diff options
| -rw-r--r-- | components/layout_2020/flow/float.rs | 117 | ||||
| -rw-r--r-- | components/layout_2020/flow/mod.rs | 7 |
2 files changed, 64 insertions, 60 deletions
diff --git a/components/layout_2020/flow/float.rs b/components/layout_2020/flow/float.rs index 0ac6529278a..9a52b50853d 100644 --- a/components/layout_2020/flow/float.rs +++ b/components/layout_2020/flow/float.rs @@ -320,7 +320,7 @@ impl ClearSide { } impl FloatBand { - // Determines whether an object fits in a band. + /// Determines whether an object fits in a band. Returns true if the object fits. fn object_fits(&self, object: &PlacementInfo, walls: &ContainingBlockPositionInfo) -> bool { match object.side { FloatSide::Left => { @@ -549,8 +549,8 @@ impl FloatBandLink { Some(this.band.clone()) } - // Inserts a new band into the tree. If the band has the same level as a pre-existing one, - // replaces the existing band with the new one. + /// Inserts a new band into the tree. If the band has the same level as a pre-existing one, + /// replaces the existing band with the new one. fn insert(&self, band: FloatBand) -> FloatBandLink { let mut this = match self.0 { None => return FloatBandLink(Some(Arc::new(FloatBandNode::new(band)))), @@ -570,13 +570,13 @@ impl FloatBandLink { FloatBandLink(Some(Arc::new(this))) } - // Corrects tree balance: - // - // T L - // / \ / \ - // L R → A T if level(T) = level(L) - // / \ / \ - // A B B R + /// Corrects tree balance: + /// + /// T L + /// / \ / \ + /// L R → A T if level(T) = level(L) + /// / \ / \ + /// A B B R fn skew(&self) -> FloatBandLink { if let Some(ref this) = self.0 { if let Some(ref left) = this.left.0 { @@ -599,13 +599,13 @@ impl FloatBandLink { (*self).clone() } - // Corrects tree balance: - // - // T R - // / \ / \ - // A R → T X if level(T) = level(X) - // / \ / \ - // B X A B + /// Corrects tree balance: + /// + /// T R + /// / \ / \ + /// A R → T X if level(T) = level(X) + /// / \ / \ + /// B X A B fn split(&self) -> FloatBandLink { if let Some(ref this) = self.0 { if let Some(ref right) = this.right.0 { @@ -637,8 +637,6 @@ impl Debug for FloatFragment { } } -// Float boxes - impl FloatBox { /// Creates a new float box. pub fn construct<'dom>( @@ -659,6 +657,9 @@ impl FloatBox { } } + /// Lay out this float box and its children. Note that the position will be relative to + /// the float containing block formatting context. A later step adjusts the position + /// to be relative to the containing block. pub fn layout( &mut self, layout_context: &LayoutContext, @@ -799,35 +800,33 @@ impl FloatBox { } } -// Float fragment storage - -// Layout state that we maintain when doing sequential traversals of the box tree in document -// order. -// -// This data is only needed for float placement and float interaction, and as such is only present -// if the current block formatting context contains floats. -// -// All coordinates here are relative to the start of the nearest ancestor block formatting context. -// -// This structure is expected to be cheap to clone, in order to allow for "snapshots" that enable -// restarting layout at any point in the tree. +/// Layout state that we maintain when doing sequential traversals of the box tree in document +/// order. +/// +/// This data is only needed for float placement and float interaction, and as such is only present +/// if the current block formatting context contains floats. +/// +/// All coordinates here are relative to the start of the nearest ancestor block formatting context. +/// +/// This structure is expected to be cheap to clone, in order to allow for "snapshots" that enable +/// restarting layout at any point in the tree. #[derive(Clone)] pub(crate) struct SequentialLayoutState { - // Holds all floats in this block formatting context. + /// Holds all floats in this block formatting context. pub(crate) floats: FloatContext, - // The (logically) bottom border edge or top padding edge of the last in-flow block. Floats - // cannot be placed above this line. - // - // This is often, but not always, the same as the float ceiling. The float ceiling can be lower - // than this value because this value is calculated based on in-flow boxes only, while - // out-of-flow floats can affect the ceiling as well (see CSS 2.1 § 9.5.1 rule 6). + /// The (logically) bottom border edge or top padding edge of the last in-flow block. Floats + /// cannot be placed above this line. + /// + /// This is often, but not always, the same as the float ceiling. The float ceiling can be lower + /// than this value because this value is calculated based on in-flow boxes only, while + /// out-of-flow floats can affect the ceiling as well (see CSS 2.1 § 9.5.1 rule 6). pub(crate) bfc_relative_block_position: Length, - // Any collapsible margins that we've encountered after `bfc_relative_block_position`. + /// Any collapsible margins that we've encountered after `bfc_relative_block_position`. pub(crate) current_margin: CollapsedMargin, } impl SequentialLayoutState { - // Creates a new empty `SequentialLayoutState`. + /// Creates a new empty `SequentialLayoutState`. pub(crate) fn new() -> SequentialLayoutState { SequentialLayoutState { floats: FloatContext::new(), @@ -836,41 +835,45 @@ impl SequentialLayoutState { } } - // Moves the current block position (logically) down by `block_distance`. - // - // Floats may not be placed higher than the current block position. + /// Moves the current block position (logically) down by `block_distance`. + /// + /// Floats may not be placed higher than the current block position. pub(crate) fn advance_block_position(&mut self, block_distance: Length) { self.bfc_relative_block_position += block_distance; self.floats.lower_ceiling(self.bfc_relative_block_position); } - pub(crate) fn update_all_containing_block_offsets( + /// Replace the entire [ContainingBlockPositionInfo] data structure stored + /// by this [SequentialLayoutState]. Return the old data structure. + pub(crate) fn replace_containing_block_position_info( &mut self, - mut new_distance: ContainingBlockPositionInfo, + mut position_info: ContainingBlockPositionInfo, ) -> ContainingBlockPositionInfo { - mem::swap(&mut new_distance, &mut self.floats.containing_block_info); - new_distance + mem::swap(&mut position_info, &mut self.floats.containing_block_info); + position_info } + /// Return the current block position in the float containing block formatting + /// context and any uncollapsed block margins. pub(crate) fn current_block_position_including_margins(&self) -> Length { self.bfc_relative_block_position + self.current_margin.solve() } - // Collapses margins, moving the block position down by the collapsed value of `current_margin` - // and resetting `current_margin` to zero. - // - // Call this method before laying out children when it is known that the start margin of the - // current fragment can't collapse with the margins of any of its children. + /// Collapses margins, moving the block position down by the collapsed value of `current_margin` + /// and resetting `current_margin` to zero. + /// + /// Call this method before laying out children when it is known that the start margin of the + /// current fragment can't collapse with the margins of any of its children. pub(crate) fn collapse_margins(&mut self) { self.advance_block_position(self.current_margin.solve()); self.current_margin = CollapsedMargin::zero(); } - // Returns the amount of clearance that a block with the given `clear` value at the current - // `bfc_relative_block_position` (with top margin included in `current_margin` if applicable) - // needs to have. - // - // https://www.w3.org/TR/2011/REC-CSS2-20110607/visuren.html#flow-control + /// Returns the amount of clearance that a block with the given `clear` value at the current + /// `bfc_relative_block_position` (with top margin included in `current_margin` if applicable) + /// needs to have. + /// + /// https://www.w3.org/TR/2011/REC-CSS2-20110607/visuren.html#flow-control pub(crate) fn calculate_clearance(&self, clear_side: ClearSide) -> Length { if clear_side == ClearSide::None { return Length::zero(); diff --git a/components/layout_2020/flow/mod.rs b/components/layout_2020/flow/mod.rs index e23c8db33e8..4101c33606b 100644 --- a/components/layout_2020/flow/mod.rs +++ b/components/layout_2020/flow/mod.rs @@ -523,8 +523,9 @@ fn layout_in_flow_non_replaced_block_level( inline_start, inline_end: inline_start + inline_size, }; - parent_containing_block_position_info = - Some(sequential_layout_state.update_all_containing_block_offsets(new_cb_offsets)); + parent_containing_block_position_info = Some( + sequential_layout_state.replace_containing_block_position_info(new_cb_offsets), + ); }, }; @@ -595,7 +596,7 @@ fn layout_in_flow_non_replaced_block_level( // Now that we're done laying out our children, we can restore the // parent's containing block position information. sequential_layout_state - .update_all_containing_block_offsets(parent_containing_block_position_info.unwrap()); + .replace_containing_block_position_info(parent_containing_block_position_info.unwrap()); // Account for padding and border. We also might have to readjust the // `bfc_relative_block_position` if it was different from the content size (i.e. was |