implement pdf export

handle correct storage management for android

android/app/build.gradle

@@ -26,7 +26,7 @@ apply plugin: 'kotlin-android'
 apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"
 
 android {
-    compileSdkVersion flutter.compileSdkVersion
+    compileSdkVersion 33
     ndkVersion flutter.ndkVersion
 
     compileOptions {

android/app/src/main/AndroidManifest.xml

@@ -1,6 +1,9 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     package="eu.heili.notes">
+    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
+    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
    <application
+           android:requestLegacyExternalStorage="true"
         android:label="notes"
         android:name="${applicationName}"
         android:icon="@mipmap/ic_launcher">

lib/app.dart

@@ -20,9 +20,7 @@ class _AppState extends State<App> {
   Widget build(BuildContext context) {
     return ChangeNotifierProvider(
       create: (ctx) {
-        final notifier = FileChangeNotifier();
-        notifier.loadAllNotes();
-        return notifier;
+        return FileChangeNotifier()..loadAllNotes();
       },
       child: Scaffold(
         floatingActionButton: _fab(),
@@ -48,27 +46,28 @@ class _AppState extends State<App> {
     switch (activePage) {
       case View.all:
       case View.folders:
-        return FloatingActionButton(
+        return Consumer<FileChangeNotifier>(
+          builder: (ctx, notifier, child) => FloatingActionButton(
             onPressed: () async {
               final now = DateTime.now();
               final name =
-                'note-${now.year}_${now.month}_${now.day}-${now.hour}_${now.minute}';
+                  'note-${now.year}_${now.month}_${now.day}-${now.hour}_${now.minute}_${now.second}';
               final filename = '$name.dbnote';
 
               Navigator.push(
-              context,
+                ctx,
                 MaterialPageRoute(
                   builder: (ctx) => DrawingPage(
                     filePath: filename,
                     name: name,
                   ),
                 ),
-            ).then((value) =>
-                Provider.of<FileChangeNotifier>(context, listen: false)
-                    .loadAllNotes());
+              ).then((v) => notifier.loadAllNotes());
             },
             backgroundColor: const Color(0xff3f3f3f),
-          child: const Icon(Icons.edit_calendar_outlined, color: Colors.orange),
+            child:
+                const Icon(Icons.edit_calendar_outlined, color: Colors.orange),
+          ),
         );
       default:
         return Container();

lib/canvas/drawing_page.dart

@@ -5,6 +5,7 @@ import 'package:fluentui_system_icons/fluentui_system_icons.dart';
 import 'package:flutter/gestures.dart';
 import 'package:flutter/material.dart';
 
+import '../export/export_pdf.dart';
 import '../savesystem/note_file.dart';
 import '../widgets/icon_material_button.dart';
 import '../widgets/tool_bar.dart';
@@ -72,6 +73,7 @@ class _DrawingPageState extends State<DrawingPage> {
               color: const Color.fromRGBO(255, 255, 255, .85),
               onPressed: () {
                 // todo implement
+                exportPDF(controller.strokes, '${widget.name}.pdf');
               },
             ),
             IconMaterialButton(

lib/canvas/paint_controller.dart

@@ -128,6 +128,7 @@ class PaintController extends ChangeNotifier {
 
           Point p = Point(offset, newWidth);
           strokes.last.addPoint(p);
+          // todo do a batch commit per stroke
           file.addPoint(strokes.last.id, p);
           break;
         case Pen.selector:

lib/context/file_change_notifier.dart

@@ -12,6 +12,10 @@ class FileChangeNotifier extends ChangeNotifier {
 
   Future<List<NoteTileData>> loadAllNotes() async {
     final path = await getSavePath();
+    if (!(await path.exists())) {
+      await path.create(recursive: true);
+    }
+
     final dta = await path
         .list()
         .where((fsentity) => fsentity.path.endsWith('.dbnote'))

lib/export/export_pdf.dart

@@ -0,0 +1,58 @@
+import 'dart:io';
+import 'dart:ui';
+
+import 'package:pdf/pdf.dart';
+import 'package:pdf/widgets.dart' as pw;
+
+import '../canvas/document_types.dart';
+import '../savesystem/path.dart';
+
+const _a4width = 210 * PdfPageFormat.mm;
+const _a4height = 297 * PdfPageFormat.mm;
+
+class _StrokePDFPaint extends pw.Widget {
+  List<Stroke> strokes;
+
+  @override
+  void layout(pw.Context context, pw.BoxConstraints constraints,
+      {bool parentUsesSize = false}) {
+    box =
+        PdfRect.fromPoints(PdfPoint.zero, const PdfPoint(_a4width, _a4height));
+  }
+
+  @override
+  void paint(pw.Context context) {
+    super.paint(context);
+
+    for (final stroke in strokes) {
+      context.canvas.setStrokeColor(PdfColor.fromInt(stroke.color.value));
+      for (int i = 0; i < stroke.points.length - 1; i++) {
+        Offset pt1 = stroke.points[i].point * PdfPageFormat.mm;
+        pt1 = Offset(pt1.dx, _a4width - pt1.dy);
+        Offset pt2 = stroke.points[i + 1].point * PdfPageFormat.mm;
+        pt2 = Offset(pt2.dx, _a4width - pt2.dy);
+
+        context.canvas.setLineWidth(stroke.points[i].thickness);
+        context.canvas.drawLine(pt1.dx, pt1.dy, pt2.dx, pt2.dy);
+        context.canvas.strokePath();
+      }
+    }
+  }
+
+  _StrokePDFPaint(this.strokes);
+}
+
+void exportPDF(List<Stroke> strokes, String name) async {
+  final pdf = pw.Document();
+
+  const PdfPageFormat a4 = PdfPageFormat(_a4width, _a4height);
+
+  pdf.addPage(pw.MultiPage(
+    pageFormat: a4,
+    build: (context) => [_StrokePDFPaint(strokes)],
+  ));
+
+  final path = await getSavePath();
+  final file = File('${path.path}${Platform.pathSeparator}$name');
+  await file.writeAsBytes(await pdf.save(), flush: true);
+}

lib/main.dart

@@ -1,15 +1,26 @@
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
+import 'package:permission_handler/permission_handler.dart';
 import 'package:sqflite/sqflite.dart';
 import 'package:sqflite_common_ffi/sqflite_ffi.dart';
 
 import 'app.dart';
 
-void main() {
+void main() async {
   if (defaultTargetPlatform != TargetPlatform.android &&
       defaultTargetPlatform != TargetPlatform.iOS) {
     sqfliteFfiInit();
     databaseFactory = databaseFactoryFfi;
   }
+
+  WidgetsFlutterBinding.ensureInitialized();
+
+  Map<Permission, PermissionStatus> statuses =
+      await [Permission.manageExternalStorage, Permission.storage].request();
+
+  if (statuses.containsValue(PermissionStatus.denied)) {
+    // todo some error handling
+  }
+
   runApp(const MaterialApp(home: App()));
 }

lib/pages/all_notes_page.dart

@@ -34,7 +34,9 @@ class _AllNotesPageState extends State<AllNotesPage> {
             IconMaterialButton(
               icon: const Icon(Icons.picture_as_pdf_outlined),
               color: const Color.fromRGBO(255, 255, 255, .85),
-              onPressed: () {},
+              onPressed: () async {
+                // todo implement pdf import
+              },
             ),
             IconMaterialButton(
               icon: const Icon(Icons.search),

lib/savesystem/note_file.dart

@@ -18,11 +18,18 @@ class NoteFile {
     final path = (await getSavePath()).path + Platform.pathSeparator + filepath;
     _db = await openDatabase(
       path,
-      onCreate: (db, version) {
-        return db.execute(
-          'CREATE TABLE strokes(id integer primary key autoincrement, color INTEGER, elevation INTEGER);'
-          'CREATE TABLE points(id integer primary key autoincrement, x INTEGER, y INTEGER, thickness REAL, strokeid INTEGER)',
-        );
+      onCreate: (db, version) async {
+        Batch batch = db.batch();
+
+        batch.execute('DROP TABLE IF EXISTS strokes;');
+        batch.execute('DROP TABLE IF EXISTS points;');
+
+        batch.execute(
+            'CREATE TABLE strokes(id integer primary key autoincrement, color INTEGER, elevation INTEGER)');
+        batch.execute(
+            'CREATE TABLE points(id integer primary key autoincrement, x INTEGER, y INTEGER, thickness REAL, strokeid INTEGER)');
+        await batch.commit();
+        return;
       },
       // Set the version. This executes the onCreate function and provides a
       // path to perform database upgrades and downgrades.

lib/savesystem/path.dart

@@ -7,8 +7,11 @@ Future<Directory> getSavePath() async {
   Directory dbpath;
   if (defaultTargetPlatform == TargetPlatform.android ||
       defaultTargetPlatform == TargetPlatform.iOS) {
+    final dir =
+        (await getExternalStorageDirectory())?.parent.parent.parent.parent ??
+            (await getApplicationDocumentsDirectory());
     dbpath = Directory(
-        '${(await getApplicationDocumentsDirectory()).path}${Platform.pathSeparator}notes');
+        '${dir.path}${Platform.pathSeparator}Documents${Platform.pathSeparator}notes');
   } else {
     dbpath = Directory(
         '${(await getApplicationDocumentsDirectory()).path}${Platform.pathSeparator}notes');

pubspec.lock

@@ -8,6 +8,13 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "0.2.1"
+  archive:
+    dependency: transitive
+    description:
+      name: archive
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "3.3.2"
   async:
     dependency: transitive
     description:
@@ -15,6 +22,13 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "2.9.0"
+  barcode:
+    dependency: transitive
+    description:
+      name: barcode
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.2.3"
   boolean_selector:
     dependency: transitive
     description:
@@ -50,6 +64,13 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "0.0.3"
+  crypto:
+    dependency: transitive
+    description:
+      name: crypto
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "3.0.2"
   fake_async:
     dependency: transitive
     description:
@@ -109,6 +130,13 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "0.0.5"
+  image:
+    dependency: transitive
+    description:
+      name: image
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "3.2.2"
   js:
     dependency: transitive
     description:
@@ -221,6 +249,48 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "2.1.3"
+  pdf:
+    dependency: "direct main"
+    description:
+      name: pdf
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "3.8.4"
+  permission_handler:
+    dependency: "direct main"
+    description:
+      name: permission_handler
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "10.2.0"
+  permission_handler_android:
+    dependency: transitive
+    description:
+      name: permission_handler_android
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "10.2.0"
+  permission_handler_apple:
+    dependency: transitive
+    description:
+      name: permission_handler_apple
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "9.0.7"
+  permission_handler_platform_interface:
+    dependency: transitive
+    description:
+      name: permission_handler_platform_interface
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "3.9.0"
+  permission_handler_windows:
+    dependency: transitive
+    description:
+      name: permission_handler_windows
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.1.2"
   petitparser:
     dependency: transitive
     description:
@@ -256,6 +326,13 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "6.0.4"
+  qr:
+    dependency: transitive
+    description:
+      name: qr
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "3.0.1"
   sky_engine:
     dependency: transitive
     description: flutter
@@ -338,6 +415,13 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "0.4.12"
+  typed_data:
+    dependency: transitive
+    description:
+      name: typed_data
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.3.1"
   vector_math:
     dependency: transitive
     description:

pubspec.yaml

@@ -36,6 +36,8 @@ dependencies:
   sqflite_common_ffi: ^2.2.0+1
   path_provider: ^2.0.11
   provider: ^6.0.4
+  pdf: ^3.8.4
+  permission_handler: ^10.2.0
 
 dev_dependencies:
   flutter_test: