feat: fall back to canvas preview for old notes

saber-notes · Dec 15, 2023 · 927d31b · 927d31b
1 parent cb383d2
commit 927d31b
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diff --git a/lib/components/canvas/canvas_preview.dart b/lib/components/canvas/canvas_preview.dart
@@ -4,6 +4,8 @@ import 'package:saber/data/editor/editor_core_info.dart';
 import 'package:saber/data/editor/page.dart';
 import 'package:saber/data/prefs.dart';
 
+typedef _CacheItem = (EditorCoreInfo coreInfo, double pageHeight);
+
 class CanvasPreview extends StatelessWidget {
   const CanvasPreview({
     super.key,
@@ -16,6 +18,41 @@ class CanvasPreview extends StatelessWidget {
   final double? height;
   final EditorCoreInfo coreInfo;
 
+  static final _previewCache = <String, Future<_CacheItem>>{};
+  static Widget fromFile({
+    Key? key,
+    required String filePath,
+  }) {
+    final Future<_CacheItem> future;
+    if (_previewCache.containsKey(filePath)) {
+      future = _previewCache[filePath]!;
+    } else {
+      _previewCache[filePath] = future = () async {
+        final coreInfo = await EditorCoreInfo.loadFromFilePath(filePath);
+        final pageHeight = coreInfo.pages.isNotEmpty
+            ? coreInfo.pages[0].previewHeight(lineHeight: coreInfo.lineHeight)
+            : EditorPage.defaultHeight * 0.1;
+        return (coreInfo, pageHeight);
+      }();
+    }
+
+    return FutureBuilder(
+      key: key,
+      future: future,
+      builder: (context, snapshot) {
+        final data = snapshot.data;
+        if (data == null) {
+          return const CircularProgressIndicator.adaptive();
+        }
+        return CanvasPreview(
+          key: key,
+          coreInfo: data.$1,
+          height: data.$2,
+        );
+      },
+    );
+  }
+
   @override
   Widget build(BuildContext context) {
     Size pageSize = coreInfo.pages.isNotEmpty

diff --git a/lib/components/home/preview_card.dart b/lib/components/home/preview_card.dart
@@ -1,8 +1,10 @@
 import 'dart:async';
+import 'dart:io';
 
 import 'package:animations/animations.dart';
 import 'package:flutter/material.dart';
 import 'package:go_router/go_router.dart';
+import 'package:saber/components/canvas/canvas_preview.dart';
 import 'package:saber/components/canvas/invert_shader.dart';
 import 'package:saber/components/canvas/shader_sampler.dart';
 import 'package:saber/components/home/uploading_indicator.dart';
@@ -114,6 +116,23 @@ class _PreviewCardState extends State<PreviewCard> {
                                   child: Image(
                                     key: ValueKey(thumbnailState.updateCount),
                                     image: thumbnailImage,
+                                    errorBuilder: (context, error, stackTrace) {
+                                      // If the thumbnail image doesn't exist,
+                                      // (i.e. for old notes), render the first page.
+                                      if (error is! PathNotFoundException) {
+                                        throw error;
+                                      }
+
+                                      return FittedBox(
+                                        child: ClipRect(
+                                          child: CanvasPreview.fromFile(
+                                            key: ValueKey(
+                                                'CanvasPreview${thumbnailState.updateCount}'),
+                                            filePath: widget.filePath,
+                                          ),
+                                        ),
+                                      );
+                                    },
                                   ),
                                 ),
                         ),