feat: 响应式分页引擎 - 基于egui Galley精确测量替代字符计数

src/book.rs

@@ -179,12 +179,18 @@ pub struct TocEntry {
     pub children: Vec<TocEntry>,
 }
 
+#[derive(Debug, Clone)]
+pub struct ContentBlock {
+    pub text: String,
+    pub is_heading: bool,
+}
+
 #[derive(Debug, Clone)]
 pub struct Section {
     pub title: String,
     pub content: String,
-    /// Populated by pagination algorithm (pre-computed char offsets for page boundaries)
-    pub pages: Vec<usize>,
+    pub blocks: Vec<ContentBlock>,
+    pub page_block_ranges: Vec<(usize, usize)>,
 }
 
 #[derive(Debug, Clone, Copy, PartialEq)]
@@ -253,7 +259,8 @@ pub fn load_epub(path: impl AsRef<Path>) -> Result<Book, String> {
         sections.push(Section {
             title,
             content: text,
-            pages: Vec::new(),
+            blocks: Vec::new(),
+            page_block_ranges: Vec::new(),
         });
     }