feat: partially implement multi-signature feature

docs/FRs.md

@@ -38,3 +38,7 @@
   * role: user
   * functionality: app provide localization support
   * benefit: improve accessibility and usability for non-English speakers
+* name: [support multiple signatures](../test/features/support_multiple_signatures.feature)
+  * role: user
+  * functionality: the ability to sign multiple locations within a PDF document
+  * benefit: documents requiring multiple signatures can be signed simultaneously

lib/data/model/model.dart

@@ -8,6 +8,8 @@ class PdfState {
   final String? pickedPdfPath;
   final Uint8List? pickedPdfBytes;
   final int? signedPage;
+  // Multiple signature placements per page, stored as UI-space rects (e.g., 400x560)
+  final Map<int, List<Rect>> placementsByPage;
   const PdfState({
     required this.loaded,
     required this.pageCount,
@@ -15,6 +17,7 @@ class PdfState {
     this.pickedPdfPath,
     this.pickedPdfBytes,
     this.signedPage,
+    this.placementsByPage = const {},
   });
   factory PdfState.initial() => const PdfState(
     loaded: false,
@@ -22,6 +25,7 @@ class PdfState {
     currentPage: 1,
     pickedPdfBytes: null,
     signedPage: null,
+    placementsByPage: {},
   );
   PdfState copyWith({
     bool? loaded,
@@ -30,6 +34,7 @@ class PdfState {
     String? pickedPdfPath,
     Uint8List? pickedPdfBytes,
     int? signedPage,
+    Map<int, List<Rect>>? placementsByPage,
   }) => PdfState(
     loaded: loaded ?? this.loaded,
     pageCount: pageCount ?? this.pageCount,
@@ -37,6 +42,7 @@ class PdfState {
     pickedPdfPath: pickedPdfPath ?? this.pickedPdfPath,
     pickedPdfBytes: pickedPdfBytes ?? this.pickedPdfBytes,
     signedPage: signedPage ?? this.signedPage,
+    placementsByPage: placementsByPage ?? this.placementsByPage,
   );
 }
 

lib/data/services/export_service.dart

@@ -32,6 +32,7 @@ class ExportService {
     required Rect? signatureRectUi,
     required Size uiPageSize,
     required Uint8List? signatureImageBytes,
+    Map<int, List<Rect>>? placementsByPage,
     double targetDpi = 144.0,
   }) async {
     // print(
@@ -51,6 +52,7 @@ class ExportService {
       signatureRectUi: signatureRectUi,
       uiPageSize: uiPageSize,
       signatureImageBytes: signatureImageBytes,
+      placementsByPage: placementsByPage,
       targetDpi: targetDpi,
     );
     if (bytes == null) return false;
@@ -70,6 +72,7 @@ class ExportService {
     required Rect? signatureRectUi,
     required Size uiPageSize,
     required Uint8List? signatureImageBytes,
+    Map<int, List<Rect>>? placementsByPage,
     double targetDpi = 144.0,
   }) async {
     final out = pw.Document(version: pdf.PdfVersion.pdf_1_4, compress: false);
@@ -91,13 +94,25 @@ class ExportService {
         final bgImg = pw.MemoryImage(bgPng);
 
         pw.MemoryImage? sigImgObj;
-        final shouldStamp =
+        final hasMulti =
+            (placementsByPage != null && placementsByPage.isNotEmpty);
+        final pagePlacements =
+            hasMulti
+                ? (placementsByPage[pageIndex] ?? const <Rect>[])
+                : const <Rect>[];
+        final shouldStampSingle =
+            !hasMulti &&
             signedPage != null &&
             pageIndex == signedPage &&
             signatureRectUi != null &&
             signatureImageBytes != null &&
             signatureImageBytes.isNotEmpty;
-        if (shouldStamp) {
+        final shouldStampMulti =
+            hasMulti &&
+            pagePlacements.isNotEmpty &&
+            signatureImageBytes != null &&
+            signatureImageBytes.isNotEmpty;
+        if (shouldStampSingle || shouldStampMulti) {
           try {
             sigImgObj = pw.MemoryImage(signatureImageBytes);
           } catch (_) {
@@ -125,7 +140,8 @@ class ExportService {
                 ),
               ];
               if (sigImgObj != null) {
-                final r = signatureRectUi!;
+                if (hasMulti && pagePlacements.isNotEmpty) {
+                  for (final r in pagePlacements) {
                     final left = r.left / uiPageSize.width * widthPts;
                     final top = r.top / uiPageSize.height * heightPts;
                     final w = r.width / uiPageSize.width * widthPts;
@@ -138,6 +154,21 @@ class ExportService {
                       ),
                     );
                   }
+                } else if (shouldStampSingle) {
+                  final r = signatureRectUi;
+                  final left = r.left / uiPageSize.width * widthPts;
+                  final top = r.top / uiPageSize.height * heightPts;
+                  final w = r.width / uiPageSize.width * widthPts;
+                  final h = r.height / uiPageSize.height * heightPts;
+                  children.add(
+                    pw.Positioned(
+                      left: left,
+                      top: top,
+                      child: pw.Image(sigImgObj, width: w, height: h),
+                    ),
+                  );
+                }
+              }
               return pw.Stack(children: children);
             },
           ),
@@ -152,13 +183,23 @@ class ExportService {
       final widthPts = pdf.PdfPageFormat.a4.width;
       final heightPts = pdf.PdfPageFormat.a4.height;
       pw.MemoryImage? sigImgObj;
-      final shouldStamp =
+      final hasMulti =
+          (placementsByPage != null && placementsByPage.isNotEmpty);
+      final pagePlacements =
+          hasMulti ? (placementsByPage[1] ?? const <Rect>[]) : const <Rect>[];
+      final shouldStampSingle =
+          !hasMulti &&
           signedPage != null &&
           signedPage == 1 &&
           signatureRectUi != null &&
           signatureImageBytes != null &&
           signatureImageBytes.isNotEmpty;
-      if (shouldStamp) {
+      final shouldStampMulti =
+          hasMulti &&
+          pagePlacements.isNotEmpty &&
+          signatureImageBytes != null &&
+          signatureImageBytes.isNotEmpty;
+      if (shouldStampSingle || shouldStampMulti) {
         try {
           // If it's already PNG, keep as-is to preserve alpha; otherwise decode/encode PNG
           final asStr = String.fromCharCodes(signatureImageBytes.take(8));
@@ -192,7 +233,8 @@ class ExportService {
               ),
             ];
             if (sigImgObj != null) {
-              final r = signatureRectUi!;
+              if (hasMulti && pagePlacements.isNotEmpty) {
+                for (final r in pagePlacements) {
                   final left = r.left / uiPageSize.width * widthPts;
                   final top = r.top / uiPageSize.height * heightPts;
                   final w = r.width / uiPageSize.width * widthPts;
@@ -205,6 +247,21 @@ class ExportService {
                     ),
                   );
                 }
+              } else if (shouldStampSingle) {
+                final r = signatureRectUi;
+                final left = r.left / uiPageSize.width * widthPts;
+                final top = r.top / uiPageSize.height * heightPts;
+                final w = r.width / uiPageSize.width * widthPts;
+                final h = r.height / uiPageSize.height * heightPts;
+                children.add(
+                  pw.Positioned(
+                    left: left,
+                    top: top,
+                    child: pw.Image(sigImgObj, width: w, height: h),
+                  ),
+                );
+              }
+            }
             return pw.Stack(children: children);
           },
         ),

lib/ui/features/pdf/view_model/view_model.dart

@@ -18,6 +18,7 @@ class PdfController extends StateNotifier<PdfState> {
       currentPage: 1,
       pickedPdfPath: null,
       signedPage: null,
+      placementsByPage: {},
     );
   }
 
@@ -33,6 +34,7 @@ class PdfController extends StateNotifier<PdfState> {
       pickedPdfPath: path,
       pickedPdfBytes: bytes,
       signedPage: null,
+      placementsByPage: {},
     );
   }
 
@@ -57,6 +59,37 @@ class PdfController extends StateNotifier<PdfState> {
     if (!state.loaded) return;
     state = state.copyWith(pageCount: count.clamp(1, 9999));
   }
+
+  // Multiple-signature helpers
+  void addPlacement({required int page, required Rect rect}) {
+    if (!state.loaded) return;
+    final p = page.clamp(1, state.pageCount);
+    final map = Map<int, List<Rect>>.from(state.placementsByPage);
+    final list = List<Rect>.from(map[p] ?? const []);
+    list.add(rect);
+    map[p] = list;
+    state = state.copyWith(placementsByPage: map);
+  }
+
+  void removePlacement({required int page, required int index}) {
+    if (!state.loaded) return;
+    final p = page.clamp(1, state.pageCount);
+    final map = Map<int, List<Rect>>.from(state.placementsByPage);
+    final list = List<Rect>.from(map[p] ?? const []);
+    if (index >= 0 && index < list.length) {
+      list.removeAt(index);
+      if (list.isEmpty) {
+        map.remove(p);
+      } else {
+        map[p] = list;
+      }
+      state = state.copyWith(placementsByPage: map);
+    }
+  }
+
+  List<Rect> placementsOn(int page) {
+    return List<Rect>.from(state.placementsByPage[page] ?? const []);
+  }
 }
 
 final pdfProvider = StateNotifierProvider<PdfController, PdfState>(

lib/ui/features/pdf/widgets/pdf_screen.dart

@@ -70,6 +70,16 @@ class _PdfSignatureHomePageState extends ConsumerState<PdfSignatureHomePage> {
     }
   }
 
+  void _placeCurrentSignatureOnPage() {
+    final pdf = ref.read(pdfProvider);
+    final sig = ref.read(signatureProvider);
+    if (!pdf.loaded || sig.rect == null) return;
+    ref
+        .read(pdfProvider.notifier)
+        .addPlacement(page: pdf.currentPage, rect: sig.rect!);
+    // Keep the active rect so the user can place multiple times if desired.
+  }
+
   void _onDragSignature(Offset delta) {
     ref.read(signatureProvider.notifier).drag(delta);
   }
@@ -130,6 +140,7 @@ class _PdfSignatureHomePageState extends ConsumerState<PdfSignatureHomePage> {
             signatureRectUi: sig.rect,
             uiPageSize: SignatureController.pageSize,
             signatureImageBytes: processed ?? sig.imageBytes,
+            placementsByPage: pdf.placementsByPage,
             targetDpi: targetDpi,
           );
           if (bytes != null) {
@@ -161,6 +172,7 @@ class _PdfSignatureHomePageState extends ConsumerState<PdfSignatureHomePage> {
             signatureRectUi: sig.rect,
             uiPageSize: SignatureController.pageSize,
             signatureImageBytes: processed ?? sig.imageBytes,
+            placementsByPage: pdf.placementsByPage,
             targetDpi: targetDpi,
           );
           if (useMock) {
@@ -187,6 +199,7 @@ class _PdfSignatureHomePageState extends ConsumerState<PdfSignatureHomePage> {
               signatureRectUi: sig.rect,
               uiPageSize: SignatureController.pageSize,
               signatureImageBytes: processed ?? sig.imageBytes,
+              placementsByPage: pdf.placementsByPage,
               targetDpi: targetDpi,
             );
           }
@@ -408,6 +421,16 @@ class _PdfSignatureHomePageState extends ConsumerState<PdfSignatureHomePage> {
             onPressed: disabled || !pdf.loaded ? null : _openDrawCanvas,
             child: Text(l.drawSignature),
           ),
+          OutlinedButton(
+            key: const Key('btn_place_signature'),
+            onPressed:
+                disabled ||
+                        !pdf.loaded ||
+                        ref.read(signatureProvider).rect == null
+                    ? null
+                    : _placeCurrentSignatureOnPage,
+            child: const Text('Place on page'),
+          ),
         ],
       ],
     );
@@ -428,7 +451,7 @@ class _PdfSignatureHomePageState extends ConsumerState<PdfSignatureHomePage> {
               key: const Key('page_stack'),
               children: [
                 Container(
-                  key: const Key('pdf_page'),
+                  key: ValueKey('pdf_page_view_${pdf.currentPage}'),
                   color: Colors.grey.shade200,
                   child: Center(
                     child: Text(
@@ -446,8 +469,8 @@ class _PdfSignatureHomePageState extends ConsumerState<PdfSignatureHomePage> {
                   builder: (context, ref, _) {
                     final sig = ref.watch(signatureProvider);
                     final visible = ref.watch(signatureVisibilityProvider);
-                    return sig.rect != null && visible
+                    return visible
-                        ? _buildSignatureOverlay(sig)
+                        ? _buildPageOverlays(sig)
                         : const SizedBox.shrink();
                   },
                 ),
@@ -486,6 +509,7 @@ class _PdfSignatureHomePageState extends ConsumerState<PdfSignatureHomePage> {
                   key: const Key('page_stack'),
                   children: [
                     PdfPageView(
+                      key: ValueKey('pdf_page_view_$pageNum'),
                       document: document,
                       pageNumber: pageNum,
                       alignment: Alignment.center,
@@ -494,8 +518,8 @@ class _PdfSignatureHomePageState extends ConsumerState<PdfSignatureHomePage> {
                       builder: (context, ref, _) {
                         final sig = ref.watch(signatureProvider);
                         final visible = ref.watch(signatureVisibilityProvider);
-                        return sig.rect != null && visible
+                        return visible
-                            ? _buildSignatureOverlay(sig)
+                            ? _buildPageOverlays(sig)
                             : const SizedBox.shrink();
                       },
                     ),
@@ -511,8 +535,11 @@ class _PdfSignatureHomePageState extends ConsumerState<PdfSignatureHomePage> {
     return const SizedBox.shrink();
   }
 
-  Widget _buildSignatureOverlay(SignatureState sig) {
+  Widget _buildSignatureOverlay(
-    final r = sig.rect!;
+    SignatureState sig,
+    Rect r, {
+    bool interactive = true,
+  }) {
     return LayoutBuilder(
       builder: (context, constraints) {
         final scaleX = constraints.maxWidth / _pageSize.width;
@@ -529,15 +556,9 @@ class _PdfSignatureHomePageState extends ConsumerState<PdfSignatureHomePage> {
               top: top,
               width: width,
               height: height,
-              child: GestureDetector(
+              child: Builder(
-                key: const Key('signature_overlay'),
+                builder: (context) {
-                behavior: HitTestBehavior.opaque,
+                  Widget content = DecoratedBox(
-                onPanStart: (_) {},
-                onPanUpdate:
-                    (d) => _onDragSignature(
-                      Offset(d.delta.dx / scaleX, d.delta.dy / scaleY),
-                    ),
-                child: DecoratedBox(
                     decoration: BoxDecoration(
                       color: Color.fromRGBO(
                         0,
@@ -565,6 +586,7 @@ class _PdfSignatureHomePageState extends ConsumerState<PdfSignatureHomePage> {
                             return Image.memory(bytes, fit: BoxFit.contain);
                           },
                         ),
+                        if (interactive)
                           Positioned(
                             right: 0,
                             bottom: 0,
@@ -583,7 +605,21 @@ class _PdfSignatureHomePageState extends ConsumerState<PdfSignatureHomePage> {
                           ),
                       ],
                     ),
+                  );
+                  if (interactive) {
+                    content = GestureDetector(
+                      key: const Key('signature_overlay'),
+                      behavior: HitTestBehavior.opaque,
+                      onPanStart: (_) {},
+                      onPanUpdate:
+                          (d) => _onDragSignature(
+                            Offset(d.delta.dx / scaleX, d.delta.dy / scaleY),
                           ),
+                      child: content,
+                    );
+                  }
+                  return content;
+                },
               ),
             ),
           ],
@@ -592,6 +628,22 @@ class _PdfSignatureHomePageState extends ConsumerState<PdfSignatureHomePage> {
     );
   }
 
+  Widget _buildPageOverlays(SignatureState sig) {
+    final pdf = ref.watch(pdfProvider);
+    final current = pdf.currentPage;
+    final placed = pdf.placementsByPage[current] ?? const <Rect>[];
+    final widgets = <Widget>[];
+    for (final r in placed) {
+      widgets.add(_buildSignatureOverlay(sig, r, interactive: false));
+    }
+    // Show the active editing rect only on the selected (signed) page
+    if (sig.rect != null &&
+        (pdf.signedPage == null || pdf.signedPage == current)) {
+      widgets.add(_buildSignatureOverlay(sig, sig.rect!, interactive: true));
+    }
+    return Stack(children: widgets);
+  }
+
   Widget _buildAdjustmentsPanel(SignatureState sig) {
     return Column(
       key: const Key('adjustments_panel'),

test/features/step/a_pdf_is_open_and_contains_multiple_placed_signatures_across_pages.dart

@@ -0,0 +1,43 @@
+import 'dart:typed_data';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:flutter/material.dart';
+import 'package:pdf_signature/ui/features/pdf/view_model/view_model.dart';
+import '_world.dart';
+
+/// Usage: a PDF is open and contains multiple placed signatures across pages
+Future<void> aPdfIsOpenAndContainsMultiplePlacedSignaturesAcrossPages(
+  WidgetTester tester,
+) async {
+  final container = TestWorld.container ?? ProviderContainer();
+  TestWorld.container = container;
+  container
+      .read(pdfProvider.notifier)
+      .openPicked(path: 'mock.pdf', pageCount: 6);
+  // Ensure signature image exists
+  container
+      .read(signatureProvider.notifier)
+      .setImageBytes(Uint8List.fromList([1, 2, 3]));
+  // Place on two pages
+  container
+      .read(pdfProvider.notifier)
+      .addPlacement(page: 1, rect: const Rect.fromLTWH(10, 10, 80, 40));
+  container
+      .read(pdfProvider.notifier)
+      .addPlacement(page: 4, rect: const Rect.fromLTWH(120, 200, 100, 50));
+  // Keep backward compatibility with existing export step expectations
+  container.read(pdfProvider.notifier).setSignedPage(1);
+  container.read(signatureProvider.notifier).placeDefaultRect();
+}
+
+/// Usage: all placed signatures appear on their corresponding pages in the output
+Future<void> allPlacedSignaturesAppearOnTheirCorrespondingPagesInTheOutput(
+  WidgetTester tester,
+) async {
+  // In this logic-level test suite, we simply assert that placements exist
+  // on multiple pages and that a simulated export has bytes.
+  final container = TestWorld.container ?? ProviderContainer();
+  expect(container.read(pdfProvider.notifier).placementsOn(1), isNotEmpty);
+  expect(container.read(pdfProvider.notifier).placementsOn(4), isNotEmpty);
+  expect(TestWorld.lastExportBytes, isNotNull);
+}

test/features/step/a_signature_image_is_loaded_or_drawn.dart

@@ -0,0 +1,14 @@
+import 'dart:typed_data';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:pdf_signature/ui/features/pdf/view_model/view_model.dart';
+import '_world.dart';
+
+/// Usage: a signature image is loaded or drawn
+Future<void> aSignatureImageIsLoadedOrDrawn(WidgetTester tester) async {
+  final container = TestWorld.container ?? ProviderContainer();
+  TestWorld.container = container;
+  container
+      .read(signatureProvider.notifier)
+      .setImageBytes(Uint8List.fromList([1, 2, 3]));
+}

test/features/step/a_signature_is_placed_on_page_2.dart

@@ -0,0 +1,40 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:flutter/material.dart';
+import 'package:pdf_signature/ui/features/pdf/view_model/view_model.dart';
+import '_world.dart';
+
+/// Usage: a signature is placed on page 2
+Future<void> aSignatureIsPlacedOnPage2(WidgetTester tester) async {
+  final container = TestWorld.container ?? ProviderContainer();
+  TestWorld.container = container;
+  container
+      .read(pdfProvider.notifier)
+      .openPicked(path: 'mock.pdf', pageCount: 8);
+  container
+      .read(pdfProvider.notifier)
+      .addPlacement(page: 2, rect: const Rect.fromLTWH(50, 100, 80, 40));
+}
+
+/// Usage: the user navigates to page 5 and places another signature
+Future<void> theUserNavigatesToPage5AndPlacesAnotherSignature(
+  WidgetTester tester,
+) async {
+  final container = TestWorld.container ?? ProviderContainer();
+  container.read(pdfProvider.notifier).jumpTo(5);
+  container
+      .read(pdfProvider.notifier)
+      .addPlacement(page: 5, rect: const Rect.fromLTWH(60, 120, 80, 40));
+}
+
+/// Usage: the signature on page 2 remains
+Future<void> theSignatureOnPage2Remains(WidgetTester tester) async {
+  final container = TestWorld.container ?? ProviderContainer();
+  expect(container.read(pdfProvider.notifier).placementsOn(2), isNotEmpty);
+}
+
+/// Usage: the signature on page 5 is shown on page 5
+Future<void> theSignatureOnPage5IsShownOnPage5(WidgetTester tester) async {
+  final container = TestWorld.container ?? ProviderContainer();
+  expect(container.read(pdfProvider.notifier).placementsOn(5), isNotEmpty);
+}

test/features/step/both_signatures_are_shown_on_their_respective_pages.dart

@@ -0,0 +1,15 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:pdf_signature/ui/features/pdf/view_model/view_model.dart';
+import '_world.dart';
+
+/// Usage: both signatures are shown on their respective pages
+Future<void> bothSignaturesAreShownOnTheirRespectivePages(
+  WidgetTester tester,
+) async {
+  final container = TestWorld.container ?? ProviderContainer();
+  final p1 = container.read(pdfProvider.notifier).placementsOn(1);
+  final p3 = container.read(pdfProvider.notifier).placementsOn(3);
+  expect(p1, isNotEmpty);
+  expect(p3, isNotEmpty);
+}

test/features/step/the_user_navigates_to_page_3_and_places_another_signature.dart

@@ -0,0 +1,20 @@
+import 'dart:typed_data';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:pdf_signature/ui/features/pdf/view_model/view_model.dart';
+import '_world.dart';
+
+/// Usage: the user navigates to page 3 and places another signature
+Future<void> theUserNavigatesToPage3AndPlacesAnotherSignature(
+  WidgetTester tester,
+) async {
+  final container = TestWorld.container ?? ProviderContainer();
+  TestWorld.container = container;
+  container.read(pdfProvider.notifier).jumpTo(3);
+  container
+      .read(signatureProvider.notifier)
+      .setImageBytes(Uint8List.fromList([1, 2, 3]));
+  container.read(signatureProvider.notifier).placeDefaultRect();
+  final rect = container.read(signatureProvider).rect!;
+  container.read(pdfProvider.notifier).addPlacement(page: 3, rect: rect);
+}

test/features/step/the_user_places_a_signature_on_page_1.dart

@@ -0,0 +1,19 @@
+import 'dart:typed_data';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:pdf_signature/ui/features/pdf/view_model/view_model.dart';
+import '_world.dart';
+
+/// Usage: the user places a signature on page 1
+Future<void> theUserPlacesASignatureOnPage1(WidgetTester tester) async {
+  final container = TestWorld.container ?? ProviderContainer();
+  TestWorld.container = container;
+  // Ensure image exists so placement is meaningful
+  container
+      .read(signatureProvider.notifier)
+      .setImageBytes(Uint8List.fromList([1, 2, 3]));
+  // Place a default rect on page 1
+  container.read(signatureProvider.notifier).placeDefaultRect();
+  final rect = container.read(signatureProvider).rect!;
+  container.read(pdfProvider.notifier).addPlacement(page: 1, rect: rect);
+}

test/features/step/the_user_places_it_in_multiple_locations_in_the_document.dart

@@ -0,0 +1,47 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:flutter/material.dart';
+import 'package:pdf_signature/ui/features/pdf/view_model/view_model.dart';
+import '_world.dart';
+
+/// Usage: the user places it in multiple locations in the document
+Future<void> theUserPlacesItInMultipleLocationsInTheDocument(
+  WidgetTester tester,
+) async {
+  final container = TestWorld.container ?? ProviderContainer();
+  TestWorld.container = container;
+  final notifier = container.read(pdfProvider.notifier);
+  // Always open a fresh doc to avoid state bleed between scenarios
+  notifier.openPicked(path: 'mock.pdf', pageCount: 6);
+  // Place two on page 2 and one on page 4
+  notifier.addPlacement(page: 2, rect: const Rect.fromLTWH(10, 10, 80, 40));
+  notifier.addPlacement(page: 2, rect: const Rect.fromLTWH(120, 50, 80, 40));
+  notifier.addPlacement(page: 4, rect: const Rect.fromLTWH(20, 200, 100, 50));
+}
+
+/// Usage: identical signature instances appear in each location
+Future<void> identicalSignatureInstancesAppearInEachLocation(
+  WidgetTester tester,
+) async {
+  final container = TestWorld.container ?? ProviderContainer();
+  TestWorld.container = container;
+  final state = container.read(pdfProvider);
+  final p2 = state.placementsByPage[2] ?? const [];
+  final p4 = state.placementsByPage[4] ?? const [];
+  expect(p2.length, greaterThanOrEqualTo(2));
+  expect(p4.length, greaterThanOrEqualTo(1));
+}
+
+/// Usage: adjusting one instance does not affect the others
+Future<void> adjustingOneInstanceDoesNotAffectTheOthers(
+  WidgetTester tester,
+) async {
+  final container = TestWorld.container ?? ProviderContainer();
+  final before = container.read(pdfProvider.notifier).placementsOn(2);
+  expect(before.length, greaterThanOrEqualTo(2));
+  final modified = before[0].inflate(5);
+  container.read(pdfProvider.notifier).removePlacement(page: 2, index: 0);
+  container.read(pdfProvider.notifier).addPlacement(page: 2, rect: modified);
+  final after = container.read(pdfProvider.notifier).placementsOn(2);
+  expect(after.any((r) => r == before[1]), isTrue);
+}

test/features/step/the_user_places_two_signatures_on_the_same_page.dart

@@ -0,0 +1,57 @@
+import 'dart:typed_data';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:flutter/material.dart';
+import 'package:pdf_signature/ui/features/pdf/view_model/view_model.dart';
+import '_world.dart';
+
+/// Usage: the user places two signatures on the same page
+Future<void> theUserPlacesTwoSignaturesOnTheSamePage(
+  WidgetTester tester,
+) async {
+  final container = TestWorld.container ?? ProviderContainer();
+  TestWorld.container = container;
+  container
+      .read(signatureProvider.notifier)
+      .setImageBytes(Uint8List.fromList([1, 2, 3]));
+  // First
+  container.read(signatureProvider.notifier).placeDefaultRect();
+  final r1 = container.read(signatureProvider).rect!;
+  container.read(pdfProvider.notifier).addPlacement(page: 1, rect: r1);
+  // Second (offset a bit)
+  final r2 = r1.shift(const Offset(30, 30));
+  container.read(pdfProvider.notifier).addPlacement(page: 1, rect: r2);
+}
+
+/// Usage: each signature can be dragged and resized independently
+Future<void> eachSignatureCanBeDraggedAndResizedIndependently(
+  WidgetTester tester,
+) async {
+  final container = TestWorld.container ?? ProviderContainer();
+  final list = container.read(pdfProvider.notifier).placementsOn(1);
+  expect(list.length, greaterThanOrEqualTo(2));
+  // Independence is modeled by distinct rects; ensure not equal and both within page
+  expect(list[0], isNot(equals(list[1])));
+  for (final r in list.take(2)) {
+    expect(r.left, greaterThanOrEqualTo(0));
+    expect(r.top, greaterThanOrEqualTo(0));
+  }
+}
+
+/// Usage: dragging or resizing one does not change the other
+Future<void> draggingOrResizingOneDoesNotChangeTheOther(
+  WidgetTester tester,
+) async {
+  final container = TestWorld.container ?? ProviderContainer();
+  final list = container.read(pdfProvider.notifier).placementsOn(1);
+  expect(list.length, greaterThanOrEqualTo(2));
+  final before = List<Rect>.from(list.take(2));
+  // Simulate changing the first only
+  final changed = before[0].shift(const Offset(5, 5));
+  container.read(pdfProvider.notifier).removePlacement(page: 1, index: 0);
+  container.read(pdfProvider.notifier).addPlacement(page: 1, rect: changed);
+  final after = container.read(pdfProvider.notifier).placementsOn(1);
+  expect(after[0], isNot(equals(before[0])));
+  // The other remains the same (order may differ after remove/add, check set containment)
+  expect(after.any((r) => r == before[1]), isTrue);
+}

test/features/step/three_signatures_are_placed_on_the_current_page.dart

@@ -0,0 +1,36 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:flutter/material.dart';
+import 'package:pdf_signature/ui/features/pdf/view_model/view_model.dart';
+import '_world.dart';
+
+/// Usage: three signatures are placed on the current page
+Future<void> threeSignaturesArePlacedOnTheCurrentPage(
+  WidgetTester tester,
+) async {
+  final container = TestWorld.container ?? ProviderContainer();
+  TestWorld.container = container;
+  container
+      .read(pdfProvider.notifier)
+      .openPicked(path: 'mock.pdf', pageCount: 5);
+  final n = container.read(pdfProvider.notifier);
+  n.addPlacement(page: 1, rect: const Rect.fromLTWH(10, 10, 80, 40));
+  n.addPlacement(page: 1, rect: const Rect.fromLTWH(100, 50, 80, 40));
+  n.addPlacement(page: 1, rect: const Rect.fromLTWH(200, 90, 80, 40));
+}
+
+/// Usage: the user deletes one selected signature
+Future<void> theUserDeletesOneSelectedSignature(WidgetTester tester) async {
+  final container = TestWorld.container ?? ProviderContainer();
+  // Remove the middle one (index 1)
+  container.read(pdfProvider.notifier).removePlacement(page: 1, index: 1);
+}
+
+/// Usage: only the selected signature is removed
+Future<void> onlyTheSelectedSignatureIsRemoved(WidgetTester tester) async {
+  final container = TestWorld.container ?? ProviderContainer();
+  final list = container.read(pdfProvider.notifier).placementsOn(1);
+  expect(list.length, 2);
+  expect(list[0].left, equals(10));
+  expect(list[1].left, equals(200));
+}

test/features/support_multiple_signatures.feature

@@ -0,0 +1,38 @@
+Feature: support multiple signatures
+
+	Scenario: Place signatures on different pages
+		Given a multi-page PDF is open
+		When the user places a signature on page 1
+		And the user navigates to page 3 and places another signature
+		Then both signatures are shown on their respective pages
+
+	Scenario: Place multiple signatures on the same page independently
+		Given a PDF page is selected for signing
+		When the user places two signatures on the same page
+		Then each signature can be dragged and resized independently
+		And dragging or resizing one does not change the other
+
+	Scenario: Reuse the same signature asset in multiple locations
+		Given a signature image is loaded or drawn
+		When the user places it in multiple locations in the document
+		Then identical signature instances appear in each location
+		And adjusting one instance does not affect the others
+
+	Scenario: Remove one of many signatures
+		Given three signatures are placed on the current page
+		When the user deletes one selected signature
+		Then only the selected signature is removed
+		And the other signatures remain unchanged
+
+	Scenario: Keep earlier signatures while navigating between pages
+		Given a signature is placed on page 2
+		When the user navigates to page 5 and places another signature
+		Then the signature on page 2 remains
+		And the signature on page 5 is shown on page 5
+
+	Scenario: Save a document with multiple signatures across pages
+		Given a PDF is open and contains multiple placed signatures across pages
+		When the user saves/exports the document
+		Then all placed signatures appear on their corresponding pages in the output
+		And other page content remains unaltered
+

test/widget/pdf_navigation_widget_test.dart

@@ -0,0 +1,86 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+
+import 'package:pdf_signature/ui/features/pdf/widgets/pdf_screen.dart';
+import 'package:pdf_signature/ui/features/pdf/view_model/view_model.dart';
+import 'package:pdf_signature/data/model/model.dart';
+import 'package:pdf_signature/data/services/providers.dart';
+import 'package:pdf_signature/l10n/app_localizations.dart';
+
+class _TestPdfController extends PdfController {
+  _TestPdfController() : super() {
+    // Start with a loaded multi-page doc, page 1 of 5
+    state = PdfState.initial().copyWith(
+      loaded: true,
+      pageCount: 5,
+      currentPage: 1,
+    );
+  }
+}
+
+void main() {
+  testWidgets('PDF navigation: prev/next and goto update page label', (
+    tester,
+  ) async {
+    await tester.pumpWidget(
+      ProviderScope(
+        overrides: [
+          useMockViewerProvider.overrideWithValue(true),
+          pdfProvider.overrideWith((ref) => _TestPdfController()),
+        ],
+        child: MaterialApp(
+          localizationsDelegates: AppLocalizations.localizationsDelegates,
+          supportedLocales: AppLocalizations.supportedLocales,
+          locale: const Locale('en'),
+          home: const PdfSignatureHomePage(),
+        ),
+      ),
+    );
+
+    // Initial label and page view key
+    expect(find.byKey(const Key('lbl_page_info')), findsOneWidget);
+    Text label() => tester.widget<Text>(find.byKey(const Key('lbl_page_info')));
+    expect(label().data, equals('Page 1/5'));
+    expect(find.byKey(const ValueKey('pdf_page_view_1')), findsOneWidget);
+
+    // Next
+    await tester.tap(find.byKey(const Key('btn_next')));
+    await tester.pumpAndSettle();
+    expect(label().data, equals('Page 2/5'));
+    expect(find.byKey(const ValueKey('pdf_page_view_2')), findsOneWidget);
+
+    // Prev
+    await tester.tap(find.byKey(const Key('btn_prev')));
+    await tester.pumpAndSettle();
+    expect(label().data, equals('Page 1/5'));
+    expect(find.byKey(const ValueKey('pdf_page_view_1')), findsOneWidget);
+
+    // Goto specific page
+    await tester.tap(find.byKey(const Key('txt_goto')));
+    await tester.pumpAndSettle();
+    await tester.enterText(find.byKey(const Key('txt_goto')), '4');
+    await tester.testTextInput.receiveAction(TextInputAction.done);
+    await tester.pumpAndSettle();
+    expect(label().data, equals('Page 4/5'));
+    expect(find.byKey(const ValueKey('pdf_page_view_4')), findsOneWidget);
+
+    // Goto beyond upper bound -> clamp to 5
+    await tester.tap(find.byKey(const Key('txt_goto')));
+    await tester.pumpAndSettle();
+    await tester.enterText(find.byKey(const Key('txt_goto')), '999');
+    await tester.testTextInput.receiveAction(TextInputAction.done);
+    await tester.pumpAndSettle();
+    expect(label().data, equals('Page 5/5'));
+    expect(find.byKey(const ValueKey('pdf_page_view_5')), findsOneWidget);
+
+    // Goto below 1 -> clamp to 1
+    await tester.tap(find.byKey(const Key('txt_goto')));
+    await tester.pumpAndSettle();
+    await tester.enterText(find.byKey(const Key('txt_goto')), '0');
+    await tester.testTextInput.receiveAction(TextInputAction.done);
+    await tester.pumpAndSettle();
+    expect(label().data, equals('Page 1/5'));
+    expect(find.byKey(const ValueKey('pdf_page_view_1')), findsOneWidget);
+  });
+}

test/widget/widget_test.dart

@@ -1,2 +0,0 @@
-// Split into multiple *_test.dart files. Intentionally left empty.
-void main() {}