Use the writing mode of the containing block when accessing CSS properties

… and converting them to flow-relative geometric values.

These values are almost always used to size and position a fragment within its containing block, so using the mode of the containing block seems more correct.

Note that the `writing-mode` and `direction` properties are disabled in Servo at the moment, so this PR by itself should have no effect: the writing mode of an element is always the same of that of its containing block since they’re both horizontal rtl.

components/layout_2020/flow/construct.rs

@@ -21,6 +21,7 @@ use rayon_croissant::ParallelIteratorExt;
 use servo_arc::Arc;
 use std::borrow::Cow;
 use std::convert::{TryFrom, TryInto};
+use style::logical_geometry::WritingMode;
 use style::properties::ComputedValues;
 use style::selector_parser::PseudoElement;
 use style::values::specified::text::TextDecorationLine;
@@ -67,7 +68,12 @@ impl BlockFormattingContext {
             inline_level_boxes,
             text_decoration_line,
         };
-        let content_sizes = content_sizes.compute(|| ifc.inline_content_sizes(context));
+        // FIXME: this is the wrong writing mode
+        // but we plan to remove eager content size computation.
+        let not_actually_containing_block_writing_mode = WritingMode::empty();
+        let content_sizes = content_sizes.compute(|| {
+            ifc.inline_content_sizes(context, not_actually_containing_block_writing_mode)
+        });
         let contents = BlockContainer::InlineFormattingContext(ifc);
         let bfc = Self {
             contents,
@@ -203,10 +209,13 @@ impl BlockContainer {
             .is_empty()
         {
             if builder.block_level_boxes.is_empty() {
+                // FIXME: this is the wrong writing mode
+                // but we plan to remove eager content size computation.
+                let not_actually_containing_block_writing_mode = info.style.writing_mode;
                 let content_sizes = content_sizes.compute(|| {
                     builder
                         .ongoing_inline_formatting_context
-                        .inline_content_sizes(context)
+                        .inline_content_sizes(context, not_actually_containing_block_writing_mode)
                 });
                 let container = BlockContainer::InlineFormattingContext(
                     builder.ongoing_inline_formatting_context,
@@ -678,6 +687,9 @@ where
         max_assign_in_flow_outer_content_sizes_to: Option<&mut ContentSizes>,
     ) -> (ArcRefCell<BlockLevelBox>, ContainsFloats) {
         let info = &self.info;
+        // FIXME: this is the wrong writing mode
+        // but we plan to remove eager content size computation.
+        let not_actually_containing_block_writing_mode = info.style.writing_mode;
         let (block_level_box, contains_floats) = match self.kind {
             BlockLevelCreator::SameFormattingContextBlock(contents) => {
                 let (contents, contains_floats, box_content_sizes) = contents.finish(
@@ -689,7 +701,10 @@ where
                     ),
                 );
                 if let Some(to) = max_assign_in_flow_outer_content_sizes_to {
-                    to.max_assign(&box_content_sizes.outer_inline(&info.style))
+                    to.max_assign(
+                        &box_content_sizes
+                            .outer_inline(&info.style, not_actually_containing_block_writing_mode),
+                    )
                 }
                 let block_level_box = ArcRefCell::new(BlockLevelBox::SameFormattingContextBlock {
                     tag: Tag::from_node_and_style_info(info),
@@ -716,7 +731,12 @@ where
                     propagated_text_decoration_line,
                 );
                 if let Some(to) = max_assign_in_flow_outer_content_sizes_to {
-                    to.max_assign(&contents.content_sizes.outer_inline(&contents.style))
+                    to.max_assign(
+                        &contents.content_sizes.outer_inline(
+                            &contents.style,
+                            not_actually_containing_block_writing_mode,
+                        ),
+                    )
                 }
                 (
                     ArcRefCell::new(BlockLevelBox::Independent(contents)),
@@ -771,7 +791,12 @@ impl IntermediateBlockContainer {
                 )
             },
             IntermediateBlockContainer::InlineFormattingContext(ifc) => {
-                let content_sizes = content_sizes.compute(|| ifc.inline_content_sizes(context));
+                // FIXME: this is the wrong writing mode
+                // but we plan to remove eager content size computation.
+                let not_actually_containing_block_writing_mode = info.style.writing_mode;
+                let content_sizes = content_sizes.compute(|| {
+                    ifc.inline_content_sizes(context, not_actually_containing_block_writing_mode)
+                });
                 // If that inline formatting context contained any float, those
                 // were already taken into account during the first phase of
                 // box construction.

components/layout_2020/flow/inline.rs

@@ -23,6 +23,7 @@ use app_units::Au;
 use atomic_refcell::AtomicRef;
 use gfx::text::text_run::GlyphRun;
 use servo_arc::Arc;
+use style::logical_geometry::WritingMode;
 use style::properties::ComputedValues;
 use style::values::computed::{Length, LengthPercentage, Percentage};
 use style::values::specified::text::TextAlignKeyword;
@@ -139,24 +140,30 @@ impl InlineFormattingContext {
     // This works on an already-constructed `InlineFormattingContext`,
     // Which would have to change if/when
     // `BlockContainer::construct` parallelize their construction.
-    pub(super) fn inline_content_sizes(&self, layout_context: &LayoutContext) -> ContentSizes {
+    pub(super) fn inline_content_sizes(
-        struct Computation {
+        &self,
+        layout_context: &LayoutContext,
+        containing_block_writing_mode: WritingMode,
+    ) -> ContentSizes {
+        struct Computation<'a> {
+            layout_context: &'a LayoutContext<'a>,
+            containing_block_writing_mode: WritingMode,
             paragraph: ContentSizes,
             current_line: ContentSizes,
             current_line_percentages: Percentage,
         }
-        impl Computation {
+        impl Computation<'_> {
-            fn traverse(
+            fn traverse(&mut self, inline_level_boxes: &[ArcRefCell<InlineLevelBox>]) {
-                &mut self,
-                layout_context: &LayoutContext,
-                inline_level_boxes: &[ArcRefCell<InlineLevelBox>],
-            ) {
                 for inline_level_box in inline_level_boxes {
                     match &*inline_level_box.borrow() {
                         InlineLevelBox::InlineBox(inline_box) => {
-                            let padding = inline_box.style.padding();
+                            let padding =
-                            let border = inline_box.style.border_width();
+                                inline_box.style.padding(self.containing_block_writing_mode);
-                            let margin = inline_box.style.margin();
+                            let border = inline_box
+                                .style
+                                .border_width(self.containing_block_writing_mode);
+                            let margin =
+                                inline_box.style.margin(self.containing_block_writing_mode);
                             macro_rules! add {
                                 ($condition: ident, $side: ident) => {
                                     if inline_box.$condition {
@@ -170,7 +177,7 @@ impl InlineFormattingContext {
                             }
 
                             add!(first_fragment, inline_start);
-                            self.traverse(layout_context, &inline_box.children);
+                            self.traverse(&inline_box.children);
                             add!(last_fragment, inline_end);
                         },
                         InlineLevelBox::TextRun(text_run) => {
@@ -178,7 +185,7 @@ impl InlineFormattingContext {
                                 runs,
                                 break_at_start,
                                 ..
-                            } = text_run.break_and_shape(layout_context);
+                            } = text_run.break_and_shape(self.layout_context);
                             if break_at_start {
                                 self.line_break_opportunity()
                             }
@@ -193,9 +200,10 @@ impl InlineFormattingContext {
                             }
                         },
                         InlineLevelBox::Atomic(atomic) => {
-                            let (outer, pc) = atomic
+                            let (outer, pc) = atomic.content_sizes.outer_inline_and_percentages(
-                                .content_sizes
+                                &atomic.style,
-                                .outer_inline_and_percentages(&atomic.style);
+                                self.containing_block_writing_mode,
+                            );
                             self.current_line.min_content += outer.min_content;
                             self.current_line.max_content += outer.max_content;
                             self.current_line_percentages += pc;
@@ -239,11 +247,13 @@ impl InlineFormattingContext {
             std::mem::replace(x, T::zero())
         }
         let mut computation = Computation {
+            layout_context,
+            containing_block_writing_mode,
             paragraph: ContentSizes::zero(),
             current_line: ContentSizes::zero(),
             current_line_percentages: Percentage::zero(),
         };
-        computation.traverse(layout_context, &self.inline_level_boxes);
+        computation.traverse(&self.inline_level_boxes);
         computation.forced_line_break();
         computation.paragraph
     }
@@ -308,6 +318,7 @@ impl InlineFormattingContext {
                             box_.clone(),
                             initial_start_corner,
                             tree_rank,
+                            ifc.containing_block,
                         );
                         let hoisted_fragment = hoisted_box.fragment.clone();
                         ifc.push_hoisted_box_to_positioning_context(hoisted_box);

components/layout_2020/flow/mod.rs

@@ -316,8 +316,12 @@ impl BlockLevelBox {
                 ))
             },
             BlockLevelBox::OutOfFlowAbsolutelyPositionedBox(box_) => {
-                let hoisted_box =
+                let hoisted_box = AbsolutelyPositionedBox::to_hoisted(
-                    AbsolutelyPositionedBox::to_hoisted(box_.clone(), Vec2::zero(), tree_rank);
+                    box_.clone(),
+                    Vec2::zero(),
+                    tree_rank,
+                    containing_block,
+                );
                 let hoisted_fragment = hoisted_box.fragment.clone();
                 positioning_context.push(hoisted_box);
                 Fragment::AbsoluteOrFixedPositioned(AbsoluteOrFixedPositionedFragment {

components/layout_2020/positioned.rs

@@ -100,6 +100,7 @@ impl AbsolutelyPositionedBox {
         self_: ArcRefCell<Self>,
         initial_start_corner: Vec2<Length>,
         tree_rank: usize,
+        containing_block: &ContainingBlock,
     ) -> HoistedAbsolutelyPositionedBox {
         fn absolute_box_offsets(
             initial_static_start: Length,
@@ -123,7 +124,7 @@ impl AbsolutelyPositionedBox {
 
         let box_offsets = {
             let box_ = self_.borrow();
-            let box_offsets = box_.contents.style.box_offsets();
+            let box_offsets = box_.contents.style.box_offsets(containing_block);
             Vec2 {
                 inline: absolute_box_offsets(
                     initial_start_corner.inline,
@@ -708,10 +709,12 @@ pub(crate) fn relative_adjustement(
 ) -> Vec2<Length> {
     let cbis = containing_block.inline_size;
     let cbbs = containing_block.block_size.auto_is(Length::zero);
-    let box_offsets = style.box_offsets().map_inline_and_block_axes(
+    let box_offsets = style
-        |v| v.percentage_relative_to(cbis),
+        .box_offsets(containing_block)
-        |v| v.percentage_relative_to(cbbs),
+        .map_inline_and_block_axes(
-    );
+            |v| v.percentage_relative_to(cbis),
+            |v| v.percentage_relative_to(cbbs),
+        );
     fn adjust(start: LengthOrAuto, end: LengthOrAuto) -> Length {
         match (start, end) {
             (LengthOrAuto::Auto, LengthOrAuto::Auto) => Length::zero(),

components/layout_2020/sizing.rs

@@ -5,6 +5,7 @@
 //! https://drafts.csswg.org/css-sizing/
 
 use crate::style_ext::ComputedValuesExt;
+use style::logical_geometry::WritingMode;
 use style::properties::longhands::box_sizing::computed_value::T as BoxSizing;
 use style::properties::ComputedValues;
 use style::values::computed::{Length, LengthPercentage, Percentage};
@@ -105,8 +106,13 @@ impl BoxContentSizes {
     }
 
     /// https://dbaron.org/css/intrinsic/#outer-intrinsic
-    pub fn outer_inline(&self, style: &ComputedValues) -> ContentSizes {
+    pub fn outer_inline(
-        let (mut outer, percentages) = self.outer_inline_and_percentages(style);
+        &self,
+        style: &ComputedValues,
+        containing_block_writing_mode: WritingMode,
+    ) -> ContentSizes {
+        let (mut outer, percentages) =
+            self.outer_inline_and_percentages(style, containing_block_writing_mode);
         outer.adjust_for_pbm_percentages(percentages);
         outer
     }
@@ -114,10 +120,11 @@ impl BoxContentSizes {
     pub(crate) fn outer_inline_and_percentages(
         &self,
         style: &ComputedValues,
+        containing_block_writing_mode: WritingMode,
     ) -> (ContentSizes, Percentage) {
-        let padding = style.padding();
+        let padding = style.padding(containing_block_writing_mode);
-        let border = style.border_width();
+        let border = style.border_width(containing_block_writing_mode);
-        let margin = style.margin();
+        let margin = style.margin(containing_block_writing_mode);
 
         let mut pbm_percentages = Percentage::zero();
         let mut decompose = |x: &LengthPercentage| {
@@ -136,20 +143,20 @@ impl BoxContentSizes {
 
         let box_sizing = style.get_position().box_sizing;
         let inline_size = style
-            .box_size()
+            .box_size(containing_block_writing_mode)
             .inline
             .non_auto()
             // Percentages for 'width' are treated as 'auto'
             .and_then(|lp| lp.to_length());
         let min_inline_size = style
-            .min_box_size()
+            .min_box_size(containing_block_writing_mode)
             .inline
             // Percentages for 'min-width' are treated as zero
             .percentage_relative_to(Length::zero())
             // FIXME: 'auto' is not zero in Flexbox
             .auto_is(Length::zero);
         let max_inline_size = style
-            .max_box_size()
+            .max_box_size(containing_block_writing_mode)
             .inline
             // Percentages for 'max-width' are treated as 'none'
             .and_then(|lp| lp.to_length());

components/layout_2020/style_ext.rs

@@ -8,6 +8,7 @@ use crate::ContainingBlock;
 use style::computed_values::mix_blend_mode::T as ComputedMixBlendMode;
 use style::computed_values::position::T as ComputedPosition;
 use style::computed_values::transform_style::T as ComputedTransformStyle;
+use style::logical_geometry::WritingMode;
 use style::properties::longhands::backface_visibility::computed_value::T as BackfaceVisiblity;
 use style::properties::longhands::box_sizing::computed_value::T as BoxSizing;
 use style::properties::ComputedValues;
@@ -64,10 +65,22 @@ pub(crate) struct PaddingBorderMargin {
 pub(crate) trait ComputedValuesExt {
     fn inline_size_is_length(&self) -> bool;
     fn inline_box_offsets_are_both_non_auto(&self) -> bool;
-    fn box_offsets(&self) -> flow_relative::Sides<LengthPercentageOrAuto<'_>>;
+    fn box_offsets(
-    fn box_size(&self) -> flow_relative::Vec2<LengthPercentageOrAuto<'_>>;
+        &self,
-    fn min_box_size(&self) -> flow_relative::Vec2<LengthPercentageOrAuto<'_>>;
+        containing_block: &ContainingBlock,
-    fn max_box_size(&self) -> flow_relative::Vec2<Option<&LengthPercentage>>;
+    ) -> flow_relative::Sides<LengthPercentageOrAuto<'_>>;
+    fn box_size(
+        &self,
+        containing_block_writing_mode: WritingMode,
+    ) -> flow_relative::Vec2<LengthPercentageOrAuto<'_>>;
+    fn min_box_size(
+        &self,
+        containing_block_writing_mode: WritingMode,
+    ) -> flow_relative::Vec2<LengthPercentageOrAuto<'_>>;
+    fn max_box_size(
+        &self,
+        containing_block_writing_mode: WritingMode,
+    ) -> flow_relative::Vec2<Option<&LengthPercentage>>;
     fn content_box_size(
         &self,
         containing_block: &ContainingBlock,
@@ -84,9 +97,18 @@ pub(crate) trait ComputedValuesExt {
         pbm: &PaddingBorderMargin,
     ) -> flow_relative::Vec2<Option<Length>>;
     fn padding_border_margin(&self, containing_block: &ContainingBlock) -> PaddingBorderMargin;
-    fn padding(&self) -> flow_relative::Sides<&LengthPercentage>;
+    fn padding(
-    fn border_width(&self) -> flow_relative::Sides<Length>;
+        &self,
-    fn margin(&self) -> flow_relative::Sides<LengthPercentageOrAuto<'_>>;
+        containing_block_writing_mode: WritingMode,
+    ) -> flow_relative::Sides<&LengthPercentage>;
+    fn border_width(
+        &self,
+        containing_block_writing_mode: WritingMode,
+    ) -> flow_relative::Sides<Length>;
+    fn margin(
+        &self,
+        containing_block_writing_mode: WritingMode,
+    ) -> flow_relative::Sides<LengthPercentageOrAuto<'_>>;
     fn has_transform_or_perspective(&self) -> bool;
     fn effective_z_index(&self) -> i32;
     fn establishes_stacking_context(&self) -> bool;
@@ -99,6 +121,7 @@ pub(crate) trait ComputedValuesExt {
 impl ComputedValuesExt for ComputedValues {
     fn inline_size_is_length(&self) -> bool {
         let position = self.get_position();
+        // FIXME: this is the wrong writing mode but we plan to remove eager content size computation.
         let size = if self.writing_mode.is_horizontal() {
             &position.width
         } else {
@@ -109,6 +132,7 @@ impl ComputedValuesExt for ComputedValues {
 
     fn inline_box_offsets_are_both_non_auto(&self) -> bool {
         let position = self.get_position();
+        // FIXME: this is the wrong writing mode but we plan to remove eager content size computation.
         let (a, b) = if self.writing_mode.is_horizontal() {
             (&position.left, &position.right)
         } else {
@@ -117,7 +141,10 @@ impl ComputedValuesExt for ComputedValues {
         !a.is_auto() && !b.is_auto()
     }
 
-    fn box_offsets(&self) -> flow_relative::Sides<LengthPercentageOrAuto<'_>> {
+    fn box_offsets(
+        &self,
+        containing_block: &ContainingBlock,
+    ) -> flow_relative::Sides<LengthPercentageOrAuto<'_>> {
         let position = self.get_position();
         flow_relative::Sides::from_physical(
             &PhysicalSides::new(
@@ -126,33 +153,42 @@ impl ComputedValuesExt for ComputedValues {
                 position.bottom.as_ref(),
                 position.left.as_ref(),
             ),
-            self.writing_mode,
+            containing_block.style.writing_mode,
         )
     }
 
-    fn box_size(&self) -> flow_relative::Vec2<LengthPercentageOrAuto<'_>> {
+    fn box_size(
+        &self,
+        containing_block_writing_mode: WritingMode,
+    ) -> flow_relative::Vec2<LengthPercentageOrAuto<'_>> {
         let position = self.get_position();
         flow_relative::Vec2::from_physical_size(
             &PhysicalSize::new(
                 size_to_length(&position.width),
                 size_to_length(&position.height),
             ),
-            self.writing_mode,
+            containing_block_writing_mode,
         )
     }
 
-    fn min_box_size(&self) -> flow_relative::Vec2<LengthPercentageOrAuto<'_>> {
+    fn min_box_size(
+        &self,
+        containing_block_writing_mode: WritingMode,
+    ) -> flow_relative::Vec2<LengthPercentageOrAuto<'_>> {
         let position = self.get_position();
         flow_relative::Vec2::from_physical_size(
             &PhysicalSize::new(
                 size_to_length(&position.min_width),
                 size_to_length(&position.min_height),
             ),
-            self.writing_mode,
+            containing_block_writing_mode,
         )
     }
 
-    fn max_box_size(&self) -> flow_relative::Vec2<Option<&LengthPercentage>> {
+    fn max_box_size(
+        &self,
+        containing_block_writing_mode: WritingMode,
+    ) -> flow_relative::Vec2<Option<&LengthPercentage>> {
         fn unwrap(max_size: &MaxSize<NonNegativeLengthPercentage>) -> Option<&LengthPercentage> {
             match max_size {
                 MaxSize::LengthPercentage(length) => Some(&length.0),
@@ -162,7 +198,7 @@ impl ComputedValuesExt for ComputedValues {
         let position = self.get_position();
         flow_relative::Vec2::from_physical_size(
             &PhysicalSize::new(unwrap(&position.max_width), unwrap(&position.max_height)),
-            self.writing_mode,
+            containing_block_writing_mode,
         )
     }
 
@@ -171,7 +207,9 @@ impl ComputedValuesExt for ComputedValues {
         containing_block: &ContainingBlock,
         pbm: &PaddingBorderMargin,
     ) -> flow_relative::Vec2<LengthOrAuto> {
-        let box_size = self.box_size().percentages_relative_to(containing_block);
+        let box_size = self
+            .box_size(containing_block.style.writing_mode)
+            .percentages_relative_to(containing_block);
         match self.get_position().box_sizing {
             BoxSizing::ContentBox => box_size,
             BoxSizing::BorderBox => flow_relative::Vec2 {
@@ -189,7 +227,7 @@ impl ComputedValuesExt for ComputedValues {
         pbm: &PaddingBorderMargin,
     ) -> flow_relative::Vec2<LengthOrAuto> {
         let min_box_size = self
-            .min_box_size()
+            .min_box_size(containing_block.style.writing_mode)
             .percentages_relative_to(containing_block);
         match self.get_position().box_sizing {
             BoxSizing::ContentBox => min_box_size,
@@ -211,7 +249,7 @@ impl ComputedValuesExt for ComputedValues {
         pbm: &PaddingBorderMargin,
     ) -> flow_relative::Vec2<Option<Length>> {
         let max_box_size = self
-            .max_box_size()
+            .max_box_size(containing_block.style.writing_mode)
             .percentages_relative_to(containing_block);
         match self.get_position().box_sizing {
             BoxSizing::ContentBox => max_box_size,
@@ -232,8 +270,10 @@ impl ComputedValuesExt for ComputedValues {
 
     fn padding_border_margin(&self, containing_block: &ContainingBlock) -> PaddingBorderMargin {
         let cbis = containing_block.inline_size;
-        let padding = self.padding().percentages_relative_to(cbis);
+        let padding = self
-        let border = self.border_width();
+            .padding(containing_block.style.writing_mode)
+            .percentages_relative_to(cbis);
+        let border = self.border_width(containing_block.style.writing_mode);
         PaddingBorderMargin {
             padding_border_sums: flow_relative::Vec2 {
                 inline: padding.inline_sum() + border.inline_sum(),
@@ -241,11 +281,16 @@ impl ComputedValuesExt for ComputedValues {
             },
             padding,
             border,
-            margin: self.margin().percentages_relative_to(cbis),
+            margin: self
+                .margin(containing_block.style.writing_mode)
+                .percentages_relative_to(cbis),
         }
     }
 
-    fn padding(&self) -> flow_relative::Sides<&LengthPercentage> {
+    fn padding(
+        &self,
+        containing_block_writing_mode: WritingMode,
+    ) -> flow_relative::Sides<&LengthPercentage> {
         let padding = self.get_padding();
         flow_relative::Sides::from_physical(
             &PhysicalSides::new(
@@ -254,11 +299,14 @@ impl ComputedValuesExt for ComputedValues {
                 &padding.padding_bottom.0,
                 &padding.padding_left.0,
             ),
-            self.writing_mode,
+            containing_block_writing_mode,
         )
     }
 
-    fn border_width(&self) -> flow_relative::Sides<Length> {
+    fn border_width(
+        &self,
+        containing_block_writing_mode: WritingMode,
+    ) -> flow_relative::Sides<Length> {
         let border = self.get_border();
         flow_relative::Sides::from_physical(
             &PhysicalSides::new(
@@ -267,11 +315,14 @@ impl ComputedValuesExt for ComputedValues {
                 border.border_bottom_width.0,
                 border.border_left_width.0,
             ),
-            self.writing_mode,
+            containing_block_writing_mode,
         )
     }
 
-    fn margin(&self) -> flow_relative::Sides<LengthPercentageOrAuto<'_>> {
+    fn margin(
+        &self,
+        containing_block_writing_mode: WritingMode,
+    ) -> flow_relative::Sides<LengthPercentageOrAuto<'_>> {
         let margin = self.get_margin();
         flow_relative::Sides::from_physical(
             &PhysicalSides::new(
@@ -280,7 +331,7 @@ impl ComputedValuesExt for ComputedValues {
                 margin.margin_bottom.as_ref(),
                 margin.margin_left.as_ref(),
             ),
-            self.writing_mode,
+            containing_block_writing_mode,
         )
     }