add saving system with sqlite

lib/canvas/document_types.dart

@@ -8,6 +8,8 @@ class Stroke {
   double _miny = double.infinity;
   double _maxy = double.negativeInfinity;
 
+  final int id;
+
   @override
   String toString() {
     return 'Stroke{points: $points}';
@@ -17,18 +19,22 @@ class Stroke {
     points.add(point);
 
     // update bounding rect
-    if (point.point.dx < _minx) _minx = point.point.dx;
-    if (point.point.dx > _maxx) _maxx = point.point.dx;
-    if (point.point.dy < _miny) _miny = point.point.dy;
-    if (point.point.dy > _maxy) _maxy = point.point.dy;
+    _updateBoundingRect(point);
+  }
+
+  void _updateBoundingRect(Point p) {
+    if (p.point.dx < _minx) _minx = p.point.dx;
+    if (p.point.dx > _maxx) _maxx = p.point.dx;
+    if (p.point.dy < _miny) _miny = p.point.dy;
+    if (p.point.dy > _maxy) _maxy = p.point.dy;
   }
 
   Rect getBoundingRect() {
     return Rect.fromPoints(Offset(_minx, _miny), Offset(_maxx, _maxy));
   }
 
-  Stroke.fromPoints(this.points);
-  Stroke();
+  Stroke.fromPoints(this.points, this.id);
+  Stroke(this.id);
 }
 
 class Point {

lib/canvas/drawing_page.dart

@@ -2,6 +2,7 @@ import 'dart:math';
 import 'dart:ui';
 import 'package:fluentui_system_icons/fluentui_system_icons.dart';
 import 'package:flutter/material.dart';
+import 'package:notes/savesystem/note_file.dart';
 import 'my_painter.dart';
 import 'paint_controller.dart';
 import 'screen_document_mapping.dart';
@@ -11,7 +12,10 @@ import '../tool_bar.dart';
 
 /// Handles input events and draws canvas element
 class DrawingPage extends StatefulWidget {
-  const DrawingPage({Key? key}) : super(key: key);
+  // path to the .dbnote file
+  final String filePath;
+
+  const DrawingPage({Key? key, required this.filePath}) : super(key: key);
 
   @override
   State<DrawingPage> createState() => _DrawingPageState();
@@ -22,18 +26,29 @@ class _DrawingPageState extends State<DrawingPage> {
   double basezoom = 1.0;
   Offset offset = const Offset(.0, .0);
 
-  PaintController controller = PaintController();
+  late PaintController controller;
+  late NoteFile noteFile = NoteFile(widget.filePath);
 
   @override
   void initState() {
     super.initState();
 
+    controller = PaintController(noteFile);
+    noteFile.init().then((value) => controller.loadStrokesFromFile());
+
     // todo might be weird behaviour if used with short side
     final screenWidth =
         (window.physicalSize.longestSide / window.devicePixelRatio);
     _calcNewPageOffset(const Offset(.0, .0), screenWidth - 45);
   }
 
+  @override
+  void dispose() {
+    super.dispose();
+
+    noteFile.close();
+  }
+
   @override
   Widget build(BuildContext context) {
     return Scaffold(

lib/canvas/paint_controller.dart

@@ -2,7 +2,9 @@ import 'dart:math';
 import 'dart:ui';
 
 import 'package:flutter/foundation.dart';
+import 'package:notes/savesystem/line_loader.dart';
 
+import '../savesystem/note_file.dart';
 import 'document_types.dart';
 import 'my_painter.dart';
 
@@ -13,6 +15,10 @@ class PaintController extends ChangeNotifier {
   List<Stroke> strokes = [];
   final bool _allowDrawWithFinger = false;
 
+  PaintController(this.file);
+
+  final NoteFile file;
+
   void changePen(Pen pen) {
     activePen = pen;
     notifyListeners();
@@ -40,7 +46,8 @@ class PaintController extends ChangeNotifier {
     return thickness;
   }
 
-  void pointDownEvent(Offset offset, PointerDeviceKind pointer, double tilt) {
+  void pointDownEvent(
+      Offset offset, PointerDeviceKind pointer, double tilt) async {
     if (_allowDrawWithFinger || pointer != PointerDeviceKind.touch) {
       // todo line drawn on edge where line left page
       if (!a4Page.contains(offset)) return;
@@ -48,8 +55,12 @@ class PaintController extends ChangeNotifier {
       // todo handle other pens
       if (activePen != Pen.pen) return;
 
-      strokes
-          .add(Stroke.fromPoints([Point(offset, _calcTiltedWidth(3.0, tilt))]));
+      int strokeid = strokes.isNotEmpty ? strokes.last.id + 1 : 0;
+      strokes.add(Stroke.fromPoints(
+          [Point(offset, _calcTiltedWidth(3.0, tilt))],
+          strokes.isNotEmpty ? strokes.last.id + 1 : 0));
+      file.addStroke(strokeid);
+
       notifyListeners();
     }
   }
@@ -58,10 +69,11 @@ class PaintController extends ChangeNotifier {
     if (activePen == Pen.eraser) return;
 
     if (_allowDrawWithFinger || pointer != PointerDeviceKind.touch) {
-      if (strokes.last.points.length <= 1) {
+      final lastStroke = strokes.last;
+      if (lastStroke.points.length <= 1) {
         // if the line consists only of one point (point) add endpoint as the same to allow drawing a line
-        // todo maybe solve this in custompainter in future
-        strokes.last.points.add(strokes.last.points.last);
+        lastStroke.points.add(lastStroke.points.last);
+        file.addPoint(lastStroke.id, lastStroke.points.last);
         notifyListeners();
       }
     }
@@ -83,6 +95,7 @@ class PaintController extends ChangeNotifier {
               // check if eraser hit an point within its range
               for (final pt in stroke.points) {
                 if (eraserrect.contains(pt.point)) {
+                  file.removeStroke(stroke.id);
                   strokes.remove(stroke);
                   notifyListeners();
                   return;
@@ -101,7 +114,9 @@ class PaintController extends ChangeNotifier {
                 pts.last, pts[pts.length - 2], newWidth);
           }
 
-          strokes.last.addPoint(Point(offset, newWidth));
+          Point p = Point(offset, newWidth);
+          strokes.last.addPoint(p);
+          file.addPoint(strokes.last.id, p);
           break;
         case Pen.highlighter:
           // TODO: Handle this case.
@@ -113,4 +128,9 @@ class PaintController extends ChangeNotifier {
       notifyListeners();
     }
   }
+
+  Future<void> loadStrokesFromFile() async {
+    strokes = await file.loadStrokes();
+    notifyListeners();
+  }
 }