Implement CSS text truncation

crates/obscura-render/src/lib.rs

@@ -452,6 +452,15 @@ pub struct LayoutStyle {
     /// until the parent's computed outer/inner display is known. The DOM
     /// top-down pass copies that provenance and then clears this marker.
     pub(crate) display_inherit: bool,
+    /// Original legacy flexbox display provenance. `Some(false)` is
+    /// `-webkit-box`; `Some(true)` is `-webkit-inline-box`. A vertical legacy
+    /// box with an active line clamp computes to flow-root/inline-block, but
+    /// retaining the specified display makes that adjustment independent of
+    /// declaration order and keeps unclamped CSSOM serialization honest.
+    pub(crate) webkit_box_display: Option<bool>,
+    /// Computed legacy box orientation. Only the vertical/block-axis form
+    /// activates the legacy WebKit line-clamp contract.
+    pub(crate) webkit_box_orient_vertical: bool,
     /// Computed CSS `container-type` (not inherited).
     pub container_type: ContainerType,
     /// The specified value was the CSS-wide `inherit` keyword. Resolved
@@ -934,6 +943,14 @@ pub struct LayoutStyle {
     /// value (or the initial `normal`). The inline shaper uses this to retain
     /// author/source newlines in code blocks and to select wrapping behavior.
     pub white_space: Option<WhiteSpace>,
+    /// Non-inherited `text-overflow`. This first implementation deliberately
+    /// models Chromium's single-value `clip|ellipsis` syntax; bidi/two-sided
+    /// markers remain a separate extension.
+    pub text_overflow: TextOverflow,
+    /// Non-inherited legacy line count. It affects direct pure-text inline
+    /// formatting contexts only; nested descendant line counting needs a real
+    /// block-line iterator and must not be approximated by clipping children.
+    pub webkit_line_clamp: Option<u32>,
     /// `overflow-wrap` (legacy alias: `word-wrap`). Inherited; `None` means
     /// inherit the nearest ancestor's value (or the initial `normal`).
     ///
@@ -1168,6 +1185,16 @@ pub enum WhiteSpace {
     BreakSpaces,
 }
 
+/// Single-value CSS `text-overflow` behavior supported by Chromium's default
+/// feature set. The marker is generated by the inline formatter and never
+/// inserted into DOM text.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
+pub enum TextOverflow {
+    #[default]
+    Clip,
+    Ellipsis,
+}
+
 /// Emergency wrapping behavior for otherwise-unbreakable text.
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
 pub enum OverflowWrap {