// 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 'package:flutter/material.dart'; import 'package:flutter/rendering.dart'; import 'package:flutter_test/flutter_test.dart'; import '../common.dart'; const Duration kBenchmarkTime = Duration(seconds: 15); // Use an Align to loosen the constraints. final Widget intrinsicTextHeight = Directionality( textDirection: TextDirection.ltr, child: Align( child: IntrinsicHeight( child: Text('A' * 100), ), ), ); Future<void> main() async { assert(false, "Don't run benchmarks in debug mode! Use 'flutter run --release'."); // We control the framePolicy below to prevent us from scheduling frames in // the engine, so that the engine does not interfere with our timings. final LiveTestWidgetsFlutterBinding binding = TestWidgetsFlutterBinding.ensureInitialized() as LiveTestWidgetsFlutterBinding; final Stopwatch watch = Stopwatch(); int iterations = 0; await benchmarkWidgets((WidgetTester tester) async { runApp(intrinsicTextHeight); // Wait for the UI to stabilize. await tester.pump(const Duration(seconds: 1)); final TestViewConfiguration big = TestViewConfiguration.fromView( size: const Size(360.0, 640.0), view: tester.view, ); final TestViewConfiguration small = TestViewConfiguration.fromView( size: const Size(100.0, 640.0), view: tester.view, ); final RenderView renderView = WidgetsBinding.instance.renderViews.single; binding.framePolicy = LiveTestWidgetsFlutterBindingFramePolicy.benchmark; watch.start(); while (watch.elapsed < kBenchmarkTime) { renderView.configuration = iterations.isEven ? big : small; await tester.pumpBenchmark(Duration(milliseconds: iterations * 16)); iterations += 1; } watch.stop(); }); final BenchmarkResultPrinter printer = BenchmarkResultPrinter(); printer.addResult( description: 'Text intrinsic height', value: watch.elapsedMicroseconds / iterations, unit: 'µs per iteration', name: 'text_intrinsic_height_iteration', ); printer.printToStdout(); }