.h

@@ -49,6 +49,9 @@ public:
 
     virtual LayoutNode& inline_wrapper() { return *this; }
 
+    StyledNode* styled_node() { return m_styled_node; }
+    const StyledNode* styled_node() const { return m_styled_node; }
+
 protected:
     explicit LayoutNode(const Node*, const StyledNode*);