blob: c5b8065abba62e43eddde0e119dcedc1ed7ded0a [file] [log] [blame]
// Copyright 2014 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
import 'dart:async';
import 'dart:typed_data';
import 'dart:ui' as ui;
import 'test_async_utils.dart';
final Map<int, ui.Image> _cache = <int, ui.Image>{};
/// Creates an arbitrarily sized image for testing.
/// If the [cache] parameter is set to true, the image will be cached for the
/// rest of this suite. This is normally desirable, assuming a test suite uses
/// images with the same dimensions in most tests, as it will save on memory
/// usage and CPU time over the course of the suite. However, it should be
/// avoided for images that are used only once in a test suite, especially if
/// the image is large, as it will require holding on to the memory for that
/// image for the duration of the suite.
/// This method requires real async work, and will not work properly in the
/// [FakeAsync] zones set up by [testWidgets]. Typically, it should be invoked
/// as a setup step before [testWidgets] are run, such as [setUp] or [setUpAll].
/// If needed, it can be invoked using [WidgetTester.runAsync].
Future<ui.Image> createTestImage({
int width = 1,
int height = 1,
bool cache = true,
}) => TestAsyncUtils.guard(() async {
assert(width != null && width > 0);
assert(height != null && height > 0);
assert(cache != null);
final int cacheKey = Object.hash(width, height);
if (cache && _cache.containsKey(cacheKey)) {
return _cache[cacheKey]!.clone();
final ui.Image image = await _createImage(width, height);
if (cache) {
_cache[cacheKey] = image.clone();
return image;
Future<ui.Image> _createImage(int width, int height) async {
final Completer<ui.Image> completer = Completer<ui.Image>();
Uint8List.fromList(List<int>.filled(width * height * 4, 0)),
(ui.Image image) {
return completer.future;