Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1629 insertions, 0 deletions

diff --git a/servo/components/style/logical_geometry.rs b/servo/components/style/logical_geometry.rs
new file mode 100644
index 0000000000..03272ae545
--- /dev/null
+++ b/servo/components/style/logical_geometry.rs
@@ -0,0 +1,1629 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+//! Geometry in flow-relative space.
+
+use crate::properties::style_structs;
+use euclid::default::{Point2D, Rect, SideOffsets2D, Size2D};
+use euclid::num::Zero;
+use std::cmp::{max, min};
+use std::fmt::{self, Debug, Error, Formatter};
+use std::ops::{Add, Sub};
+use unicode_bidi as bidi;
+
+pub enum BlockFlowDirection {
+    TopToBottom,
+    RightToLeft,
+    LeftToRight,
+}
+
+pub enum InlineBaseDirection {
+    LeftToRight,
+    RightToLeft,
+}
+
+// TODO: improve the readability of the WritingMode serialization, refer to the Debug:fmt()
+#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, PartialEq, Serialize)]
+#[repr(C)]
+pub struct WritingMode(u8);
+bitflags!(
+    impl WritingMode: u8 {
+        /// A vertical writing mode; writing-mode is vertical-rl,
+        /// vertical-lr, sideways-lr, or sideways-rl.
+        const VERTICAL = 1 << 0;
+        /// The inline flow direction is reversed against the physical
+        /// direction (i.e. right-to-left or bottom-to-top); writing-mode is
+        /// sideways-lr or direction is rtl (but not both).
+        ///
+        /// (This bit can be derived from the others, but we store it for
+        /// convenience.)
+        const INLINE_REVERSED = 1 << 1;
+        /// A vertical writing mode whose block progression direction is left-
+        /// to-right; writing-mode is vertical-lr or sideways-lr.
+        ///
+        /// Never set without VERTICAL.
+        const VERTICAL_LR = 1 << 2;
+        /// The line-over/line-under sides are inverted with respect to the
+        /// block-start/block-end edge; writing-mode is vertical-lr.
+        ///
+        /// Never set without VERTICAL and VERTICAL_LR.
+        const LINE_INVERTED = 1 << 3;
+        /// direction is rtl.
+        const RTL = 1 << 4;
+        /// All text within a vertical writing mode is displayed sideways
+        /// and runs top-to-bottom or bottom-to-top; set in these cases:
+        ///
+        /// * writing-mode: sideways-rl;
+        /// * writing-mode: sideways-lr;
+        ///
+        /// Never set without VERTICAL.
+        const VERTICAL_SIDEWAYS = 1 << 5;
+        /// Similar to VERTICAL_SIDEWAYS, but is set via text-orientation;
+        /// set in these cases:
+        ///
+        /// * writing-mode: vertical-rl; text-orientation: sideways;
+        /// * writing-mode: vertical-lr; text-orientation: sideways;
+        ///
+        /// Never set without VERTICAL.
+        const TEXT_SIDEWAYS = 1 << 6;
+        /// Horizontal text within a vertical writing mode is displayed with each
+        /// glyph upright; set in these cases:
+        ///
+        /// * writing-mode: vertical-rl; text-orientation: upright;
+        /// * writing-mode: vertical-lr: text-orientation: upright;
+        ///
+        /// Never set without VERTICAL.
+        const UPRIGHT = 1 << 7;
+    }
+);
+
+impl WritingMode {
+    /// Return a WritingMode bitflags from the relevant CSS properties.
+    pub fn new(inheritedbox_style: &style_structs::InheritedBox) -> Self {
+        use crate::properties::longhands::direction::computed_value::T as Direction;
+        use crate::properties::longhands::writing_mode::computed_value::T as SpecifiedWritingMode;
+
+        let mut flags = WritingMode::empty();
+
+        let direction = inheritedbox_style.clone_direction();
+        let writing_mode = inheritedbox_style.clone_writing_mode();
+
+        match direction {
+            Direction::Ltr => {},
+            Direction::Rtl => {
+                flags.insert(WritingMode::RTL);
+            },
+        }
+
+        match writing_mode {
+            SpecifiedWritingMode::HorizontalTb => {
+                if direction == Direction::Rtl {
+                    flags.insert(WritingMode::INLINE_REVERSED);
+                }
+            },
+            SpecifiedWritingMode::VerticalRl => {
+                flags.insert(WritingMode::VERTICAL);
+                if direction == Direction::Rtl {
+                    flags.insert(WritingMode::INLINE_REVERSED);
+                }
+            },
+            SpecifiedWritingMode::VerticalLr => {
+                flags.insert(WritingMode::VERTICAL);
+                flags.insert(WritingMode::VERTICAL_LR);
+                flags.insert(WritingMode::LINE_INVERTED);
+                if direction == Direction::Rtl {
+                    flags.insert(WritingMode::INLINE_REVERSED);
+                }
+            },
+            #[cfg(feature = "gecko")]
+            SpecifiedWritingMode::SidewaysRl => {
+                flags.insert(WritingMode::VERTICAL);
+                flags.insert(WritingMode::VERTICAL_SIDEWAYS);
+                if direction == Direction::Rtl {
+                    flags.insert(WritingMode::INLINE_REVERSED);
+                }
+            },
+            #[cfg(feature = "gecko")]
+            SpecifiedWritingMode::SidewaysLr => {
+                flags.insert(WritingMode::VERTICAL);
+                flags.insert(WritingMode::VERTICAL_LR);
+                flags.insert(WritingMode::VERTICAL_SIDEWAYS);
+                if direction == Direction::Ltr {
+                    flags.insert(WritingMode::INLINE_REVERSED);
+                }
+            },
+        }
+
+        #[cfg(feature = "gecko")]
+        {
+            use crate::properties::longhands::text_orientation::computed_value::T as TextOrientation;
+
+            // text-orientation only has an effect for vertical-rl and
+            // vertical-lr values of writing-mode.
+            match writing_mode {
+                SpecifiedWritingMode::VerticalRl | SpecifiedWritingMode::VerticalLr => {
+                    match inheritedbox_style.clone_text_orientation() {
+                        TextOrientation::Mixed => {},
+                        TextOrientation::Upright => {
+                            flags.insert(WritingMode::UPRIGHT);
+
+                            // https://drafts.csswg.org/css-writing-modes-3/#valdef-text-orientation-upright:
+                            //
+                            // > This value causes the used value of direction
+                            // > to be ltr, and for the purposes of bidi
+                            // > reordering, causes all characters to be treated
+                            // > as strong LTR.
+                            flags.remove(WritingMode::RTL);
+                            flags.remove(WritingMode::INLINE_REVERSED);
+                        },
+                        TextOrientation::Sideways => {
+                            flags.insert(WritingMode::TEXT_SIDEWAYS);
+                        },
+                    }
+                },
+                _ => {},
+            }
+        }
+
+        flags
+    }
+
+    /// Returns the `horizontal-tb` value.
+    pub fn horizontal_tb() -> Self {
+        Self::empty()
+    }
+
+    #[inline]
+    pub fn is_vertical(&self) -> bool {
+        self.intersects(WritingMode::VERTICAL)
+    }
+
+    #[inline]
+    pub fn is_horizontal(&self) -> bool {
+        !self.is_vertical()
+    }
+
+    /// Assuming .is_vertical(), does the block direction go left to right?
+    #[inline]
+    pub fn is_vertical_lr(&self) -> bool {
+        self.intersects(WritingMode::VERTICAL_LR)
+    }
+
+    /// Assuming .is_vertical(), does the inline direction go top to bottom?
+    #[inline]
+    pub fn is_inline_tb(&self) -> bool {
+        // https://drafts.csswg.org/css-writing-modes-3/#logical-to-physical
+        !self.intersects(WritingMode::INLINE_REVERSED)
+    }
+
+    #[inline]
+    pub fn is_bidi_ltr(&self) -> bool {
+        !self.intersects(WritingMode::RTL)
+    }
+
+    #[inline]
+    pub fn is_sideways(&self) -> bool {
+        self.intersects(WritingMode::VERTICAL_SIDEWAYS | WritingMode::TEXT_SIDEWAYS)
+    }
+
+    #[inline]
+    pub fn is_upright(&self) -> bool {
+        self.intersects(WritingMode::UPRIGHT)
+    }
+
+    /// https://drafts.csswg.org/css-writing-modes/#logical-to-physical
+    ///
+    /// | Return  | line-left is… | line-right is… |
+    /// |---------|---------------|----------------|
+    /// | `true`  | inline-start  | inline-end     |
+    /// | `false` | inline-end    | inline-start   |
+    #[inline]
+    pub fn line_left_is_inline_start(&self) -> bool {
+        // https://drafts.csswg.org/css-writing-modes/#inline-start
+        // “For boxes with a used direction value of ltr, this means the line-left side.
+        //  For boxes with a used direction value of rtl, this means the line-right side.”
+        self.is_bidi_ltr()
+    }
+
+    #[inline]
+    pub fn inline_start_physical_side(&self) -> PhysicalSide {
+        match (self.is_vertical(), self.is_inline_tb(), self.is_bidi_ltr()) {
+            (false, _, true) => PhysicalSide::Left,
+            (false, _, false) => PhysicalSide::Right,
+            (true, true, _) => PhysicalSide::Top,
+            (true, false, _) => PhysicalSide::Bottom,
+        }
+    }
+
+    #[inline]
+    pub fn inline_end_physical_side(&self) -> PhysicalSide {
+        match (self.is_vertical(), self.is_inline_tb(), self.is_bidi_ltr()) {
+            (false, _, true) => PhysicalSide::Right,
+            (false, _, false) => PhysicalSide::Left,
+            (true, true, _) => PhysicalSide::Bottom,
+            (true, false, _) => PhysicalSide::Top,
+        }
+    }
+
+    #[inline]
+    pub fn block_start_physical_side(&self) -> PhysicalSide {
+        match (self.is_vertical(), self.is_vertical_lr()) {
+            (false, _) => PhysicalSide::Top,
+            (true, true) => PhysicalSide::Left,
+            (true, false) => PhysicalSide::Right,
+        }
+    }
+
+    #[inline]
+    pub fn block_end_physical_side(&self) -> PhysicalSide {
+        match (self.is_vertical(), self.is_vertical_lr()) {
+            (false, _) => PhysicalSide::Bottom,
+            (true, true) => PhysicalSide::Right,
+            (true, false) => PhysicalSide::Left,
+        }
+    }
+
+    #[inline]
+    pub fn start_start_physical_corner(&self) -> PhysicalCorner {
+        PhysicalCorner::from_sides(
+            self.block_start_physical_side(),
+            self.inline_start_physical_side(),
+        )
+    }
+
+    #[inline]
+    pub fn start_end_physical_corner(&self) -> PhysicalCorner {
+        PhysicalCorner::from_sides(
+            self.block_start_physical_side(),
+            self.inline_end_physical_side(),
+        )
+    }
+
+    #[inline]
+    pub fn end_start_physical_corner(&self) -> PhysicalCorner {
+        PhysicalCorner::from_sides(
+            self.block_end_physical_side(),
+            self.inline_start_physical_side(),
+        )
+    }
+
+    #[inline]
+    pub fn end_end_physical_corner(&self) -> PhysicalCorner {
+        PhysicalCorner::from_sides(
+            self.block_end_physical_side(),
+            self.inline_end_physical_side(),
+        )
+    }
+
+    #[inline]
+    pub fn block_flow_direction(&self) -> BlockFlowDirection {
+        match (self.is_vertical(), self.is_vertical_lr()) {
+            (false, _) => BlockFlowDirection::TopToBottom,
+            (true, true) => BlockFlowDirection::LeftToRight,
+            (true, false) => BlockFlowDirection::RightToLeft,
+        }
+    }
+
+    #[inline]
+    pub fn inline_base_direction(&self) -> InlineBaseDirection {
+        if self.intersects(WritingMode::RTL) {
+            InlineBaseDirection::RightToLeft
+        } else {
+            InlineBaseDirection::LeftToRight
+        }
+    }
+
+    #[inline]
+    /// The default bidirectional embedding level for this writing mode.
+    ///
+    /// Returns bidi level 0 if the mode is LTR, or 1 otherwise.
+    pub fn to_bidi_level(&self) -> bidi::Level {
+        if self.is_bidi_ltr() {
+            bidi::Level::ltr()
+        } else {
+            bidi::Level::rtl()
+        }
+    }
+
+    #[inline]
+    /// Is the text layout vertical?
+    pub fn is_text_vertical(&self) -> bool {
+        self.is_vertical() && !self.is_sideways()
+    }
+}
+
+impl fmt::Display for WritingMode {
+    fn fmt(&self, formatter: &mut Formatter) -> Result<(), Error> {
+        if self.is_vertical() {
+            write!(formatter, "V")?;
+            if self.is_vertical_lr() {
+                write!(formatter, " LR")?;
+            } else {
+                write!(formatter, " RL")?;
+            }
+            if self.is_sideways() {
+                write!(formatter, " Sideways")?;
+            }
+            if self.intersects(WritingMode::LINE_INVERTED) {
+                write!(formatter, " Inverted")?;
+            }
+        } else {
+            write!(formatter, "H")?;
+        }
+        if self.is_bidi_ltr() {
+            write!(formatter, " LTR")
+        } else {
+            write!(formatter, " RTL")
+        }
+    }
+}
+
+/// Wherever logical geometry is used, the writing mode is known based on context:
+/// every method takes a `mode` parameter.
+/// However, this context is easy to get wrong.
+/// In debug builds only, logical geometry objects store their writing mode
+/// (in addition to taking it as a parameter to methods) and check it.
+/// In non-debug builds, make this storage zero-size and the checks no-ops.
+#[cfg(not(debug_assertions))]
+#[derive(Clone, Copy, Eq, PartialEq)]
+#[cfg_attr(feature = "servo", derive(Serialize))]
+struct DebugWritingMode;
+
+#[cfg(debug_assertions)]
+#[derive(Clone, Copy, Eq, PartialEq)]
+#[cfg_attr(feature = "servo", derive(Serialize))]
+struct DebugWritingMode {
+    mode: WritingMode,
+}
+
+#[cfg(not(debug_assertions))]
+impl DebugWritingMode {
+    #[inline]
+    fn check(&self, _other: WritingMode) {}
+
+    #[inline]
+    fn check_debug(&self, _other: DebugWritingMode) {}
+
+    #[inline]
+    fn new(_mode: WritingMode) -> DebugWritingMode {
+        DebugWritingMode
+    }
+}
+
+#[cfg(debug_assertions)]
+impl DebugWritingMode {
+    #[inline]
+    fn check(&self, other: WritingMode) {
+        assert_eq!(self.mode, other)
+    }
+
+    #[inline]
+    fn check_debug(&self, other: DebugWritingMode) {
+        assert_eq!(self.mode, other.mode)
+    }
+
+    #[inline]
+    fn new(mode: WritingMode) -> DebugWritingMode {
+        DebugWritingMode { mode }
+    }
+}
+
+impl Debug for DebugWritingMode {
+    #[cfg(not(debug_assertions))]
+    fn fmt(&self, formatter: &mut Formatter) -> Result<(), Error> {
+        write!(formatter, "?")
+    }
+
+    #[cfg(debug_assertions)]
+    fn fmt(&self, formatter: &mut Formatter) -> Result<(), Error> {
+        write!(formatter, "{}", self.mode)
+    }
+}
+
+// Used to specify the logical direction.
+#[derive(Clone, Copy, Debug, PartialEq)]
+#[cfg_attr(feature = "servo", derive(Serialize))]
+pub enum Direction {
+    Inline,
+    Block,
+}
+
+/// A 2D size in flow-relative dimensions
+#[derive(Clone, Copy, Eq, PartialEq)]
+#[cfg_attr(feature = "servo", derive(Serialize))]
+pub struct LogicalSize<T> {
+    pub inline: T, // inline-size, a.k.a. logical width, a.k.a. measure
+    pub block: T,  // block-size, a.k.a. logical height, a.k.a. extent
+    debug_writing_mode: DebugWritingMode,
+}
+
+impl<T: Debug> Debug for LogicalSize<T> {
+    fn fmt(&self, formatter: &mut Formatter) -> Result<(), Error> {
+        write!(
+            formatter,
+            "LogicalSize({:?}, i{:?}×b{:?})",
+            self.debug_writing_mode, self.inline, self.block
+        )
+    }
+}
+
+// Can not implement the Zero trait: its zero() method does not have the `mode` parameter.
+impl<T: Zero> LogicalSize<T> {
+    #[inline]
+    pub fn zero(mode: WritingMode) -> LogicalSize<T> {
+        LogicalSize {
+            inline: Zero::zero(),
+            block: Zero::zero(),
+            debug_writing_mode: DebugWritingMode::new(mode),
+        }
+    }
+}
+
+impl<T> LogicalSize<T> {
+    #[inline]
+    pub fn new(mode: WritingMode, inline: T, block: T) -> LogicalSize<T> {
+        LogicalSize {
+            inline: inline,
+            block: block,
+            debug_writing_mode: DebugWritingMode::new(mode),
+        }
+    }
+
+    #[inline]
+    pub fn from_physical(mode: WritingMode, size: Size2D<T>) -> LogicalSize<T> {
+        if mode.is_vertical() {
+            LogicalSize::new(mode, size.height, size.width)
+        } else {
+            LogicalSize::new(mode, size.width, size.height)
+        }
+    }
+}
+
+impl<T: Copy> LogicalSize<T> {
+    #[inline]
+    pub fn width(&self, mode: WritingMode) -> T {
+        self.debug_writing_mode.check(mode);
+        if mode.is_vertical() {
+            self.block
+        } else {
+            self.inline
+        }
+    }
+
+    #[inline]
+    pub fn set_width(&mut self, mode: WritingMode, width: T) {
+        self.debug_writing_mode.check(mode);
+        if mode.is_vertical() {
+            self.block = width
+        } else {
+            self.inline = width
+        }
+    }
+
+    #[inline]
+    pub fn height(&self, mode: WritingMode) -> T {
+        self.debug_writing_mode.check(mode);
+        if mode.is_vertical() {
+            self.inline
+        } else {
+            self.block
+        }
+    }
+
+    #[inline]
+    pub fn set_height(&mut self, mode: WritingMode, height: T) {
+        self.debug_writing_mode.check(mode);
+        if mode.is_vertical() {
+            self.inline = height
+        } else {
+            self.block = height
+        }
+    }
+
+    #[inline]
+    pub fn to_physical(&self, mode: WritingMode) -> Size2D<T> {
+        self.debug_writing_mode.check(mode);
+        if mode.is_vertical() {
+            Size2D::new(self.block, self.inline)
+        } else {
+            Size2D::new(self.inline, self.block)
+        }
+    }
+
+    #[inline]
+    pub fn convert(&self, mode_from: WritingMode, mode_to: WritingMode) -> LogicalSize<T> {
+        if mode_from == mode_to {
+            self.debug_writing_mode.check(mode_from);
+            *self
+        } else {
+            LogicalSize::from_physical(mode_to, self.to_physical(mode_from))
+        }
+    }
+}
+
+impl<T: Add<T, Output = T>> Add for LogicalSize<T> {
+    type Output = LogicalSize<T>;
+
+    #[inline]
+    fn add(self, other: LogicalSize<T>) -> LogicalSize<T> {
+        self.debug_writing_mode
+            .check_debug(other.debug_writing_mode);
+        LogicalSize {
+            debug_writing_mode: self.debug_writing_mode,
+            inline: self.inline + other.inline,
+            block: self.block + other.block,
+        }
+    }
+}
+
+impl<T: Sub<T, Output = T>> Sub for LogicalSize<T> {
+    type Output = LogicalSize<T>;
+
+    #[inline]
+    fn sub(self, other: LogicalSize<T>) -> LogicalSize<T> {
+        self.debug_writing_mode
+            .check_debug(other.debug_writing_mode);
+        LogicalSize {
+            debug_writing_mode: self.debug_writing_mode,
+            inline: self.inline - other.inline,
+            block: self.block - other.block,
+        }
+    }
+}
+
+/// A 2D point in flow-relative dimensions
+#[derive(Clone, Copy, Eq, PartialEq)]
+#[cfg_attr(feature = "servo", derive(Serialize))]
+pub struct LogicalPoint<T> {
+    /// inline-axis coordinate
+    pub i: T,
+    /// block-axis coordinate
+    pub b: T,
+    debug_writing_mode: DebugWritingMode,
+}
+
+impl<T: Debug> Debug for LogicalPoint<T> {
+    fn fmt(&self, formatter: &mut Formatter) -> Result<(), Error> {
+        write!(
+            formatter,
+            "LogicalPoint({:?} (i{:?}, b{:?}))",
+            self.debug_writing_mode, self.i, self.b
+        )
+    }
+}
+
+// Can not implement the Zero trait: its zero() method does not have the `mode` parameter.
+impl<T: Zero> LogicalPoint<T> {
+    #[inline]
+    pub fn zero(mode: WritingMode) -> LogicalPoint<T> {
+        LogicalPoint {
+            i: Zero::zero(),
+            b: Zero::zero(),
+            debug_writing_mode: DebugWritingMode::new(mode),
+        }
+    }
+}
+
+impl<T: Copy> LogicalPoint<T> {
+    #[inline]
+    pub fn new(mode: WritingMode, i: T, b: T) -> LogicalPoint<T> {
+        LogicalPoint {
+            i: i,
+            b: b,
+            debug_writing_mode: DebugWritingMode::new(mode),
+        }
+    }
+}
+
+impl<T: Copy + Sub<T, Output = T>> LogicalPoint<T> {
+    #[inline]
+    pub fn from_physical(
+        mode: WritingMode,
+        point: Point2D<T>,
+        container_size: Size2D<T>,
+    ) -> LogicalPoint<T> {
+        if mode.is_vertical() {
+            LogicalPoint {
+                i: if mode.is_inline_tb() {
+                    point.y
+                } else {
+                    container_size.height - point.y
+                },
+                b: if mode.is_vertical_lr() {
+                    point.x
+                } else {
+                    container_size.width - point.x
+                },
+                debug_writing_mode: DebugWritingMode::new(mode),
+            }
+        } else {
+            LogicalPoint {
+                i: if mode.is_bidi_ltr() {
+                    point.x
+                } else {
+                    container_size.width - point.x
+                },
+                b: point.y,
+                debug_writing_mode: DebugWritingMode::new(mode),
+            }
+        }
+    }
+
+    #[inline]
+    pub fn x(&self, mode: WritingMode, container_size: Size2D<T>) -> T {
+        self.debug_writing_mode.check(mode);
+        if mode.is_vertical() {
+            if mode.is_vertical_lr() {
+                self.b
+            } else {
+                container_size.width - self.b
+            }
+        } else {
+            if mode.is_bidi_ltr() {
+                self.i
+            } else {
+                container_size.width - self.i
+            }
+        }
+    }
+
+    #[inline]
+    pub fn set_x(&mut self, mode: WritingMode, x: T, container_size: Size2D<T>) {
+        self.debug_writing_mode.check(mode);
+        if mode.is_vertical() {
+            self.b = if mode.is_vertical_lr() {
+                x
+            } else {
+                container_size.width - x
+            }
+        } else {
+            self.i = if mode.is_bidi_ltr() {
+                x
+            } else {
+                container_size.width - x
+            }
+        }
+    }
+
+    #[inline]
+    pub fn y(&self, mode: WritingMode, container_size: Size2D<T>) -> T {
+        self.debug_writing_mode.check(mode);
+        if mode.is_vertical() {
+            if mode.is_inline_tb() {
+                self.i
+            } else {
+                container_size.height - self.i
+            }
+        } else {
+            self.b
+        }
+    }
+
+    #[inline]
+    pub fn set_y(&mut self, mode: WritingMode, y: T, container_size: Size2D<T>) {
+        self.debug_writing_mode.check(mode);
+        if mode.is_vertical() {
+            self.i = if mode.is_inline_tb() {
+                y
+            } else {
+                container_size.height - y
+            }
+        } else {
+            self.b = y
+        }
+    }
+
+    #[inline]
+    pub fn to_physical(&self, mode: WritingMode, container_size: Size2D<T>) -> Point2D<T> {
+        self.debug_writing_mode.check(mode);
+        if mode.is_vertical() {
+            Point2D::new(
+                if mode.is_vertical_lr() {
+                    self.b
+                } else {
+                    container_size.width - self.b
+                },
+                if mode.is_inline_tb() {
+                    self.i
+                } else {
+                    container_size.height - self.i
+                },
+            )
+        } else {
+            Point2D::new(
+                if mode.is_bidi_ltr() {
+                    self.i
+                } else {
+                    container_size.width - self.i
+                },
+                self.b,
+            )
+        }
+    }
+
+    #[inline]
+    pub fn convert(
+        &self,
+        mode_from: WritingMode,
+        mode_to: WritingMode,
+        container_size: Size2D<T>,
+    ) -> LogicalPoint<T> {
+        if mode_from == mode_to {
+            self.debug_writing_mode.check(mode_from);
+            *self
+        } else {
+            LogicalPoint::from_physical(
+                mode_to,
+                self.to_physical(mode_from, container_size),
+                container_size,
+            )
+        }
+    }
+}
+
+impl<T: Copy + Add<T, Output = T>> LogicalPoint<T> {
+    /// This doesn’t really makes sense,
+    /// but happens when dealing with multiple origins.
+    #[inline]
+    pub fn add_point(&self, other: &LogicalPoint<T>) -> LogicalPoint<T> {
+        self.debug_writing_mode
+            .check_debug(other.debug_writing_mode);
+        LogicalPoint {
+            debug_writing_mode: self.debug_writing_mode,
+            i: self.i + other.i,
+            b: self.b + other.b,
+        }
+    }
+}
+
+impl<T: Copy + Add<T, Output = T>> Add<LogicalSize<T>> for LogicalPoint<T> {
+    type Output = LogicalPoint<T>;
+
+    #[inline]
+    fn add(self, other: LogicalSize<T>) -> LogicalPoint<T> {
+        self.debug_writing_mode
+            .check_debug(other.debug_writing_mode);
+        LogicalPoint {
+            debug_writing_mode: self.debug_writing_mode,
+            i: self.i + other.inline,
+            b: self.b + other.block,
+        }
+    }
+}
+
+impl<T: Copy + Sub<T, Output = T>> Sub<LogicalSize<T>> for LogicalPoint<T> {
+    type Output = LogicalPoint<T>;
+
+    #[inline]
+    fn sub(self, other: LogicalSize<T>) -> LogicalPoint<T> {
+        self.debug_writing_mode
+            .check_debug(other.debug_writing_mode);
+        LogicalPoint {
+            debug_writing_mode: self.debug_writing_mode,
+            i: self.i - other.inline,
+            b: self.b - other.block,
+        }
+    }
+}
+
+/// A "margin" in flow-relative dimensions
+/// Represents the four sides of the margins, borders, or padding of a CSS box,
+/// or a combination of those.
+/// A positive "margin" can be added to a rectangle to obtain a bigger rectangle.
+#[derive(Clone, Copy, Eq, PartialEq)]
+#[cfg_attr(feature = "servo", derive(Serialize))]
+pub struct LogicalMargin<T> {
+    pub block_start: T,
+    pub inline_end: T,
+    pub block_end: T,
+    pub inline_start: T,
+    debug_writing_mode: DebugWritingMode,
+}
+
+impl<T: Debug> Debug for LogicalMargin<T> {
+    fn fmt(&self, formatter: &mut Formatter) -> Result<(), Error> {
+        let writing_mode_string = if cfg!(debug_assertions) {
+            format!("{:?}, ", self.debug_writing_mode)
+        } else {
+            "".to_owned()
+        };
+
+        write!(
+            formatter,
+            "LogicalMargin({}i:{:?}..{:?} b:{:?}..{:?})",
+            writing_mode_string,
+            self.inline_start,
+            self.inline_end,
+            self.block_start,
+            self.block_end
+        )
+    }
+}
+
+impl<T: Zero> LogicalMargin<T> {
+    #[inline]
+    pub fn zero(mode: WritingMode) -> LogicalMargin<T> {
+        LogicalMargin {
+            block_start: Zero::zero(),
+            inline_end: Zero::zero(),
+            block_end: Zero::zero(),
+            inline_start: Zero::zero(),
+            debug_writing_mode: DebugWritingMode::new(mode),
+        }
+    }
+}
+
+impl<T> LogicalMargin<T> {
+    #[inline]
+    pub fn new(
+        mode: WritingMode,
+        block_start: T,
+        inline_end: T,
+        block_end: T,
+        inline_start: T,
+    ) -> LogicalMargin<T> {
+        LogicalMargin {
+            block_start,
+            inline_end,
+            block_end,
+            inline_start,
+            debug_writing_mode: DebugWritingMode::new(mode),
+        }
+    }
+
+    #[inline]
+    pub fn from_physical(mode: WritingMode, offsets: SideOffsets2D<T>) -> LogicalMargin<T> {
+        let block_start;
+        let inline_end;
+        let block_end;
+        let inline_start;
+        if mode.is_vertical() {
+            if mode.is_vertical_lr() {
+                block_start = offsets.left;
+                block_end = offsets.right;
+            } else {
+                block_start = offsets.right;
+                block_end = offsets.left;
+            }
+            if mode.is_inline_tb() {
+                inline_start = offsets.top;
+                inline_end = offsets.bottom;
+            } else {
+                inline_start = offsets.bottom;
+                inline_end = offsets.top;
+            }
+        } else {
+            block_start = offsets.top;
+            block_end = offsets.bottom;
+            if mode.is_bidi_ltr() {
+                inline_start = offsets.left;
+                inline_end = offsets.right;
+            } else {
+                inline_start = offsets.right;
+                inline_end = offsets.left;
+            }
+        }
+        LogicalMargin::new(mode, block_start, inline_end, block_end, inline_start)
+    }
+}
+
+impl<T: Copy> LogicalMargin<T> {
+    #[inline]
+    pub fn new_all_same(mode: WritingMode, value: T) -> LogicalMargin<T> {
+        LogicalMargin::new(mode, value, value, value, value)
+    }
+
+    #[inline]
+    pub fn top(&self, mode: WritingMode) -> T {
+        self.debug_writing_mode.check(mode);
+        if mode.is_vertical() {
+            if mode.is_inline_tb() {
+                self.inline_start
+            } else {
+                self.inline_end
+            }
+        } else {
+            self.block_start
+        }
+    }
+
+    #[inline]
+    pub fn set_top(&mut self, mode: WritingMode, top: T) {
+        self.debug_writing_mode.check(mode);
+        if mode.is_vertical() {
+            if mode.is_inline_tb() {
+                self.inline_start = top
+            } else {
+                self.inline_end = top
+            }
+        } else {
+            self.block_start = top
+        }
+    }
+
+    #[inline]
+    pub fn right(&self, mode: WritingMode) -> T {
+        self.debug_writing_mode.check(mode);
+        if mode.is_vertical() {
+            if mode.is_vertical_lr() {
+                self.block_end
+            } else {
+                self.block_start
+            }
+        } else {
+            if mode.is_bidi_ltr() {
+                self.inline_end
+            } else {
+                self.inline_start
+            }
+        }
+    }
+
+    #[inline]
+    pub fn set_right(&mut self, mode: WritingMode, right: T) {
+        self.debug_writing_mode.check(mode);
+        if mode.is_vertical() {
+            if mode.is_vertical_lr() {
+                self.block_end = right
+            } else {
+                self.block_start = right
+            }
+        } else {
+            if mode.is_bidi_ltr() {
+                self.inline_end = right
+            } else {
+                self.inline_start = right
+            }
+        }
+    }
+
+    #[inline]
+    pub fn bottom(&self, mode: WritingMode) -> T {
+        self.debug_writing_mode.check(mode);
+        if mode.is_vertical() {
+            if mode.is_inline_tb() {
+                self.inline_end
+            } else {
+                self.inline_start
+            }
+        } else {
+            self.block_end
+        }
+    }
+
+    #[inline]
+    pub fn set_bottom(&mut self, mode: WritingMode, bottom: T) {
+        self.debug_writing_mode.check(mode);
+        if mode.is_vertical() {
+            if mode.is_inline_tb() {
+                self.inline_end = bottom
+            } else {
+                self.inline_start = bottom
+            }
+        } else {
+            self.block_end = bottom
+        }
+    }
+
+    #[inline]
+    pub fn left(&self, mode: WritingMode) -> T {
+        self.debug_writing_mode.check(mode);
+        if mode.is_vertical() {
+            if mode.is_vertical_lr() {
+                self.block_start
+            } else {
+                self.block_end
+            }
+        } else {
+            if mode.is_bidi_ltr() {
+                self.inline_start
+            } else {
+                self.inline_end
+            }
+        }
+    }
+
+    #[inline]
+    pub fn set_left(&mut self, mode: WritingMode, left: T) {
+        self.debug_writing_mode.check(mode);
+        if mode.is_vertical() {
+            if mode.is_vertical_lr() {
+                self.block_start = left
+            } else {
+                self.block_end = left
+            }
+        } else {
+            if mode.is_bidi_ltr() {
+                self.inline_start = left
+            } else {
+                self.inline_end = left
+            }
+        }
+    }
+
+    #[inline]
+    pub fn to_physical(&self, mode: WritingMode) -> SideOffsets2D<T> {
+        self.debug_writing_mode.check(mode);
+        let top;
+        let right;
+        let bottom;
+        let left;
+        if mode.is_vertical() {
+            if mode.is_vertical_lr() {
+                left = self.block_start;
+                right = self.block_end;
+            } else {
+                right = self.block_start;
+                left = self.block_end;
+            }
+            if mode.is_inline_tb() {
+                top = self.inline_start;
+                bottom = self.inline_end;
+            } else {
+                bottom = self.inline_start;
+                top = self.inline_end;
+            }
+        } else {
+            top = self.block_start;
+            bottom = self.block_end;
+            if mode.is_bidi_ltr() {
+                left = self.inline_start;
+                right = self.inline_end;
+            } else {
+                right = self.inline_start;
+                left = self.inline_end;
+            }
+        }
+        SideOffsets2D::new(top, right, bottom, left)
+    }
+
+    #[inline]
+    pub fn convert(&self, mode_from: WritingMode, mode_to: WritingMode) -> LogicalMargin<T> {
+        if mode_from == mode_to {
+            self.debug_writing_mode.check(mode_from);
+            *self
+        } else {
+            LogicalMargin::from_physical(mode_to, self.to_physical(mode_from))
+        }
+    }
+}
+
+impl<T: PartialEq + Zero> LogicalMargin<T> {
+    #[inline]
+    pub fn is_zero(&self) -> bool {
+        self.block_start == Zero::zero() &&
+            self.inline_end == Zero::zero() &&
+            self.block_end == Zero::zero() &&
+            self.inline_start == Zero::zero()
+    }
+}
+
+impl<T: Copy + Add<T, Output = T>> LogicalMargin<T> {
+    #[inline]
+    pub fn inline_start_end(&self) -> T {
+        self.inline_start + self.inline_end
+    }
+
+    #[inline]
+    pub fn block_start_end(&self) -> T {
+        self.block_start + self.block_end
+    }
+
+    #[inline]
+    pub fn start_end(&self, direction: Direction) -> T {
+        match direction {
+            Direction::Inline => self.inline_start + self.inline_end,
+            Direction::Block => self.block_start + self.block_end,
+        }
+    }
+
+    #[inline]
+    pub fn top_bottom(&self, mode: WritingMode) -> T {
+        self.debug_writing_mode.check(mode);
+        if mode.is_vertical() {
+            self.inline_start_end()
+        } else {
+            self.block_start_end()
+        }
+    }
+
+    #[inline]
+    pub fn left_right(&self, mode: WritingMode) -> T {
+        self.debug_writing_mode.check(mode);
+        if mode.is_vertical() {
+            self.block_start_end()
+        } else {
+            self.inline_start_end()
+        }
+    }
+}
+
+impl<T: Add<T, Output = T>> Add for LogicalMargin<T> {
+    type Output = LogicalMargin<T>;
+
+    #[inline]
+    fn add(self, other: LogicalMargin<T>) -> LogicalMargin<T> {
+        self.debug_writing_mode
+            .check_debug(other.debug_writing_mode);
+        LogicalMargin {
+            debug_writing_mode: self.debug_writing_mode,
+            block_start: self.block_start + other.block_start,
+            inline_end: self.inline_end + other.inline_end,
+            block_end: self.block_end + other.block_end,
+            inline_start: self.inline_start + other.inline_start,
+        }
+    }
+}
+
+impl<T: Sub<T, Output = T>> Sub for LogicalMargin<T> {
+    type Output = LogicalMargin<T>;
+
+    #[inline]
+    fn sub(self, other: LogicalMargin<T>) -> LogicalMargin<T> {
+        self.debug_writing_mode
+            .check_debug(other.debug_writing_mode);
+        LogicalMargin {
+            debug_writing_mode: self.debug_writing_mode,
+            block_start: self.block_start - other.block_start,
+            inline_end: self.inline_end - other.inline_end,
+            block_end: self.block_end - other.block_end,
+            inline_start: self.inline_start - other.inline_start,
+        }
+    }
+}
+
+/// A rectangle in flow-relative dimensions
+#[derive(Clone, Copy, Eq, PartialEq)]
+#[cfg_attr(feature = "servo", derive(Serialize))]
+pub struct LogicalRect<T> {
+    pub start: LogicalPoint<T>,
+    pub size: LogicalSize<T>,
+    debug_writing_mode: DebugWritingMode,
+}
+
+impl<T: Debug> Debug for LogicalRect<T> {
+    fn fmt(&self, formatter: &mut Formatter) -> Result<(), Error> {
+        let writing_mode_string = if cfg!(debug_assertions) {
+            format!("{:?}, ", self.debug_writing_mode)
+        } else {
+            "".to_owned()
+        };
+
+        write!(
+            formatter,
+            "LogicalRect({}i{:?}×b{:?}, @ (i{:?},b{:?}))",
+            writing_mode_string, self.size.inline, self.size.block, self.start.i, self.start.b
+        )
+    }
+}
+
+impl<T: Zero> LogicalRect<T> {
+    #[inline]
+    pub fn zero(mode: WritingMode) -> LogicalRect<T> {
+        LogicalRect {
+            start: LogicalPoint::zero(mode),
+            size: LogicalSize::zero(mode),
+            debug_writing_mode: DebugWritingMode::new(mode),
+        }
+    }
+}
+
+impl<T: Copy> LogicalRect<T> {
+    #[inline]
+    pub fn new(
+        mode: WritingMode,
+        inline_start: T,
+        block_start: T,
+        inline: T,
+        block: T,
+    ) -> LogicalRect<T> {
+        LogicalRect {
+            start: LogicalPoint::new(mode, inline_start, block_start),
+            size: LogicalSize::new(mode, inline, block),
+            debug_writing_mode: DebugWritingMode::new(mode),
+        }
+    }
+
+    #[inline]
+    pub fn from_point_size(
+        mode: WritingMode,
+        start: LogicalPoint<T>,
+        size: LogicalSize<T>,
+    ) -> LogicalRect<T> {
+        start.debug_writing_mode.check(mode);
+        size.debug_writing_mode.check(mode);
+        LogicalRect {
+            start: start,
+            size: size,
+            debug_writing_mode: DebugWritingMode::new(mode),
+        }
+    }
+}
+
+impl<T: Copy + Add<T, Output = T> + Sub<T, Output = T>> LogicalRect<T> {
+    #[inline]
+    pub fn from_physical(
+        mode: WritingMode,
+        rect: Rect<T>,
+        container_size: Size2D<T>,
+    ) -> LogicalRect<T> {
+        let inline_start;
+        let block_start;
+        let inline;
+        let block;
+        if mode.is_vertical() {
+            inline = rect.size.height;
+            block = rect.size.width;
+            if mode.is_vertical_lr() {
+                block_start = rect.origin.x;
+            } else {
+                block_start = container_size.width - (rect.origin.x + rect.size.width);
+            }
+            if mode.is_inline_tb() {
+                inline_start = rect.origin.y;
+            } else {
+                inline_start = container_size.height - (rect.origin.y + rect.size.height);
+            }
+        } else {
+            inline = rect.size.width;
+            block = rect.size.height;
+            block_start = rect.origin.y;
+            if mode.is_bidi_ltr() {
+                inline_start = rect.origin.x;
+            } else {
+                inline_start = container_size.width - (rect.origin.x + rect.size.width);
+            }
+        }
+        LogicalRect {
+            start: LogicalPoint::new(mode, inline_start, block_start),
+            size: LogicalSize::new(mode, inline, block),
+            debug_writing_mode: DebugWritingMode::new(mode),
+        }
+    }
+
+    #[inline]
+    pub fn inline_end(&self) -> T {
+        self.start.i + self.size.inline
+    }
+
+    #[inline]
+    pub fn block_end(&self) -> T {
+        self.start.b + self.size.block
+    }
+
+    #[inline]
+    pub fn to_physical(&self, mode: WritingMode, container_size: Size2D<T>) -> Rect<T> {
+        self.debug_writing_mode.check(mode);
+        let x;
+        let y;
+        let width;
+        let height;
+        if mode.is_vertical() {
+            width = self.size.block;
+            height = self.size.inline;
+            if mode.is_vertical_lr() {
+                x = self.start.b;
+            } else {
+                x = container_size.width - self.block_end();
+            }
+            if mode.is_inline_tb() {
+                y = self.start.i;
+            } else {
+                y = container_size.height - self.inline_end();
+            }
+        } else {
+            width = self.size.inline;
+            height = self.size.block;
+            y = self.start.b;
+            if mode.is_bidi_ltr() {
+                x = self.start.i;
+            } else {
+                x = container_size.width - self.inline_end();
+            }
+        }
+        Rect {
+            origin: Point2D::new(x, y),
+            size: Size2D::new(width, height),
+        }
+    }
+
+    #[inline]
+    pub fn convert(
+        &self,
+        mode_from: WritingMode,
+        mode_to: WritingMode,
+        container_size: Size2D<T>,
+    ) -> LogicalRect<T> {
+        if mode_from == mode_to {
+            self.debug_writing_mode.check(mode_from);
+            *self
+        } else {
+            LogicalRect::from_physical(
+                mode_to,
+                self.to_physical(mode_from, container_size),
+                container_size,
+            )
+        }
+    }
+
+    pub fn translate_by_size(&self, offset: LogicalSize<T>) -> LogicalRect<T> {
+        LogicalRect {
+            start: self.start + offset,
+            ..*self
+        }
+    }
+
+    pub fn translate(&self, offset: &LogicalPoint<T>) -> LogicalRect<T> {
+        LogicalRect {
+            start: self.start +
+                LogicalSize {
+                    inline: offset.i,
+                    block: offset.b,
+                    debug_writing_mode: offset.debug_writing_mode,
+                },
+            size: self.size,
+            debug_writing_mode: self.debug_writing_mode,
+        }
+    }
+}
+
+impl<T: Copy + Ord + Add<T, Output = T> + Sub<T, Output = T>> LogicalRect<T> {
+    #[inline]
+    pub fn union(&self, other: &LogicalRect<T>) -> LogicalRect<T> {
+        self.debug_writing_mode
+            .check_debug(other.debug_writing_mode);
+
+        let inline_start = min(self.start.i, other.start.i);
+        let block_start = min(self.start.b, other.start.b);
+        LogicalRect {
+            start: LogicalPoint {
+                i: inline_start,
+                b: block_start,
+                debug_writing_mode: self.debug_writing_mode,
+            },
+            size: LogicalSize {
+                inline: max(self.inline_end(), other.inline_end()) - inline_start,
+                block: max(self.block_end(), other.block_end()) - block_start,
+                debug_writing_mode: self.debug_writing_mode,
+            },
+            debug_writing_mode: self.debug_writing_mode,
+        }
+    }
+}
+
+impl<T: Copy + Add<T, Output = T> + Sub<T, Output = T>> Add<LogicalMargin<T>> for LogicalRect<T> {
+    type Output = LogicalRect<T>;
+
+    #[inline]
+    fn add(self, other: LogicalMargin<T>) -> LogicalRect<T> {
+        self.debug_writing_mode
+            .check_debug(other.debug_writing_mode);
+        LogicalRect {
+            start: LogicalPoint {
+                // Growing a rectangle on the start side means pushing its
+                // start point on the negative direction.
+                i: self.start.i - other.inline_start,
+                b: self.start.b - other.block_start,
+                debug_writing_mode: self.debug_writing_mode,
+            },
+            size: LogicalSize {
+                inline: self.size.inline + other.inline_start_end(),
+                block: self.size.block + other.block_start_end(),
+                debug_writing_mode: self.debug_writing_mode,
+            },
+            debug_writing_mode: self.debug_writing_mode,
+        }
+    }
+}
+
+impl<T: Copy + Add<T, Output = T> + Sub<T, Output = T>> Sub<LogicalMargin<T>> for LogicalRect<T> {
+    type Output = LogicalRect<T>;
+
+    #[inline]
+    fn sub(self, other: LogicalMargin<T>) -> LogicalRect<T> {
+        self.debug_writing_mode
+            .check_debug(other.debug_writing_mode);
+        LogicalRect {
+            start: LogicalPoint {
+                // Shrinking a rectangle on the start side means pushing its
+                // start point on the positive direction.
+                i: self.start.i + other.inline_start,
+                b: self.start.b + other.block_start,
+                debug_writing_mode: self.debug_writing_mode,
+            },
+            size: LogicalSize {
+                inline: self.size.inline - other.inline_start_end(),
+                block: self.size.block - other.block_start_end(),
+                debug_writing_mode: self.debug_writing_mode,
+            },
+            debug_writing_mode: self.debug_writing_mode,
+        }
+    }
+}
+
+#[derive(Clone, Copy, Debug, PartialEq)]
+#[repr(u8)]
+pub enum LogicalAxis {
+    Block = 0,
+    Inline,
+}
+
+impl LogicalAxis {
+    #[inline]
+    pub fn to_physical(self, wm: WritingMode) -> PhysicalAxis {
+        if wm.is_horizontal() == (self == Self::Inline) {
+            PhysicalAxis::Horizontal
+        } else {
+            PhysicalAxis::Vertical
+        }
+    }
+}
+
+#[derive(Clone, Copy, Debug, PartialEq)]
+#[repr(u8)]
+pub enum LogicalSide {
+    BlockStart = 0,
+    BlockEnd,
+    InlineStart,
+    InlineEnd,
+}
+
+impl LogicalSide {
+    fn is_block(self) -> bool {
+        matches!(self, Self::BlockStart | Self::BlockEnd)
+    }
+
+    #[inline]
+    pub fn to_physical(self, wm: WritingMode) -> PhysicalSide {
+        // Block mapping depends only on vertical+vertical-lr
+        static BLOCK_MAPPING: [[PhysicalSide; 2]; 4] = [
+            [PhysicalSide::Top, PhysicalSide::Bottom], // horizontal-tb
+            [PhysicalSide::Right, PhysicalSide::Left], // vertical-rl
+            [PhysicalSide::Bottom, PhysicalSide::Top], // (horizontal-bt)
+            [PhysicalSide::Left, PhysicalSide::Right], // vertical-lr
+        ];
+
+        if self.is_block() {
+            let vertical = wm.is_vertical();
+            let lr = wm.is_vertical_lr();
+            let index = (vertical as usize) | ((lr as usize) << 1);
+            return BLOCK_MAPPING[index][self as usize];
+        }
+
+        // start = 0, end = 1
+        let edge = self as usize - 2;
+        // Inline axis sides depend on all three of writing-mode, text-orientation and direction,
+        // which are encoded in the VERTICAL, INLINE_REVERSED, VERTICAL_LR and LINE_INVERTED bits.
+        //
+        //   bit 0 = the VERTICAL value
+        //   bit 1 = the INLINE_REVERSED value
+        //   bit 2 = the VERTICAL_LR value
+        //   bit 3 = the LINE_INVERTED value
+        //
+        // Note that not all of these combinations can actually be specified via CSS: there is no
+        // horizontal-bt writing-mode, and no text-orientation value that produces "inverted"
+        // text. (The former 'sideways-left' value, no longer in the spec, would have produced
+        // this in vertical-rl mode.)
+        static INLINE_MAPPING: [[PhysicalSide; 2]; 16] = [
+            [PhysicalSide::Left, PhysicalSide::Right], // horizontal-tb               ltr
+            [PhysicalSide::Top, PhysicalSide::Bottom], // vertical-rl                 ltr
+            [PhysicalSide::Right, PhysicalSide::Left], // horizontal-tb               rtl
+            [PhysicalSide::Bottom, PhysicalSide::Top], // vertical-rl                 rtl
+            [PhysicalSide::Right, PhysicalSide::Left], // (horizontal-bt)  (inverted) ltr
+            [PhysicalSide::Top, PhysicalSide::Bottom], // sideways-lr                 rtl
+            [PhysicalSide::Left, PhysicalSide::Right], // (horizontal-bt)  (inverted) rtl
+            [PhysicalSide::Bottom, PhysicalSide::Top], // sideways-lr                 ltr
+            [PhysicalSide::Left, PhysicalSide::Right], // horizontal-tb    (inverted) rtl
+            [PhysicalSide::Top, PhysicalSide::Bottom], // vertical-rl      (inverted) rtl
+            [PhysicalSide::Right, PhysicalSide::Left], // horizontal-tb    (inverted) ltr
+            [PhysicalSide::Bottom, PhysicalSide::Top], // vertical-rl      (inverted) ltr
+            [PhysicalSide::Left, PhysicalSide::Right], // (horizontal-bt)             ltr
+            [PhysicalSide::Top, PhysicalSide::Bottom], // vertical-lr                 ltr
+            [PhysicalSide::Right, PhysicalSide::Left], // (horizontal-bt)             rtl
+            [PhysicalSide::Bottom, PhysicalSide::Top], // vertical-lr                 rtl
+        ];
+
+        debug_assert!(
+            WritingMode::VERTICAL.bits() == 0x01 &&
+                WritingMode::INLINE_REVERSED.bits() == 0x02 &&
+                WritingMode::VERTICAL_LR.bits() == 0x04 &&
+                WritingMode::LINE_INVERTED.bits() == 0x08
+        );
+        let index = (wm.bits() & 0xF) as usize;
+        INLINE_MAPPING[index][edge]
+    }
+}
+
+#[derive(Clone, Copy, Debug, PartialEq)]
+#[repr(u8)]
+pub enum LogicalCorner {
+    StartStart = 0,
+    StartEnd,
+    EndStart,
+    EndEnd,
+}
+
+impl LogicalCorner {
+    #[inline]
+    pub fn to_physical(self, wm: WritingMode) -> PhysicalCorner {
+        static CORNER_TO_SIDES: [[LogicalSide; 2]; 4] = [
+            [LogicalSide::BlockStart, LogicalSide::InlineStart],
+            [LogicalSide::BlockStart, LogicalSide::InlineEnd],
+            [LogicalSide::BlockEnd, LogicalSide::InlineStart],
+            [LogicalSide::BlockEnd, LogicalSide::InlineEnd],
+        ];
+
+        let [block, inline] = CORNER_TO_SIDES[self as usize];
+        let block = block.to_physical(wm);
+        let inline = inline.to_physical(wm);
+        PhysicalCorner::from_sides(block, inline)
+    }
+}
+
+#[derive(Clone, Copy, Debug, PartialEq)]
+#[repr(u8)]
+pub enum PhysicalAxis {
+    Vertical = 0,
+    Horizontal,
+}
+
+#[derive(Clone, Copy, Debug, PartialEq)]
+#[repr(u8)]
+pub enum PhysicalSide {
+    Top = 0,
+    Right,
+    Bottom,
+    Left,
+}
+
+impl PhysicalSide {
+    fn orthogonal_to(self, other: Self) -> bool {
+        matches!(self, Self::Top | Self::Bottom) != matches!(other, Self::Top | Self::Bottom)
+    }
+}
+
+#[derive(Clone, Copy, Debug, PartialEq)]
+#[repr(u8)]
+pub enum PhysicalCorner {
+    TopLeft = 0,
+    TopRight,
+    BottomRight,
+    BottomLeft,
+}
+
+impl PhysicalCorner {
+    fn from_sides(a: PhysicalSide, b: PhysicalSide) -> Self {
+        debug_assert!(a.orthogonal_to(b), "Sides should be orthogonal");
+        // Only some of these are possible, since we expect only orthogonal values. If the two
+        // sides were to be parallel, we fall back to returning TopLeft.
+        const IMPOSSIBLE: PhysicalCorner = PhysicalCorner::TopLeft;
+        static SIDES_TO_CORNER: [[PhysicalCorner; 4]; 4] = [
+            [
+                IMPOSSIBLE,
+                PhysicalCorner::TopRight,
+                IMPOSSIBLE,
+                PhysicalCorner::TopLeft,
+            ],
+            [
+                PhysicalCorner::TopRight,
+                IMPOSSIBLE,
+                PhysicalCorner::BottomRight,
+                IMPOSSIBLE,
+            ],
+            [
+                IMPOSSIBLE,
+                PhysicalCorner::BottomRight,
+                IMPOSSIBLE,
+                PhysicalCorner::BottomLeft,
+            ],
+            [
+                PhysicalCorner::TopLeft,
+                IMPOSSIBLE,
+                PhysicalCorner::BottomLeft,
+                IMPOSSIBLE,
+            ],
+        ];
+        SIDES_TO_CORNER[a as usize][b as usize]
+    }
+}