LibWeb: Use Optional instead of undefined-lengths for widths/heights

Userland/Libraries/LibWeb/CSS/ComputedValues.h

@@ -108,12 +108,12 @@ public:
     CSS::JustifyContent justify_content() const { return m_noninherited.justify_content; }
     Vector<BoxShadowData> const& box_shadow() const { return m_noninherited.box_shadow; }
     CSS::BoxSizing box_sizing() const { return m_noninherited.box_sizing; }
-    CSS::LengthPercentage const& width() const { return m_noninherited.width; }
+    Optional<CSS::LengthPercentage> const& width() const { return m_noninherited.width; }
-    CSS::LengthPercentage const& min_width() const { return m_noninherited.min_width; }
+    Optional<CSS::LengthPercentage> const& min_width() const { return m_noninherited.min_width; }
-    CSS::LengthPercentage const& max_width() const { return m_noninherited.max_width; }
+    Optional<CSS::LengthPercentage> const& max_width() const { return m_noninherited.max_width; }
-    CSS::LengthPercentage const& height() const { return m_noninherited.height; }
+    Optional<CSS::LengthPercentage> const& height() const { return m_noninherited.height; }
-    CSS::LengthPercentage const& min_height() const { return m_noninherited.min_height; }
+    Optional<CSS::LengthPercentage> const& min_height() const { return m_noninherited.min_height; }
-    CSS::LengthPercentage const& max_height() const { return m_noninherited.max_height; }
+    Optional<CSS::LengthPercentage> const& max_height() const { return m_noninherited.max_height; }
 
     const CSS::LengthBox& offset() const { return m_noninherited.offset; }
     const CSS::LengthBox& margin() const { return m_noninherited.margin; }
@@ -174,12 +174,12 @@ protected:
         CSS::TextDecorationLine text_decoration_line { InitialValues::text_decoration_line() };
         CSS::TextDecorationStyle text_decoration_style { InitialValues::text_decoration_style() };
         CSS::Position position { InitialValues::position() };
-        CSS::LengthPercentage width { Length::make_auto() };
+        Optional<CSS::LengthPercentage> width;
-        CSS::LengthPercentage min_width { Length::make_auto() };
+        Optional<CSS::LengthPercentage> min_width;
-        CSS::LengthPercentage max_width { Length::make_auto() };
+        Optional<CSS::LengthPercentage> max_width;
-        CSS::LengthPercentage height { Length::make_auto() };
+        Optional<CSS::LengthPercentage> height;
-        CSS::LengthPercentage min_height { Length::make_auto() };
+        Optional<CSS::LengthPercentage> min_height;
-        CSS::LengthPercentage max_height { Length::make_auto() };
+        Optional<CSS::LengthPercentage> max_height;
         CSS::LengthBox offset;
         CSS::LengthBox margin;
         CSS::LengthBox padding;

Userland/Libraries/LibWeb/CSS/ResolvedCSSStyleDeclaration.cpp

@@ -536,25 +536,25 @@ RefPtr<StyleValue> ResolvedCSSStyleDeclaration::style_value_for_property(Layout:
         return StyleValueList::create(move(box_shadow), StyleValueList::Separator::Comma);
     }
     case CSS::PropertyID::Width:
-        return style_value_for_length_percentage(layout_node.computed_values().width());
+        return style_value_for_length_percentage(layout_node.computed_values().width().value_or(Length::make_auto()));
     case CSS::PropertyID::MinWidth:
-        if (layout_node.computed_values().min_width().is_length() && layout_node.computed_values().min_width().length().is_undefined_or_auto())
+        if (!layout_node.computed_values().min_width().has_value())
             return IdentifierStyleValue::create(CSS::ValueID::Auto);
-        return style_value_for_length_percentage(layout_node.computed_values().min_width());
+        return style_value_for_length_percentage(layout_node.computed_values().min_width().value());
     case CSS::PropertyID::MaxWidth:
-        if (layout_node.computed_values().max_width().is_length() && layout_node.computed_values().max_width().length().is_undefined())
+        if (!layout_node.computed_values().max_width().has_value())
             return IdentifierStyleValue::create(CSS::ValueID::None);
-        return style_value_for_length_percentage(layout_node.computed_values().max_width());
+        return style_value_for_length_percentage(layout_node.computed_values().max_width().value());
     case CSS::PropertyID::Height:
-        return style_value_for_length_percentage(layout_node.computed_values().height());
+        return style_value_for_length_percentage(layout_node.computed_values().height().value_or(Length::make_auto()));
     case CSS::PropertyID::MinHeight:
-        if (layout_node.computed_values().min_height().is_length() && layout_node.computed_values().min_height().length().is_undefined_or_auto())
+        if (!layout_node.computed_values().min_height().has_value())
             return IdentifierStyleValue::create(CSS::ValueID::Auto);
-        return style_value_for_length_percentage(layout_node.computed_values().min_height());
+        return style_value_for_length_percentage(layout_node.computed_values().min_height().value());
     case CSS::PropertyID::MaxHeight:
-        if (layout_node.computed_values().max_height().is_length() && layout_node.computed_values().max_height().length().is_undefined())
+        if (!layout_node.computed_values().max_height().has_value())
             return IdentifierStyleValue::create(CSS::ValueID::None);
-        return style_value_for_length_percentage(layout_node.computed_values().max_height());
+        return style_value_for_length_percentage(layout_node.computed_values().max_height().value());
     case CSS::PropertyID::Margin: {
         auto margin = layout_node.computed_values().margin();
         auto values = NonnullRefPtrVector<StyleValue> {};

Userland/Libraries/LibWeb/CSS/StyleProperties.cpp

@@ -64,10 +64,15 @@ Length StyleProperties::length_or_fallback(CSS::PropertyID id, Length const& fal
 }
 
 LengthPercentage StyleProperties::length_percentage_or_fallback(CSS::PropertyID id, LengthPercentage const& fallback) const
+{
+    return length_percentage(id).value_or(fallback);
+}
+
+Optional<LengthPercentage> StyleProperties::length_percentage(CSS::PropertyID id) const
 {
     auto maybe_value = property(id);
     if (!maybe_value.has_value())
-        return fallback;
+        return {};
     auto& value = maybe_value.value();
 
     if (value->is_calculated())
@@ -79,7 +84,7 @@ LengthPercentage StyleProperties::length_percentage_or_fallback(CSS::PropertyID
     if (value->has_length())
         return value->to_length();
 
-    return fallback;
+    return {};
 }
 
 LengthBox StyleProperties::length_box(CSS::PropertyID left_id, CSS::PropertyID top_id, CSS::PropertyID right_id, CSS::PropertyID bottom_id, const CSS::Length& default_value) const

Userland/Libraries/LibWeb/CSS/StyleProperties.h

@@ -41,6 +41,7 @@ public:
 
     Length length_or_fallback(CSS::PropertyID, Length const& fallback) const;
     LengthPercentage length_percentage_or_fallback(CSS::PropertyID, LengthPercentage const& fallback) const;
+    Optional<LengthPercentage> length_percentage(CSS::PropertyID) const;
     LengthBox length_box(CSS::PropertyID left_id, CSS::PropertyID top_id, CSS::PropertyID right_id, CSS::PropertyID bottom_id, const CSS::Length& default_value) const;
     Color color_or_fallback(CSS::PropertyID, Layout::NodeWithStyle const&, Color fallback) const;
     Optional<CSS::TextAlign> text_align() const;

Userland/Libraries/LibWeb/Layout/BlockFormattingContext.cpp

@@ -195,14 +195,14 @@ void BlockFormattingContext::compute_width(Box& box)
         return width;
     };
 
-    auto specified_width = computed_values.width().resolved(box, width_of_containing_block_as_length).resolved_or_auto(box);
+    auto specified_width = computed_values.width().has_value() ? computed_values.width()->resolved(box, width_of_containing_block_as_length).resolved_or_auto(box) : CSS::Length::make_auto();
 
     // 1. The tentative used width is calculated (without 'min-width' and 'max-width')
     auto used_width = try_compute_width(specified_width);
 
     // 2. The tentative used width is greater than 'max-width', the rules above are applied again,
     //    but this time using the computed value of 'max-width' as the computed value for 'width'.
-    auto specified_max_width = computed_values.max_width().resolved(box, width_of_containing_block_as_length).resolved_or_auto(box);
+    auto specified_max_width = computed_values.max_width().has_value() ? computed_values.max_width()->resolved(box, width_of_containing_block_as_length).resolved_or_auto(box) : CSS::Length::make_auto();
     if (!specified_max_width.is_auto()) {
         if (used_width.to_px(box) > specified_max_width.to_px(box)) {
             used_width = try_compute_width(specified_max_width);
@@ -211,7 +211,7 @@ void BlockFormattingContext::compute_width(Box& box)
 
     // 3. If the resulting width is smaller than 'min-width', the rules above are applied again,
     //    but this time using the value of 'min-width' as the computed value for 'width'.
-    auto specified_min_width = computed_values.min_width().resolved(box, width_of_containing_block_as_length).resolved_or_auto(box);
+    auto specified_min_width = computed_values.min_width().has_value() ? computed_values.min_width()->resolved(box, width_of_containing_block_as_length).resolved_or_auto(box) : CSS::Length::make_auto();
     if (!specified_min_width.is_auto()) {
         if (used_width.to_px(box) < specified_min_width.to_px(box)) {
             used_width = try_compute_width(specified_min_width);
@@ -246,7 +246,7 @@ void BlockFormattingContext::compute_width_for_floating_box(Box& box)
     if (margin_right.is_auto())
         margin_right = zero_value;
 
-    auto width = computed_values.width().resolved(box, width_of_containing_block_as_length).resolved_or_auto(box);
+    auto width = computed_values.width().has_value() ? computed_values.width()->resolved(box, width_of_containing_block_as_length).resolved_or_auto(box) : CSS::Length::make_auto();
 
     // If 'width' is computed as 'auto', the used value is the "shrink-to-fit" width.
     if (width.is_auto()) {
@@ -285,8 +285,8 @@ float BlockFormattingContext::compute_theoretical_height(Box const& box)
     auto& containing_block = *box.containing_block();
     auto containing_block_height = CSS::Length::make_px(containing_block.content_height());
 
-    auto is_absolute = [](CSS::LengthPercentage const& length_percentage) {
+    auto is_absolute = [](Optional<CSS::LengthPercentage> const& length_percentage) {
-        return length_percentage.is_length() && length_percentage.length().is_absolute();
+        return length_percentage.has_value() && length_percentage->is_length() && length_percentage->length().is_absolute();
     };
 
     // Then work out what the height is, based on box type and CSS properties.
@@ -294,21 +294,22 @@ float BlockFormattingContext::compute_theoretical_height(Box const& box)
     if (is<ReplacedBox>(box)) {
         height = compute_height_for_replaced_element(verify_cast<ReplacedBox>(box));
     } else {
-        if ((box.computed_values().height().is_length() && box.computed_values().height().length().is_undefined_or_auto())
+        if (!box.computed_values().height().has_value()
-            || (computed_values.height().is_percentage() && !is_absolute(containing_block.computed_values().height()))) {
+            || (box.computed_values().height()->is_length() && box.computed_values().height()->length().is_undefined_or_auto())
+            || (computed_values.height().has_value() && computed_values.height()->is_percentage() && !is_absolute(containing_block.computed_values().height()))) {
             height = compute_auto_height_for_block_level_element(box, ConsiderFloats::No);
         } else {
-            height = computed_values.height().resolved(box, containing_block_height).resolved_or_auto(box).to_px(box);
+            height = computed_values.height().has_value() ? computed_values.height()->resolved(box, containing_block_height).resolved_or_auto(box).to_px(box) : 0;
         }
     }
 
-    auto specified_max_height = computed_values.max_height().resolved(box, containing_block_height).resolved_or_auto(box);
+    auto specified_max_height = computed_values.max_height().has_value() ? computed_values.max_height()->resolved(box, containing_block_height).resolved_or_auto(box) : CSS::Length::make_auto();
     if (!specified_max_height.is_auto()
-        && !(computed_values.max_height().is_percentage() && !is_absolute(containing_block.computed_values().height())))
+        && !(computed_values.max_height().has_value() && computed_values.max_height()->is_percentage() && !is_absolute(containing_block.computed_values().height())))
         height = min(height, specified_max_height.to_px(box));
-    auto specified_min_height = computed_values.min_height().resolved(box, containing_block_height).resolved_or_auto(box);
+    auto specified_min_height = computed_values.min_height().has_value() ? computed_values.min_height()->resolved(box, containing_block_height).resolved_or_auto(box) : CSS::Length::make_auto();
     if (!specified_min_height.is_auto()
-        && !(computed_values.min_height().is_percentage() && !is_absolute(containing_block.computed_values().height())))
+        && !(computed_values.min_height().has_value() && computed_values.min_height()->is_percentage() && !is_absolute(containing_block.computed_values().height())))
         height = max(height, specified_min_height.to_px(box));
     return height;
 }
@@ -439,7 +440,8 @@ void BlockFormattingContext::layout_block_level_children(BlockContainer& block_c
     });
 
     if (layout_mode != LayoutMode::Default) {
-        if (block_container.computed_values().width().is_length() && block_container.computed_values().width().length().is_undefined_or_auto())
+        auto& width = block_container.computed_values().width();
+        if (!width.has_value() || (width->is_length() && width->length().is_undefined_or_auto()))
             block_container.set_content_width(content_width);
     }
 }

Userland/Libraries/LibWeb/Layout/FlexFormattingContext.cpp

@@ -17,17 +17,19 @@
 
 namespace Web::Layout {
 
-static float get_pixel_size(Box const& box, CSS::LengthPercentage const& length_percentage)
+static float get_pixel_size(Box const& box, Optional<CSS::LengthPercentage> const& length_percentage)
 {
+    if (!length_percentage.has_value())
+        return 0;
     auto inner_main_size = CSS::Length::make_px(box.containing_block()->content_width());
-    return length_percentage.resolved(box, inner_main_size)
+    return length_percentage->resolved(box, inner_main_size).resolved(CSS::Length::make_px(0), box).to_px(box);
-        .resolved(CSS::Length::make_px(0), box)
-        .to_px(box);
 }
 
-static bool is_undefined_or_auto(CSS::LengthPercentage const& length_percentage)
+static bool is_undefined_or_auto(Optional<CSS::LengthPercentage> const& length_percentage)
 {
-    return length_percentage.is_length() && length_percentage.length().is_undefined_or_auto();
+    if (!length_percentage.has_value())
+        return true;
+    return length_percentage->is_length() && length_percentage->length().is_undefined_or_auto();
 }
 
 FlexFormattingContext::FlexFormattingContext(Box& flex_container, FormattingContext* parent)
@@ -143,16 +145,27 @@ void FlexFormattingContext::generate_anonymous_flex_items()
         flex_container().set_content_width(flex_container().containing_block()->content_width());
     } else {
         auto container_width = flex_container().containing_block()->content_width();
-        auto width = flex_container().computed_values().width().resolved(flex_container(), CSS::Length::make_px(container_width)).resolved_or_zero(flex_container()).to_px(flex_container());
+
-        flex_container().set_content_width(width);
+        auto& maybe_width = flex_container().computed_values().width();
+        if (maybe_width.has_value()) {
+            auto width = maybe_width->resolved(flex_container(), CSS::Length::make_px(container_width)).resolved_or_zero(flex_container()).to_px(flex_container());
+            flex_container().set_content_width(width);
+        } else {
+            flex_container().set_content_width(0);
+        }
     }
 
     if (!flex_container().has_definite_height()) {
         flex_container().set_content_height(flex_container().containing_block()->content_height());
     } else {
         auto container_height = flex_container().containing_block()->content_height();
-        auto height = flex_container().computed_values().height().resolved(flex_container(), CSS::Length::make_px(container_height)).resolved_or_zero(flex_container()).to_px(flex_container());
+        auto& maybe_height = flex_container().computed_values().height();
-        flex_container().set_content_height(height);
+        if (maybe_height.has_value()) {
+            auto height = maybe_height->resolved(flex_container(), CSS::Length::make_px(container_height)).resolved_or_zero(flex_container()).to_px(flex_container());
+            flex_container().set_content_height(height);
+        } else {
+            flex_container().set_content_height(0);
+        }
     }
 
     flex_container().for_each_child_of_type<Box>([&](Box& child_box) {
@@ -219,8 +232,11 @@ bool FlexFormattingContext::cross_size_is_absolute_or_resolved_nicely(NodeWithSt
 {
     auto length_percentage = is_row_layout() ? box.computed_values().height() : box.computed_values().width();
 
-    if (length_percentage.is_length()) {
+    if (!length_percentage.has_value())
-        auto& length = length_percentage.length();
+        return false;
+
+    if (length_percentage->is_length()) {
+        auto& length = length_percentage->length();
         if (length.is_absolute() || length.is_relative())
             return true;
         if (length.is_undefined_or_auto())
@@ -229,7 +245,7 @@ bool FlexFormattingContext::cross_size_is_absolute_or_resolved_nicely(NodeWithSt
 
     if (!box.parent())
         return false;
-    if (length_percentage.is_percentage() && cross_size_is_absolute_or_resolved_nicely(*box.parent()))
+    if (length_percentage->is_percentage() && cross_size_is_absolute_or_resolved_nicely(*box.parent()))
         return true;
     return false;
 }
@@ -237,8 +253,10 @@ bool FlexFormattingContext::cross_size_is_absolute_or_resolved_nicely(NodeWithSt
 float FlexFormattingContext::specified_main_size_of_child_box(Box const& child_box) const
 {
     auto main_size_of_parent = specified_main_size(flex_container());
-    auto value = is_row_layout() ? child_box.computed_values().width() : child_box.computed_values().height();
+    auto& value = is_row_layout() ? child_box.computed_values().width() : child_box.computed_values().height();
-    return value.resolved(child_box, CSS::Length::make_px(main_size_of_parent)).resolved_or_zero(child_box).to_px(child_box);
+    if (!value.has_value())
+        return 0;
+    return value->resolved(child_box, CSS::Length::make_px(main_size_of_parent)).resolved_or_zero(child_box).to_px(child_box);
 }
 
 float FlexFormattingContext::specified_main_min_size(Box const& box) const
@@ -290,9 +308,8 @@ float FlexFormattingContext::calculated_main_size(Box const& box) const
 
 bool FlexFormattingContext::is_cross_auto(Box const& box) const
 {
-    if (is_row_layout())
+    auto& cross_length = is_row_layout() ? box.computed_values().height() : box.computed_values().width();
-        return box.computed_values().height().is_length() && box.computed_values().height().length().is_auto();
+    return cross_length.has_value() && cross_length->length().is_auto();
-    return box.computed_values().width().is_length() && box.computed_values().width().length().is_auto();
 }
 
 bool FlexFormattingContext::is_main_axis_margin_first_auto(Box const& box) const

Userland/Libraries/LibWeb/Layout/FormattingContext.cpp

@@ -157,10 +157,10 @@ static Gfx::FloatSize solve_replaced_size_constraint(float w, float h, const Rep
     auto width_of_containing_block = CSS::Length::make_px(containing_block.content_width());
     auto height_of_containing_block = CSS::Length::make_px(containing_block.content_height());
 
-    auto specified_min_width = box.computed_values().min_width().resolved(box, width_of_containing_block).resolved_or_zero(box).to_px(box);
+    auto specified_min_width = box.computed_values().min_width().has_value() ? box.computed_values().min_width()->resolved(box, width_of_containing_block).resolved_or_zero(box).to_px(box) : 0;
-    auto specified_max_width = box.computed_values().max_width().resolved(box, width_of_containing_block).resolved(CSS::Length::make_px(w), box).to_px(box);
+    auto specified_max_width = box.computed_values().max_width().has_value() ? box.computed_values().max_width()->resolved(box, width_of_containing_block).resolved(CSS::Length::make_px(w), box).to_px(box) : w;
-    auto specified_min_height = box.computed_values().min_height().resolved(box, height_of_containing_block).resolved_or_auto(box).to_px(box);
+    auto specified_min_height = box.computed_values().min_height().has_value() ? box.computed_values().min_height()->resolved(box, height_of_containing_block).resolved_or_auto(box).to_px(box) : 0;
-    auto specified_max_height = box.computed_values().max_height().resolved(box, height_of_containing_block).resolved(CSS::Length::make_px(h), box).to_px(box);
+    auto specified_max_height = box.computed_values().max_height().has_value() ? box.computed_values().max_height()->resolved(box, height_of_containing_block).resolved(CSS::Length::make_px(h), box).to_px(box) : h;
 
     auto min_width = min(specified_min_width, specified_max_width);
     auto max_width = max(specified_min_width, specified_max_width);
@@ -252,7 +252,7 @@ float FormattingContext::tentative_width_for_replaced_element(ReplacedBox const&
 {
     auto& containing_block = *box.containing_block();
     auto height_of_containing_block = CSS::Length::make_px(containing_block.content_height());
-    auto computed_height = box.computed_values().height().resolved(box, height_of_containing_block).resolved_or_auto(box);
+    auto computed_height = box.computed_values().height().has_value() ? box.computed_values().height()->resolved(box, height_of_containing_block).resolved_or_auto(box) : CSS::Length::make_auto();
 
     float used_width = computed_width.to_px(box);
 
@@ -323,14 +323,14 @@ float FormattingContext::compute_width_for_replaced_element(const ReplacedBox& b
     if (margin_right.is_auto())
         margin_right = zero_value;
 
-    auto specified_width = box.computed_values().width().resolved(box, width_of_containing_block).resolved_or_auto(box);
+    auto specified_width = box.computed_values().width().has_value() ? box.computed_values().width()->resolved(box, width_of_containing_block).resolved_or_auto(box) : CSS::Length::make_auto();
 
     // 1. The tentative used width is calculated (without 'min-width' and 'max-width')
     auto used_width = tentative_width_for_replaced_element(box, specified_width);
 
     // 2. The tentative used width is greater than 'max-width', the rules above are applied again,
     //    but this time using the computed value of 'max-width' as the computed value for 'width'.
-    auto specified_max_width = box.computed_values().max_width().resolved(box, width_of_containing_block).resolved_or_auto(box);
+    auto specified_max_width = box.computed_values().max_width().has_value() ? box.computed_values().max_width()->resolved(box, width_of_containing_block).resolved_or_auto(box) : CSS::Length::make_auto();
     if (!specified_max_width.is_auto()) {
         if (used_width > specified_max_width.to_px(box)) {
             used_width = tentative_width_for_replaced_element(box, specified_max_width);
@@ -339,7 +339,7 @@ float FormattingContext::compute_width_for_replaced_element(const ReplacedBox& b
 
     // 3. If the resulting width is smaller than 'min-width', the rules above are applied again,
     //    but this time using the value of 'min-width' as the computed value for 'width'.
-    auto specified_min_width = box.computed_values().min_width().resolved(box, width_of_containing_block).resolved_or_auto(box);
+    auto specified_min_width = box.computed_values().min_width().has_value() ? box.computed_values().min_width()->resolved(box, width_of_containing_block).resolved_or_auto(box) : CSS::Length::make_auto();
     if (!specified_min_width.is_auto()) {
         if (used_width < specified_min_width.to_px(box)) {
             used_width = tentative_width_for_replaced_element(box, specified_min_width);
@@ -355,7 +355,7 @@ float FormattingContext::tentative_height_for_replaced_element(ReplacedBox const
 {
     auto& containing_block = *box.containing_block();
     auto width_of_containing_block = CSS::Length::make_px(containing_block.content_width());
-    auto computed_width = box.computed_values().width().resolved(box, width_of_containing_block).resolved_or_auto(box);
+    auto computed_width = box.computed_values().width().has_value() ? box.computed_values().width()->resolved(box, width_of_containing_block).resolved_or_auto(box) : CSS::Length::make_auto();
 
     // If 'height' and 'width' both have computed values of 'auto' and the element also has
     // an intrinsic height, then that intrinsic height is the used value of 'height'.
@@ -389,8 +389,8 @@ float FormattingContext::compute_height_for_replaced_element(const ReplacedBox&
     auto& containing_block = *box.containing_block();
     auto width_of_containing_block = CSS::Length::make_px(containing_block.content_width());
     auto height_of_containing_block = CSS::Length::make_px(containing_block.content_height());
-    auto specified_width = box.computed_values().width().resolved(box, width_of_containing_block).resolved_or_auto(box);
+    auto specified_width = box.computed_values().width().has_value() ? box.computed_values().width()->resolved(box, width_of_containing_block).resolved_or_auto(box) : CSS::Length::make_auto();
-    auto specified_height = box.computed_values().height().resolved(box, height_of_containing_block).resolved_or_auto(box);
+    auto specified_height = box.computed_values().height().has_value() ? box.computed_values().height()->resolved(box, height_of_containing_block).resolved_or_auto(box) : CSS::Length::make_auto();
 
     float used_height = tentative_height_for_replaced_element(box, specified_height);
 
@@ -511,14 +511,14 @@ void FormattingContext::compute_width_for_absolutely_positioned_non_replaced_ele
         return width;
     };
 
-    auto specified_width = computed_values.width().resolved(box, width_of_containing_block).resolved_or_auto(box);
+    auto specified_width = computed_values.width().has_value() ? computed_values.width()->resolved(box, width_of_containing_block).resolved_or_auto(box) : CSS::Length::make_auto();
 
     // 1. The tentative used width is calculated (without 'min-width' and 'max-width')
     auto used_width = try_compute_width(specified_width);
 
     // 2. The tentative used width is greater than 'max-width', the rules above are applied again,
     //    but this time using the computed value of 'max-width' as the computed value for 'width'.
-    auto specified_max_width = computed_values.max_width().resolved(box, width_of_containing_block).resolved_or_auto(box);
+    auto specified_max_width = computed_values.max_width().has_value() ? computed_values.max_width()->resolved(box, width_of_containing_block).resolved_or_auto(box) : CSS::Length::make_auto();
     if (!specified_max_width.is_auto()) {
         if (used_width.to_px(box) > specified_max_width.to_px(box)) {
             used_width = try_compute_width(specified_max_width);
@@ -527,7 +527,7 @@ void FormattingContext::compute_width_for_absolutely_positioned_non_replaced_ele
 
     // 3. If the resulting width is smaller than 'min-width', the rules above are applied again,
     //    but this time using the value of 'min-width' as the computed value for 'width'.
-    auto specified_min_width = computed_values.min_width().resolved(box, width_of_containing_block).resolved_or_auto(box);
+    auto specified_min_width = computed_values.min_width().has_value() ? computed_values.min_width()->resolved(box, width_of_containing_block).resolved_or_auto(box) : CSS::Length::make_auto();
     if (!specified_min_width.is_auto()) {
         if (used_width.to_px(box) < specified_min_width.to_px(box)) {
             used_width = try_compute_width(specified_min_width);
@@ -561,16 +561,17 @@ void FormattingContext::compute_height_for_absolutely_positioned_non_replaced_el
 
     CSS::Length specified_top = computed_values.offset().top.resolved(box, height_of_containing_block).resolved_or_auto(box);
     CSS::Length specified_bottom = computed_values.offset().bottom.resolved(box, height_of_containing_block).resolved_or_auto(box);
-    CSS::Length specified_height;
+    CSS::Length specified_height = CSS::Length::make_auto();
 
-    if (computed_values.height().is_percentage() && !(containing_block.computed_values().height().is_length() && containing_block.computed_values().height().length().is_absolute())) {
+    if (computed_values.height().has_value() && computed_values.height()->is_percentage()
-        specified_height = CSS::Length::make_auto();
+        && !(containing_block.computed_values().height().has_value() && containing_block.computed_values().height()->is_length() && containing_block.computed_values().height()->length().is_absolute())) {
+        // specified_height is already auto
     } else {
-        specified_height = computed_values.height().resolved(box, height_of_containing_block).resolved_or_auto(box);
+        specified_height = computed_values.height().has_value() ? computed_values.height()->resolved(box, height_of_containing_block).resolved_or_auto(box) : CSS::Length::make_auto();
     }
 
-    auto specified_max_height = computed_values.max_height().resolved(box, height_of_containing_block).resolved_or_auto(box);
+    auto specified_max_height = computed_values.max_height().has_value() ? computed_values.max_height()->resolved(box, height_of_containing_block).resolved_or_auto(box) : CSS::Length::make_auto();
-    auto specified_min_height = computed_values.min_height().resolved(box, height_of_containing_block).resolved_or_auto(box);
+    auto specified_min_height = computed_values.min_height().has_value() ? computed_values.min_height()->resolved(box, height_of_containing_block).resolved_or_auto(box) : CSS::Length::make_auto();
 
     box.box_model().margin.top = computed_values.margin().top.resolved(box, width_of_containing_block).resolved_or_zero(box).to_px(box);
     box.box_model().margin.bottom = computed_values.margin().bottom.resolved(box, width_of_containing_block).resolved_or_zero(box).to_px(box);
@@ -613,7 +614,7 @@ void FormattingContext::layout_absolutely_positioned_element(Box& box)
     auto height_of_containing_block = CSS::Length::make_px(containing_block.content_height());
     auto& box_model = box.box_model();
 
-    auto specified_width = box.computed_values().width().resolved(box, width_of_containing_block).resolved_or_auto(box);
+    auto specified_width = box.computed_values().width().has_value() ? box.computed_values().width()->resolved(box, width_of_containing_block).resolved_or_auto(box) : CSS::Length::make_auto();
 
     compute_width_for_absolutely_positioned_element(box);
     auto independent_formatting_context = layout_inside(box, LayoutMode::Default);

Userland/Libraries/LibWeb/Layout/InlineFormattingContext.cpp

@@ -125,7 +125,8 @@ void InlineFormattingContext::dimension_box_on_line(Box& box, LayoutMode layout_
     if (box.is_inline_block()) {
         auto& inline_block = const_cast<BlockContainer&>(verify_cast<BlockContainer>(box));
 
-        if (inline_block.computed_values().width().is_length() && inline_block.computed_values().width().length().is_undefined_or_auto()) {
+        auto& width_value = inline_block.computed_values().width();
+        if (!width_value.has_value() || (width_value->is_length() && width_value->length().is_undefined_or_auto())) {
             auto result = calculate_shrink_to_fit_widths(inline_block);
 
             auto available_width = containing_block().content_width()
@@ -140,16 +141,17 @@ void InlineFormattingContext::dimension_box_on_line(Box& box, LayoutMode layout_
             inline_block.set_content_width(width);
         } else {
             auto container_width = CSS::Length::make_px(containing_block().content_width());
-            inline_block.set_content_width(inline_block.computed_values().width().resolved(box, container_width).resolved_or_zero(inline_block).to_px(inline_block));
+            inline_block.set_content_width(width_value->resolved(box, container_width).resolved_or_zero(inline_block).to_px(inline_block));
         }
         auto independent_formatting_context = layout_inside(inline_block, layout_mode);
 
-        if (inline_block.computed_values().height().is_length() && inline_block.computed_values().height().length().is_undefined_or_auto()) {
+        auto& height_value = inline_block.computed_values().height();
+        if (!height_value.has_value() || (height_value->is_length() && height_value->length().is_undefined_or_auto())) {
             // FIXME: (10.6.6) If 'height' is 'auto', the height depends on the element's descendants per 10.6.7.
             BlockFormattingContext::compute_height(inline_block);
         } else {
             auto container_height = CSS::Length::make_px(containing_block().content_height());
-            inline_block.set_content_height(inline_block.computed_values().height().resolved(box, container_height).resolved_or_zero(inline_block).to_px(inline_block));
+            inline_block.set_content_height(height_value->resolved(box, container_height).resolved_or_zero(inline_block).to_px(inline_block));
         }
 
         independent_formatting_context->parent_context_did_dimension_child_root_box();

Userland/Libraries/LibWeb/Layout/Node.cpp

@@ -430,15 +430,21 @@ void NodeWithStyle::apply_style(const CSS::StyleProperties& specified_style)
 
     if (auto width = specified_style.property(CSS::PropertyID::Width); width.has_value() && !width.value()->has_auto())
         m_has_definite_width = true;
-    computed_values.set_width(specified_style.length_percentage_or_fallback(CSS::PropertyID::Width, CSS::Length {}));
+    if (auto maybe_length_percentage = specified_style.length_percentage(CSS::PropertyID::Width); maybe_length_percentage.has_value())
-    computed_values.set_min_width(specified_style.length_percentage_or_fallback(CSS::PropertyID::MinWidth, CSS::Length {}));
+        computed_values.set_width(maybe_length_percentage.release_value());
-    computed_values.set_max_width(specified_style.length_percentage_or_fallback(CSS::PropertyID::MaxWidth, CSS::Length {}));
+    if (auto maybe_length_percentage = specified_style.length_percentage(CSS::PropertyID::MinWidth); maybe_length_percentage.has_value())
+        computed_values.set_min_width(maybe_length_percentage.release_value());
+    if (auto maybe_length_percentage = specified_style.length_percentage(CSS::PropertyID::MaxWidth); maybe_length_percentage.has_value())
+        computed_values.set_max_width(maybe_length_percentage.release_value());
 
     if (auto height = specified_style.property(CSS::PropertyID::Height); height.has_value() && !height.value()->has_auto())
         m_has_definite_height = true;
-    computed_values.set_height(specified_style.length_percentage_or_fallback(CSS::PropertyID::Height, CSS::Length {}));
+    if (auto maybe_length_percentage = specified_style.length_percentage(CSS::PropertyID::Height); maybe_length_percentage.has_value())
-    computed_values.set_min_height(specified_style.length_percentage_or_fallback(CSS::PropertyID::MinHeight, CSS::Length {}));
+        computed_values.set_height(maybe_length_percentage.release_value());
-    computed_values.set_max_height(specified_style.length_percentage_or_fallback(CSS::PropertyID::MaxHeight, CSS::Length {}));
+    if (auto maybe_length_percentage = specified_style.length_percentage(CSS::PropertyID::MinHeight); maybe_length_percentage.has_value())
+        computed_values.set_min_height(maybe_length_percentage.release_value());
+    if (auto maybe_length_percentage = specified_style.length_percentage(CSS::PropertyID::MaxHeight); maybe_length_percentage.has_value())
+        computed_values.set_max_height(maybe_length_percentage.release_value());
 
     computed_values.set_offset(specified_style.length_box(CSS::PropertyID::Left, CSS::PropertyID::Top, CSS::PropertyID::Right, CSS::PropertyID::Bottom, CSS::Length::make_auto()));
     computed_values.set_margin(specified_style.length_box(CSS::PropertyID::MarginLeft, CSS::PropertyID::MarginTop, CSS::PropertyID::MarginRight, CSS::PropertyID::MarginBottom, CSS::Length::make_px(0)));
@@ -457,7 +463,7 @@ void NodeWithStyle::apply_style(const CSS::StyleProperties& specified_style)
         if (border.line_style == CSS::LineStyle::None)
             border.width = 0;
         else
-            border.width = specified_style.length_or_fallback(width_property, {}).resolved_or_zero(*this).to_px(*this);
+            border.width = specified_style.length_or_fallback(width_property, CSS::Length::make_px(0)).resolved_or_zero(*this).to_px(*this);
     };
 
     do_border_style(computed_values.border_left(), CSS::PropertyID::BorderLeftWidth, CSS::PropertyID::BorderLeftColor, CSS::PropertyID::BorderLeftStyle);

Userland/Libraries/LibWeb/Layout/TableFormattingContext.cpp

@@ -52,7 +52,7 @@ void TableFormattingContext::run(Box& box, LayoutMode)
             content_height += row.content_height();
         });
 
-        if (row_group_box.computed_values().width().is_length() && row_group_box.computed_values().width().length().is_auto())
+        if (row_group_box.computed_values().width().has_value() && row_group_box.computed_values().width()->is_length() && row_group_box.computed_values().width()->length().is_auto())
             row_group_box.set_content_width(content_width);
         row_group_box.set_content_height(content_height);
 
@@ -61,7 +61,7 @@ void TableFormattingContext::run(Box& box, LayoutMode)
         total_content_width = max(total_content_width, row_group_box.content_width());
     });
 
-    if (box.computed_values().width().is_length() && box.computed_values().width().length().is_auto())
+    if (box.computed_values().width().has_value() && box.computed_values().width()->is_length() && box.computed_values().width()->length().is_auto())
         box.set_content_width(total_content_width);
 
     // FIXME: This is a total hack, we should respect the 'height' property.
@@ -72,7 +72,7 @@ void TableFormattingContext::calculate_column_widths(Box& row, Vector<float>& co
 {
     size_t column_index = 0;
     auto* table = row.first_ancestor_of_type<TableBox>();
-    bool use_auto_layout = !table || (table->computed_values().width().is_length() && table->computed_values().width().length().is_undefined_or_auto());
+    bool use_auto_layout = !table || (!table->computed_values().width().has_value() || (table->computed_values().width()->is_length() && table->computed_values().width()->length().is_undefined_or_auto()));
     row.for_each_child_of_type<TableCellBox>([&](auto& cell) {
         compute_width(cell);
         if (use_auto_layout) {
@@ -91,7 +91,7 @@ void TableFormattingContext::layout_row(Box& row, Vector<float>& column_widths)
     float tallest_cell_height = 0;
     float content_width = 0;
     auto* table = row.first_ancestor_of_type<TableBox>();
-    bool use_auto_layout = !table || (table->computed_values().width().is_length() && table->computed_values().width().length().is_undefined_or_auto());
+    bool use_auto_layout = !table || (!table->computed_values().width().has_value() || (table->computed_values().width()->is_length() && table->computed_values().width()->length().is_undefined_or_auto()));
 
     row.for_each_child_of_type<TableCellBox>([&](auto& cell) {
         cell.set_offset(row.effective_offset().translated(content_width, 0));