squash pdf export + storage permissions

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: