tweak: use high quality strokes for thumbnail gen

Author: adil192

lib/components/canvas/canvas_preview.dart

@@ -1,6 +1,7 @@
 import 'dart:async';
 
 import 'package:flutter/material.dart';
+import 'package:saber/components/canvas/_stroke.dart';
 import 'package:saber/components/canvas/inner_canvas.dart';
 import 'package:saber/data/editor/editor_core_info.dart';
 import 'package:saber/data/editor/page.dart';
@@ -14,12 +15,16 @@ class CanvasPreview extends StatelessWidget implements PreferredSizeWidget {
     this.pageIndex = 0,
     required this.height,
     required this.coreInfo,
+    this.highQuality = false,
   });
 
   final int pageIndex;
   final double? height;
   final EditorCoreInfo coreInfo;
 
+  /// Whether to draw [Stroke.highQualityPath] or [Stroke.lowQualityPath].
+  final bool highQuality;
+
   late final pageSize =
       coreInfo.pages.getOrNull(pageIndex)?.size ?? EditorPage.defaultSize;
   @override
@@ -69,7 +74,7 @@ class CanvasPreview extends StatelessWidget implements PreferredSizeWidget {
       currentStrokeDetectedShape: null,
       currentSelection: null,
       currentToolIsSelect: false,
-      currentScale: double.minPositive,
+      currentScale: highQuality ? double.maxFinite : double.minPositive,
     );
   }
 }

lib/pages/editor/editor.dart

@@ -987,7 +987,7 @@ class EditorState extends State<Editor> {
             width: thumbnailSize.width,
             height: thumbnailSize.height,
             child: FittedBox(
-              child: pagePreviewBuilder(
+              child: pageBuilderForScreenshot(
                 context,
                 pageIndex: 0,
                 previewHeight: previewHeight,
@@ -1876,7 +1876,7 @@ class EditorState extends State<Editor> {
     );
   }
 
-  Widget pagePreviewBuilder(
+  Widget pageBuilderForScreenshot(
     BuildContext context, {
     required int pageIndex,
     double? previewHeight,
@@ -1887,6 +1887,7 @@ class EditorState extends State<Editor> {
       pageIndex: pageIndex,
       height: previewHeight,
       coreInfo: coreInfo,
+      highQuality: true,
     );
   }