diff options
Diffstat (limited to 'components/style/logical_geometry.rs')
| -rw-r--r-- | components/style/logical_geometry.rs | 103 |
1 files changed, 78 insertions, 25 deletions
diff --git a/components/style/logical_geometry.rs b/components/style/logical_geometry.rs index 3817c12dcf0..38ffb25a740 100644 --- a/components/style/logical_geometry.rs +++ b/components/style/logical_geometry.rs @@ -26,16 +26,48 @@ pub enum InlineBaseDirection { // TODO: improve the readability of the WritingMode serialization, refer to the Debug:fmt() bitflags!( #[cfg_attr(feature = "servo", derive(MallocSizeOf, Serialize))] + #[repr(C)] pub struct WritingMode: u8 { - const RTL = 1 << 0; - const VERTICAL = 1 << 1; + /// 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; - /// For vertical writing modes only. When set, line-over/line-under - /// sides are inverted from block-start/block-end. This flag is - /// set when sideways-lr is used. + /// 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; - const SIDEWAYS = 1 << 4; - const UPRIGHT = 1 << 5; + /// direction is rtl. + const RTL = 1 << 4; + /// Horizontal text within a vertical writing mode is displayed sideways + /// and runs top-to-bottom or bottom-to-top; set in these cases: + /// + /// * writing-mode: vertical-rl; text-orientation: sideways; + /// * writing-mode: vertical-lr; text-orientation: sideways; + /// * writing-mode: sideways-rl; + /// * writing-mode: sideways-lr; + /// + /// Never set without VERTICAL. + const SIDEWAYS = 1 << 5; + /// 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 << 6; } ); @@ -47,33 +79,52 @@ impl WritingMode { let mut flags = WritingMode::empty(); - match inheritedbox_style.clone_direction() { + 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 inheritedbox_style.clone_writing_mode() { - SpecifiedWritingMode::HorizontalTb => {}, + 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::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::LINE_INVERTED); flags.insert(WritingMode::SIDEWAYS); + if direction == Direction::Ltr { + flags.insert(WritingMode::INLINE_REVERSED); + } }, } @@ -81,19 +132,21 @@ impl WritingMode { { use crate::properties::longhands::text_orientation::computed_value::T as TextOrientation; - // If FLAG_SIDEWAYS is already set, this means writing-mode is - // either sideways-rl or sideways-lr, and for both of these values, - // text-orientation has no effect. - if !flags.intersects(WritingMode::SIDEWAYS) { - match inheritedbox_style.clone_text_orientation() { - TextOrientation::Mixed => {}, - TextOrientation::Upright => { - flags.insert(WritingMode::UPRIGHT); - }, - TextOrientation::Sideways => { - flags.insert(WritingMode::SIDEWAYS); - }, - } + // 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); + }, + TextOrientation::Sideways => { + flags.insert(WritingMode::SIDEWAYS); + }, + } + }, + _ => {}, } } @@ -115,7 +168,7 @@ impl WritingMode { #[inline] pub fn is_inline_tb(&self) -> bool { // https://drafts.csswg.org/css-writing-modes-3/#logical-to-physical - self.intersects(WritingMode::RTL) == self.intersects(WritingMode::LINE_INVERTED) + !self.intersects(WritingMode::INLINE_REVERSED) } #[inline] |