Custom drawing implementation

lib/features/sheet_viewer/widgets/pdf_page_display.dart

@@ -4,20 +4,33 @@ import 'package:flutter/material.dart';
 import 'package:pdfrx/pdfrx.dart';
 
 import '../../../core/models/config.dart';
+import '../drawing/drawing.dart';
 
-/// Displays PDF pages with optional two-page mode.
+/// Displays PDF pages with optional two-page mode and drawing overlay.
 class PdfPageDisplay extends StatelessWidget {
   final PdfDocument document;
   final int numPages;
   final int currentPageNumber;
   final Config config;
 
+  /// Controller for the left/main page drawing
+  final DrawingController? leftDrawingController;
+
+  /// Controller for the right page drawing (two-page mode only)
+  final DrawingController? rightDrawingController;
+
+  /// Whether drawing is enabled
+  final bool drawingEnabled;
+
   const PdfPageDisplay({
     super.key,
     required this.document,
     required this.numPages,
     required this.currentPageNumber,
     required this.config,
+    this.leftDrawingController,
+    this.rightDrawingController,
+    this.drawingEnabled = false,
   });
 
   /// Whether two-page mode is active and we have enough pages.
@@ -25,55 +38,102 @@ class PdfPageDisplay extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    return Row(
-      mainAxisAlignment: MainAxisAlignment.center,
-      crossAxisAlignment: CrossAxisAlignment.center,
-      children: [_buildLeftPage(), if (_showTwoPages) _buildRightPage()],
-    );
-  }
+    return LayoutBuilder(
+      builder: (context, constraints) {
+        final maxSize = Size(constraints.maxWidth, constraints.maxHeight);
+        final (leftSize, rightSize) = calculateScaledPageSizes(maxSize);
 
-  Widget _buildLeftPage() {
-    return Expanded(
-      child: Stack(
-        children: [
-          PdfPageView(
-            key: ValueKey(currentPageNumber),
-            document: document,
+        if (_showTwoPages) {
+          // Two-page mode: pages touch each other and are centered together
+          return Center(
+            child: Row(
+              mainAxisSize: MainAxisSize.min,
+              crossAxisAlignment: CrossAxisAlignment.center,
+              children: [
+                _buildPage(
+                  pageNumber: currentPageNumber,
+                  pageSize: leftSize,
+                  controller: leftDrawingController,
+                ),
+                // Only show right page if there is one
+                if (currentPageNumber < numPages)
+                  _buildPage(
+                    pageNumber: currentPageNumber + 1,
+                    pageSize: rightSize!,
+                    controller: rightDrawingController,
+                  )
+                else
+                  // Empty space to keep left page position consistent on last page
+                  SizedBox(width: rightSize!.width, height: rightSize.height),
+              ],
+            ),
+          );
+        }
+
+        // Single page mode
+        return Center(
+          child: _buildPage(
             pageNumber: currentPageNumber,
-            maximumDpi: 300,
-            alignment: _showTwoPages ? Alignment.centerRight : Alignment.center,
+            pageSize: leftSize,
+            controller: leftDrawingController,
           ),
-          _buildPageIndicator(currentPageNumber),
-        ],
-      ),
+        );
+      },
     );
   }
 
-  Widget _buildRightPage() {
-    final rightPageNumber = currentPageNumber + 1;
-
-    return Expanded(
+  Widget _buildPage({
+    required int pageNumber,
+    required Size pageSize,
+    required DrawingController? controller,
+  }) {
+    final pdfPage = SizedBox(
+      width: pageSize.width,
+      height: pageSize.height,
       child: Stack(
         children: [
           PdfPageView(
-            key: ValueKey(rightPageNumber),
+            key: ValueKey(pageNumber),
             document: document,
-            pageNumber: rightPageNumber,
+            pageNumber: pageNumber,
             maximumDpi: 300,
-            alignment: Alignment.centerLeft,
+            alignment: Alignment.center,
           ),
-          _buildPageIndicator(rightPageNumber),
+          _buildPageIndicator(pageNumber, pageSize),
         ],
       ),
     );
+
+    // If no controller, just show the PDF
+    if (controller == null) {
+      return pdfPage;
+    }
+
+    // Wrap with DrawingBoard
+    return DrawingBoard(
+      boardSize: pageSize,
+      controller: controller,
+      drawingEnabled: drawingEnabled,
+      minScale: 1.0,
+      maxScale: 3.0,
+      alignment: Alignment.center,
+      child: pdfPage,
+    );
   }
 
-  Widget _buildPageIndicator(int pageNumber) {
-    return Positioned.fill(
-      child: Container(
-        alignment: Alignment.bottomCenter,
-        padding: const EdgeInsets.only(bottom: 5),
-        child: Text('$pageNumber / $numPages'),
+  Widget _buildPageIndicator(int pageNumber, Size pageSize) {
+    return Positioned(
+      bottom: 5,
+      left: 0,
+      right: 0,
+      child: Center(
+        child: Text(
+          '$pageNumber / $numPages',
+          style: const TextStyle(
+            fontSize: 12,
+            color: Colors.black54,
+          ),
+        ),
       ),
     );
   }