diff --git a/components/layout/display_list/builder.rs b/components/layout/display_list/builder.rs index 9d5f1e100ab..0be8183e2a7 100644 --- a/components/layout/display_list/builder.rs +++ b/components/layout/display_list/builder.rs @@ -1571,6 +1571,11 @@ impl Fragment { return; } + // If this fragment takes up no space, we don't need to build any display items for it. + if self.has_non_invertible_transform() { + return; + } + debug!( "Fragment::build_display_list at rel={:?}, abs={:?}: {:?}", self.border_box, stacking_relative_border_box, self @@ -2376,6 +2381,11 @@ impl BlockFlow { state: &mut StackingContextCollectionState, flags: StackingContextCollectionFlags, ) { + // This block flow produces no stacking contexts if it takes up no space. + if self.has_non_invertible_transform() { + return; + } + let mut preserved_state = SavedStackingContextCollectionState::new(state); let stacking_context_type = self.stacking_context_type(flags); diff --git a/components/layout/display_list/items.rs b/components/layout/display_list/items.rs index 27b4ec1fa88..4800abe7e53 100644 --- a/components/layout/display_list/items.rs +++ b/components/layout/display_list/items.rs @@ -217,6 +217,12 @@ impl StackingContext { parent_clipping_and_scrolling: ClippingAndScrolling, established_reference_frame: Option, ) -> StackingContext { + if let Some(ref t) = transform { + // These are used as scale values by webrender, and it can't handle + // divisors of 0 when scaling. + assert_ne!(t.m11, 0.); + assert_ne!(t.m22, 0.); + } StackingContext { id, context_type, diff --git a/components/layout/flow.rs b/components/layout/flow.rs index c2d01b7f9f9..acea20ad4d4 100644 --- a/components/layout/flow.rs +++ b/components/layout/flow.rs @@ -273,6 +273,22 @@ pub trait Flow: HasBaseFlow + fmt::Debug + Sync + Send + 'static { might_have_floats_in_or_out } + fn has_non_invertible_transform(&self) -> bool { + if !self.class().is_block_like() || + self.as_block() + .fragment + .style + .get_box() + .transform + .0 + .is_empty() + { + return false; + } + + self.as_block().fragment.has_non_invertible_transform() + } + fn get_overflow_in_parent_coordinates(&self) -> Overflow { // FIXME(#2795): Get the real container size. let container_size = Size2D::zero(); @@ -1160,7 +1176,9 @@ impl BaseFlow { state: &mut StackingContextCollectionState, ) { for kid in self.children.iter_mut() { - kid.collect_stacking_contexts(state); + if !kid.has_non_invertible_transform() { + kid.collect_stacking_contexts(state); + } } } diff --git a/components/layout/fragment.rs b/components/layout/fragment.rs index 062db9c0a7e..10c0fb072cc 100644 --- a/components/layout/fragment.rs +++ b/components/layout/fragment.rs @@ -2730,6 +2730,12 @@ impl Fragment { self.style().get_box().perspective != Perspective::None } + /// Returns true if this fragment has a transform applied that causes it to take up no space. + pub fn has_non_invertible_transform(&self) -> bool { + self.transform_matrix(&Rect::default()) + .map_or(false, |matrix| !matrix.is_invertible()) + } + /// Returns true if this fragment establishes a new stacking context and false otherwise. pub fn establishes_stacking_context(&self) -> bool { // Text fragments shouldn't create stacking contexts. diff --git a/components/layout/inline.rs b/components/layout/inline.rs index dfdb20e309b..ee9980c4f1a 100644 --- a/components/layout/inline.rs +++ b/components/layout/inline.rs @@ -1871,6 +1871,11 @@ impl Flow for InlineFlow { let previous_cb_clipping_and_scrolling = state.containing_block_clipping_and_scrolling; for fragment in self.fragments.fragments.iter_mut() { + // If a particular fragment would establish a stacking context but has a transform + // applied that causes it to take up no space, we can skip it entirely. + if fragment.has_non_invertible_transform() { + continue; + } state.containing_block_clipping_and_scrolling = previous_cb_clipping_and_scrolling; let abspos_containing_block = fragment.style.get_box().position != Position::Static; diff --git a/components/layout/traversal.rs b/components/layout/traversal.rs index 88a6514433b..5c66004bc1a 100644 --- a/components/layout/traversal.rs +++ b/components/layout/traversal.rs @@ -346,6 +346,10 @@ pub struct BuildDisplayList<'a> { impl<'a> BuildDisplayList<'a> { #[inline] pub fn traverse(&mut self, flow: &mut dyn Flow) { + if flow.has_non_invertible_transform() { + return; + } + let parent_stacking_context_id = self.state.current_stacking_context_id; self.state.current_stacking_context_id = flow.base().stacking_context_id;