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

src/app.rs

@@ -22,6 +22,7 @@ pub struct AppState {
     pub sidebar_open: bool,
     pub file_path: Option<PathBuf>,
     pub error_message: Option<String>,
+    pub pending_anchor: Option<theme::ReadingPosition>,
 }
 
 impl AppState {
@@ -32,7 +33,7 @@ impl AppState {
             } else if self.current_section > 0 {
                 self.current_section -= 1;
                 self.current_page = book.sections[self.current_section]
-                    .pages.len().saturating_sub(2);
+                    .page_block_ranges.len().saturating_sub(1);
             }
         }
     }
@@ -40,7 +41,7 @@ impl AppState {
     pub fn next_page(&mut self) {
         if let Some(ref book) = self.book {
             if self.current_page + 1 < book.sections[self.current_section]
-                .pages.len().saturating_sub(1)
+                .page_block_ranges.len()
             {
                 self.current_page += 1;
             } else if self.current_section + 1 < book.sections.len() {
@@ -64,6 +65,7 @@ impl App {
                 sidebar_open: false,
                 file_path: None,
                 error_message: None,
+                pending_anchor: None,
             },
             settings,
             settings_dir,
@@ -78,7 +80,7 @@ impl App {
         match crate::book::load_epub(&path) {
             Ok(book) => {
                 let path_str = path.to_string_lossy().to_string();
-                let pos = self.settings.reading_positions.get(&path_str).copied();
+                let pos = self.settings.reading_positions.get(&path_str).cloned();
                 let mut recent = Vec::new();
                 recent.push(path_str.clone());
                 for f in &self.settings.recent_files {
@@ -91,8 +93,9 @@ impl App {
                 }
                 self.settings.recent_files = recent;
                 self.state.book = Some(book);
-                self.state.current_section = pos.map(|p| p.section).unwrap_or(0);
-                self.state.current_page = pos.map(|p| p.page).unwrap_or(0);
+                self.state.current_section = pos.as_ref().map(|p| p.section).unwrap_or(0);
+                self.state.current_page = pos.as_ref().map(|p| p.page).unwrap_or(0);
+                self.state.pending_anchor = pos;
                 self.state.sidebar_open = false;
                 self.state.file_path = Some(path);
                 self.state.error_message = None;
@@ -117,11 +120,27 @@ impl App {
     fn save_reading_position(&mut self) {
         if let Some(ref path) = self.state.file_path {
             let path_str = path.to_string_lossy().to_string();
+            let (block_index, text_snippet) = if let Some(ref book) = self.state.book {
+                let section = &book.sections[self.state.current_section];
+                if let Some(&(start, _end)) = section.page_block_ranges.get(self.state.current_page) {
+                    let first_block = start;
+                    let snippet = section.blocks.get(first_block)
+                        .map(|b| b.text.chars().take(30).collect())
+                        .unwrap_or_default();
+                    (Some(first_block), Some(snippet))
+                } else {
+                    (None, None)
+                }
+            } else {
+                (None, None)
+            };
             self.settings.reading_positions.insert(
                 path_str,
                 theme::ReadingPosition {
                     section: self.state.current_section,
                     page: self.state.current_page,
+                    block_index,
+                    text_snippet,
                 },
             );
         }
@@ -395,6 +414,24 @@ BgType::Custom(ref path) if !path.is_empty() => {
              }
          }
 
+         if let Some(anchor) = self.state.pending_anchor.take() {
+             if let Some(ref book) = self.state.book {
+                 if anchor.section < book.sections.len() {
+                     let section = &book.sections[anchor.section];
+                     let restored = if let Some(block_idx) = anchor.block_index {
+                         crate::reader::find_page_for_block(section, block_idx)
+                     } else if let Some(ref snippet) = anchor.text_snippet {
+                         crate::reader::find_page_by_snippet(section, snippet)
+                     } else {
+                         None
+                     };
+                     if let Some(page) = restored {
+                         self.state.current_page = page;
+                     }
+                 }
+             }
+         }
+
          // Sync style changes back to active profile (outside closure)
          if let Some(p) = self.settings.profiles.iter_mut()
              .find(|p| p.name == self.settings.active_profile)