dev/tracing_tests/test/image_painting_event_test.dart

// 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:convert' show jsonEncode;
import 'dart:developer' as developer;
import 'dart:typed_data';
import 'dart:ui' as ui;

import 'package:flutter/painting.dart';
import 'package:flutter/widgets.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:vm_service/vm_service.dart';
import 'package:vm_service/vm_service_io.dart';

void main() {
  VmService vmService;
  LiveTestWidgetsFlutterBinding binding;
  setUpAll(() async {
    final developer.ServiceProtocolInfo info =
        await developer.Service.getInfo();

    if (info.serverUri == null) {
      fail('This test _must_ be run with --enable-vmservice.');
    }

    vmService = await vmServiceConnectUri('ws://localhost:${info.serverUri.port}${info.serverUri.path}ws');
    await vmService.streamListen(EventStreams.kExtension);

    // Initialize bindings
    binding = LiveTestWidgetsFlutterBinding();
    binding.framePolicy = LiveTestWidgetsFlutterBindingFramePolicy.fullyLive;
    binding.attachRootWidget(const SizedBox.expand());
    expect(binding.framesEnabled, true);
    // Pump two frames to make sure we clear out any inter-frame comparisons.
    await binding.endOfFrame;
    await binding.endOfFrame;
  });

  tearDownAll(() {
    vmService.dispose();
  });

  test('Image painting events - deduplicates across frames', () async {
    final Completer<Event> completer = Completer<Event>();
    vmService.onExtensionEvent.first.then(completer.complete);

    const TestImage image = TestImage(width: 300, height: 300);
    final TestCanvas canvas = TestCanvas();
    paintImage(
      canvas: canvas,
      rect: const Rect.fromLTWH(50.0, 75.0, 200.0, 100.0),
      image: image,
      debugImageLabel: 'test.png',
    );

    // Make sure that we don't report an identical image size info if we
    // redraw in the next frame.
    await binding.endOfFrame;

    paintImage(
      canvas: canvas,
      rect: const Rect.fromLTWH(50.0, 75.0, 200.0, 100.0),
      image: image,
      debugImageLabel: 'test.png',
    );
    await binding.endOfFrame;

    final Event event = await completer.future;
    expect(event.extensionKind, 'Flutter.ImageSizesForFrame');
    expect(
      jsonEncode(event.extensionData.data),
      '{"test.png":{"source":"test.png","displaySize":{"width":200.0,"height":100.0},"imageSize":{"width":300.0,"height":300.0},"displaySizeInBytes":106666,"decodedSizeInBytes":480000}}',
    );
  }, skip: isBrowser); // uses dart:isolate and io

  test('Image painting events - deduplicates across frames', () async {
    final Completer<Event> completer = Completer<Event>();
    vmService.onExtensionEvent.first.then(completer.complete);

    const TestImage image = TestImage(width: 300, height: 300);
    final TestCanvas canvas = TestCanvas();
    paintImage(
      canvas: canvas,
      rect: const Rect.fromLTWH(50.0, 75.0, 200.0, 100.0),
      image: image,
      debugImageLabel: 'test.png',
    );

    paintImage(
      canvas: canvas,
      rect: const Rect.fromLTWH(50.0, 75.0, 300.0, 300.0),
      image: image,
      debugImageLabel: 'test.png',
    );
    await binding.endOfFrame;

    final Event event = await completer.future;
    expect(event.extensionKind, 'Flutter.ImageSizesForFrame');
    expect(
      jsonEncode(event.extensionData.data),
      '{"test.png":{"source":"test.png","displaySize":{"width":300.0,"height":300.0},"imageSize":{"width":300.0,"height":300.0},"displaySizeInBytes":480000,"decodedSizeInBytes":480000}}',
    );
  }, skip: isBrowser); // uses dart:isolate and io
}

class TestImage implements ui.Image {
  const TestImage({this.height = 0, this.width = 0});
  @override
  final int height;
  @override
  final int width;

  @override
  void dispose() {}

  @override
  Future<ByteData> toByteData(
      {ui.ImageByteFormat format = ui.ImageByteFormat.rawRgba}) {
    throw UnimplementedError();
  }
}

class TestCanvas implements Canvas {
  @override
  void noSuchMethod(Invocation invocation) {}
}