feat: add tab stop parsing and improved tab rendering

crates/office2pdf/src/ir/style.rs

@@ -28,6 +28,39 @@ pub struct ParagraphStyle {
     pub heading_level: Option<u8>,
     /// Text direction for bidirectional rendering (RTL for Arabic/Hebrew).
     pub direction: Option<TextDirection>,
+    /// Custom tab stop positions for this paragraph.
+    pub tab_stops: Option<Vec<TabStop>>,
+}
+
+/// A custom tab stop definition.
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub struct TabStop {
+    /// Position in points from the left margin.
+    pub position: f64,
+    /// Alignment of text at this tab stop.
+    pub alignment: TabAlignment,
+    /// Leader character filling the space before this tab stop.
+    pub leader: TabLeader,
+}
+
+/// Tab stop alignment type.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
+pub enum TabAlignment {
+    #[default]
+    Left,
+    Center,
+    Right,
+    Decimal,
+}
+
+/// Leader character for a tab stop.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
+pub enum TabLeader {
+    #[default]
+    None,
+    Dot,
+    Hyphen,
+    Underscore,
 }
 
 /// Text direction for bidirectional (BiDi) rendering.

crates/office2pdf/src/lib.rs

@@ -495,6 +495,41 @@ mod tests {
         assert!(pdf.starts_with(b"%PDF"));
     }
 
+    #[test]
+    fn test_render_document_with_tab_leader() {
+        let doc = Document {
+            metadata: Metadata::default(),
+            pages: vec![Page::Flow(FlowPage {
+                size: PageSize::default(),
+                margins: Margins::default(),
+                content: vec![Block::Paragraph(Paragraph {
+                    style: ParagraphStyle {
+                        tab_stops: Some(vec![TabStop {
+                            position: 144.0,
+                            alignment: TabAlignment::Left,
+                            leader: TabLeader::Dot,
+                        }]),
+                        ..ParagraphStyle::default()
+                    },
+                    runs: vec![Run {
+                        text: "Heading\t12".to_string(),
+                        style: TextStyle::default(),
+                        href: None,
+                        footnote: None,
+                    }],
+                })],
+                header: None,
+                footer: None,
+                columns: None,
+            })],
+            styles: StyleSheet::default(),
+        };
+
+        let pdf = render_document(&doc).unwrap();
+        assert!(!pdf.is_empty());
+        assert!(pdf.starts_with(b"%PDF"));
+    }
+
     #[test]
     fn test_render_document_styled_text() {
         let doc = Document {