Make dispose a no-op on HTML backend (flutter#35835)

knopp · Aug 31, 2022 · 9d9d89a · 9d9d89a
1 parent 86a2c93
commit 9d9d89a
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Showing 2 changed files with 25 additions and 3 deletions.
diff --git a/lib/web_ui/lib/src/engine/text/canvas_paragraph.dart b/lib/web_ui/lib/src/engine/text/canvas_paragraph.dart
@@ -260,8 +260,9 @@ class CanvasParagraph implements ui.Paragraph {
 
   @override
   void dispose() {
-    spans.clear();
-    plainText = '';
+    // TODO(dnfield): It should be possible to clear resources here, but would
+    // need refcounting done on any surfaces/pictures holding references to this
+    // object.
     _disposed = true;
   }
 
@@ -270,7 +271,7 @@ class CanvasParagraph implements ui.Paragraph {
     if (assertionsEnabled) {
       return _disposed;
     }
-    throw StateError('Vertices.debugDisposed is only avialalbe when asserts are enabled.');
+    throw StateError('Paragraph.debugDisposed is only avialalbe when asserts are enabled.');
   }
 }
 

diff --git a/lib/web_ui/test/text/canvas_paragraph_test.dart b/lib/web_ui/test/text/canvas_paragraph_test.dart
@@ -780,6 +780,27 @@ Future<void> testMain() async {
     expect(paragraph.width, 30);
     expect(paragraph.height, 10);
   });
+
+  test('Render after dispose', () {
+    final ui.Paragraph paragraph = plain(ahemStyle, 'abc');
+    paragraph.layout(const ui.ParagraphConstraints(width: 30.8));
+
+    final ui.PictureRecorder recorder = ui.PictureRecorder();
+    final ui.Canvas canvas = ui.Canvas(recorder);
+    canvas.drawParagraph(paragraph, ui.Offset.zero);
+    final ui.Picture picture = recorder.endRecording();
+
+    paragraph.dispose();
+
+    final ui.SceneBuilder builder = ui.SceneBuilder();
+    builder.addPicture(ui.Offset.zero, picture);
+    final ui.Scene scene = builder.build();
+
+    ui.window.render(scene);
+
+    picture.dispose();
+    scene.dispose();
+  });
 }
 
 /// Shortcut to create a [ui.TextBox] with an optional [ui.TextDirection].