save correct color to db

use different pointer for highlighter

lib/savesystem/line_loader.dart

@@ -5,9 +5,13 @@ import 'note_file.dart';
 
 extension LineLoading on NoteFile {
   Future<List<Stroke>> loadStrokes() async {
-    final query = await db().query('points',
-        orderBy: 'strokeid',
-        columns: ['x', 'y', 'thickness', 'strokeid', 'id']);
+    const sql = '''
+SELECT x, y, thickness, strokeid, points.id, s.color
+from points
+         JOIN strokes s on s.id = strokeid
+ORDER BY strokeid
+''';
+    final query = await db().rawQuery(sql);
     int strokeid = -1;
     List<Stroke> strokes = [];
 
@@ -15,7 +19,7 @@ extension LineLoading on NoteFile {
       final int csid = i['strokeid'] as int;
       if (csid != strokeid) {
         strokeid = csid;
-        strokes.add(Stroke(strokeid, Colors.green));
+        strokes.add(Stroke(strokeid, Color(i['color'] as int)));
       }
       final Point p = Point(
           Offset(i['x'] as double, i['y'] as double), i['thickness'] as double);
@@ -26,11 +30,12 @@ extension LineLoading on NoteFile {
   }
 
   // create new stroke in file and return strokeid
-  Future<void> addStroke(int newStrokeId) async {
+  Future<void> addStroke(int newStrokeId, Color color) async {
     await db().insert(
-        'strokes', {'color': 0xffffff, 'elevation': 0, 'id': newStrokeId});
+        'strokes', {'color': color.value, 'elevation': 0, 'id': newStrokeId});
   }
 
+  // add one point to a stroke in db
   Future<void> addPoint(int strokeid, Point p) async {
     await db().insert('points', {
       'x': p.point.dx,
@@ -40,6 +45,7 @@ extension LineLoading on NoteFile {
     });
   }
 
+  // add list of points to a stroke in db
   Future<void> addPoints(int strokeid, List<Point> pts) async {
     final batch = db().batch();
     for (final p in pts) {